Commit Graph

317 Commits

Author SHA1 Message Date
Xianglai Li
8ef7f3132e LoongArch: Add cpuhotplug hooks to fix high cpu usage of vCPU threads
When the CPU is offline, the timer of LoongArch is not correctly closed.
This is harmless for real machines, but resulting in an excessively high
cpu usage rate of the offline vCPU thread in the virtual machines.

To correctly close the timer, we have made the following modifications:

Register the cpu hotplug event (CPUHP_AP_LOONGARCH_ARCH_TIMER_STARTING)
for LoongArch. This event's hooks will be called to close the timer when
the CPU is offline.

Clear the timer interrupt when the timer is turned off. Since before the
timer is turned off, there may be a timer interrupt that has already been
in the pending state due to the interruption of the disabled, which also
affects the halt state of the offline vCPU.

Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2025-08-20 22:23:44 +08:00
Linus Torvalds
0bd0a41a51 pci-v6.17-changes
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Merge tag 'pci-v6.17-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci

Pull PCI updates from Bjorn Helgaas:
 "Enumeration:

   - Allow built-in drivers, not just modular drivers, to use async
     initial probing (Lukas Wunner)

   - Support Immediate Readiness even on devices with no PM Capability
     (Sean Christopherson)

   - Consolidate definition of PCIE_RESET_CONFIG_WAIT_MS (100ms), the
     required delay between a reset and sending config requests to a
     device (Niklas Cassel)

   - Add pci_is_display() to check for "Display" base class and use it
     in ALSA hda, vfio, vga_switcheroo, vt-d (Mario Limonciello)

   - Allow 'isolated PCI functions' (multi-function devices without a
     function 0) for LoongArch, similar to s390 and jailhouse (Huacai
     Chen)

  Power control:

   - Add ability to enable optional slot clock for cases where the PCIe
     host controller and the slot are supplied by different clocks
     (Marek Vasut)

  PCIe native device hotplug:

   - Fix runtime PM ref imbalance on Hot-Plug Capable ports caused by
     misinterpreting a config read failure after a device has been
     removed (Lukas Wunner)

   - Avoid creating a useless PCIe port service device for pciehp if the
     slot is handled by the ACPI hotplug driver (Lukas Wunner)

   - Ignore ACPI hotplug slots when calculating depth of pciehp hotplug
     ports (Lukas Wunner)

  Virtualization:

   - Save VF resizable BAR state and restore it after reset (Michał
     Winiarski)

   - Allow IOV resources (VF BARs) to be resized (Michał Winiarski)

   - Add pci_iov_vf_bar_set_size() so drivers can control VF BAR size
     (Michał Winiarski)

  Endpoint framework:

   - Add RC-to-EP doorbell support using platform MSI controller,
     including a test case (Frank Li)

   - Allow BAR assignment via configfs so platforms have flexibility in
     determining BAR usage (Jerome Brunet)

  Native PCIe controller drivers:

   - Convert amazon,al-alpine-v[23]-pcie, apm,xgene-pcie,
     axis,artpec6-pcie, marvell,armada-3700-pcie, st,spear1340-pcie to
     DT schema format (Rob Herring)

   - Use dev_fwnode() instead of of_fwnode_handle() to remove OF
     dependency in altera (fixes an unused variable), designware-host,
     mediatek, mediatek-gen3, mobiveil, plda, xilinx, xilinx-dma,
     xilinx-nwl (Jiri Slaby, Arnd Bergmann)

   - Convert aardvark, altera, brcmstb, designware-host, iproc,
     mediatek, mediatek-gen3, mobiveil, plda, rcar-host, vmd, xilinx,
     xilinx-dma, xilinx-nwl from using pci_msi_create_irq_domain() to
     using msi_create_parent_irq_domain() instead; this makes the
     interrupt controller per-PCI device, allows dynamic allocation of
     vectors after initialization, and allows support of IMS (Nam Cao)

  APM X-Gene PCIe controller driver:

   - Rewrite MSI handling to MSI CPU affinity, drop useless CPU hotplug
     bits, use device-managed memory allocations, and clean things up
     (Marc Zyngier)

   - Probe xgene-msi as a standard platform driver rather than a
     subsys_initcall (Marc Zyngier)

  Broadcom STB PCIe controller driver:

   - Add optional DT 'num-lanes' property and if present, use it to
     override the Maximum Link Width advertised in Link Capabilities
     (Jim Quinlan)

  Cadence PCIe controller driver:

   - Use PCIe Message routing types from the PCI core rather than
     defining private ones (Hans Zhang)

  Freescale i.MX6 PCIe controller driver:

   - Add IMX8MQ_EP third 64-bit BAR in epc_features (Richard Zhu)

   - Add IMX8MM_EP and IMX8MP_EP fixed 256-byte BAR 4 in epc_features
     (Richard Zhu)

   - Configure LUT for MSI/IOMMU in Endpoint mode so Root Complex can
     trigger doorbel on Endpoint (Frank Li)

   - Remove apps_reset (LTSSM_EN) from
     imx_pcie_{assert,deassert}_core_reset(), which fixes a hotplug
     regression on i.MX8MM (Richard Zhu)

   - Delay Endpoint link start until configfs 'start' written (Richard
     Zhu)

  Intel VMD host bridge driver:

   - Add Intel Panther Lake (PTL)-H/P/U Vendor ID (George D Sworo)

  Qualcomm PCIe controller driver:

   - Add DT binding and driver support for SA8255p, which supports ECAM
     for Configuration Space access (Mayank Rana)

   - Update DT binding and driver to describe PHYs and per-Root Port
     resets in a Root Port stanza and deprecate describing them in the
     host bridge; this makes it possible to support multiple Root Ports
     in the future (Krishna Chaitanya Chundru)

   - Add Qualcomm QCS615 to SM8150 DT binding (Ziyue Zhang)

   - Add Qualcomm QCS8300 to SA8775p DT binding (Ziyue Zhang)

   - Drop TBU and ref clocks from Qualcomm SM8150 and SC8180x DT
     bindings (Konrad Dybcio)

   - Document 'link_down' reset in Qualcomm SA8775P DT binding (Ziyue
     Zhang)

   - Add required PCIE_RESET_CONFIG_WAIT_MS delay after Link up IRQ
     (Niklas Cassel)

  Rockchip PCIe controller driver:

   - Drop unused PCIe Message routing and code definitions (Hans Zhang)

   - Remove several unused header includes (Hans Zhang)

   - Use standard PCIe config register definitions instead of
     rockchip-specific redefinitions (Geraldo Nascimento)

   - Set Target Link Speed to 5.0 GT/s before retraining so we have a
     chance to train at a higher speed (Geraldo Nascimento)

  Rockchip DesignWare PCIe controller driver:

   - Prevent race between link training and register update via DBI by
     inhibiting link training after hot reset and link down (Wilfred
     Mallawa)

   - Add required PCIE_RESET_CONFIG_WAIT_MS delay after Link up IRQ
     (Niklas Cassel)

  Sophgo PCIe controller driver:

   - Add DT binding and driver for Sophgo SG2044 PCIe controller driver
     in Root Complex mode (Inochi Amaoto)

  Synopsys DesignWare PCIe controller driver:

   - Add required PCIE_RESET_CONFIG_WAIT_MS after waiting for Link up on
     Ports that support > 5.0 GT/s. Slower Ports still rely on the
     not-quite-correct PCIE_LINK_WAIT_SLEEP_MS 90ms default delay while
     waiting for the Link (Niklas Cassel)"

* tag 'pci-v6.17-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (116 commits)
  dt-bindings: PCI: qcom,pcie-sa8775p: Document 'link_down' reset
  dt-bindings: PCI: Remove 83xx-512x-pci.txt
  dt-bindings: PCI: Convert amazon,al-alpine-v[23]-pcie to DT schema
  dt-bindings: PCI: Convert marvell,armada-3700-pcie to DT schema
  dt-bindings: PCI: Convert apm,xgene-pcie to DT schema
  dt-bindings: PCI: Convert axis,artpec6-pcie to DT schema
  dt-bindings: PCI: Convert st,spear1340-pcie to DT schema
  PCI: Move is_pciehp check out of pciehp_is_native()
  PCI: pciehp: Use is_pciehp instead of is_hotplug_bridge
  PCI/portdrv: Use is_pciehp instead of is_hotplug_bridge
  PCI/ACPI: Fix runtime PM ref imbalance on Hot-Plug Capable ports
  selftests: pci_endpoint: Add doorbell test case
  misc: pci_endpoint_test: Add doorbell test case
  PCI: endpoint: pci-epf-test: Add doorbell test support
  PCI: endpoint: Add pci_epf_align_inbound_addr() helper for inbound address alignment
  PCI: endpoint: pci-ep-msi: Add checks for MSI parent and mutability
  PCI: endpoint: Add RC-to-EP doorbell support using platform MSI controller
  PCI: dwc: Add Sophgo SG2044 PCIe controller driver in Root Complex mode
  PCI: vmd: Switch to msi_create_parent_irq_domain()
  PCI: vmd: Convert to lock guards
  ...
2025-08-01 13:59:07 -07:00
Marc Zyngier
e612423be3 cpu/hotplug: Remove unused cpuhp_state CPUHP_PCI_XGENE_DEAD
Now that the XGene MSI driver has been mostly rewritten and doesn't
use the CPU hotplug infrastructure, CPUHP_PCI_XGENE_DEAD is unused.

Remove it to reduce the size of cpuhp_hp_states[].

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20250708173404.1278635-14-maz@kernel.org
2025-07-22 15:33:16 -05:00
Vladimir Kondratiev
df0f030ee7 irqchip/thead-c900-aclint-sswi: Generalize aclint-sswi driver and add MIPS P800 support
Refactor the Thead specific implementation of the ACLINT-SSWI irqchip:

 - Rename the source file and related details to reflect the generic nature
   of the driver

 - Factor out the generic code that serves both Thead and MIPS variants.
   This generic part is compliant with the RISC-V draft spec [1]

 - Provide generic and Thead specific initialization functions

Signed-off-by: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250612143911.3224046-5-vladimir.kondratiev@mobileye.com
Link: https://github.com/riscvarchive/riscv-aclint [1]
2025-06-26 16:06:40 +02:00
Frederic Weisbecker
f400565faa perf: Remove too early and redundant CPU hotplug handling
The CPU hotplug handlers are called twice: at prepare and online stage.

Their role is to:

1) Enable/disable a CPU context. This is irrelevant and even buggy at
   the prepare stage because the CPU is still offline. On early
   secondary CPU up, creating an event attached to that CPU might
   silently fail because the CPU context is observed as online but the
   context installation's IPI failure is ignored.

2) Update the scope cpumasks and re-migrate the events accordingly in
   the CPU down case. This is irrelevant at the prepare stage.

3) Remove the events attached to the context of the offlining CPU. It
   even uses an (unnecessary) IPI for it. This is also irrelevant at the
   prepare stage.

Also none of the *_PREPARE and *_STARTING architecture perf related CPU
hotplug callbacks rely on CPUHP_PERF_PREPARE.

CPUHP_AP_PERF_ONLINE is enough and the right place to perform the work.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250424161128.29176-4-frederic@kernel.org
2025-05-08 21:50:19 +02:00
Yosry Ahmed
07864f1a57 mm: zsmalloc: remove object mapping APIs and per-CPU map areas
zs_map_object() and zs_unmap_object() are no longer used, remove them. 
Since these are the only users of per-CPU mapping_areas, remove them and
the associated CPU hotplug callbacks too.

[yosry.ahmed@linux.dev: update the docs]
  Link: https://lkml.kernel.org/r/Z8ier-ZZp8T6MOTH@google.com
Link: https://lkml.kernel.org/r/20250305061134.4105762-5-yosry.ahmed@linux.dev
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Acked-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 00:05:41 -07:00
Frederic Weisbecker
d1a8919758 kthread: Default affine kthread to its preferred NUMA node
Kthreads attached to a preferred NUMA node for their task structure
allocation can also be assumed to run preferrably within that same node.

A more precise affinity is usually notified by calling
kthread_create_on_cpu() or kthread_bind[_mask]() before the first wakeup.

For the others, a default affinity to the node is desired and sometimes
implemented with more or less success when it comes to deal with hotplug
events and nohz_full / CPU Isolation interactions:

- kcompactd is affine to its node and handles hotplug but not CPU Isolation
- kswapd is affine to its node and ignores hotplug and CPU Isolation
- A bunch of drivers create their kthreads on a specific node and
  don't take care about affining further.

Handle that default node affinity preference at the generic level
instead, provided a kthread is created on an actual node and doesn't
apply any specific affinity such as a given CPU or a custom cpumask to
bind to before its first wake-up.

This generic handling is aware of CPU hotplug events and CPU isolation
such that:

* When a housekeeping CPU goes up that is part of the node of a given
  kthread, the related task is re-affined to that own node if it was
  previously running on the default last resort online housekeeping set
  from other nodes.

* When a housekeeping CPU goes down while it was part of the node of a
  kthread, the running task is migrated (or the sleeping task is woken
  up) automatically by the scheduler to other housekeepers within the
  same node or, as a last resort, to all housekeepers from other nodes.

Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2025-01-08 18:15:03 +01:00
Linus Torvalds
5c2b050848 A set of updates for the interrupt subsystem:
- Tree wide:
 
     * Make nr_irqs static to the core code and provide accessor functions
       to remove existing and prevent future aliasing problems with local
       variables or function arguments of the same name.
 
