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bh=dRYHBkwyvmPF18RLIZHw7p8MOtdtL6YSJr/G0xeFlzQ=; b=zEWCakrInMqn5oJdwFlWdVR1bTiPOQ9NIdk84vWVsSDO+0wpfjtdiubg0uTMq0kUHuGjZ9 3FfeUzf+ihx1FENrKOsveknejOg3V5AkrZ2aXqMXEobocdsi5s0uR4wxUQ5qRElhIdH55n /XlYNHaUnwhc0BletQhJN8TuOTgaiEL0tvr+GRe5nhlfSl1o3D4dTnUav7rMiPwekRsmt8 htmaY0ctogb52HwU4lUQkEsCUwwy8qByKF4tHyEbOsjbhL+bJpWW5OqBY21vpvF8o+XBGF NCbidDHHMkG4H4R2J0YU2HePbHVnJ6V8U3+ek12j4fMRxnTHnHJ8njrQb0pVfQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1746700426; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dRYHBkwyvmPF18RLIZHw7p8MOtdtL6YSJr/G0xeFlzQ=; b=tK937q8eUVpJlPgVKz1qpEZwlvk3zZga+JDV0zsDppn+zO3ztmji3yMTU/8td6Ri15bY// 3OszVO73BA35SyAg== From: "tip-bot2 for Sebastian Andrzej Siewior" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/futex] selftests/futex: Add futex_priv_hash Cc: Sebastian Andrzej Siewior , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20250416162921.513656-21-bigeasy@linutronix.de> References: <20250416162921.513656-21-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <174670042580.406.16015210835876114664.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the locking/futex branch of tip: Commit-ID: cda95faef7bcf26ba3f54c3cddce66d50116d146 Gitweb: https://git.kernel.org/tip/cda95faef7bcf26ba3f54c3cddce66d50= 116d146 Author: Sebastian Andrzej Siewior AuthorDate: Wed, 16 Apr 2025 18:29:20 +02:00 Committer: Peter Zijlstra CommitterDate: Sat, 03 May 2025 12:02:10 +02:00 selftests/futex: Add futex_priv_hash Test the basic functionality of the private hash: - Upon start, with no threads there is no private hash. - The first thread initializes the private hash. - More than four threads will increase the size of the private hash if the system has more than 16 CPUs online. - Once the user sets the size of private hash, auto scaling is disabled. - The user is only allowed to use numbers to the power of two. - The user may request the global or make the hash immutable. - Once the global hash has been set or the hash has been made immutable, further changes are not allowed. - Futex operations should work the whole time. It must be possible to hold a lock, such a PI initialised mutex, during the resize operation. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20250416162921.513656-21-bigeasy@linutronix= .de --- tools/testing/selftests/futex/functional/.gitignore | 5 +- tools/testing/selftests/futex/functional/Makefile | 1 +- tools/testing/selftests/futex/functional/futex_priv_hash.c | 315 +++++++- tools/testing/selftests/futex/functional/run.sh | 4 +- 4 files changed, 323 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/futex/functional/futex_priv_has= h.c diff --git a/tools/testing/selftests/futex/functional/.gitignore b/tools/te= sting/selftests/futex/functional/.gitignore index fbcbdb6..d37ae7c 100644 --- a/tools/testing/selftests/futex/functional/.gitignore +++ b/tools/testing/selftests/futex/functional/.gitignore @@ -1,11 +1,12 @@ # SPDX-License-Identifier: GPL-2.0-only +futex_priv_hash +futex_requeue futex_requeue_pi futex_requeue_pi_mismatched_ops futex_requeue_pi_signal_restart +futex_wait futex_wait_private_mapped_file futex_wait_timeout futex_wait_uninitialized_heap futex_wait_wouldblock -futex_wait -futex_requeue futex_waitv diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/test= ing/selftests/futex/functional/Makefile index f79f9ba..67d9e16 100644 --- a/tools/testing/selftests/futex/functional/Makefile +++ b/tools/testing/selftests/futex/functional/Makefile @@ -17,6 +17,7 @@ TEST_GEN_PROGS :=3D \ futex_wait_private_mapped_file \ futex_wait \ futex_requeue \ + futex_priv_hash \ futex_waitv =20 TEST_PROGS :=3D run.sh diff --git a/tools/testing/selftests/futex/functional/futex_priv_hash.c b/t= ools/testing/selftests/futex/functional/futex_priv_hash.c new file mode 100644 index 0000000..4d37650 --- /dev/null +++ b/tools/testing/selftests/futex/functional/futex_priv_hash.