glibc/sysdeps/unix/sysv/linux/tst-affinity-pid.c

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Remove CPU set size checking from affinity functions [BZ #19143] With current kernel versions, the check does not reliably detect that unavailable CPUs are requested, for these reasons: (1) The kernel will silently ignore non-allowed CPUs, that is, CPUs which are physically present but disallowed for the thread based on system configuration. (2) Similarly, CPU bits which lack an online CPU (possible CPUs) are ignored. (3) The existing probing code assumes that the CPU mask size is a power of two and at least 1024. Neither has it to be a power of two, nor is the minimum possible value 1024, so the value determined is often too large. This means that the CPU set size check in glibc accepts CPU bits beyond the actual hard system limit. (4) Future kernel versions may not even have a fixed CPU set size. After the removal of the probing code, the kernel still returns EINVAL if no CPU in the requested set remains which can run the thread after the affinity change. Applications which care about the exact affinity mask will have to query it using sched_getaffinity after setting it. Due to the effects described above, this commit does not change this. The new tests supersede tst-getcpu, which is removed. This addresses bug 19164 because the new tests allocate CPU sets dynamically. * nptl/check-cpuset.h: Remove. * nptl/pthread_attr_setaffinity.c (__pthread_attr_setaffinity_new): Remove CPU set size check. * nptl/pthread_setattr_default_np.c (pthread_setattr_default_np): Likewise. * sysdeps/unix/sysv/linux/check-cpuset.h: Remove. * sysdeps/unix/sysv/linux/pthread_setaffinity.c (__kernel_cpumask_size, __determine_cpumask_size): Remove. (__pthread_setaffinity_new): Remove CPU set size check. * sysdeps/unix/sysv/linux/sched_setaffinity.c (__kernel_cpumask_size): Remove. (__sched_setaffinity_new): Remove CPU set size check. * manual/threads.texi (Default Thread Attributes): Remove stale reference to check_cpuset_attr, determine_cpumask_size in comment. * sysdeps/unix/sysv/linux/Makefile [$(subdir) == posix] (tests): Remove tst-getcpu. Add tst-affinity, tst-affinity-pid. [$(subdir) == nptl] (tests): Add tst-thread-affinity-pthread, tst-thread-affinity-pthread2, tst-thread-affinity-sched. * sysdeps/unix/sysv/linux/tst-affinity.c: New file. * sysdeps/unix/sysv/linux/tst-affinity-pid.c: New file. * sysdeps/unix/sysv/linux/tst-skeleton-affinity.c: New skeleton test file. * sysdeps/unix/sysv/linux/tst-thread-affinity-sched.c: New file. * sysdeps/unix/sysv/linux/tst-thread-affinity-pthread.c: New file. * sysdeps/unix/sysv/linux/tst-thread-affinity-pthread2.c: New file. * sysdeps/unix/sysv/linux/tst-thread-skeleton-affinity.c: New skeleton test file. * sysdeps/unix/sysv/linux/tst-getcpu.c: Remove. Superseded by tst-affinity-pid.
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/* Test for sched_getaffinity and sched_setaffinity, PID version.
Copyright (C) 2015-2023 Free Software Foundation, Inc.