   - Core code:
 
     * Prevent freeing an interrupt in the devres code which is not managed
       by devres in the first place.
 
     * Use seq_put_decimal_ull_width() for decimal values output in
       /proc/interrupts which increases performance significantly as it
       avoids parsing the format strings over and over.
 
     * Optimize raising the timer and hrtimer soft interrupts by using the
       'set bit only' variants instead of the combined version which checks
       whether ksoftirqd should be woken up. The latter is a pointless
       exercise as both soft interrupts are raised in the context of the
       timer interrupt and therefore never wake up ksoftirqd.
 
     * Delegate timer/hrtimer soft interrupt processing to a dedicated thread
       on RT.
 
       Timer and hrtimer soft interrupts are always processed in ksoftirqd
       on RT enabled kernels. This can lead to high latencies when other
       soft interrupts are delegated to ksoftirqd as well.
 
       The separate thread allows to run them seperately under a RT
       scheduling policy to reduce the latency overhead.
 
   - Drivers:
 
     * New drivers or extensions of existing drivers to support Renesas
       RZ/V2H(P), Aspeed AST27XX, T-HEAD C900 and ATMEL sam9x7 interrupt
       chips
 
     * Support for multi-cluster GICs on MIPS.
 
       MIPS CPUs can come with multiple CPU clusters, where each CPU cluster
       has its own GIC (Generic Interrupt Controller). This requires to
       access the GIC of a remote cluster through a redirect register block.
 
       This is encapsulated into a set of helper functions to keep the
       complexity out of the actual code paths which handle the GIC details.
 
     * Support for encrypted guests in the ARM GICV3 ITS driver
 
       The ITS page needs to be shared with the hypervisor and therefore
       must be decrypted.
 
     * Small cleanups and fixes all over the place
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Merge tag 'irq-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull interrupt subsystem updates from Thomas Gleixner:
 "Tree wide:

   - Make nr_irqs static to the core code and provide accessor functions
     to remove existing and prevent future aliasing problems with local
     variables or function arguments of the same name.

  Core code:

   - Prevent freeing an interrupt in the devres code which is not
     managed by devres in the first place.

   - Use seq_put_decimal_ull_width() for decimal values output in
     /proc/interrupts which increases performance significantly as it
     avoids parsing the format strings over and over.

   - Optimize raising the timer and hrtimer soft interrupts by using the
     'set bit only' variants instead of the combined version which
     checks whether ksoftirqd should be woken up. The latter is a
     pointless exercise as both soft interrupts are raised in the
     context of the timer interrupt and therefore never wake up
     ksoftirqd.

   - Delegate timer/hrtimer soft interrupt processing to a dedicated
     thread on RT.

     Timer and hrtimer soft interrupts are always processed in ksoftirqd
     on RT enabled kernels. This can lead to high latencies when other
     soft interrupts are delegated to ksoftirqd as well.

     The separate thread allows to run them seperately under a RT
     scheduling policy to reduce the latency overhead.

  Drivers:

   - New drivers or extensions of existing drivers to support Renesas
     RZ/V2H(P), Aspeed AST27XX, T-HEAD C900 and ATMEL sam9x7 interrupt
     chips

   - Support for multi-cluster GICs on MIPS.

     MIPS CPUs can come with multiple CPU clusters, where each CPU
     cluster has its own GIC (Generic Interrupt Controller). This
     requires to access the GIC of a remote cluster through a redirect
     register block.

     This is encapsulated into a set of helper functions to keep the
     complexity out of the actual code paths which handle the GIC
     details.

   - Support for encrypted guests in the ARM GICV3 ITS driver

     The ITS page needs to be shared with the hypervisor and therefore
     must be decrypted.

   - Small cleanups and fixes all over the place"

* tag 'irq-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
  irqchip/riscv-aplic: Prevent crash when MSI domain is missing
  genirq/proc: Use seq_put_decimal_ull_width() for decimal values
  softirq: Use a dedicated thread for timer wakeups on PREEMPT_RT.
  timers: Use __raise_softirq_irqoff() to raise the softirq.
  hrtimer: Use __raise_softirq_irqoff() to raise the softirq
  riscv: defconfig: Enable T-HEAD C900 ACLINT SSWI drivers
  irqchip: Add T-HEAD C900 ACLINT SSWI driver
  dt-bindings: interrupt-controller: Add T-HEAD C900 ACLINT SSWI device
  irqchip/stm32mp-exti: Use of_property_present() for non-boolean properties
  irqchip/mips-gic: Fix selection of GENERIC_IRQ_EFFECTIVE_AFF_MASK
  irqchip/mips-gic: Prevent indirect access to clusters without CPU cores
  irqchip/mips-gic: Multi-cluster support
  irqchip/mips-gic: Setup defaults in each cluster
  irqchip/mips-gic: Support multi-cluster in for_each_online_cpu_gic()
  irqchip/mips-gic: Replace open coded online CPU iterations
  genirq/irqdesc: Use str_enabled_disabled() helper in wakeup_show()
  genirq/devres: Don't free interrupt which is not managed by devres
  irqchip/gic-v3-its: Fix over allocation in itt_alloc_pool()
  irqchip/aspeed-intc: Add AST27XX INTC support
  dt-bindings: interrupt-controller: Add support for ASPEED AST27XX INTC
  ...
2024-11-19 15:54:19 -08:00
Linus Torvalds
f41dac3efb Performance events changes for v6.13:
- Uprobes:
     - Add BPF session support (Jiri Olsa)
     - Switch to RCU Tasks Trace flavor for better performance (Andrii Nakryiko)
     - Massively increase uretprobe SMP scalability by SRCU-protecting
       the uretprobe lifetime (Andrii Nakryiko)
     - Kill xol_area->slot_count (Oleg Nesterov)
 
  - Core facilities:
     - Implement targeted high-frequency profiling by adding the ability
       for an event to "pause" or "resume" AUX area tracing (Adrian Hunter)
 
  - VM profiling/sampling:
     - Correct perf sampling with guest VMs (Colton Lewis)
 
  - New hardware support:
     - x86/intel: Add PMU support for Intel ArrowLake-H CPUs (Dapeng Mi)
 
  - Misc fixes and enhancements:
     - x86/intel/pt: Fix buffer full but size is 0 case (Adrian Hunter)
     - x86/amd: Warn only on new bits set (Breno Leitao)
     - x86/amd/uncore: Avoid a false positive warning about snprintf
                       truncation in amd_uncore_umc_ctx_init (Jean Delvare)
     - uprobes: Re-order struct uprobe_task to save some space (Christophe JAILLET)
     - x86/rapl: Move the pmu allocation out of CPU hotplug (Kan Liang)
     - x86/rapl: Clean up cpumask and hotplug (Kan Liang)
     - uprobes: Deuglify xol_get_insn_slot/xol_free_insn_slot paths (Oleg Nesterov)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull performance events updates from Ingo Molnar:
 "Uprobes:
    - Add BPF session support (Jiri Olsa)
    - Switch to RCU Tasks Trace flavor for better performance (Andrii
      Nakryiko)
    - Massively increase uretprobe SMP scalability by SRCU-protecting
      the uretprobe lifetime (Andrii Nakryiko)
    - Kill xol_area->slot_count (Oleg Nesterov)

  Core facilities:
    - Implement targeted high-frequency profiling by adding the ability
      for an event to "pause" or "resume" AUX area tracing (Adrian
      Hunter)

  VM profiling/sampling:
    - Correct perf sampling with guest VMs (Colton Lewis)

  New hardware support:
    - x86/intel: Add PMU support for Intel ArrowLake-H CPUs (Dapeng Mi)

  Misc fixes and enhancements:
    - x86/intel/pt: Fix buffer full but size is 0 case (Adrian Hunter)
    - x86/amd: Warn only on new bits set (Breno Leitao)
    - x86/amd/uncore: Avoid a false positive warning about snprintf
      truncation in amd_uncore_umc_ctx_init (Jean Delvare)
    - uprobes: Re-order struct uprobe_task to save some space
      (Christophe JAILLET)
    - x86/rapl: Move the pmu allocation out of CPU hotplug (Kan Liang)
    - x86/rapl: Clean up cpumask and hotplug (Kan Liang)
    - uprobes: Deuglify xol_get_insn_slot/xol_free_insn_slot paths (Oleg
      Nesterov)"

* tag 'perf-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
  perf/core: Correct perf sampling with guest VMs
  perf/x86: Refactor misc flag assignments
  perf/powerpc: Use perf_arch_instruction_pointer()
  perf/core: Hoist perf_instruction_pointer() and perf_misc_flags()
  perf/arm: Drop unused functions
  uprobes: Re-order struct uprobe_task to save some space
  perf/x86/amd/uncore: Avoid a false positive warning about snprintf truncation in amd_uncore_umc_ctx_init
  perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling
  perf/x86/intel/pt: Add support for pause / resume
  perf/core: Add aux_pause, aux_resume, aux_start_paused
  perf/x86/intel/pt: Fix buffer full but size is 0 case
  uprobes: SRCU-protect uretprobe lifetime (with timeout)
  uprobes: allow put_uprobe() from non-sleepable softirq context
  perf/x86/rapl: Clean up cpumask and hotplug
  perf/x86/rapl: Move the pmu allocation out of CPU hotplug
  uprobe: Add support for session consumer
  uprobe: Add data pointer to consumer handlers
  perf/x86/amd: Warn only on new bits set
  uprobes: fold xol_take_insn_slot() into xol_get_insn_slot()
  uprobes: kill xol_area->slot_count
  ...
2024-11-19 13:34:06 -08:00
Inochi Amaoto
25caea955c irqchip: Add T-HEAD C900 ACLINT SSWI driver
Add a driver for the T-HEAD C900 ACLINT SSWI device. This device allows
the system with T-HEAD cpus to send ipi via fast device interface.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241031060859.722258-3-inochiama@gmail.com
2024-11-07 00:28:27 +01:00
Kan Liang
9e9af8bbb5 perf/x86/rapl: Clean up cpumask and hotplug
The rapl pmu is die scope, which is supported by the generic perf_event
subsystem now.

Set the scope for the rapl PMU and remove all the cpumask and hotplug
codes.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Oliver Sang <oliver.sang@intel.com>
Tested-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Link: https://lore.kernel.org/r/20241010142604.770192-2-kan.liang@linux.intel.com
2024-10-30 22:42:19 +01:00
Gowthami Thiagarajan
e1dce56443 perf/marvell: Marvell PEM performance monitor support
PCI Express Interface PMU includes various performance counters
to monitor the data that is transmitted over the PCIe link. The
counters track various inbound and outbound transactions which
includes separate counters for posted/non-posted/completion TLPs.
Also, inbound and outbound memory read requests along with their
latencies can also be monitored. Address Translation Services(ATS)events
such as ATS Translation, ATS Page Request, ATS Invalidation along with
their corresponding latencies are also supported.

The performance counters are 64 bits wide.

For instance,
perf stat -e ib_tlp_pr <workload>
tracks the inbound posted TLPs for the workload.

Co-developed-by: Linu Cherian <lcherian@marvell.com>
Signed-off-by: Linu Cherian <lcherian@marvell.com>
Signed-off-by: Gowthami Thiagarajan <gthiagarajan@marvell.com>
Link: https://lore.kernel.org/r/20241028055309.17893-1-gthiagarajan@marvell.com
Signed-off-by: Will Deacon <will@kernel.org>
2024-10-28 17:35:35 +00:00
Linus Torvalds
9f0c253ddd Performance events changes for v6.12:
- Implement per-PMU context rescheduling to significantly improve single-PMU
    performance, and related cleanups/fixes. (by Peter Zijlstra and Namhyung Kim)
 
  - Fix ancient bug resulting in a lot of events being dropped erroneously
    at higher sampling frequencies. (by Luo Gengkun)
 
  - uprobes enhancements:
 
      - Implement RCU-protected hot path optimizations for better performance:
 
          "For baseline vs SRCU, peak througput increased from 3.7 M/s (million uprobe
           triggerings per second) up to about 8 M/s. For uretprobes it's a bit more
           modest with bump from 2.4 M/s to 5 M/s.
 
           For SRCU vs RCU Tasks Trace, peak throughput for uprobes increases further from
           8 M/s to 10.3 M/s (+28%!), and for uretprobes from 5.3 M/s to 5.8 M/s (+11%),
           as we have more work to do on uretprobes side.
 
           Even single-thread (no contention) performance is slightly better: 3.276 M/s to
           3.396 M/s (+3.5%) for uprobes, and 2.055 M/s to 2.174 M/s (+5.8%)
           for uretprobes."
 
