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use sysinfo call on linux to determine physical memory (as _SC_PHYSPAGES may cause allocation) (issue #1100)

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daanx 2025-06-10 11:28:03 -07:00
parent 53f88dce76
commit c9541ac6e8
1 changed files with 16 additions and 8 deletions
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24
src/prim/unix/prim.c
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@ -32,6 +32,7 @@ terms of the MIT license. A copy of the license can be found in the file
#if defined(__linux__) #if defined(__linux__)
#include <features.h> #include <features.h>
#include <sys/prctl.h> // THP disable, PR_SET_VMA #include <sys/prctl.h> // THP disable, PR_SET_VMA
#include <sys/sysinfo.h> // sysinfo
#if defined(__GLIBC__) && !defined(PR_SET_VMA) #if defined(__GLIBC__) && !defined(PR_SET_VMA)
#include <linux/prctl.h> #include <linux/prctl.h>
#endif #endif
@ -156,18 +157,25 @@ static void unix_detect_physical_memory( size_t page_size, size_t* physical_memo
int mib[2] = { CTL_HW, HW_MEMSIZE }; int mib[2] = { CTL_HW, HW_MEMSIZE };
#endif #endif
const int err = sysctl(mib, 2, &physical_memory, &length, NULL, 0); const int err = sysctl(mib, 2, &physical_memory, &length, NULL, 0);
if (err == 0 && physical_memory > 0) { if (err==0 && physical_memory > 0) {
const int64_t phys_in_kib = physical_memory / MI_KiB; const int64_t phys_in_kib = physical_memory / MI_KiB;
if (phys_in_kib > 0 && (uint64_t)phys_in_kib <= SIZE_MAX) { if (phys_in_kib > 0 && (uint64_t)phys_in_kib <= SIZE_MAX) {
*physical_memory_in_kib = (size_t)phys_in_kib; *physical_memory_in_kib = (size_t)phys_in_kib;
} }
} }
#elif defined(_SC_PHYS_PAGES) // linux #elif defined(__linux__)
MI_UNUSED(page_size);
struct sysinfo info; _mi_memzero_var(info);
const int err = sysinfo(&info);
if (err==0 && info.totalram > 0 && info.totalram <= SIZE_MAX) {
*physical_memory_in_kib = (size_t)info.totalram / MI_KiB;
}
#elif defined(_SC_PHYS_PAGES) // do not use by default as it might cause allocation (by using `fopen` to parse /proc/meminfo) (issue #1100)
const long pphys = sysconf(_SC_PHYS_PAGES); const long pphys = sysconf(_SC_PHYS_PAGES);
const size_t psize_in_kib = page_size / MI_KiB; const size_t psize_in_kib = page_size / MI_KiB;
if (psize_in_kib > 0 && pphys > 0 && (unsigned long)pphys < SIZE_MAX && (size_t)pphys <= (SIZE_MAX/psize_in_kib)) { if (psize_in_kib > 0 && pphys > 0 && (unsigned long)pphys <= SIZE_MAX && (size_t)pphys <= (SIZE_MAX/psize_in_kib)) {
*physical_memory_in_kib = (size_t)pphys * psize_in_kib; *physical_memory_in_kib = (size_t)pphys * psize_in_kib;
} }
#endif #endif
} }
@ -472,7 +480,7 @@ int _mi_prim_decommit(void* start, size_t size, bool* needs_recommit) {
#else #else
// decommit: use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE) // decommit: use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE)
err = unix_madvise(start, size, MADV_DONTNEED); err = unix_madvise(start, size, MADV_DONTNEED);
#endif #endif
#if !MI_DEBUG && MI_SECURE<=2 #if !MI_DEBUG && MI_SECURE<=2
*needs_recommit = false; *needs_recommit = false;
#else #else
@ -493,8 +501,8 @@ int _mi_prim_reset(void* start, size_t size) {
int err = 0; int err = 0;
// on macOS can use MADV_FREE_REUSABLE (but we disable this for now as it seems slower) // on macOS can use MADV_FREE_REUSABLE (but we disable this for now as it seems slower)
#if 0 && defined(__APPLE__) && defined(MADV_FREE_REUSABLE) #if 0 && defined(__APPLE__) && defined(MADV_FREE_REUSABLE)
err = unix_madvise(start, size, MADV_FREE_REUSABLE); err = unix_madvise(start, size, MADV_FREE_REUSABLE);
if (err==0) return 0; if (err==0) return 0;
// fall through // fall through
#endif #endif