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| author | Badari Pulavarty <pbadari@us.ibm.com> | 2005-11-07 00:59:27 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-07 07:53:37 -0800 |
| commit | bf8f972d3a1daf969cf44f64cc36d53bfd76441f (patch) | |
| tree | c3f0ac2f789c695d13858171144aa5f4ecdc84c1 | |
| parent | d8ba3b731086bcae5468f9ea509f39a921b3f9a6 (diff) | |
| download | linux-bf8f972d3a1daf969cf44f64cc36d53bfd76441f.tar.bz2 | |
[PATCH] SHM_NORESERVE flags for shmget()
Add SHM_NORESERVE functionality similar to MAP_NORESERVE for shared memory
segments.
This is mainly to avoid abuse of OVERCOMMIT_ALWAYS and this flag is ignored
for OVERCOMMIT_NEVER.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | include/linux/shm.h | 1 | ||||
| -rw-r--r-- | ipc/shm.c | 10 |
2 files changed, 10 insertions, 1 deletions
diff --git a/include/linux/shm.h b/include/linux/shm.h index 80113a1f60bc..a2c896ad0bef 100644 --- a/include/linux/shm.h +++ b/include/linux/shm.h @@ -92,6 +92,7 @@ struct shmid_kernel /* private to the kernel */ #define SHM_DEST 01000 /* segment will be destroyed on last detach */ #define SHM_LOCKED 02000 /* segment will not be swapped */ #define SHM_HUGETLB 04000 /* segment will use huge TLB pages */ +#define SHM_NORESERVE 010000 /* don't check for reservations */ #ifdef CONFIG_SYSVIPC long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr); diff --git a/ipc/shm.c b/ipc/shm.c index b58c651d31ae..587d836d80d9 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -212,8 +212,16 @@ static int newseg (key_t key, int shmflg, size_t size) file = hugetlb_zero_setup(size); shp->mlock_user = current->user; } else { + int acctflag = VM_ACCOUNT; + /* + * Do not allow no accounting for OVERCOMMIT_NEVER, even + * if it's asked for. + */ + if ((shmflg & SHM_NORESERVE) && + sysctl_overcommit_memory != OVERCOMMIT_NEVER) + acctflag = 0; sprintf (name, "SYSV%08x", key); - file = shmem_file_setup(name, size, VM_ACCOUNT); + file = shmem_file_setup(name, size, acctflag); } error = PTR_ERR(file); if (IS_ERR(file)) |