           (by Andrii Nakryiko et al)
 
      - Document mmap_lock, don't abuse get_user_pages_remote(). (by Oleg Nesterov)
 
      - Cleanups & fixes to prepare for future work:
 
         - Remove uprobe_register_refctr()
 	- Simplify error handling for alloc_uprobe()
         - Make uprobe_register() return struct uprobe *
         - Fold __uprobe_unregister() into uprobe_unregister()
         - Shift put_uprobe() from delete_uprobe() to uprobe_unregister()
         - BPF: Fix use-after-free in bpf_uprobe_multi_link_attach()
 
           (by Oleg Nesterov)
 
  - New feature & ABI extension: allow events to use PERF_SAMPLE READ with
    inheritance, enabling sample based profiling of a group of counters over
    a hierarchy of processes or threads.  (by Ben Gainey)
 
  - Intel uncore & power events updates:
 
       - Add Arrow Lake and Lunar Lake support
       - Add PERF_EV_CAP_READ_SCOPE
       - Clean up and enhance cpumask and hotplug support
 
         (by Kan Liang)
 
       - Add LNL uncore iMC freerunning support
       - Use D0:F0 as a default device
 
         (by Zhenyu Wang)
 
  - Intel PT: fix AUX snapshot handling race. (by Adrian Hunter)
 
  - Misc fixes and cleanups. (by James Clark, Jiri Olsa, Oleg Nesterov and Peter Zijlstra)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2024-09-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf events updates from Ingo Molnar:

 - Implement per-PMU context rescheduling to significantly improve
   single-PMU performance, and related cleanups/fixes (Peter Zijlstra
   and Namhyung Kim)

 - Fix ancient bug resulting in a lot of events being dropped
   erroneously at higher sampling frequencies (Luo Gengkun)

 - uprobes enhancements:

     - Implement RCU-protected hot path optimizations for better
       performance:

         "For baseline vs SRCU, peak througput increased from 3.7 M/s
          (million uprobe triggerings per second) up to about 8 M/s. For
          uretprobes it's a bit more modest with bump from 2.4 M/s to
          5 M/s.

          For SRCU vs RCU Tasks Trace, peak throughput for uprobes
          increases further from 8 M/s to 10.3 M/s (+28%!), and for
          uretprobes from 5.3 M/s to 5.8 M/s (+11%), as we have more
          work to do on uretprobes side.

          Even single-thread (no contention) performance is slightly
          better: 3.276 M/s to 3.396 M/s (+3.5%) for uprobes, and 2.055
          M/s to 2.174 M/s (+5.8%) for uretprobes."

          (Andrii Nakryiko et al)

     - Document mmap_lock, don't abuse get_user_pages_remote() (Oleg
       Nesterov)

     - Cleanups & fixes to prepare for future work:
        - Remove uprobe_register_refctr()
	- Simplify error handling for alloc_uprobe()
        - Make uprobe_register() return struct uprobe *
        - Fold __uprobe_unregister() into uprobe_unregister()
        - Shift put_uprobe() from delete_uprobe() to uprobe_unregister()
        - BPF: Fix use-after-free in bpf_uprobe_multi_link_attach()
          (Oleg Nesterov)

 - New feature & ABI extension: allow events to use PERF_SAMPLE READ
   with inheritance, enabling sample based profiling of a group of
   counters over a hierarchy of processes or threads (Ben Gainey)

 - Intel uncore & power events updates:

      - Add Arrow Lake and Lunar Lake support
      - Add PERF_EV_CAP_READ_SCOPE
      - Clean up and enhance cpumask and hotplug support
        (Kan Liang)

      - Add LNL uncore iMC freerunning support
      - Use D0:F0 as a default device
        (Zhenyu Wang)

 - Intel PT: fix AUX snapshot handling race (Adrian Hunter)

 - Misc fixes and cleanups (James Clark, Jiri Olsa, Oleg Nesterov and
   Peter Zijlstra)

* tag 'perf-core-2024-09-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
  dmaengine: idxd: Clean up cpumask and hotplug for perfmon
  iommu/vt-d: Clean up cpumask and hotplug for perfmon
  perf/x86/intel/cstate: Clean up cpumask and hotplug
  perf: Add PERF_EV_CAP_READ_SCOPE
  perf: Generic hotplug support for a PMU with a scope
  uprobes: perform lockless SRCU-protected uprobes_tree lookup
  rbtree: provide rb_find_rcu() / rb_find_add_rcu()
  perf/uprobe: split uprobe_unregister()
  uprobes: travers uprobe's consumer list locklessly under SRCU protection
  uprobes: get rid of enum uprobe_filter_ctx in uprobe filter callbacks
  uprobes: protected uprobe lifetime with SRCU
  uprobes: revamp uprobe refcounting and lifetime management
  bpf: Fix use-after-free in bpf_uprobe_multi_link_attach()
  perf/core: Fix small negative period being ignored
  perf: Really fix event_function_call() locking
  perf: Optimize __pmu_ctx_sched_out()
  perf: Add context time freeze
  perf: Fix event_function_call() locking
  perf: Extract a few helpers
  perf: Optimize context reschedule for single PMU cases
  ...
2024-09-18 15:03:58 +02:00
Linus Torvalds
cb69d86550 Updates for the interrupt subsystem:
- Core:
 	- Remove a global lock in the affinity setting code
 
 	  The lock protects a cpumask for intermediate results and the lock
 	  causes a bottleneck on simultaneous start of multiple virtual
 	  machines. Replace the lock and the static cpumask with a per CPU
 	  cpumask which is nicely serialized by raw spinlock held when
 	  executing this code.
 
 	- Provide support for giving a suffix to interrupt domain names.
 
 	  That's required to support devices with subfunctions so that the
 	  domain names are distinct even if they originate from the same
 	  device node.
 
 	- The usual set of cleanups and enhancements all over the place
 
   - Drivers:
 
 	- Support for longarch AVEC interrupt chip
 
 	- Refurbishment of the Armada driver so it can be extended for new
           variants.
 
 	- The usual set of cleanups and enhancements all over the place
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Merge tag 'irq-core-2024-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq updates from Thomas Gleixner:
 "Core:

   - Remove a global lock in the affinity setting code

     The lock protects a cpumask for intermediate results and the lock
     causes a bottleneck on simultaneous start of multiple virtual
     machines. Replace the lock and the static cpumask with a per CPU
     cpumask which is nicely serialized by raw spinlock held when
     executing this code.

   - Provide support for giving a suffix to interrupt domain names.

     That's required to support devices with subfunctions so that the
     domain names are distinct even if they originate from the same
     device node.

   - The usual set of cleanups and enhancements all over the place

  Drivers:

   - Support for longarch AVEC interrupt chip

   - Refurbishment of the Armada driver so it can be extended for new
     variants.

   - The usual set of cleanups and enhancements all over the place"

* tag 'irq-core-2024-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (73 commits)
  genirq: Use cpumask_intersects()
  genirq/cpuhotplug: Use cpumask_intersects()
  irqchip/apple-aic: Only access system registers on SoCs which provide them
  irqchip/apple-aic: Add a new "Global fast IPIs only" feature level
  irqchip/apple-aic: Skip unnecessary enabling of use_fast_ipi
  dt-bindings: apple,aic: Document A7-A11 compatibles
  irqdomain: Use IS_ERR_OR_NULL() in irq_domain_trim_hierarchy()
  genirq/msi: Use kmemdup_array() instead of kmemdup()
  genirq/proc: Change the return value for set affinity permission error
  genirq/proc: Use irq_move_pending() in show_irq_affinity()
  genirq/proc: Correctly set file permissions for affinity control files
  genirq: Get rid of global lock in irq_do_set_affinity()
  genirq: Fix typo in struct comment
  irqchip/loongarch-avec: Add AVEC irqchip support
  irqchip/loongson-pch-msi: Prepare get_pch_msi_handle() for AVECINTC
  irqchip/loongson-eiointc: Rename CPUHP_AP_IRQ_LOONGARCH_STARTING
  LoongArch: Architectural preparation for AVEC irqchip
  LoongArch: Move irqchip function prototypes to irq-loongson.h
  irqchip/loongson-pch-msi: Switch to MSI parent domains
  softirq: Remove unused 'action' parameter from action callback
  ...
2024-09-17 07:09:17 +02:00
Kan Liang
08155c7f2a perf/x86/intel/cstate: Clean up cpumask and hotplug
There are three cstate PMUs with different scopes, core, die and module.
The scopes are supported by the generic perf_event subsystem now.

Set the scope for each PMU and remove all the cpumask and hotplug codes.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240802151643.1691631-4-kan.liang@linux.intel.com
2024-09-10 11:44:13 +02:00
Tianyang Zhang
ae16f05c92 irqchip/loongarch-avec: Add AVEC irqchip support
Introduce the advanced extended interrupt controllers (AVECINTC). This
feature will allow each core to have 256 independent interrupt vectors
and MSI interrupts can be independently routed to any vector on any CPU.

The whole topology of irqchips in LoongArch machines looks like this if
AVECINTC is supported:

  +-----+     +-----------------------+     +-------+
  | IPI | --> |        CPUINTC        | <-- | Timer |
  +-----+     +-----------------------+     +-------+
               ^          ^          ^
               |          |          |
        +---------+ +----------+ +---------+     +-------+
        | EIOINTC | | AVECINTC | | LIOINTC | <-- | UARTs |
        +---------+ +----------+ +---------+     +-------+
             ^            ^
             |            |
        +---------+  +---------+
        | PCH-PIC |  | PCH-MSI |
        +---------+  +---------+
          ^     ^           ^
          |     |           |
  +---------+ +---------+ +---------+
  | Devices | | PCH-LPC | | Devices |
  +---------+ +---------+ +---------+
                   ^
                   |
              +---------+
              | Devices |
              +---------+

Co-developed-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Co-developed-by: Liupu Wang <wangliupu@loongson.cn>
Signed-off-by: Liupu Wang <wangliupu@loongson.cn>
Co-developed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240823104337.25577-2-zhangtianyang@loongson.cn
2024-08-23 20:40:27 +02:00
Huacai Chen
9e83dd3ebb irqchip/loongson-eiointc: Rename CPUHP_AP_IRQ_LOONGARCH_STARTING
Rename CPUHP_AP_IRQ_LOONGARCH_STARTING to CPUHP_AP_IRQ_EIOINTC_STARTING
because the upcoming AVECINTC irqchip driver will introduce a new state
and so both are clearly identifiable.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240823103936.25092-3-zhangtianyang@loongson.cn
2024-08-23 20:40:27 +02:00
Linus Torvalds
948752d2e0 RISC-V Fixes for 6.11-rc2
* A fix to avoid dropping some of the internal pseudo-extensions, which
   breaks *envcfg dependency parsing.
 * The kernel entry address is now aligned in purgatory, which avoids a
   misaligned load that can lead to crash on systems that don't support
   misaligned accesses early in boot.
 * The FW_SFENCE_VMA_RECEIVED perf event was duplicated in a handful of
   perf JSON configurations, one of them been updated to
   FW_SFENCE_VMA_ASID_SENT.
 * The starfive cache driver is now restricted to 64-bit systems, as it
   isn't 32-bit clean.
 * A fix for to avoid aliasing legacy-mode perf counters with software
   perf counters.
 * VM_FAULT_SIGSEGV is now handled in the page fault code.
 * A fix for stalls during CPU hotplug due to IPIs being disabled.
 * A fix for memblock bounds checking.  This manifests as a crash on
   systems with discontinuous memory maps that have regions that don't
   fit in the linear map.
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Merge tag 'riscv-for-linus-6.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:

 - A fix to avoid dropping some of the internal pseudo-extensions, which
   breaks *envcfg dependency parsing

 - The kernel entry address is now aligned in purgatory, which avoids a
   misaligned load that can lead to crash on systems that don't support
   misaligned accesses early in boot

 - The FW_SFENCE_VMA_RECEIVED perf event was duplicated in a handful of
   perf JSON configurations, one of them been updated to
   FW_SFENCE_VMA_ASID_SENT

 - The starfive cache driver is now restricted to 64-bit systems, as it
   isn't 32-bit clean

 - A fix for to avoid aliasing legacy-mode perf counters with software
   perf counters

 - VM_FAULT_SIGSEGV is now handled in the page fault code

 - A fix for stalls during CPU hotplug due to IPIs being disabled

 - A fix for memblock bounds checking. This manifests as a crash on
   systems with discontinuous memory maps that have regions that don't
   fit in the linear map

* tag 'riscv-for-linus-6.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: Fix linear mapping checks for non-contiguous memory regions
  RISC-V: Enable the IPI before workqueue_online_cpu()
  riscv/mm: Add handling for VM_FAULT_SIGSEGV in mm_fault_error()
  perf: riscv: Fix selecting counters in legacy mode
  cache: StarFive: Require a 64-bit system
  perf arch events: Fix duplicate RISC-V SBI firmware event name
  riscv/purgatory: align riscv_kernel_entry
  riscv: cpufeature: Do not drop Linux-internal extensions
2024-08-02 09:33:35 -07:00
Nick Hu
3908ba2e0b
RISC-V: Enable the IPI before workqueue_online_cpu()
Sometimes the hotplug cpu stalls at the arch_cpu_idle() for a while after
workqueue_online_cpu(). When cpu stalls at the idle loop, the reschedule
IPI is pending. However the enable bit is not enabled yet so the cpu stalls
at WFI until watchdog timeout. Therefore enable the IPI before the
workqueue_online_cpu() to fix the issue.

Fixes: 63c5484e74 ("workqueue: Add multiple affinity scopes and interface to select them")
Signed-off-by: Nick Hu <nick.hu@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20240717031714.1946036-1-nick.hu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-08-01 07:15:43 -07:00
Linus Torvalds
2accfdb7ef profiling: attempt to remove per-cpu profile flip buffer
This is the really old legacy kernel profiling code, which has long
since been obviated by "real profiling" (ie 'prof' and company), and
mainly remains as a source of syzbot reports.

