summaryrefslogtreecommitdiff
path: root/sysdeps/unix/sysv/linux/getsysstats.c
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/unix/sysv/linux/getsysstats.c')
-rw-r--r--sysdeps/unix/sysv/linux/getsysstats.c68
1 files changed, 18 insertions, 50 deletions
diff --git a/sysdeps/unix/sysv/linux/getsysstats.c b/sysdeps/unix/sysv/linux/getsysstats.c
index e9c0dc4d83..1e3d88676d 100644
--- a/sysdeps/unix/sysv/linux/getsysstats.c
+++ b/sysdeps/unix/sysv/linux/getsysstats.c
@@ -28,61 +28,29 @@
#include <sys/sysinfo.h>
#include <sysdep.h>
-/* Compute the population count of the entire array. */
-static int
-__get_nprocs_count (const unsigned long int *array, size_t length)
-{
- int count = 0;
- for (size_t i = 0; i < length; ++i)
- if (__builtin_add_overflow (count, __builtin_popcountl (array[i]),
- &count))
- return INT_MAX;
- return count;
-}
-
-/* __get_nprocs with a large buffer. */
-static int
-__get_nprocs_large (void)
-{
- /* This code cannot use scratch_buffer because it is used during
- malloc initialization. */
- size_t pagesize = GLRO (dl_pagesize);
- unsigned long int *page = __mmap (0, pagesize, PROT_READ | PROT_WRITE,
- MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
- if (page == MAP_FAILED)
- return 2;
- int r = INTERNAL_SYSCALL_CALL (sched_getaffinity, 0, pagesize, page);
- int count;
- if (r > 0)
- count = __get_nprocs_count (page, pagesize / sizeof (unsigned long int));
- else if (r == -EINVAL)
- /* One page is still not enough to store the bits. A more-or-less
- arbitrary value. This assumes t hat such large systems never
- happen in practice. */
- count = GLRO (dl_pagesize) * CHAR_BIT;
- else
- count = 2;
- __munmap (page, GLRO (dl_pagesize));
- return count;
-}
-
int
__get_nprocs (void)
{
- /* Fast path for most systems. The kernel expects a buffer size
- that is a multiple of 8. */
- unsigned long int small_buffer[1024 / CHAR_BIT / sizeof (unsigned long int)];
- int r = INTERNAL_SYSCALL_CALL (sched_getaffinity, 0,
- sizeof (small_buffer), small_buffer);
+ enum
+ {
+ max_num_cpus = 32768,
+ cpu_bits_size = CPU_ALLOC_SIZE (32768)
+ };
+
+ /* This cannot use malloc because it is used on malloc initialization. */
+ __cpu_mask cpu_bits[cpu_bits_size / sizeof (__cpu_mask)];
+ int r = INTERNAL_SYSCALL_CALL (sched_getaffinity, 0, cpu_bits_size,
+ cpu_bits);
if (r > 0)
- return __get_nprocs_count (small_buffer, r / sizeof (unsigned long int));
+ return CPU_COUNT_S (cpu_bits_size, (cpu_set_t*) cpu_bits);
else if (r == -EINVAL)
- /* The kernel requests a larger buffer to store the data. */
- return __get_nprocs_large ();
- else
- /* Some other error. 2 is conservative (not a uniprocessor
- system, so atomics are needed). */
- return 2;
+ /* The input buffer is still not enough to store the number of cpus. This
+ 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;
}
libc_hidden_def (__get_nprocs)
weak_alias (__get_nprocs, get_nprocs)