Remove CPU set size checking from affinity functions [BZ #19143] With current kernel versions, the check does not reliably detect that unavailable CPUs are requested, for these reasons: (1) The kernel will silently ignore non-allowed CPUs, that is, CPUs which are physically present but disallowed for the thread based on system configuration. (2) Similarly, CPU bits which lack an online CPU (possible CPUs) are ignored. (3) The existing probing code assumes that the CPU mask size is a power of two and at least 1024. Neither has it to be a power of two, nor is the minimum possible value 1024, so the value determined is often too large. This means that the CPU set size check in glibc accepts CPU bits beyond the actual hard system limit. (4) Future kernel versions may not even have a fixed CPU set size. After the removal of the probing code, the kernel still returns EINVAL if no CPU in the requested set remains which can run the thread after the affinity change. Applications which care about the exact affinity mask will have to query it using sched_getaffinity after setting it. Due to the effects described above, this commit does not change this. The new tests supersede tst-getcpu, which is removed. This addresses bug 19164 because the new tests allocate CPU sets dynamically. * nptl/check-cpuset.h: Remove. * nptl/pthread_attr_setaffinity.c (__pthread_attr_setaffinity_new): Remove CPU set size check. * nptl/pthread_setattr_default_np.c (pthread_setattr_default_np): Likewise. * sysdeps/unix/sysv/linux/check-cpuset.h: Remove. * sysdeps/unix/sysv/linux/pthread_setaffinity.c (__kernel_cpumask_size, __determine_cpumask_size): Remove. (__pthread_setaffinity_new): Remove CPU set size check. * sysdeps/unix/sysv/linux/sched_setaffinity.c (__kernel_cpumask_size): Remove. (__sched_setaffinity_new): Remove CPU set size check. * manual/threads.texi (Default Thread Attributes): Remove stale reference to check_cpuset_attr, determine_cpumask_size in comment. * sysdeps/unix/sysv/linux/Makefile [$(subdir) == posix] (tests): Remove tst-getcpu. Add tst-affinity, tst-affinity-pid. [$(subdir) == nptl] (tests): Add tst-thread-affinity-pthread, tst-thread-affinity-pthread2, tst-thread-affinity-sched. * sysdeps/unix/sysv/linux/tst-affinity.c: New file. * sysdeps/unix/sysv/linux/tst-affinity-pid.c: New file. * sysdeps/unix/sysv/linux/tst-skeleton-affinity.c: New skeleton test file. * sysdeps/unix/sysv/linux/tst-thread-affinity-sched.c: New file. * sysdeps/unix/sysv/linux/tst-thread-affinity-pthread.c: New file. * sysdeps/unix/sysv/linux/tst-thread-affinity-pthread2.c: New file. * sysdeps/unix/sysv/linux/tst-thread-skeleton-affinity.c: New skeleton test file. * sysdeps/unix/sysv/linux/tst-getcpu.c: Remove. Superseded by tst-affinity-pid.
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This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 05:40:42 +00:00
<https://www.gnu.org/licenses/>. */
Remove CPU set size checking from affinity functions [BZ #19143] With current kernel versions, the check does not reliably detect that unavailable CPUs are requested, for these reasons: (1) The kernel will silently ignore non-allowed CPUs, that is, CPUs which are physically present but disallowed for the thread based on system configuration. (2) Similarly, CPU bits which lack an online CPU (possible CPUs) are ignored. (3) The existing probing code assumes that the CPU mask size is a power of two and at least 1024. Neither has it to be a power of two, nor is the minimum possible value 1024, so the value determined is often too large. This means that the CPU set size check in glibc accepts CPU bits beyond the actual hard system limit. (4) Future kernel versions may not even have a fixed CPU set size. After the removal of the probing code, the kernel still returns EINVAL if no CPU in the requested set remains which can run the thread after the affinity change. Applications which care about the exact affinity mask will have to query it using sched_getaffinity after setting it. Due to the effects described above, this commit does not change this. The new tests supersede tst-getcpu, which is removed. This addresses bug 19164 because the new tests allocate CPU sets dynamically. * nptl/check-cpuset.h: Remove. * nptl/pthread_attr_setaffinity.c (__pthread_attr_setaffinity_new): Remove CPU set size check. * nptl/pthread_setattr_default_np.c (pthread_setattr_default_np): Likewise. * sysdeps/unix/sysv/linux/check-cpuset.h: Remove. * sysdeps/unix/sysv/linux/pthread_setaffinity.c (__kernel_cpumask_size, __determine_cpumask_size): Remove. (__pthread_setaffinity_new): Remove CPU set size check. * sysdeps/unix/sysv/linux/sched_setaffinity.c (__kernel_cpumask_size): Remove. (__sched_setaffinity_new): Remove CPU set size check. * manual/threads.texi (Default Thread Attributes): Remove stale reference to check_cpuset_attr, determine_cpumask_size in comment. * sysdeps/unix/sysv/linux/Makefile [$(subdir) == posix] (tests): Remove tst-getcpu. Add tst-affinity, tst-affinity-pid. [$(subdir) == nptl] (tests): Add tst-thread-affinity-pthread, tst-thread-affinity-pthread2, tst-thread-affinity-sched. * sysdeps/unix/sysv/linux/tst-affinity.c: New file. * sysdeps/unix/sysv/linux/tst-affinity-pid.c: New file. * sysdeps/unix/sysv/linux/tst-skeleton-affinity.c: New skeleton test file. * sysdeps/unix/sysv/linux/tst-thread-affinity-sched.c: New file. * sysdeps/unix/sysv/linux/tst-thread-affinity-pthread.c: New file. * sysdeps/unix/sysv/linux/tst-thread-affinity-pthread2.c: New file. * sysdeps/unix/sysv/linux/tst-thread-skeleton-affinity.c: New skeleton test file. * sysdeps/unix/sysv/linux/tst-getcpu.c: Remove. Superseded by tst-affinity-pid.