There are anecdotal reports that people still use it for boot-time
profiling, but it's unlikely that such use would care about the old NUMA
optimizations in this code from 2004 (commit ad02973d42: "profile: 512x
Altix timer interrupt livelock fix" in the BK import archive at [1])

So in order to head off future syzbot reports, let's try to simplify
this code and get rid of the per-cpu profile buffers that are quite a
large portion of the complexity footprint of this thing (including CPU
hotplug callbacks etc).

It's unlikely anybody will actually notice, or possibly, as Thomas put
it: "Only people who indulge in nostalgia will notice :)".

That said, if it turns out that this code is actually actively used by
somebody, we can always revert this removal.  Thus the "attempt" in the
summary line.

[ Note: in a small nod to "the profiling code can cause NUMA problems",
  this also removes the "increment the last entry in the profiling array
  on any unknown hits" logic. That would account any program counter in
  a module to that single counter location, and might exacerbate any
  NUMA cacheline bouncing issues ]

Link: https://lore.kernel.org/all/CAHk-=wgs52BxT4Zjmjz8aNvHWKxf5_ThBY4bYL1Y6CTaNL2dTw@mail.gmail.com/
Link:  https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git [1]
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-07-29 10:58:28 -07:00
Linus Torvalds
5256184b61 Fixes and minor updates for the timer migration code:
- Stop testing the group->parent pointer as it is not guaranteed to be
       stable over a chain of operations by design. This includes a warning
       which would be nice to have but it produces false positives due to
       the racy nature of the check.
 
     - Plug a race between CPUs going in and out of idle and a CPU hotplug
       operation. The latter can create and connect a new hierarchy level
       which is missed in the concurrent updates of CPUs which go into idle.
       As a result the events of such a CPU might not be processed and
       timers go stale.
 
       Cure it by splitting the hotplug operation into a prepare and online
       callback. The prepare callback is guaranteed to run on an online and
       therefore active CPU. This CPU updates the hierarchy and being online
       ensures that there is always at least one migrator active which
       handles the modified hierarchy correctly when going idle. The online
       callback which runs on the incoming CPU then just marks the CPU
       active and brings it into operation.
 
     - Improve tracing and polish the code further so it is more obvious
       what's going on.
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Merge tag 'timers-urgent-2024-07-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer migration updates from Thomas Gleixner:
 "Fixes and minor updates for the timer migration code:

   - Stop testing the group->parent pointer as it is not guaranteed to
     be stable over a chain of operations by design.

     This includes a warning which would be nice to have but it produces
     false positives due to the racy nature of the check.

   - Plug a race between CPUs going in and out of idle and a CPU hotplug
     operation. The latter can create and connect a new hierarchy level
     which is missed in the concurrent updates of CPUs which go into
     idle. As a result the events of such a CPU might not be processed
     and timers go stale.

     Cure it by splitting the hotplug operation into a prepare and
     online callback. The prepare callback is guaranteed to run on an
     online and therefore active CPU. This CPU updates the hierarchy and
     being online ensures that there is always at least one migrator
     active which handles the modified hierarchy correctly when going
     idle. The online callback which runs on the incoming CPU then just
     marks the CPU active and brings it into operation.

   - Improve tracing and polish the code further so it is more obvious
     what's going on"

* tag 'timers-urgent-2024-07-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers/migration: Fix grammar in comment
  timers/migration: Spare write when nothing changed
  timers/migration: Rename childmask by groupmask to make naming more obvious
  timers/migration: Read childmask and parent pointer in a single place
  timers/migration: Use a single struct for hierarchy walk data
  timers/migration: Improve tracing
  timers/migration: Move hierarchy setup into cpuhotplug prepare callback
  timers/migration: Do not rely always on group->parent
2024-07-27 10:19:55 -07:00
Anna-Maria Behnsen
10a0e6f3d3 timers/migration: Move hierarchy setup into cpuhotplug prepare callback
When a CPU comes online the first time, it is possible that a new top level
group will be created. In general all propagation is done from the bottom
to top. This minimizes complexity and prevents possible races. But when a
new top level group is created, the formely top level group needs to be
connected to the new level. This is the only time, when the direction to
propagate changes is changed: the changes are propagated from top (new top
level group) to bottom (formerly top level group).

This introduces two races (see (A) and (B)) as reported by Frederic:

(A) This race happens, when marking the formely top level group as active,
but the last active CPU of the formerly top level group goes idle. Then
it's likely that formerly group is no longer active, but marked
nevertheless as active in new top level group:

		  [GRP0:0]
	       migrator = 0
	       active   = 0
	       nextevt  = KTIME_MAX
	       /         \
	      0         1 .. 7
	  active         idle

0) Hierarchy has for now only 8 CPUs and CPU 0 is the only active CPU.

			     [GRP1:0]
			migrator = TMIGR_NONE
			active   = NONE
			nextevt  = KTIME_MAX
					 \
		 [GRP0:0]                  [GRP0:1]
	      migrator = 0              migrator = TMIGR_NONE
	      active   = 0              active   = NONE
	      nextevt  = KTIME_MAX      nextevt  = KTIME_MAX
		/         \
	      0          1 .. 7                8
	  active         idle                !online

1) CPU 8 is booting and creates a new group in first level GRP0:1 and
   therefore also a new top group GRP1:0. For now the setup code proceeded
   only until the connected between GRP0:1 to the new top group. The
   connection between CPU8 and GRP0:1 is not yet established and CPU 8 is
   still !online.

			     [GRP1:0]
			migrator = TMIGR_NONE
			active   = NONE
			nextevt  = KTIME_MAX
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = 0              migrator = TMIGR_NONE
	      active   = 0              active   = NONE
	      nextevt  = KTIME_MAX      nextevt  = KTIME_MAX
		/         \
	      0          1 .. 7                8
	  active         idle                !online

2) Setup code now connects GRP0:0 to GRP1:0 and observes while in
   tmigr_connect_child_parent() that GRP0:0 is not TMIGR_NONE. So it
   prepares to call tmigr_active_up() on it. It hasn't done it yet.

			     [GRP1:0]
			migrator = TMIGR_NONE
			active   = NONE
			nextevt  = KTIME_MAX
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = TMIGR_NONE        migrator = TMIGR_NONE
	      active   = NONE              active   = NONE
	      nextevt  = KTIME_MAX         nextevt  = KTIME_MAX
		/         \
	      0          1 .. 7                8
	    idle         idle                !online

3) CPU 0 goes idle. Since GRP0:0->parent has been updated by CPU 8 with
   GRP0:0->lock held, CPU 0 observes GRP1:0 after calling
   tmigr_update_events() and it propagates the change to the top (no change
   there and no wakeup programmed since there is no timer).

			     [GRP1:0]
			migrator = GRP0:0
			active   = GRP0:0
			nextevt  = KTIME_MAX
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = TMIGR_NONE       migrator = TMIGR_NONE
	      active   = NONE             active   = NONE
	      nextevt  = KTIME_MAX        nextevt  = KTIME_MAX
		/         \
	      0          1 .. 7                8
	    idle         idle                !online

4) Now the setup code finally calls tmigr_active_up() to and sets GRP0:0
   active in GRP1:0

			     [GRP1:0]
			migrator = GRP0:0
			active   = GRP0:0, GRP0:1
			nextevt  = KTIME_MAX
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = TMIGR_NONE       migrator = 8
	      active   = NONE             active   = 8
	      nextevt  = KTIME_MAX        nextevt  = KTIME_MAX
		/         \                    |
	      0          1 .. 7                8
	    idle         idle                active

5) Now CPU 8 is connected with GRP0:1 and CPU 8 calls tmigr_active_up() out
   of tmigr_cpu_online().

			     [GRP1:0]
			migrator = GRP0:0
			active   = GRP0:0
			nextevt  = T8
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = TMIGR_NONE         migrator = TMIGR_NONE
	      active   = NONE               active   = NONE
	      nextevt  = KTIME_MAX          nextevt  = T8
		/         \                    |
	      0          1 .. 7                8
	    idle         idle                  idle

5) CPU 8 goes idle with a timer T8 and relies on GRP0:0 as the migrator.
   But it's not really active, so T8 gets ignored.

--> The update which is done in third step is not noticed by setup code. So
    a wrong migrator is set to top level group and a timer could get
    ignored.

(B) Reading group->parent and group->childmask when an hierarchy update is
ongoing and reaches the formerly top level group is racy as those values
could be inconsistent. (The notation of migrator and active now slightly
changes in contrast to the above example, as now the childmasks are used.)

			     [GRP1:0]
			migrator = TMIGR_NONE
			active   = 0x00
			nextevt  = KTIME_MAX
					 \
		 [GRP0:0]                  [GRP0:1]
	      migrator = TMIGR_NONE     migrator = TMIGR_NONE
	      active   = 0x00           active   = 0x00
	      nextevt  = KTIME_MAX      nextevt  = KTIME_MAX
	      childmask= 0		childmask= 1
	      parent   = NULL		parent   = GRP1:0
		/         \
	      0          1 .. 7                8
	  idle           idle                !online
	  childmask=1

1) Hierarchy has 8 CPUs. CPU 8 is at the moment in the process of onlining
   but did not yet connect GRP0:0 to GRP1:0.

			     [GRP1:0]
			migrator = TMIGR_NONE
			active   = 0x00
			nextevt  = KTIME_MAX
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = TMIGR_NONE     migrator = TMIGR_NONE
	      active   = 0x00           active   = 0x00
	      nextevt  = KTIME_MAX      nextevt  = KTIME_MAX
	      childmask= 0		childmask= 1
	      parent   = GRP1:0		parent   = GRP1:0
		/         \
	      0          1 .. 7                8
	  idle           idle                !online
	  childmask=1

2) Setup code (running on CPU 8) now connects GRP0:0 to GRP1:0, updates
   parent pointer of GRP0:0 and ...

			     [GRP1:0]
			migrator = TMIGR_NONE
			active   = 0x00
			nextevt  = KTIME_MAX
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = 0x01           migrator = TMIGR_NONE
	      active   = 0x01           active   = 0x00
	      nextevt  = KTIME_MAX      nextevt  = KTIME_MAX
	      childmask= 0		childmask= 1
	      parent   = GRP1:0		parent   = GRP1:0
		/         \
	      0          1 .. 7                8
	  active          idle                !online
	  childmask=1

	  tmigr_walk.childmask = 0

3) ... CPU 0 comes active in the same time. As migrator in GRP0:0 was
   TMIGR_NONE, childmask of GRP0:0 is stored in update propagation data
   structure tmigr_walk (as update of childmask is not yet
   visible/updated). And now ...

			     [GRP1:0]
			migrator = TMIGR_NONE
			active   = 0x00
			nextevt  = KTIME_MAX
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = 0x01           migrator = TMIGR_NONE
	      active   = 0x01           active   = 0x00
	      nextevt  = KTIME_MAX      nextevt  = KTIME_MAX
	      childmask= 2		childmask= 1
	      parent   = GRP1:0		parent   = GRP1:0
		/         \
	      0          1 .. 7                8
	  active          idle                !online
	  childmask=1

	  tmigr_walk.childmask = 0

4) ... childmask of GRP0:0 is updated by CPU 8 (still part of setup
   code).

			     [GRP1:0]
			migrator = 0x00
			active   = 0x00
			nextevt  = KTIME_MAX
		       /                  \
		 [GRP0:0]                  [GRP0:1]
	      migrator = 0x01           migrator = TMIGR_NONE
	      active   = 0x01           active   = 0x00
	      nextevt  = KTIME_MAX      nextevt  = KTIME_MAX
	      childmask= 2		childmask= 1
	      parent   = GRP1:0		parent   = GRP1:0
		/         \
	      0          1 .. 7                8
	  active          idle                !online
	  childmask=1

	  tmigr_walk.childmask = 0

5) CPU 0 sees the connection to GRP1:0 and now propagates active state to
   GRP1:0 but with childmask = 0 as stored in propagation data structure.

--> Now GRP1:0 always has a migrator as 0x00 != TMIGR_NONE and for all CPUs
    it looks like GRP1:0 is always active.

To prevent those races, the setup of the hierarchy is moved into the
cpuhotplug prepare callback. The prepare callback is not executed by the
CPU which will come online, it is executed by the CPU which prepares
onlining of the other CPU. This CPU is active while it is connecting the
formerly top level to the new one. This prevents from (A) to happen and it
also prevents from any further walk above the formerly top level until that
active CPU becomes inactive, releasing the new ->parent and ->childmask
updates to be visible by any subsequent walk up above the formerly top
level hierarchy. This prevents from (B) to happen. The direction for the
updates is now forced to look like "from bottom to top".

However if the active CPU prevents from tmigr_cpu_(in)active() to walk up
with the update not-or-half visible, nothing prevents walking up to the new
top with a 0 childmask in tmigr_handle_remote_up() or
tmigr_requires_handle_remote_up() if the active CPU doing the prepare is
not the migrator. But then it looks fine because:

  * tmigr_check_migrator() should just return false
  * The migrator is active and should eventually observe the new childmask
    at some point in a future tick.

Split setup functionality of online callback into the cpuhotplug prepare
callback and setup hotplug state. Change init call into early_initcall() to
make sure an already active CPU prepares everything for newly upcoming
CPUs. Reorder the code, that all prepare related functions are close to
each other and online and offline callbacks are also close together.

