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authorTomasz Majchrzak <tomasz.majchrzak@intel.com>2016-06-24 15:20:16 +0300
committerShaohua Li <shli@fb.com>2016-07-20 01:20:28 +0300
commit0e5313e2d4ef93bdf6c22dad647d28635b86472a (patch)
treeb470429e5ae7c501d920a12550bf76592bac04d0 /drivers/md/raid10.h
parent573275b58ee9e1d2ec89f9608060f58931c3cde3 (diff)
downloadlinux-0e5313e2d4ef93bdf6c22dad647d28635b86472a.tar.xz
raid10: improve random reads performance
RAID10 random read performance is lower than expected due to excessive spinlock utilisation which is required mostly for rebuild/resync. Simplify allow_barrier as it's in IO path and encounters a lot of unnecessary congestion. As lower_barrier just takes a lock in order to decrement a counter, convert counter (nr_pending) into atomic variable and remove the spin lock. There is also a congestion for wake_up (it uses lock internally) so call it only when it's really needed. As wake_up is not called constantly anymore, ensure process waiting to raise a barrier is notified when there are no more waiting IOs. Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid10.h')
-rw-r--r--drivers/md/raid10.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 6fc2c75759bf..18ec1f7a98bf 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -64,10 +64,11 @@ struct r10conf {
int pending_count;
spinlock_t resync_lock;
- int nr_pending;
+ atomic_t nr_pending;
int nr_waiting;
int nr_queued;
int barrier;
+ int array_freeze_pending;
sector_t next_resync;
int fullsync; /* set to 1 if a full sync is needed,
* (fresh device added).