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quota: Make global quota locks cacheline aligned

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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@suse.cz>
CC: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Jan Kara
2009-01-26 15:32:46 +01:00
parent 884d179dff
commit c516610cfe
1 changed files with 3 additions and 3 deletions
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6
fs/quota/dquot.c
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@@ -129,9 +129,9 @@
* i_mutex on quota files is special (it's below dqio_mutex) * i_mutex on quota files is special (it's below dqio_mutex)
*/ */
static DEFINE_SPINLOCK(dq_list_lock); static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
static DEFINE_SPINLOCK(dq_state_lock); static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
DEFINE_SPINLOCK(dq_data_lock); __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
EXPORT_SYMBOL(dq_data_lock); EXPORT_SYMBOL(dq_data_lock);
static char *quotatypes[] = INITQFNAMES; static char *quotatypes[] = INITQFNAMES;