Fixes: 7ee9887703 ("timers: Implement the hierarchical pull model")
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240717094940.18687-1-anna-maria@linutronix.de
2024-07-22 18:03:34 +02:00
Linus Torvalds
4fd9435641 Updates for timers, timekeeping and related functionality:
- Core:
 
     - Make the takeover of a hrtimer based broadcast timer reliable during
       CPU hot-unplug. The current implementation suffers from a race which
       can lead to broadcast timer starvation in the worst case.
 
     - VDSO related cleanups and simplifications
 
     - Small cleanups and enhancements all over the place
 
   - PTP:
 
     - Replace the architecture specific base clock to clocksource, e.g. ART
       to TSC, conversion function with generic functionality to avoid
       exposing such internals to drivers and convert all existing drivers
       over. This also allows to provide functionality which converts the
       other way round in the core code based on the same parameter set.
 
     - Provide a function to convert CLOCK_REALTIME to the base clock to
       support the upcoming PPS output driver on Intel platforms.
 
   - Drivers:
 
     - A set of Device Tree bindings for new hardware
 
     - Cleanups and enhancements all over the place
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Merge tag 'timers-core-2024-07-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "Updates for timers, timekeeping and related functionality:

  Core:

   - Make the takeover of a hrtimer based broadcast timer reliable
     during CPU hot-unplug. The current implementation suffers from a
     race which can lead to broadcast timer starvation in the worst
     case.

   - VDSO related cleanups and simplifications

   - Small cleanups and enhancements all over the place

  PTP:

   - Replace the architecture specific base clock to clocksource, e.g.
     ART to TSC, conversion function with generic functionality to avoid
     exposing such internals to drivers and convert all existing drivers
     over. This also allows to provide functionality which converts the
     other way round in the core code based on the same parameter set.

   - Provide a function to convert CLOCK_REALTIME to the base clock to
     support the upcoming PPS output driver on Intel platforms.

  Drivers:

   - A set of Device Tree bindings for new hardware

   - Cleanups and enhancements all over the place"

* tag 'timers-core-2024-07-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits)
  clocksource/drivers/realtek: Add timer driver for rtl-otto platforms
  dt-bindings: timer: Add schema for realtek,otto-timer
  dt-bindings: timer: Add SOPHGO SG2002 clint
  dt-bindings: timer: renesas,tmu: Add R-Car Gen2 support
  dt-bindings: timer: renesas,tmu: Add RZ/G1 support
  dt-bindings: timer: renesas,tmu: Add R-Mobile APE6 support
  clocksource/drivers/mips-gic-timer: Correct sched_clock width
  clocksource/drivers/mips-gic-timer: Refine rating computation
  clocksource/drivers/sh_cmt: Address race condition for clock events
  clocksource/driver/arm_global_timer: Remove unnecessary ‘0’ values from err
  clocksource/drivers/arm_arch_timer: Remove unnecessary ‘0’ values from irq
  tick/broadcast: Make takeover of broadcast hrtimer reliable
  tick/sched: Combine WARN_ON_ONCE and print_once
  x86/vdso: Remove unused include
  x86/vgtod: Remove unused typedef gtod_long_t
  x86/vdso: Fix function reference in comment
  vdso: Add comment about reason for vdso struct ordering
  vdso/gettimeofday: Clarify comment about open coded function
  timekeeping: Add missing kernel-doc function comments
  tick: Remove unnused tick_nohz_get_idle_calls()
  ...
2024-07-15 15:03:09 -07:00
Chris Packham
4bdc3eaa10 clocksource/drivers/realtek: Add timer driver for rtl-otto platforms
The timer/counter block on the Realtek SoCs provides up to 5 timers. It
also includes a watchdog timer which is handled by the
realtek_otto_wdt.c driver.

One timer will be used per CPU as a local clock event generator. An
additional timer will be used as an overal stable clocksource.

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Signed-off-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-12 16:07:06 +02:00
Costa Shulyupin
f45a6051d5 cpu/hotplug: Fix typo in comment
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240325163810.669459-1-costa.shul@redhat.com
2024-06-17 15:17:44 +02:00
Anup Patel
21a8f8a0eb irqchip: Add RISC-V incoming MSI controller early driver
The RISC-V advanced interrupt architecture (AIA) specification
defines a new MSI controller called incoming message signalled
interrupt controller (IMSIC) which manages MSI on per-HART (or
per-CPU) basis. It also supports IPIs as software injected MSIs.
(For more details refer https://github.com/riscv/riscv-aia)

Add an early irqchip driver for RISC-V IMSIC which sets up the
IMSIC state and provide IPIs.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20240307140307.646078-3-apatel@ventanamicro.com
2024-03-25 17:38:28 +01:00
Frederic Weisbecker
3ad6eb0683 tick: Start centralizing tick related CPU hotplug operations
During the CPU offlining process, the various timer tick features are
shut down from scattered places, sometimes from teardown callbacks on
stop machine, sometimes through explicit calls, sometimes from the
control CPU after the CPU died. The reason why these shutdown operations
are spread around is not always clear and it makes the tick lifecycle
hard to follow.

The tick should be shut down in order from highest to lowest level:

On stop machine from the dying CPU (high-level):

 1) Hand-over the timekeeping duty (tick_handover_do_timer())
 2) Cancel the tick implementation called by the clockevent callback
    (tick_cancel_sched_timer())
 3) Shutdown broadcasting (tick_offline_cpu() / tick_broadcast_offline())

On stop machine from the dying CPU (low-level):

 4) Shutdown clockevents drivers (CPUHP_AP_*_TIMER_STARTING states)

From the control CPU after the CPU died (low-level):

 5) Shutdown/unregister/cleanup clockevents for the dead CPU
    (tick_cleanup_dead_cpu())

Instead the current order is 2, 4 (both from CPU hotplug states), then
1 and 3 through direct calls. This layout and order don't make much
sense. The operations 1, 2, 3 should be gathered together and in order.

Sort this situation with creating a new TICK shut-down CPU hotplug state
and start with introducing the timekeeping duty hand-over there. The
state must precede hrtimers migration because the tick hrtimer will be
stopped from it in a further patch.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240225225508.11587-8-frederic@kernel.org
2024-02-26 11:37:31 +01:00
Anna-Maria Behnsen
7ee9887703 timers: Implement the hierarchical pull model
Placing timers at enqueue time on a target CPU based on dubious heuristics
does not make any sense:

 1) Most timer wheel timers are canceled or rearmed before they expire.

 2) The heuristics to predict which CPU will be busy when the timer expires
    are wrong by definition.

So placing the timers at enqueue wastes precious cycles.

The proper solution to this problem is to always queue the timers on the
local CPU and allow the non pinned timers to be pulled onto a busy CPU at
expiry time.

Therefore split the timer storage into local pinned and global timers:
Local pinned timers are always expired on the CPU on which they have been
queued. Global timers can be expired on any CPU.

As long as a CPU is busy it expires both local and global timers. When a
CPU goes idle it arms for the first expiring local timer. If the first
expiring pinned (local) timer is before the first expiring movable timer,
then no action is required because the CPU will wake up before the first
movable timer expires. If the first expiring movable timer is before the
first expiring pinned (local) timer, then this timer is queued into an idle
timerqueue and eventually expired by another active CPU.

To avoid global locking the timerqueues are implemented as a hierarchy. The
lowest level of the hierarchy holds the CPUs. The CPUs are associated to
groups of 8, which are separated per node. If more than one CPU group
exist, then a second level in the hierarchy collects the groups. Depending
on the size of the system more than 2 levels are required. Each group has a
"migrator" which checks the timerqueue during the tick for remote expirable
timers.

If the last CPU in a group goes idle it reports the first expiring event in
the group up to the next group(s) in the hierarchy. If the last CPU goes
idle it arms its timer for the first system wide expiring timer to ensure
that no timer event is missed.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240222103710.32582-1-anna-maria@linutronix.de
2024-02-22 17:52:32 +01:00
Linus Torvalds
fb46e22a9e Many singleton patches against the MM code. The patch series which
are included in this merge do the following:
 
 - Peng Zhang has done some mapletree maintainance work in the
   series
 
 	"maple_tree: add mt_free_one() and mt_attr() helpers"
 	"Some cleanups of maple tree"
 
 - In the series "mm: use memmap_on_memory semantics for dax/kmem"
   Vishal Verma has altered the interworking between memory-hotplug
   and dax/kmem so that newly added 'device memory' can more easily
   have its memmap placed within that newly added memory.
 
 - Matthew Wilcox continues folio-related work (including a few
   fixes) in the patch series
 
 	"Add folio_zero_tail() and folio_fill_tail()"
 	"Make folio_start_writeback return void"
 	"Fix fault handler's handling of poisoned tail pages"
 	"Convert aops->error_remove_page to ->error_remove_folio"
 	"Finish two folio conversions"
 	"More swap folio conversions"
 
 - Kefeng Wang has also contributed folio-related work in the series
 
 	"mm: cleanup and use more folio in page fault"
 
 - Jim Cromie has improved the kmemleak reporting output in the
   series "tweak kmemleak report format".
 
 - In the series "stackdepot: allow evicting stack traces" Andrey
   Konovalov to permits clients (in this case KASAN) to cause
   eviction of no longer needed stack traces.
 
 - Charan Teja Kalla has fixed some accounting issues in the page
   allocator's atomic reserve calculations in the series "mm:
   page_alloc: fixes for high atomic reserve caluculations".
 
 - Dmitry Rokosov has added to the samples/ dorectory some sample
   code for a userspace memcg event listener application.  See the
   series "samples: introduce cgroup events listeners".
 
 - Some mapletree maintanance work from Liam Howlett in the series
   "maple_tree: iterator state changes".
 
 - Nhat Pham has improved zswap's approach to writeback in the
   series "workload-specific and memory pressure-driven zswap
   writeback".
 
 - DAMON/DAMOS feature and maintenance work from SeongJae Park in
   the series
 
 	"mm/damon: let users feed and tame/auto-tune DAMOS"
 	"selftests/damon: add Python-written DAMON functionality tests"
 	"mm/damon: misc updates for 6.8"
 
 - Yosry Ahmed has improved memcg's stats flushing in the series
   "mm: memcg: subtree stats flushing and thresholds".
 
 - In the series "Multi-size THP for anonymous memory" Ryan Roberts
   has added a runtime opt-in feature to transparent hugepages which
   improves performance by allocating larger chunks of memory during
   anonymous page faults.
 
 - Matthew Wilcox has also contributed some cleanup and maintenance
   work against eh buffer_head code int he series "More buffer_head
   cleanups".
 
 - Suren Baghdasaryan has done work on Andrea Arcangeli's series
   "userfaultfd move option".  UFFDIO_MOVE permits userspace heap
   compaction algorithms to move userspace's pages around rather than
   UFFDIO_COPY'a alloc/copy/free.
 
 - Stefan Roesch has developed a "KSM Advisor", in the series
   "mm/ksm: Add ksm advisor".  This is a governor which tunes KSM's
   scanning aggressiveness in response to userspace's current needs.
 
 - Chengming Zhou has optimized zswap's temporary working memory
   use in the series "mm/zswap: dstmem reuse optimizations and
   cleanups".
 
 - Matthew Wilcox has performed some maintenance work on the
   writeback code, both code and within filesystems.  The series is
   "Clean up the writeback paths".
 
 - Andrey Konovalov has optimized KASAN's handling of alloc and
   free stack traces for secondary-level allocators, in the series
   "kasan: save mempool stack traces".
 
 - Andrey also performed some KASAN maintenance work in the series
   "kasan: assorted clean-ups".
 
 - David Hildenbrand has gone to town on the rmap code.  Cleanups,
   more pte batching, folio conversions and more.  See the series
   "mm/rmap: interface overhaul".
 
 - Kinsey Ho has contributed some maintenance work on the MGLRU
   code in the series "mm/mglru: Kconfig cleanup".
 
 - Matthew Wilcox has contributed lruvec page accounting code
   cleanups in the series "Remove some lruvec page accounting
   functions".
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Merge tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Peng Zhang has done some mapletree maintainance work in the series

	'maple_tree: add mt_free_one() and mt_attr() helpers'
	'Some cleanups of maple tree'

   - In the series 'mm: use memmap_on_memory semantics for dax/kmem'
     Vishal Verma has altered the interworking between memory-hotplug
     and dax/kmem so that newly added 'device memory' can more easily
     have its memmap placed within that newly added memory.

   - Matthew Wilcox continues folio-related work (including a few fixes)
     in the patch series

	'Add folio_zero_tail() and folio_fill_tail()'
	'Make folio_start_writeback return void'
	'Fix fault handler's handling of poisoned tail pages'
	'Convert aops->error_remove_page to ->error_remove_folio'
	'Finish two folio conversions'
	'More swap folio conversions'

   - Kefeng Wang has also contributed folio-related work in the series

	'mm: cleanup and use more folio in page fault'

   - Jim Cromie has improved the kmemleak reporting output in the series
     'tweak kmemleak report format'.

   - In the series 'stackdepot: allow evicting stack traces' Andrey
     Konovalov to permits clients (in this case KASAN) to cause eviction
     of no longer needed stack traces.

   - Charan Teja Kalla has fixed some accounting issues in the page
     allocator's atomic reserve calculations in the series 'mm:
     page_alloc: fixes for high atomic reserve caluculations'.