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2025 Sebastian Andrzej Siewior + */ + +#define _GNU_SOURCE + +#include +#include +#include +#include +#include + +#include +#include + +#include "logging.h" + +#define MAX_THREADS 64 + +static pthread_barrier_t barrier_main; +static pthread_mutex_t global_lock; +static pthread_t threads[MAX_THREADS]; +static int counter; + +#ifndef PR_FUTEX_HASH +#define PR_FUTEX_HASH 78 +# define PR_FUTEX_HASH_SET_SLOTS 1 +# define PR_FUTEX_HASH_GET_SLOTS 2 +# define PR_FUTEX_HASH_GET_IMMUTABLE 3 +#endif + +static int futex_hash_slots_set(unsigned int slots, int immutable) +{ + return prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS, slots, immutable); +} + +static int futex_hash_slots_get(void) +{ + return prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_GET_SLOTS); +} + +static int futex_hash_immutable_get(void) +{ + return prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_GET_IMMUTABLE); +} + +static void futex_hash_slots_set_verify(int slots) +{ + int ret; + + ret =3D futex_hash_slots_set(slots, 0); + if (ret !=3D 0) { + error("Failed to set slots to %d\n", errno, slots); + exit(1); + } + ret =3D futex_hash_slots_get(); + if (ret !=3D slots) { + error("Set %d slots but PR_FUTEX_HASH_GET_SLOTS returns: %d\n", + errno, slots, ret); + exit(1); + } +} + +static void futex_hash_slots_set_must_fail(int slots, int immutable) +{ + int ret; + + ret =3D futex_hash_slots_set(slots, immutable); + if (ret < 0) + return; + + fail("futex_hash_slots_set(%d, %d) expected to fail but succeeded.\n", + slots, immutable); + exit(1); +} + +static void *thread_return_fn(void *arg) +{ + return NULL; +} + +static void *thread_lock_fn(void *arg) +{ + pthread_barrier_wait(&barrier_main); + + pthread_mutex_lock(&global_lock); + counter++; + usleep(20); + pthread_mutex_unlock(&global_lock); + return NULL; +} + +static void create_max_threads(void *(*thread_fn)(void *)) +{ + int i, ret; + + for (i =3D 0; i < MAX_THREADS; i++) { + ret =3D pthread_create(&threads[i], NULL, thread_fn, NULL); + if (ret) { + error("pthread_create failed\n", errno); + exit(1); + } + } +} + +static void join_max_threads(void) +{ + int i, ret; + + for (i =3D 0; i < MAX_THREADS; i++) { + ret =3D pthread_join(threads[i], NULL); + if (ret) { + error("pthread_join failed for thread %d\n", errno, i); + exit(1); + } + } +} + +static void usage(char *prog) +{ + printf("Usage: %s\n", prog); + printf(" -c Use color\n"); + printf(" -g Test global hash instead intead local immutable \n"); + printf(" -h Display this help message\n"); + printf(" -v L Verbosity level: %d=3DQUIET %d=3DCRITICAL %d=3DINFO\n", + VQUIET, VCRITICAL, VINFO); +} + +int main(int argc, char *argv[]) +{ + int futex_slots1, futex_slotsn, online_cpus; + pthread_mutexattr_t mutex_attr_pi; + int use_global_hash =3D 0; + int ret; + char c; + + while ((c =3D getopt(argc, argv, "cghv:")) !=3D -1) { + switch (c) { + case 'c': + log_color(1); + break; + case 'g': + use_global_hash =3D 1; + break; + case 'h': + usage(basename(argv[0])); + exit(0); + break; + case 'v': + log_verbosity(atoi(optarg)); + break; + default: + usage(basename(argv[0])); + exit(1); + } + } + + + ret =3D pthread_mutexattr_init(&mutex_attr_pi); + ret |=3D pthread_mutexattr_setprotocol(&mutex_attr_pi, PTHREAD_PRIO_INHER= IT); + ret |=3D pthread_mutex_init(&global_lock, &mutex_attr_pi); + if (ret !=3D 0) { + fail("Failed to initialize pthread mutex.\n"); + return 1; + } + + /* First thread, expect to be 0, not yet initialized */ + ret =3D futex_hash_slots_get(); + if (ret !=3D 0) { + error("futex_hash_slots_get() failed: %d\n", errno, ret); + return 1; + } + ret =3D futex_hash_immutable_get(); + if (ret !=3D 0) { + error("futex_hash_immutable_get() failed: %d\n", errno, ret); + return 1; + } + + ret =3D pthread_create(&threads[0], NULL, thread_return_fn, NULL); + if (ret !