Andrew Morton has suggested that three global quota locks can end up in the same cacheline which can result in bad cacheline ping-pong on SMP machines. Make locks cacheline aligned so that we avoid this problem (thanks goes to Andrew for the idea). Signed-off-by: Jan Kara <jack@xxxxxxx> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/quota/dquot.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 28aa146..e840fa2 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -129,9 +129,9 @@ * i_mutex on quota files is special (it's below dqio_mutex) */ -static DEFINE_SPINLOCK(dq_list_lock); -static DEFINE_SPINLOCK(dq_state_lock); -DEFINE_SPINLOCK(dq_data_lock); +static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock); +static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock); +__cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock); EXPORT_SYMBOL(dq_data_lock); static char *quotatypes[] = INITQFNAMES; -- 1.6.0.2 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