   - Dmitry Rokosov has added to the samples/ dorectory some sample code
     for a userspace memcg event listener application. See the series
     'samples: introduce cgroup events listeners'.

   - Some mapletree maintanance work from Liam Howlett in the series
     'maple_tree: iterator state changes'.

   - Nhat Pham has improved zswap's approach to writeback in the series
     'workload-specific and memory pressure-driven zswap writeback'.

   - DAMON/DAMOS feature and maintenance work from SeongJae Park in the
     series

	'mm/damon: let users feed and tame/auto-tune DAMOS'
	'selftests/damon: add Python-written DAMON functionality tests'
	'mm/damon: misc updates for 6.8'

   - Yosry Ahmed has improved memcg's stats flushing in the series 'mm:
     memcg: subtree stats flushing and thresholds'.

   - In the series 'Multi-size THP for anonymous memory' Ryan Roberts
     has added a runtime opt-in feature to transparent hugepages which
     improves performance by allocating larger chunks of memory during
     anonymous page faults.

   - Matthew Wilcox has also contributed some cleanup and maintenance
     work against eh buffer_head code int he series 'More buffer_head
     cleanups'.

   - Suren Baghdasaryan has done work on Andrea Arcangeli's series
     'userfaultfd move option'. UFFDIO_MOVE permits userspace heap
     compaction algorithms to move userspace's pages around rather than
     UFFDIO_COPY'a alloc/copy/free.

   - Stefan Roesch has developed a 'KSM Advisor', in the series 'mm/ksm:
     Add ksm advisor'. This is a governor which tunes KSM's scanning
     aggressiveness in response to userspace's current needs.

   - Chengming Zhou has optimized zswap's temporary working memory use
     in the series 'mm/zswap: dstmem reuse optimizations and cleanups'.

   - Matthew Wilcox has performed some maintenance work on the writeback
     code, both code and within filesystems. The series is 'Clean up the
     writeback paths'.

   - Andrey Konovalov has optimized KASAN's handling of alloc and free
     stack traces for secondary-level allocators, in the series 'kasan:
     save mempool stack traces'.

   - Andrey also performed some KASAN maintenance work in the series
     'kasan: assorted clean-ups'.

   - David Hildenbrand has gone to town on the rmap code. Cleanups, more
     pte batching, folio conversions and more. See the series 'mm/rmap:
     interface overhaul'.

   - Kinsey Ho has contributed some maintenance work on the MGLRU code
     in the series 'mm/mglru: Kconfig cleanup'.

   - Matthew Wilcox has contributed lruvec page accounting code cleanups
     in the series 'Remove some lruvec page accounting functions'"

* tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (361 commits)
  mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
  mm, treewide: introduce NR_PAGE_ORDERS
  selftests/mm: add separate UFFDIO_MOVE test for PMD splitting
  selftests/mm: skip test if application doesn't has root privileges
  selftests/mm: conform test to TAP format output
  selftests: mm: hugepage-mmap: conform to TAP format output
  selftests/mm: gup_test: conform test to TAP format output
  mm/selftests: hugepage-mremap: conform test to TAP format output
  mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING
  mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large
  mm/memcontrol: remove __mod_lruvec_page_state()
  mm/khugepaged: use a folio more in collapse_file()
  slub: use a folio in __kmalloc_large_node
  slub: use folio APIs in free_large_kmalloc()
  slub: use alloc_pages_node() in alloc_slab_page()
  mm: remove inc/dec lruvec page state functions
  mm: ratelimit stat flush from workingset shrinker
  kasan: stop leaking stack trace handles
  mm/mglru: remove CONFIG_TRANSPARENT_HUGEPAGE
  mm/mglru: add dummy pmd_dirty()
  ...
2024-01-09 11:18:47 -08:00
Linus Torvalds
d30e51aa7b slab updates for 6.8
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Merge tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab updates from Vlastimil Babka:

 - SLUB: delayed freezing of CPU partial slabs (Chengming Zhou)

   Freezing is an operation involving double_cmpxchg() that makes a slab
   exclusive for a particular CPU. Chengming noticed that we use it also
   in situations where we are not yet installing the slab as the CPU
   slab, because freezing also indicates that the slab is not on the
   shared list. This results in redundant freeze/unfreeze operation and
   can be avoided by marking separately the shared list presence by
   reusing the PG_workingset flag.

   This approach neatly avoids the issues described in 9b1ea29bc0
   ("Revert "mm, slub: consider rest of partial list if acquire_slab()
   fails"") as we can now grab a slab from the shared list in a quick
   and guaranteed way without the cmpxchg_double() operation that
   amplifies the lock contention and can fail.

   As a result, lkp has reported 34.2% improvement of
   stress-ng.rawudp.ops_per_sec

 - SLAB removal and SLUB cleanups (Vlastimil Babka)

   The SLAB allocator has been deprecated since 6.5 and nobody has
   objected so far. We agreed at LSF/MM to wait until the next LTS,
   which is 6.6, so we should be good to go now.

   This doesn't yet erase all traces of SLAB outside of mm/ so some dead
   code, comments or documentation remain, and will be cleaned up
   gradually (some series are already in the works).

   Removing the choice of allocators has already allowed to simplify and
   optimize the code wiring up the kmalloc APIs to the SLUB
   implementation.

* tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (34 commits)
  mm/slub: free KFENCE objects in slab_free_hook()
  mm/slub: handle bulk and single object freeing separately
  mm/slub: introduce __kmem_cache_free_bulk() without free hooks
  mm/slub: fix bulk alloc and free stats
  mm/slub: optimize free fast path code layout
  mm/slub: optimize alloc fastpath code layout
  mm/slub: remove slab_alloc() and __kmem_cache_alloc_lru() wrappers
  mm/slab: move kmalloc() functions from slab_common.c to slub.c
  mm/slab: move kmalloc_slab() to mm/slab.h
  mm/slab: move kfree() from slab_common.c to slub.c
  mm/slab: move struct kmem_cache_node from slab.h to slub.c
  mm/slab: move memcg related functions from slab.h to slub.c
  mm/slab: move pre/post-alloc hooks from slab.h to slub.c
  mm/slab: consolidate includes in the internal mm/slab.h
  mm/slab: move the rest of slub_def.h to mm/slab.h
  mm/slab: move struct kmem_cache_cpu declaration to slub.c
  mm/slab: remove mm/slab.c and slab_def.h
  mm/mempool/dmapool: remove CONFIG_DEBUG_SLAB ifdefs
  mm/slab: remove CONFIG_SLAB code from slab common code
  cpu/hotplug: remove CPUHP_SLAB_PREPARE hooks
  ...
2024-01-09 10:36:07 -08:00
Chengming Zhou
8ba2f844f0 mm/zswap: change per-cpu mutex and buffer to per-acomp_ctx
First of all, we need to rename acomp_ctx->dstmem field to buffer, since
we are now using for purposes other than compression.

Then we change per-cpu mutex and buffer to per-acomp_ctx, since them
belong to the acomp_ctx and are necessary parts when used in the
compress/decompress contexts.

So we can remove the old per-cpu mutex and dstmem.

Link: https://lkml.kernel.org/r/20231213-zswap-dstmem-v5-5-9382162bbf05@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Chris Li <chrisl@kernel.org> (Google)
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-29 11:58:29 -08:00
xiaoming Wang
fe22944cf0 cpu/hotplug: Increase the number of dynamic states
The dynamically allocatable hotplug state space can be exhausted by
the existing drivers and infrastructure which install CPU hotplug
states dynamically. That prevents new drivers and infrastructure from
installing dynamically allocated states.

Increase the size of the CPUHP_AP_ONLINE_DYN state by 10 to make
room.

Signed-off-by: Xiaoming Wang <xiaoming.wang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20231219033411.816100-1-xiaoming.wang@intel.com
2023-12-20 16:25:15 +01:00
Zenghui Yu
15bece7bec cpu/hotplug: Remove unused CPU hotplug states
There are unused hotplug states which either have never been used or the
removal of the usage did not remove the state constant.

Drop them to reduce the size of the cpuhp_hp_states array.

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20231124121615.1604-1-yuzenghui@huawei.com
2023-12-06 16:31:03 +01:00
Vlastimil Babka
70da1d01ed cpu/hotplug: remove CPUHP_SLAB_PREPARE hooks
The CPUHP_SLAB_PREPARE hooks are only used by SLAB which is removed.
SLUB defines them as NULL, so we can remove those altogether.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2023-12-05 11:17:58 +01:00
Linus Torvalds
b0014556a2 - Do the push of pending hrtimers away from a CPU which is being
offlined earlier in the offlining process in order to prevent
   a deadlock
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Merge tag 'timers_urgent_for_v6.7_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fix from Borislav Petkov:

 - Do the push of pending hrtimers away from a CPU which is being
   offlined earlier in the offlining process in order to prevent a
   deadlock

* tag 'timers_urgent_for_v6.7_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  hrtimers: Push pending hrtimers away from outgoing CPU earlier
2023-11-19 13:35:07 -08:00
Thomas Gleixner
5c0930ccaa hrtimers: Push pending hrtimers away from outgoing CPU earlier
2b8272ff4a ("cpu/hotplug: Prevent self deadlock on CPU hot-unplug")
solved the straight forward CPU hotplug deadlock vs. the scheduler
bandwidth timer. Yu discovered a more involved variant where a task which
has a bandwidth timer started on the outgoing CPU holds a lock and then
gets throttled. If the lock required by one of the CPU hotplug callbacks
the hotplug operation deadlocks because the unthrottling timer event is not
handled on the dying CPU and can only be recovered once the control CPU
reaches the hotplug state which pulls the pending hrtimers from the dead
CPU.

Solve this by pushing the hrtimers away from the dying CPU in the dying
callbacks. Nothing can queue a hrtimer on the dying CPU at that point because
all other CPUs spin in stop_machine() with interrupts disabled and once the
operation is finished the CPU is marked offline.

Reported-by: Yu Liao <liaoyu15@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Liu Tie <liutie4@huawei.com>
Link: https://lore.kernel.org/r/87a5rphara.ffs@tglx
2023-11-11 18:06:42 +01:00
Linus Torvalds
56ec8e4cd8 arm64 updates for 6.7:
* Major refactoring of the CPU capability detection logic resulting in
   the removal of the cpus_have_const_cap() function and migrating the
   code to "alternative" branches where possible
 
 * Backtrace/kgdb: use IPIs and pseudo-NMI
 
 * Perf and PMU:
 
   - Add support for Ampere SoC PMUs
 
   - Multi-DTC improvements for larger CMN configurations with multiple
     Debug & Trace Controllers
 
   - Rework the Arm CoreSight PMU driver to allow separate registration of
     vendor backend modules
 
   - Fixes: add missing MODULE_DEVICE_TABLE to the amlogic perf
     driver; use device_get_match_data() in the xgene driver; fix NULL
     pointer dereference in the hisi driver caused by calling
     cpuhp_state_remove_instance(); use-after-free in the hisi driver
 
 * HWCAP updates:
 
   - FEAT_SVE_B16B16 (BFloat16)
 
   - FEAT_LRCPC3 (release consistency model)
 
   - FEAT_LSE128 (128-bit atomic instructions)
 
 * SVE: remove a couple of pseudo registers from the cpufeature code.
   There is logic in place already to detect mismatched SVE features
 
 * Miscellaneous:
 
   - Reduce the default swiotlb size (currently 64MB) if no ZONE_DMA
     bouncing is needed. The buffer is still required for small kmalloc()
     buffers
 
   - Fix module PLT counting with !RANDOMIZE_BASE
 
   - Restrict CPU_BIG_ENDIAN to LLVM IAS 15.x or newer move
     synchronisation code out of the set_ptes() loop
 
   - More compact cpufeature displaying enabled cores
 
   - Kselftest updates for the new CPU features
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "No major architecture features this time around, just some new HWCAP
  definitions, support for the Ampere SoC PMUs and a few fixes/cleanups.

  The bulk of the changes is reworking of the CPU capability checking
  code (cpus_have_cap() etc).