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/* Function definitions for the benefit of tst-skeleton-affinity.c.
This variant forks a child process which then invokes
sched_getaffinity and sched_setaffinity on the parent PID. */
#include <errno.h>
#include <stdlib.h>
#include <sched.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
static int
write_fully (int fd, const void *buffer, size_t length)
{
const void *end = buffer + length;
while (buffer < end)
{
ssize_t bytes_written = TEMP_FAILURE_RETRY
(write (fd, buffer, end - buffer));
if (bytes_written < 0)
return -1;
if (bytes_written == 0)
{
errno = ENOSPC;
return -1;
}
buffer += bytes_written;
}
return 0;
}
static ssize_t
read_fully (int fd, void *buffer, size_t length)
{
const void *start = buffer;
const void *end = buffer + length;
while (buffer < end)
{
ssize_t bytes_read = TEMP_FAILURE_RETRY
(read (fd, buffer, end - buffer));
if (bytes_read < 0)
return -1;
if (bytes_read == 0)
return buffer - start;
buffer += bytes_read;
}
return length;
}
static int
process_child_response (int *pipes, pid_t child,
cpu_set_t *set, size_t size)
{
close (pipes[1]);
int value_from_child;
ssize_t bytes_read = read_fully
(pipes[0], &value_from_child, sizeof (value_from_child));
if (bytes_read < 0)
{
printf ("error: read from child: %m\n");
exit (1);
}
if (bytes_read != sizeof (value_from_child))
{
printf ("error: not enough bytes from child: %zd\n", bytes_read);
exit (1);
}
if (value_from_child == 0)
{
bytes_read = read_fully (pipes[0], set, size);
if (bytes_read < 0)
{
printf ("error: read: %m\n");
exit (1);
}
if (bytes_read != size)
{
printf ("error: not enough bytes from child: %zd\n", bytes_read);
exit (1);
}
}
int status;
if (waitpid (child, &status, 0) < 0)
{
printf ("error: waitpid: %m\n");
exit (1);
}
if (!(WIFEXITED (status) && WEXITSTATUS (status) == 0))
{
printf ("error: invalid status from : %m\n");
exit (1);
}
close (pipes[0]);
if (value_from_child != 0)
{
errno = value_from_child;
return -1;
}
return 0;
}
static int
getaffinity (size_t size, cpu_set_t *set)
{
int pipes[2];
if (pipe (pipes) < 0)
{
printf ("error: pipe: %m\n");
exit (1);
}
int ret = fork ();
if (ret < 0)
{
printf ("error: fork: %m\n");
exit (1);
}
if (ret == 0)
{
/* Child. */
int ret = sched_getaffinity (getppid (), size, set);
if (ret < 0)
ret = errno;
if (write_fully (pipes[1], &ret, sizeof (ret)) < 0
|| write_fully (pipes[1], set, size) < 0
|| (ret == 0 && write_fully (pipes[1], set, size) < 0))
{
printf ("error: write: %m\n");
_exit (1);
}
_exit (0);
}
/* Parent. */
return process_child_response (pipes, ret, set, size);
}
static int
setaffinity (size_t size, const cpu_set_t *set)
{
int pipes[2];
if (pipe (pipes) < 0)
{
printf ("error: pipe: %m\n");
exit (1);
}
int ret = fork ();
if (ret < 0)
{
printf ("error: fork: %m\n");
exit (1);
}
if (ret == 0)
{
/* Child. */
int ret = sched_setaffinity (getppid (), size, set);
if (write_fully (pipes[1], &ret, sizeof (ret)) < 0)
{
printf ("error: write: %m\n");
_exit (1);
}
_exit (0);
}
/* Parent. There is no affinity mask to read from the child, so the
size is 0. */
return process_child_response (pipes, ret, NULL, 0);
}
struct conf;
static bool early_test (struct conf *unused)
{
return true;
}
#include "tst-skeleton-affinity.c"