mirror_ubuntu-kernels/arch/ia64/kernel
Linus Torvalds 005b2a9dc8 tif-task_work.arch-2020-12-14
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Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block

Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe:
 "This sits on top of of the core entry/exit and x86 entry branch from
  the tip tree, which contains the generic and x86 parts of this work.

  Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL.

  With that done, we can get rid of JOBCTL_TASK_WORK from task_work and
  signal.c, and also remove a deadlock work-around in io_uring around
  knowing that signal based task_work waking is invoked with the sighand
  wait queue head lock.

  The motivation for this work is to decouple signal notify based
  task_work, of which io_uring is a heavy user of, from sighand. The
  sighand lock becomes a huge contention point, particularly for
  threaded workloads where it's shared between threads. Even outside of
  threaded applications it's slower than it needs to be.

  Roman Gershman <romger@amazon.com> reported that his networked
  workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU
  after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all
  spent hammering on the sighand lock, showing 57% of the CPU time there
  [1].

  There are further cleanups possible on top of this. One example is
  TIF_PATCH_PENDING, where a patch already exists to use
  TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more
  consolidation, but the work stands on its own as well"

[1] https://github.com/axboe/liburing/issues/215

* tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits)
  io_uring: remove 'twa_signal_ok' deadlock work-around
  kernel: remove checking for TIF_NOTIFY_SIGNAL
  signal: kill JOBCTL_TASK_WORK
  io_uring: JOBCTL_TASK_WORK is no longer used by task_work
  task_work: remove legacy TWA_SIGNAL path
  sparc: add support for TIF_NOTIFY_SIGNAL
  riscv: add support for TIF_NOTIFY_SIGNAL
  nds32: add support for TIF_NOTIFY_SIGNAL
  ia64: add support for TIF_NOTIFY_SIGNAL
  h8300: add support for TIF_NOTIFY_SIGNAL
  c6x: add support for TIF_NOTIFY_SIGNAL
  alpha: add support for TIF_NOTIFY_SIGNAL
  xtensa: add support for TIF_NOTIFY_SIGNAL
  arm: add support for TIF_NOTIFY_SIGNAL
  microblaze: add support for TIF_NOTIFY_SIGNAL
  hexagon: add support for TIF_NOTIFY_SIGNAL
  csky: add support for TIF_NOTIFY_SIGNAL
  openrisc: add support for TIF_NOTIFY_SIGNAL
  sh: add support for TIF_NOTIFY_SIGNAL
  um: add support for TIF_NOTIFY_SIGNAL
  ...
2020-12-16 12:33:35 -08:00
..
syscalls mm/madvise: introduce process_madvise() syscall: an external memory hinting API 2020-10-18 09:27:10 -07:00
.gitignore
acpi-ext.c
acpi.c
asm-offsets.c
audit.c
brl_emu.c
crash_dump.c
crash.c
cyclone.c
dma-mapping.c dma-mapping: split <linux/dma-mapping.h> 2020-10-06 07:07:03 +02:00
efi_stub.S
efi.c
elfcore.c
entry.h
entry.S
err_inject.c
esi_stub.S
esi.c
fsys.S
fsyscall_gtod_data.h
ftrace.c
gate-data.S
gate.lds.S
gate.S
head.S
ia64_ksyms.c
iosapic.c
irq_ia64.c
irq_lsapic.c
irq.c
irq.h
ivt.S
kprobes.c
machine_kexec.c
Makefile ia64: fix build error with !COREDUMP 2020-10-18 09:27:09 -07:00
Makefile.gate
mca_asm.S
mca_drv_asm.S
mca_drv.c
mca_drv.h
mca.c
minstate.h
module.c
msi_ia64.c
nr-irqs.c
numa.c
pal.S
palinfo.c
patch.c
pci-dma.c
perfmon_default_smpl.c
perfmon_generic.h
perfmon_itanium.h
perfmon_mckinley.h
perfmon_montecito.h
process.c tif-task_work.arch-2020-12-14 2020-12-16 12:33:35 -08:00
ptrace.c [ia64] ptrace_[sg]etregs(): use access_elf_reg() instead of access_uarea() 2020-10-25 20:03:04 -04:00
relocate_kernel.S
sal.c
salinfo.c
setup.c
sigframe.h
signal.c
smp.c
smpboot.c
stacktrace.c
sys_ia64.c
time.c asm-generic: cross-architecture timer cleanup 2020-12-16 00:07:17 -08:00
topology.c
traps.c
unaligned.c
uncached.c
unwind_decoder.c
unwind_i.h
unwind.c
vmlinux.lds.S