It has been decided to remove the support IMMUTABLE futex.
perf bench was one of the eary users for testing purposes. Now that the
API is removed before it could be used in an official release, remove
the bits from perf, too.
Remove Remove support for IMMUTABLE futex.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250710110011.384614-7-bigeasy@linutronix.de
Namhyung Kim reported:
I've updated the perf-tools-next to v6.16-rc1 and found a build error
like below on alpine linux 3.18.
In file included from bench/futex.c:6:
/usr/include/sys/prctl.h:88:8: error: redefinition of 'struct prctl_mm_map'
88 | struct prctl_mm_map {
| ^~~~~~~~~~~~
In file included from bench/futex.c:5:
/linux/tools/include/uapi/linux/prctl.h:134:8: note: originally defined here
134 | struct prctl_mm_map {
| ^~~~~~~~~~~~
make[4]: *** [/linux/tools/build/Makefile.build:86: /build/bench/futex.o] Error 1
git bisect says it's the first commit introduced the failure.
So both /usr/include/sys/prctl.h and /linux/tools/include/uapi/linux/prctl.h
provide struct prctl_mm_map but their include guard must be different.
/usr/include/sys/prctl.h provided by glibc contains the
prctl() declaration. It includes also linux/prctl.h.
The /usr/include/sys/prctl.h on alpine linux is different. This is
probably coming from musl. It contains the PR_* definition and the
prctl() declaration. So it clashes here because now the one struct is
available twice.
The man page for prctl(2) says:
| #include <linux/prctl.h> /* Definition of PR_* constants */
| #include <sys/prctl.h>
so musl doesn't follow this.
So don't include linux/prctl.h explicitely and add some new defines
needed if they aren't available.
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Namhyung Kim <namhyung@kernel.org>
Closes: https://lore.kernel.org/r/20250611092542.F4ooE2FL@linutronix.de
Link: https://www.openwall.com/lists/musl/2025/06/12/11
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The prctl.h ABI header was slightly updated during the development of
the interface. In particular the "immutable" parameter became a bit in
the option argument.
Synchronize prctl.h ABI header again and make use of the definition in
the testsuite and "perf bench futex".
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20250517151455.1065363-5-bigeasy@linutronix.de
Add the -b/ --buckets argument to specify the number of hash buckets for
the private futex hash. This is directly passed to
prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS, buckets, immutable)
and must return without an error if specified. The `immutable' is 0 by
default and can be set to 1 via the -I/ --immutable argument.
The size of the private hash is verified with PR_FUTEX_HASH_GET_SLOTS.
If PR_FUTEX_HASH_GET_SLOTS failed then it is assumed that an older
kernel was used without the support and that the global hash is used.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250416162921.513656-20-bigeasy@linutronix.de