   - Major refactoring of the CPU capability detection logic resulting
     in the removal of the cpus_have_const_cap() function and migrating
     the code to "alternative" branches where possible

   - Backtrace/kgdb: use IPIs and pseudo-NMI

   - Perf and PMU:

      - Add support for Ampere SoC PMUs

      - Multi-DTC improvements for larger CMN configurations with
        multiple Debug & Trace Controllers

      - Rework the Arm CoreSight PMU driver to allow separate
        registration of vendor backend modules

      - Fixes: add missing MODULE_DEVICE_TABLE to the amlogic perf
        driver; use device_get_match_data() in the xgene driver; fix
        NULL pointer dereference in the hisi driver caused by calling
        cpuhp_state_remove_instance(); use-after-free in the hisi driver

   - HWCAP updates:

      - FEAT_SVE_B16B16 (BFloat16)

      - FEAT_LRCPC3 (release consistency model)

      - FEAT_LSE128 (128-bit atomic instructions)

   - SVE: remove a couple of pseudo registers from the cpufeature code.
     There is logic in place already to detect mismatched SVE features

   - Miscellaneous:

      - Reduce the default swiotlb size (currently 64MB) if no ZONE_DMA
        bouncing is needed. The buffer is still required for small
        kmalloc() buffers

      - Fix module PLT counting with !RANDOMIZE_BASE

      - Restrict CPU_BIG_ENDIAN to LLVM IAS 15.x or newer move
        synchronisation code out of the set_ptes() loop

      - More compact cpufeature displaying enabled cores

      - Kselftest updates for the new CPU features"

 * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (83 commits)
  arm64: Restrict CPU_BIG_ENDIAN to GNU as or LLVM IAS 15.x or newer
  arm64: module: Fix PLT counting when CONFIG_RANDOMIZE_BASE=n
  arm64, irqchip/gic-v3, ACPI: Move MADT GICC enabled check into a helper
  perf: hisi: Fix use-after-free when register pmu fails
  drivers/perf: hisi_pcie: Initialize event->cpu only on success
  drivers/perf: hisi_pcie: Check the type first in pmu::event_init()
  arm64: cpufeature: Change DBM to display enabled cores
  arm64: cpufeature: Display the set of cores with a feature
  perf/arm-cmn: Enable per-DTC counter allocation
  perf/arm-cmn: Rework DTC counters (again)
  perf/arm-cmn: Fix DTC domain detection
  drivers: perf: arm_pmuv3: Drop some unused arguments from armv8_pmu_init()
  drivers: perf: arm_pmuv3: Read PMMIR_EL1 unconditionally
  drivers/perf: hisi: use cpuhp_state_remove_instance_nocalls() for hisi_hns3_pmu uninit process
  clocksource/drivers/arm_arch_timer: limit XGene-1 workaround
  arm64: Remove system_uses_lse_atomics()
  arm64: Mark the 'addr' argument to set_ptes() and __set_pte_at() as unused
  drivers/perf: xgene: Use device_get_match_data()
  perf/amlogic: add missing MODULE_DEVICE_TABLE
  arm64/mm: Hoist synchronization out of set_ptes() loop
  ...
2023-11-01 09:34:55 -10:00
Thomas Gleixner
a940daa521 Merge branch 'linus' into smp/core
Pull in upstream to get the fixes so depending changes can be applied.
2023-10-17 21:40:46 +02:00
Mark Rutland
20f3b8eafe arm64/arm: xen: enlighten: Fix KPTI checks
When KPTI is in use, we cannot register a runstate region as XEN
requires that this is always a valid VA, which we cannot guarantee. Due
to this, xen_starting_cpu() must avoid registering each CPU's runstate
region, and xen_guest_init() must avoid setting up features that depend
upon it.

We tried to ensure that in commit:

  f88af7229f (" xen/arm: do not setup the runstate info page if kpti is enabled")

... where we added checks for xen_kernel_unmapped_at_usr(), which wraps
arm64_kernel_unmapped_at_el0() on arm64 and is always false on 32-bit
arm.

Unfortunately, as xen_guest_init() is an early_initcall, this happens
before secondary CPUs are booted and arm64 has finalized the
ARM64_UNMAP_KERNEL_AT_EL0 cpucap which backs
arm64_kernel_unmapped_at_el0(), and so this can subsequently be set as
secondary CPUs are onlined. On a big.LITTLE system where the boot CPU
does not require KPTI but some secondary CPUs do, this will result in
xen_guest_init() intializing features that depend on the runstate
region, and xen_starting_cpu() registering the runstate region on some
CPUs before KPTI is subsequent enabled, resulting the the problems the
aforementioned commit tried to avoid.

Handle this more robsutly by deferring the initialization of the
runstate region until secondary CPUs have been initialized and the
ARM64_UNMAP_KERNEL_AT_EL0 cpucap has been finalized. The per-cpu work is
moved into a new hotplug starting function which is registered later
when we're certain that KPTI will not be used.

Fixes: f88af7229f ("xen/arm: do not setup the runstate info page if kpti is enabled")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Bertrand Marquis <bertrand.marquis@arm.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2023-10-16 12:57:43 +01:00
Mark Rutland
166b76a073 clocksource/drivers/arm_arch_timer: Initialize evtstrm after finalizing cpucaps
We attempt to initialize each CPU's arch_timer event stream in
arch_timer_evtstrm_enable(), which we call from the
arch_timer_starting_cpu() cpu hotplug callback which is registered early
in boot. As this is registered before we initialize the system cpucaps,
the test for ARM64_HAS_ECV will always be false for CPUs present at boot
time, and will only be taken into account for CPUs onlined late
(including those which are hotplugged out and in again).

Due to this, CPUs present and boot time may not use the intended divider
and scale factor to generate the event stream, and may differ from other
CPUs.

Correct this by only initializing the event stream after cpucaps have been
finalized, registering a separate CPU hotplug callback for the event stream
configuration. Since the caps must be finalized by this point, use
cpus_have_final_cap() to verify this.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2023-10-16 12:57:39 +01:00
Olaf Hering
32e4fa37fa cpu/hotplug: Remove unused cpuhp_state CPUHP_AP_X86_VDSO_VMA_ONLINE
Commit b2e2ba578e ("x86/vdso: Initialize the CPU/node NR segment
descriptor earlier") removed the single user of this constant.

Remove it to reduce the size of cpuhp_hp_states[].

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230904121350.18055-1-olaf@aepfle.de
2023-09-15 21:13:13 +02:00
Darrick J. Wong
ef7d959339 xfs: remove CPU hotplug infrastructure
There are no users of the cpu hotplug hooks in xfs now, so remove it.
This reverts f1653c2e28 ("xfs: introduce CPU hotplug
infrastructure").

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-09-11 08:39:04 -07:00
Anna-Maria Behnsen
e0a99a839f Documentation: core-api/cpuhotplug: Fix state names
Dynamic allocated hotplug states in documentation and the comment above
cpuhp_state enum do not match the code. To not get confused by wrong
documentation, change to proper state names.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230515162038.62703-1-anna-maria@linutronix.de
2023-08-08 10:55:58 +02:00
Linus Torvalds
9244724fbf A large update for SMP management:
- Parallel CPU bringup
 
     The reason why people are interested in parallel bringup is to shorten
     the (kexec) reboot time of cloud servers to reduce the downtime of the
     VM tenants.
 
     The current fully serialized bringup does the following per AP:
 
       1) Prepare callbacks (allocate, intialize, create threads)
       2) Kick the AP alive (e.g. INIT/SIPI on x86)
       3) Wait for the AP to report alive state
       4) Let the AP continue through the atomic bringup
       5) Let the AP run the threaded bringup to full online state
 
     There are two significant delays:
 
       #3 The time for an AP to report alive state in start_secondary() on
          x86 has been measured in the range between 350us and 3.5ms
          depending on vendor and CPU type, BIOS microcode size etc.
 
       #4 The atomic bringup does the microcode update. This has been
          measured to take up to ~8ms on the primary threads depending on
          the microcode patch size to apply.
 
     On a two socket SKL server with 56 cores (112 threads) the boot CPU
     spends on current mainline about 800ms busy waiting for the APs to come
     up and apply microcode. That's more than 80% of the actual onlining
     procedure.
 
     This can be reduced significantly by splitting the bringup mechanism
     into two parts:
 
       1) Run the prepare callbacks and kick the AP alive for each AP which
       	 needs to be brought up.
 
 	 The APs wake up, do their firmware initialization and run the low
       	 level kernel startup code including microcode loading in parallel
       	 up to the first synchronization point. (#1 and #2 above)
 
       2) Run the rest of the bringup code strictly serialized per CPU
       	 (#3 - #5 above) as it's done today.
 
 	 Parallelizing that stage of the CPU bringup might be possible in
 	 theory, but it's questionable whether required surgery would be
 	 justified for a pretty small gain.
 
     If the system is large enough the first AP is already waiting at the
     first synchronization point when the boot CPU finished the wake-up of
     the last AP. That reduces the AP bringup time on that SKL from ~800ms
     to ~80ms, i.e. by a factor ~10x.
 
     The actual gain varies wildly depending on the system, CPU, microcode
     patch size and other factors. There are some opportunities to reduce
     the overhead further, but that needs some deep surgery in the x86 CPU
     bringup code.
 
     For now this is only enabled on x86, but the core functionality
     obviously works for all SMP capable architectures.
 
   - Enhancements for SMP function call tracing so it is possible to locate
     the scheduling and the actual execution points. That allows to measure
     IPI delivery time precisely.
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Merge tag 'smp-core-2023-06-26' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull SMP updates from Thomas Gleixner:
 "A large update for SMP management:

   - Parallel CPU bringup

     The reason why people are interested in parallel bringup is to
     shorten the (kexec) reboot time of cloud servers to reduce the
     downtime of the VM tenants.

     The current fully serialized bringup does the following per AP:

       1) Prepare callbacks (allocate, intialize, create threads)
       2) Kick the AP alive (e.g. INIT/SIPI on x86)
       3) Wait for the AP to report alive state
       4) Let the AP continue through the atomic bringup
       5) Let the AP run the threaded bringup to full online state

     There are two significant delays:

       #3 The time for an AP to report alive state in start_secondary()
          on x86 has been measured in the range between 350us and 3.5ms
          depending on vendor and CPU type, BIOS microcode size etc.

       #4 The atomic bringup does the microcode update. This has been
          measured to take up to ~8ms on the primary threads depending
          on the microcode patch size to apply.

     On a two socket SKL server with 56 cores (112 threads) the boot CPU
     spends on current mainline about 800ms busy waiting for the APs to
     come up and apply microcode. That's more than 80% of the actual
     onlining procedure.

     This can be reduced significantly by splitting the bringup
     mechanism into two parts:

       1) Run the prepare callbacks and kick the AP alive for each AP
          which needs to be brought up.

          The APs wake up, do their firmware initialization and run the
          low level kernel startup code including microcode loading in
          parallel up to the first synchronization point. (#1 and #2
          above)

       2) Run the rest of the bringup code strictly serialized per CPU
          (#3 - #5 above) as it's done today.

          Parallelizing that stage of the CPU bringup might be possible
          in theory, but it's questionable whether required surgery
          would be justified for a pretty small gain.

     If the system is large enough the first AP is already waiting at
     the first synchronization point when the boot CPU finished the
     wake-up of the last AP. That reduces the AP bringup time on that
     SKL from ~800ms to ~80ms, i.e. by a factor ~10x.

     The actual gain varies wildly depending on the system, CPU,
     microcode patch size and other factors. There are some
     opportunities to reduce the overhead further, but that needs some
     deep surgery in the x86 CPU bringup code.

     For now this is only enabled on x86, but the core functionality
     obviously works for all SMP capable architectures.

   - Enhancements for SMP function call tracing so it is possible to
     locate the scheduling and the actual execution points. That allows
     to measure IPI delivery time precisely"

* tag 'smp-core-2023-06-26' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
  trace,smp: Add tracepoints for scheduling remotelly called functions
  trace,smp: Add tracepoints around remotelly called functions
  MAINTAINERS: Add CPU HOTPLUG entry
  x86/smpboot: Fix the parallel bringup decision
  x86/realmode: Make stack lock work in trampoline_compat()
  x86/smp: Initialize cpu_primary_thread_mask late
  cpu/hotplug: Fix off by one in cpuhp_bringup_mask()
  x86/apic: Fix use of X{,2}APIC_ENABLE in asm with older binutils
  x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and enable it
  x86/smpboot: Support parallel startup of secondary CPUs
  x86/smpboot: Implement a bit spinlock to protect the realmode stack
  x86/apic: Save the APIC virtual base address
  cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE
  x86/apic: Provide cpu_primary_thread mask
  x86/smpboot: Enable split CPU startup
  cpu/hotplug: Provide a split up CPUHP_BRINGUP mechanism
  cpu/hotplug: Reset task stack state in _cpu_up()
  cpu/hotplug: Remove unused state functions
  riscv: Switch to hotplug core state synchronization
  parisc: Switch to hotplug core state synchronization
  ...
2023-06-26 13:59:56 -07:00
Michael Kelley
9636be85cc x86/hyperv: Fix hyperv_pcpu_input_arg handling when CPUs go online/offline
These commits

a494aef23d ("PCI: hv: Replace retarget_msi_interrupt_params with hyperv_pcpu_input_arg")
2c6ba42168 ("PCI: hv: Enable PCI pass-thru devices in Confidential VMs")

update the Hyper-V virtual PCI driver to use the hyperv_pcpu_input_arg
because that memory will be correctly marked as decrypted or encrypted
for all VM types (CoCo or normal). But problems ensue when CPUs in the
VM go online or offline after virtual PCI devices have been configured.

When a CPU is brought online, the hyperv_pcpu_input_arg for that CPU is
initialized by hv_cpu_init() running under state CPUHP_AP_ONLINE_DYN.
But this state occurs after state CPUHP_AP_IRQ_AFFINITY_ONLINE, which
may call the virtual PCI driver and fault trying to use the as yet
uninitialized hyperv_pcpu_input_arg. A similar problem occurs in a CoCo
VM if the MMIO read and write hypercalls are used from state
CPUHP_AP_IRQ_AFFINITY_ONLINE.

When a CPU is taken offline, IRQs may be reassigned in state
CPUHP_TEARDOWN_CPU. Again, the virtual PCI driver may fault trying to
use the hyperv_pcpu_input_arg that has already been freed by a
higher state.

Fix the onlining problem by adding state CPUHP_AP_HYPERV_ONLINE
immediately after CPUHP_AP_ONLINE_IDLE (similar to CPUHP_AP_KVM_ONLINE)
and before CPUHP_AP_IRQ_AFFINITY_ONLINE. Use this new state for
Hyper-V initialization so that hyperv_pcpu_input_arg is allocated
early enough.