=3D 0) { + error("pthread_create() failed: %d\n", errno, ret); + return 1; + } + ret =3D pthread_join(threads[0], NULL); + if (ret !=3D 0) { + error("pthread_join() failed: %d\n", errno, ret); + return 1; + } + /* First thread, has to initialiaze private hash */ + futex_slots1 =3D futex_hash_slots_get(); + if (futex_slots1 <=3D 0) { + fail("Expected > 0 hash buckets, got: %d\n", futex_slots1); + return 1; + } + + online_cpus =3D sysconf(_SC_NPROCESSORS_ONLN); + ret =3D pthread_barrier_init(&barrier_main, NULL, MAX_THREADS + 1); + if (ret !=3D 0) { + error("pthread_barrier_init failed.\n", errno); + return 1; + } + + ret =3D pthread_mutex_lock(&global_lock); + if (ret !=3D 0) { + error("pthread_mutex_lock failed.\n", errno); + return 1; + } + + counter =3D 0; + create_max_threads(thread_lock_fn); + pthread_barrier_wait(&barrier_main); + + /* + * The current default size of hash buckets is 16. The auto increase + * works only if more than 16 CPUs are available. + */ + if (online_cpus > 16) { + futex_slotsn =3D futex_hash_slots_get(); + if (futex_slotsn < 0 || futex_slots1 =3D=3D futex_slotsn) { + fail("Expected increase of hash buckets but got: %d -> %d\n", + futex_slots1, futex_slotsn); + info("Online CPUs: %d\n", online_cpus); + return 1; + } + } + ret =3D pthread_mutex_unlock(&global_lock); + + /* Once the user changes it, it has to be what is set */ + futex_hash_slots_set_verify(2); + futex_hash_slots_set_verify(4); + futex_hash_slots_set_verify(8); + futex_hash_slots_set_verify(32); + futex_hash_slots_set_verify(16); + + ret =3D futex_hash_slots_set(15, 0); + if (ret >=3D 0) { + fail("Expected to fail with 15 slots but succeeded: %d.\n", ret); + return 1; + } + futex_hash_slots_set_verify(2); + join_max_threads(); + if (counter !=3D MAX_THREADS) { + fail("Expected thread counter at %d but is %d\n", + MAX_THREADS, counter); + return 1; + } + counter =3D 0; + /* Once the user set something, auto reisze must be disabled */ + ret =3D pthread_barrier_init(&barrier_main, NULL, MAX_THREADS); + + create_max_threads(thread_lock_fn); + join_max_threads(); + + ret =3D futex_hash_slots_get(); + if (ret !=3D 2) { + printf("Expected 2 slots, no auto-resize, got %d\n", ret); + return 1; + } + + futex_hash_slots_set_must_fail(1 << 29, 0); + + /* + * Once the private hash has been made immutable or global hash has been = requested, + * then this requested can not be undone. + */ + if (use_global_hash) { + ret =3D futex_hash_slots_set(0, 0); + if (ret !=3D 0) { + printf("Can't request global hash: %m\n"); + return 1; + } + } else { + ret =3D futex_hash_slots_set(4, 1); + if (ret !=3D 0) { + printf("Immutable resize to 4 failed: %m\n"); + return 1; + } + } + + futex_hash_slots_set_must_fail(4, 0); + futex_hash_slots_set_must_fail(4, 1); + futex_hash_slots_set_must_fail(8, 0); + futex_hash_slots_set_must_fail(8, 1); + futex_hash_slots_set_must_fail(0, 1); + futex_hash_slots_set_must_fail(6, 1); + + ret =3D pthread_barrier_init(&barrier_main, NULL, MAX_THREADS); + if (ret !=3D 0) { + error("pthread_barrier_init failed.\n", errno); + return 1; + } + create_max_threads(thread_lock_fn); + join_max_threads(); + + ret =3D futex_hash_slots_get(); + if (use_global_hash) { + if (ret !=3D 0) { + error("Expected global hash, got %d\n", errno, ret); + return 1; + } + } else { + if (ret !=3D 4) { + error("Expected 4 slots, no auto-resize, got %d\n", errno, ret); + return 1; + } + } + + ret =3D futex_hash_immutable_get(); + if (ret !=3D 1) { + fail("Expected immutable private hash, got %d\n", ret); + return 1; + } + return 0; +} diff --git a/tools/testing/selftests/futex/functional/run.sh b/tools/testin= g/selftests/futex/functional/run.sh index 5ccd599..f0f0d2b 100755 --- a/tools/testing/selftests/futex/functional/run.sh +++ b/tools/testing/selftests/futex/functional/run.sh @@ -82,3 +82,7 @@ echo =20 echo ./futex_waitv $COLOR + +echo +./futex_priv_hash $COLOR +./futex_priv_hash -g $COLOR