mirror of
https://github.com/php/php-src.git
synced 2024-12-16 21:37:49 +08:00
e67565f54c
The new Linux 5.17 feature PR_SET_VMA_ANON_NAME can give names to anonymous private memory, see: https://lwn.net/Articles/867818/ It can be useful while debugging, to identify which portion of the process's memory belongs to which subsystem. This is how /proc/PID/maps can look like: 555ccd400000-555ccdc00000 r-xp 00000000 00:00 0 [anon:huge_code_pages] 7f6ec6600000-7f6ec6800000 rw-p 00000000 00:00 0 [anon:zend_alloc] The first mapping is the PHP executable copied to anonymous memory by option "opcache.huge_code_pages". The second one is a memory area for the "zend_alloc.h" memory allocator library. Unfortunately, it is not possible to give names to shared memory (MAP_SHARED), because Linux MAP_SHARED really maps /dev/zero (see shmem_zero_setup()), which makes madvise_vma_anon_name() believe this is a file mapping, failing the prctl() with EBADF.
45 lines
1.5 KiB
C
45 lines
1.5 KiB
C
/*
|
|
+----------------------------------------------------------------------+
|
|
| This source file is subject to version 2.00 of the Zend license, |
|
|
| that is bundled with this package in the file LICENSE, and is |
|
|
| available through the world-wide-web at the following url: |
|
|
| http://www.zend.com/license/2_00.txt. |
|
|
| If you did not receive a copy of the Zend license and are unable to |
|
|
| obtain it through the world-wide-web, please send a note to |
|
|
| license@zend.com so we can mail you a copy immediately. |
|
|
+----------------------------------------------------------------------+
|
|
| Authors: Max Kellermann <max.kellermann@ionos.com> |
|
|
+----------------------------------------------------------------------+
|
|
*/
|
|
|
|
#ifndef ZEND_MMAP_H
|
|
#define ZEND_MMAP_H
|
|
|
|
#include "zend_portability.h"
|
|
|
|
#ifdef __linux__
|
|
# include <sys/prctl.h>
|
|
|
|
/* fallback definitions if our libc is older than the kernel */
|
|
# ifndef PR_SET_VMA
|
|
# define PR_SET_VMA 0x53564d41
|
|
# endif
|
|
# ifndef PR_SET_VMA_ANON_NAME
|
|
# define PR_SET_VMA_ANON_NAME 0
|
|
# endif
|
|
#endif // __linux__
|
|
|
|
/**
|
|
* Set a name for the specified memory area.
|
|
*
|
|
* This feature requires Linux 5.17.
|
|
*/
|
|
static zend_always_inline void zend_mmap_set_name(const void *start, size_t len, const char *name)
|
|
{
|
|
#ifdef __linux__
|
|
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, (unsigned long)start, len, (unsigned long)name);
|
|
#endif
|
|
}
|
|
|
|
#endif /* ZEND_MMAP_H */
|