Fix the offlining problem by not freeing hyperv_pcpu_input_arg when
a CPU goes offline. Retain the allocated memory, and reuse it if
the CPU comes back online later.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/r/1684862062-51576-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2023-06-17 23:09:47 +00:00
Thomas Gleixner
18415f33e2 cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE
There is often significant latency in the early stages of CPU bringup, and
time is wasted by waking each CPU (e.g. with SIPI/INIT/INIT on x86) and
then waiting for it to respond before moving on to the next.

Allow a platform to enable parallel setup which brings all to be onlined
CPUs up to the CPUHP_BP_KICK_AP state. While this state advancement on the
control CPU (BP) is single-threaded the important part is the last state
CPUHP_BP_KICK_AP which wakes the to be onlined CPUs up.

This allows the CPUs to run up to the first sychronization point
cpuhp_ap_sync_alive() where they wait for the control CPU to release them
one by one for the full onlining procedure.

This parallelism depends on the CPU hotplug core sync mechanism which
ensures that the parallel brought up CPUs wait for release before touching
any state which would make the CPU visible to anything outside the hotplug
control mechanism.

To handle the SMT constraints of X86 correctly the bringup happens in two
iterations when CONFIG_HOTPLUG_SMT is enabled. The control CPU brings up
the primary SMT threads of each core first, which can load the microcode
without the need to rendevouz with the thread siblings. Once that's
completed it brings up the secondary SMT threads.

Co-developed-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.240231377@linutronix.de
2023-05-15 13:45:02 +02:00
Thomas Gleixner
a631be92b9 cpu/hotplug: Provide a split up CPUHP_BRINGUP mechanism
The bring up logic of a to be onlined CPU consists of several parts, which
are considered to be a single hotplug state:

  1) Control CPU issues the wake-up

  2) To be onlined CPU starts up, does the minimal initialization,
     reports to be alive and waits for release into the complete bring-up.

  3) Control CPU waits for the alive report and releases the upcoming CPU
     for the complete bring-up.

Allow to split this into two states:

  1) Control CPU issues the wake-up

     After that the to be onlined CPU starts up, does the minimal
     initialization, reports to be alive and waits for release into the
     full bring-up. As this can run after the control CPU dropped the
     hotplug locks the code which is executed on the AP before it reports
     alive has to be carefully audited to not violate any of the hotplug
     constraints, especially not modifying any of the various cpumasks.

     This is really only meant to avoid waiting for the AP to react on the
     wake-up. Of course an architecture can move strict CPU related setup
     functionality, e.g. microcode loading, with care before the
     synchronization point to save further pointless waiting time.

  2) Control CPU waits for the alive report and releases the upcoming CPU
     for the complete bring-up.

This allows that the two states can be split up to run all to be onlined
CPUs up to state #1 on the control CPU and then at a later point run state
#2. This spares some of the latencies of the full serialized per CPU
bringup by avoiding the per CPU wakeup/wait serialization. The assumption
is that the first AP already waits when the last AP has been woken up. This
obvioulsy depends on the hardware latencies and depending on the timings
this might still not completely eliminate all wait scenarios.

This split is just a preparatory step for enabling the parallel bringup
later. The boot time bringup is still fully serialized. It has a separate
config switch so that architectures which want to support parallel bringup
can test the split of the CPUHP_BRINGUG step separately.

To enable this the architecture must support the CPU hotplug core sync
mechanism and has to be audited that there are no implicit hotplug state
dependencies which require a fully serialized bringup.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.080801387@linutronix.de
2023-05-15 13:45:01 +02:00
Thomas Gleixner
6f0621238b cpu/hotplug: Add CPU state tracking and synchronization
The CPU state tracking and synchronization mechanism in smpboot.c is
completely independent of the hotplug code and all logic around it is
implemented in architecture specific code.

Except for the state reporting of the AP there is absolutely nothing
architecture specific and the sychronization and decision functions can be
moved into the generic hotplug core code.

Provide an integrated variant and add the core synchronization and decision
points. This comes in two flavours:

  1) DEAD state synchronization

     Updated by the architecture code once the AP reaches the point where
     it is ready to be torn down by the control CPU, e.g. by removing power
     or clocks or tear down via the hypervisor.

     The control CPU waits for this state to be reached with a timeout. If
     the state is reached an architecture specific cleanup function is
     invoked.

  2) Full state synchronization

     This extends #1 with AP alive synchronization. This is new
     functionality, which allows to replace architecture specific wait
     mechanims, e.g. cpumasks, completely.

     It also prevents that an AP which is in a limbo state can be brought
     up again. This can happen when an AP failed to report dead state
     during a previous off-line operation.

The dead synchronization is what most architectures use. Only x86 makes a
bringup decision based on that state at the moment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.476305035@linutronix.de
2023-05-15 13:44:55 +02:00
Linus Torvalds
df45da57cb arm64 updates for 6.4
ACPI:
 	* Improve error reporting when failing to manage SDEI on AGDI device
 	  removal
 
 Assembly routines:
 	* Improve register constraints so that the compiler can make use of
 	  the zero register instead of moving an immediate #0 into a GPR
 
 	* Allow the compiler to allocate the registers used for CAS
 	  instructions
 
 CPU features and system registers:
 	* Cleanups to the way in which CPU features are identified from the
 	  ID register fields
 
 	* Extend system register definition generation to handle Enum types
 	  when defining shared register fields
 
 	* Generate definitions for new _EL2 registers and add new fields
 	  for ID_AA64PFR1_EL1
 
 	* Allow SVE to be disabled separately from SME on the kernel
 	  command-line
 
 Tracing:
 	* Support for "direct calls" in ftrace, which enables BPF tracing
 	  for arm64
 
 Kdump:
 	* Don't bother unmapping the crashkernel from the linear mapping,
 	  which then allows us to use huge (block) mappings and reduce
 	  TLB pressure when a crashkernel is loaded.
 
 Memory management:
 	* Try again to remove data cache invalidation from the coherent DMA
 	  allocation path
 
 	* Simplify the fixmap code by mapping at page granularity
 
 	* Allow the kfence pool to be allocated early, preventing the rest
 	  of the linear mapping from being forced to page granularity
 
 Perf and PMU:
 	* Move CPU PMU code out to drivers/perf/ where it can be reused
 	  by the 32-bit ARM architecture when running on ARMv8 CPUs
 
 	* Fix race between CPU PMU probing and pKVM host de-privilege
 
 	* Add support for Apple M2 CPU PMU
 
 	* Adjust the generic PERF_COUNT_HW_BRANCH_INSTRUCTIONS event
 	  dynamically, depending on what the CPU actually supports
 
 	* Minor fixes and cleanups to system PMU drivers
 
 Stack tracing:
 	* Use the XPACLRI instruction to strip PAC from pointers, rather
 	  than rolling our own function in C
 
 	* Remove redundant PAC removal for toolchains that handle this in
 	  their builtins
 
 	* Make backtracing more resilient in the face of instrumentation
 
 Miscellaneous:
 	* Fix single-step with KGDB
 
 	* Remove harmless warning when 'nokaslr' is passed on the kernel
 	  command-line
 
 	* Minor fixes and cleanups across the board
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
 "ACPI:

   - Improve error reporting when failing to manage SDEI on AGDI device
     removal

  Assembly routines:

   - Improve register constraints so that the compiler can make use of
     the zero register instead of moving an immediate #0 into a GPR

   - Allow the compiler to allocate the registers used for CAS
     instructions

  CPU features and system registers:

   - Cleanups to the way in which CPU features are identified from the
     ID register fields

   - Extend system register definition generation to handle Enum types
     when defining shared register fields

   - Generate definitions for new _EL2 registers and add new fields for
     ID_AA64PFR1_EL1

   - Allow SVE to be disabled separately from SME on the kernel
     command-line

  Tracing:

   - Support for "direct calls" in ftrace, which enables BPF tracing for
     arm64

  Kdump:

   - Don't bother unmapping the crashkernel from the linear mapping,
     which then allows us to use huge (block) mappings and reduce TLB
     pressure when a crashkernel is loaded.

  Memory management:

   - Try again to remove data cache invalidation from the coherent DMA
     allocation path

   - Simplify the fixmap code by mapping at page granularity

   - Allow the kfence pool to be allocated early, preventing the rest of
     the linear mapping from being forced to page granularity

  Perf and PMU:

   - Move CPU PMU code out to drivers/perf/ where it can be reused by
     the 32-bit ARM architecture when running on ARMv8 CPUs

   - Fix race between CPU PMU probing and pKVM host de-privilege

   - Add support for Apple M2 CPU PMU

   - Adjust the generic PERF_COUNT_HW_BRANCH_INSTRUCTIONS event
     dynamically, depending on what the CPU actually supports

   - Minor fixes and cleanups to system PMU drivers

  Stack tracing:

   - Use the XPACLRI instruction to strip PAC from pointers, rather than
     rolling our own function in C

   - Remove redundant PAC removal for toolchains that handle this in
     their builtins

   - Make backtracing more resilient in the face of instrumentation

  Miscellaneous:

   - Fix single-step with KGDB

   - Remove harmless warning when 'nokaslr' is passed on the kernel
     command-line

   - Minor fixes and cleanups across the board"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (72 commits)
  KVM: arm64: Ensure CPU PMU probes before pKVM host de-privilege
  arm64: kexec: include reboot.h
  arm64: delete dead code in this_cpu_set_vectors()
  arm64/cpufeature: Use helper macro to specify ID register for capabilites
  drivers/perf: hisi: add NULL check for name
  drivers/perf: hisi: Remove redundant initialized of pmu->name
  arm64/cpufeature: Consistently use symbolic constants for min_field_value
  arm64/cpufeature: Pull out helper for CPUID register definitions
  arm64/sysreg: Convert HFGITR_EL2 to automatic generation
  ACPI: AGDI: Improve error reporting for problems during .remove()
  arm64: kernel: Fix kernel warning when nokaslr is passed to commandline
  perf/arm-cmn: Fix port detection for CMN-700
  arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-step
  arm64: move PAC masks to <asm/pointer_auth.h>
  arm64: use XPACLRI to strip PAC
  arm64: avoid redundant PAC stripping in __builtin_return_address()
  arm64/sme: Fix some comments of ARM SME
  arm64/signal: Alloc tpidr2 sigframe after checking system_supports_tpidr2()
  arm64/signal: Use system_supports_tpidr2() to check TPIDR2
  arm64/idreg: Don't disable SME when disabling SVE
  ...
2023-04-25 12:39:01 -07:00
Kan Liang
16812c9655 iommu/vt-d: Fix an IOMMU perfmon warning when CPU hotplug
A warning can be triggered when hotplug CPU 0.
$ echo 0 > /sys/devices/system/cpu/cpu0/online

 ------------[ cut here ]------------
 Voluntary context switch within RCU read-side critical section!
 WARNING: CPU: 0 PID: 19 at kernel/rcu/tree_plugin.h:318
          rcu_note_context_switch+0x4f4/0x580
 RIP: 0010:rcu_note_context_switch+0x4f4/0x580
 Call Trace:
  <TASK>
  ? perf_event_update_userpage+0x104/0x150
  __schedule+0x8d/0x960
  ? perf_event_set_state.part.82+0x11/0x50
  schedule+0x44/0xb0
  schedule_timeout+0x226/0x310
  ? __perf_event_disable+0x64/0x1a0
  ? _raw_spin_unlock+0x14/0x30
  wait_for_completion+0x94/0x130
  __wait_rcu_gp+0x108/0x130
  synchronize_rcu+0x67/0x70
  ? invoke_rcu_core+0xb0/0xb0
  ? __bpf_trace_rcu_stall_warning+0x10/0x10
  perf_pmu_migrate_context+0x121/0x370
  iommu_pmu_cpu_offline+0x6a/0xa0
  ? iommu_pmu_del+0x1e0/0x1e0
  cpuhp_invoke_callback+0x129/0x510
  cpuhp_thread_fun+0x94/0x150
  smpboot_thread_fn+0x183/0x220
  ? sort_range+0x20/0x20
  kthread+0xe6/0x110
  ? kthread_complete_and_exit+0x20/0x20
  ret_from_fork+0x1f/0x30
  </TASK>
 ---[ end trace 0000000000000000 ]---

The synchronize_rcu() will be invoked in the perf_pmu_migrate_context(),
when migrating a PMU to a new CPU. However, the current for_each_iommu()
is within RCU read-side critical section.

Two methods were considered to fix the issue.
- Use the dmar_global_lock to replace the RCU read lock when going
  through the drhd list. But it triggers a lockdep warning.
- Use the cpuhp_setup_state_multi() to set up a dedicated state for each
  IOMMU PMU. The lock can be avoided.

The latter method is implemented in this patch. Since each IOMMU PMU has
a dedicated state, add cpuhp_node and cpu in struct iommu_pmu to track
the state. The state can be dynamically allocated now. Remove the
CPUHP_AP_PERF_X86_IOMMU_PERF_ONLINE.

Fixes: 46284c6ceb ("iommu/vt-d: Support cpumask for IOMMU perfmon")
Reported-by: Ammy Yi <ammy.yi@intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20230328182028.1366416-1-kan.liang@linux.intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20230329134721.469447-4-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-03-31 10:06:16 +02:00