diff options
Diffstat (limited to 'sysdeps')
-rw-r--r-- | sysdeps/unix/sysv/linux/getsysstats.c | 68 |
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) |