+ ipc-semc-cacheline-align-the-ipc-spinlock-for-semaphores.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     [PATCH] ipc/sem.c: cacheline align the ipc spinlock for semaphores
has been added to the -mm tree.  Its filename is
     ipc-semc-cacheline-align-the-ipc-spinlock-for-semaphores.patch

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------------------------------------------------------
Subject: [PATCH] ipc/sem.c: cacheline align the ipc spinlock for semaphores
From: Manfred Spraul <manfred@colorfullife.com>

This patch cacheline aligns 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>
---

 include/linux/sem.h |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff -puN include/linux/sem.h~ipc-semc-cacheline-align-the-ipc-spinlock-for-semaphores include/linux/sem.h
--- a/include/linux/sem.h~ipc-semc-cacheline-align-the-ipc-spinlock-for-semaphores
+++ a/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 */
_

Patches currently in -mm which might be from manfred@colorfullife.com are

ipc-semc-optimize-update_queue-for-bulk-wakeup-calls.patch
ipc-semc-optimize-update_queue-for-bulk-wakeup-calls-fix.patch
ipc-semc-move-wake_up_process-out-of-the-spinlock-section.patch
ipc-semc-move-wake_up_process-out-of-the-spinlock-section-fix.patch
ipc-semc-cacheline-align-the-ipc-spinlock-for-semaphores.patch
slab-leaks3-default-y.patch