[PATCH 3/3] [PATCH] ipc/sem.c: cacheline align the ipc spinlock for semaphores
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From: Manfred Spraul on 28 Apr 2010 15:10 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(a)colorfullife.com> --- 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 8a4adbe..f2961af 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 */ -- 1.6.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |