- Switch the reference counting to a RCU based per-CPU reference to
address a performance bottleneck vs. the single instance rcuref
variant.
- Make the futex selftest build on 32-bit architectures which only
support 64-bit time_t, e.g. RISCV-32.
- Cleanups and improvements in selftests and futex bench
-----BEGIN PGP SIGNATURE-----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=WqFq
-----END PGP SIGNATURE-----
Merge tag 'locking-futex-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull futex updates from Thomas Gleixner:
- Switch the reference counting to a RCU based per-CPU reference to
address a performance bottleneck vs the single instance rcuref
variant
- Make the futex selftest build on 32-bit architectures which only
support 64-bit time_t, e.g. RISCV-32
- Cleanups and improvements in selftests and futex bench
* tag 'locking-futex-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests/futex: Fix spelling mistake "Succeffuly" -> "Successfully"
selftests/futex: Define SYS_futex on 32-bit architectures with 64-bit time_t
perf bench futex: Remove support for IMMUTABLE
selftests/futex: Remove support for IMMUTABLE
futex: Remove support for IMMUTABLE
futex: Make futex_private_hash_get() static
futex: Use RCU-based per-CPU reference counting instead of rcuref_t
selftests/futex: Adapt the private hash test to RCU related changes
The kernel does not provide sys_futex() on 32-bit architectures that do not
support 32-bit time representations, such as riscv32.
As a result, glibc cannot define SYS_futex, causing compilation failures in
tests that rely on this syscall. Define SYS_futex as SYS_futex_time64 in
such cases to ensure successful compilation and compatibility.
Signed-off-by: Cynthia Huang <cynthia@andestech.com>
Signed-off-by: Ben Zong-You Xie <ben717@andestech.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/all/20250710103630.3156130-1-ben717@andestech.com
sys_futex_wait() expects a struct __kernel_timespec pointer for the
timeout, but the provided struct timespec pointer is of type struct
old_timespec32 when compiled for 32-bit architectures, unless they use
64-bit timespecs already.
Make it work for all variants by converting the provided timespec value
into a local struct __kernel_timespec and provide a pointer to it to the
syscall. This is a pointless operation for 64-bit, but this is not a
hotpath operation, so keep it simple.
This fix is based off [1]
Originally-by: Wei Gao <wegao@suse.com>
Signed-off-by: Terry Tritton <terry.tritton@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250704190234.14230-1-terry.tritton@linaro.org
Link: https://lore.kernel.org/all/20231203235117.29677-1-wegao@suse.com/ [1]
Test the basic functionality for the NUMA and MPOL flags:
- FUTEX2_NUMA should take the NUMA node which is after the uaddr
and use it.
- Only update the node if FUTEX_NO_NODE was set by the user
- FUTEX2_MPOL should use the memory based on the policy. I attempted to
set the node with mbind() and then use this with MPOL but this fails
and futex falls back to the default node for the current CPU.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250416162921.513656-22-bigeasy@linutronix.de
Create a new file to test the waitv mechanism. Test both private and
shared futexes. Wake the last futex in the array, and check if the
return value from futex_waitv() is the right index.
Signed-off-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210923171111.300673-20-andrealmeid@collabora.com
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert test to use ksft TAP13 framework to print user friendly
test output which is consistent across kselftest suite.
Acked-by: Darren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Most of the tests under selftests follow a pattern for their results,
which can then be parsed easily by other external tools easily. Though
futex tests do print the test results very well, it doesn't really
follow the general selftests pattern.
This patch makes necessary changes to fix that.
Output before this patch:
futex_requeue_pi: Test requeue functionality
Arguments: broadcast=0 locked=0 owner=0 timeout=0ns
Result: PASS
Output after this patch:
futex_requeue_pi: Test requeue functionality
Arguments: broadcast=0 locked=0 owner=0 timeout=0ns
selftests: futex-requeue-pi [PASS]
Signed-off-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Add kselftest.h to logging.h and increment the pass and fail counters as
part of the print_result routine which is called by all futex tests.
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: linux-api@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
The futextest testsuite [1] provides functional, stress, and
performance tests for the various futex op codes. Those tests will be of
more use to futex developers if they are included with the kernel
source.
Copy the core infrastructure and the functional tests into selftests,
but adapt them for inclusion in the kernel:
- Update the Makefile to include the run_tests target, remove reference
to the performance and stress tests from the contributed sources.
- Replace my dead IBM email address with my current Intel email address.
- Remove the warrantee and write-to paragraphs from the license blurbs.
- Remove the NAME section as the filename is easily determined. ;-)
- Make the whitespace usage consistent in a couple of places.
- Cleanup various CodingStyle violations.
A future effort will explore moving the performance and stress tests
into the kernel.
1. http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: linux-api@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
