raid5: only wakeup necessary threads
If there are not enough stripes to handle, we'd better not always
queue all available work_structs. If one worker can only handle small
or even none stripes, it will impact request merge and create lock
contention.
With this patch, the number of work_struct running will depend on
pending stripes number. Note: some statistics info used in the patch
are accessed without locking protection. This should doesn't matter,
we just try best to avoid queue unnecessary work_struct.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 435b12d..2113ffa 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -213,6 +213,7 @@
enum reconstruct_states reconstruct_state;
spinlock_t stripe_lock;
int cpu;
+ struct r5worker_group *group;
/**
* struct stripe_operations
* @target - STRIPE_OP_COMPUTE_BLK target
@@ -369,12 +370,14 @@
struct r5worker {
struct work_struct work;
struct r5worker_group *group;
+ bool working;
};
struct r5worker_group {
struct list_head handle_list;
struct r5conf *conf;
struct r5worker *workers;
+ int stripes_cnt;
};
struct r5conf {