diff options
| author | Manfred Spraul <manfred@colorfullife.com> | 2010-05-26 14:43:42 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-27 09:12:49 -0700 |
| commit | 31a7c4746e9925512afab30557dd445d677cc802 (patch) | |
| tree | 7f7b39331aa51b77c159b046d406b12aec24de11 | |
| parent | 0a2b9d4c79671b05956806ede5d054e03ae56280 (diff) | |
ipc/sem.c: cacheline align the ipc spinlock for semaphores
Cacheline align the spinlock for sysv semaphores. Without the patch, the
spinlock and sem_otime [written by every semop that modified the array]
and sem_base [read in the hot path of try_atomic_semop()] can be in the
same cacheline.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/sem.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/sem.h b/include/linux/sem.h index 8a4adbef8a0..f2961afa2f6 100644 --- a/include/linux/sem.h +++ b/include/linux/sem.h @@ -79,6 +79,7 @@ struct seminfo { #ifdef __KERNEL__ #include <asm/atomic.h> #include <linux/rcupdate.h> +#include <linux/cache.h> struct task_struct; @@ -91,7 +92,8 @@ struct sem { /* One sem_array data structure for each set of semaphores in the system. */ struct sem_array { - struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */ + struct kern_ipc_perm ____cacheline_aligned_in_smp + sem_perm; /* permissions .. see ipc.h */ time_t sem_otime; /* last semop time */ time_t sem_ctime; /* last change time */ struct sem *sem_base; /* ptr to first semaphore in array */ |