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authorBadari Pulavarty <pbadari@us.ibm.com>2005-11-07 00:59:27 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-07 07:53:37 -0800
commitbf8f972d3a1daf969cf44f64cc36d53bfd76441f (patch)
treec3f0ac2f789c695d13858171144aa5f4ecdc84c1
parent[PATCH] fuse: remove dead code from fuse_permission (diff)
downloadlinux-dev-bf8f972d3a1daf969cf44f64cc36d53bfd76441f.tar.xz
linux-dev-bf8f972d3a1daf969cf44f64cc36d53bfd76441f.zip
[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.h1
-rw-r--r--ipc/shm.c10
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))