glibc/glibc-upstream-2.34-110.patch
Florian Weimer abcc04a5bf Sync with upstream branch release/2.34/master
Upstream commit: 224d8c1890b6c57c7e4e8ddbb792dd9552086704

- debug: Synchronize feature guards in fortified functions [BZ #28746]
- debug: Autogenerate _FORTIFY_SOURCE tests
- Enable _FORTIFY_SOURCE=3 for gcc 12 and above
- fortify: Fix spurious warning with realpath
- __glibc_unsafe_len: Fix comment
- debug: Add tests for _FORTIFY_SOURCE=3
- Make sure that the fortified function conditionals are constant
- Don't add access size hints to fortifiable functions
- nss: Protect against errno changes in function lookup (bug 28953)
- nss: Do not mention NSS test modules in <gnu/lib-names.h>
- io: Add fsync call in tst-stat
- hppa: Fix warnings from _dl_lookup_address
- nptl: Fix cleanups for stack grows up [BZ# 28899]
- hppa: Revise gettext trampoline design
- hppa: Fix swapcontext
- Fix elf/tst-audit2 on hppa
- localedef: Handle symbolic links when generating locale-archive
- NEWS: Add a bug fix entry for BZ #28896
- x86: Fix TEST_NAME to make it a string in tst-strncmp-rtm.c
- x86: Test wcscmp RTM in the wcsncmp overflow case [BZ #28896]
- x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896]
- string: Add a testcase for wcsncmp with SIZE_MAX [BZ #28755]
- linux: fix accuracy of get_nprocs and get_nprocs_conf [BZ #28865]
- Add reference to BZ#28860 on NEWS
- linux: Fix missing __convert_scm_timestamps (BZ #28860)
2022-03-15 08:56:55 +01:00

193 lines
5.2 KiB
Diff

commit 007e054d786be340699c634e3a3b30ab1fde1a7a
Author: Dmitry V. Levin <ldv@altlinux.org>
Date: Sat Feb 5 08:00:00 2022 +0000
linux: fix accuracy of get_nprocs and get_nprocs_conf [BZ #28865]
get_nprocs() and get_nprocs_conf() use various methods to obtain an
accurate number of processors. Re-introduce __get_nprocs_sched() as
a source of information, and fix the order in which these methods are
used to return the most accurate information. The primary source of
information used in both functions remains unchanged.
This also changes __get_nprocs_sched() error return value from 2 to 0,
but all its users are already prepared to handle that.
Old fallback order:
get_nprocs:
/sys/devices/system/cpu/online -> /proc/stat -> 2
get_nprocs_conf:
/sys/devices/system/cpu/ -> /proc/stat -> 2
New fallback order:
get_nprocs:
/sys/devices/system/cpu/online -> /proc/stat -> sched_getaffinity -> 2
get_nprocs_conf:
/sys/devices/system/cpu/ -> /proc/stat -> sched_getaffinity -> 2
Fixes: 342298278e ("linux: Revert the use of sched_getaffinity on get_nproc")
Closes: BZ #28865
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit e1d32b836410767270a3adf1f82b1a47e6e4cd51)
diff --git a/sysdeps/unix/sysv/linux/getsysstats.c b/sysdeps/unix/sysv/linux/getsysstats.c
index 7babd947aa902e77..327802b14c7326a3 100644
--- a/sysdeps/unix/sysv/linux/getsysstats.c
+++ b/sysdeps/unix/sysv/linux/getsysstats.c
@@ -51,9 +51,8 @@ __get_nprocs_sched (void)
is an arbitrary values assuming such systems should be rare and there
is no offline cpus. */
return max_num_cpus;
- /* Some other error. 2 is conservative (not a uniprocessor system, so
- atomics are needed). */
- return 2;
+ /* Some other error. */
+ return 0;
}
static char *
@@ -109,22 +108,19 @@ next_line (int fd, char *const buffer, char **cp, char **re,
}
static int
-get_nproc_stat (char *buffer, size_t buffer_size)
+get_nproc_stat (void)
{
+ enum { buffer_size = 1024 };
+ char buffer[buffer_size];
char *buffer_end = buffer + buffer_size;
char *cp = buffer_end;
char *re = buffer_end;
-
- /* Default to an SMP system in case we cannot obtain an accurate
- number. */
- int result = 2;
+ int result = 0;
const int flags = O_RDONLY | O_CLOEXEC;
int fd = __open_nocancel ("/proc/stat", flags);
if (fd != -1)
{
- result = 0;
-
char *l;
while ((l = next_line (fd, buffer, &cp, &re, buffer_end)) != NULL)
/* The current format of /proc/stat has all the cpu* entries
@@ -140,8 +136,8 @@ get_nproc_stat (char *buffer, size_t buffer_size)
return result;
}
-int
-__get_nprocs (void)
+static int
+get_nprocs_cpu_online (void)
{
enum { buffer_size = 1024 };
char buffer[buffer_size];
@@ -180,7 +176,8 @@ __get_nprocs (void)
}
}
- result += m - n + 1;
+ if (m >= n)
+ result += m - n + 1;
l = endp;
if (l < re && *l == ',')
@@ -189,28 +186,18 @@ __get_nprocs (void)
while (l < re && *l != '\n');
__close_nocancel_nostatus (fd);
-
- if (result > 0)
- return result;
}
- return get_nproc_stat (buffer, buffer_size);
+ return result;
}
-libc_hidden_def (__get_nprocs)
-weak_alias (__get_nprocs, get_nprocs)
-
-/* On some architectures it is possible to distinguish between configured
- and active cpus. */
-int
-__get_nprocs_conf (void)
+static int
+get_nprocs_cpu (void)
{
- /* Try to use the sysfs filesystem. It has actual information about
- online processors. */
+ int count = 0;
DIR *dir = __opendir ("/sys/devices/system/cpu");
if (dir != NULL)
{
- int count = 0;
struct dirent64 *d;
while ((d = __readdir64 (dir)) != NULL)
@@ -225,12 +212,57 @@ __get_nprocs_conf (void)
__closedir (dir);
- return count;
}
+ return count;
+}
- enum { buffer_size = 1024 };
- char buffer[buffer_size];
- return get_nproc_stat (buffer, buffer_size);
+static int
+get_nprocs_fallback (void)
+{
+ int result;
+
+ /* Try /proc/stat first. */
+ result = get_nproc_stat ();
+ if (result != 0)
+ return result;
+
+ /* Try sched_getaffinity. */
+ result = __get_nprocs_sched ();
+ if (result != 0)
+ return result;
+
+ /* We failed to obtain an accurate number. Be conservative: return
+ the smallest number meaning that this is not a uniprocessor system,
+ so atomics are needed. */
+ return 2;
+}
+
+int
+__get_nprocs (void)
+{
+ /* Try /sys/devices/system/cpu/online first. */
+ int result = get_nprocs_cpu_online ();
+ if (result != 0)
+ return result;
+
+ /* Fall back to /proc/stat and sched_getaffinity. */
+ return get_nprocs_fallback ();
+}
+libc_hidden_def (__get_nprocs)
+weak_alias (__get_nprocs, get_nprocs)
+
+/* On some architectures it is possible to distinguish between configured
+ and active cpus. */
+int
+__get_nprocs_conf (void)
+{
+ /* Try /sys/devices/system/cpu/ first. */
+ int result = get_nprocs_cpu ();
+ if (result != 0)
+ return result;
+
+ /* Fall back to /proc/stat and sched_getaffinity. */
+ return get_nprocs_fallback ();
}
libc_hidden_def (__get_nprocs_conf)
weak_alias (__get_nprocs_conf, get_nprocs_conf)