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author | Joe Thornber <ejt@redhat.com> | 2015-02-20 12:58:03 +0000 |
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committer | Mike Snitzer <snitzer@redhat.com> | 2015-03-31 12:03:48 -0400 |
commit | 75da39bf256c27e25f395b191ead79f323772672 (patch) | |
tree | 8cd4fc26659bdef11314cab2aea3d8a61e290fc8 /drivers/md/dm-cache-policy-mq.c | |
parent | ac1f9ef211d5dd70110fa4bec6e8866b2c3a965e (diff) | |
download | op-kernel-dev-75da39bf256c27e25f395b191ead79f323772672.zip op-kernel-dev-75da39bf256c27e25f395b191ead79f323772672.tar.gz |
dm cache policy mq: keep track of the number of entries in a multiqueue
Small optimisation, now queue_empty() doesn't need to walk all levels of
the multiqueue.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-cache-policy-mq.c')
-rw-r--r-- | drivers/md/dm-cache-policy-mq.c | 25 |
1 files changed, 12 insertions, 13 deletions
diff --git a/drivers/md/dm-cache-policy-mq.c b/drivers/md/dm-cache-policy-mq.c index 13f547a..ca05d69 100644 --- a/drivers/md/dm-cache-policy-mq.c +++ b/drivers/md/dm-cache-policy-mq.c @@ -126,6 +126,7 @@ static void iot_examine_bio(struct io_tracker *t, struct bio *bio) #define NR_QUEUE_LEVELS 16u struct queue { + unsigned nr_elts; struct list_head qs[NR_QUEUE_LEVELS]; }; @@ -133,23 +134,14 @@ static void queue_init(struct queue *q) { unsigned i; + q->nr_elts = 0; for (i = 0; i < NR_QUEUE_LEVELS; i++) INIT_LIST_HEAD(q->qs + i); } -/* - * Checks to see if the queue is empty. - * FIXME: reduce cpu usage. - */ static bool queue_empty(struct queue *q) { - unsigned i; - - for (i = 0; i < NR_QUEUE_LEVELS; i++) - if (!list_empty(q->qs + i)) - return false; - - return true; + return q->nr_elts == 0; } /* @@ -157,11 +149,13 @@ static bool queue_empty(struct queue *q) */ static void queue_push(struct queue *q, unsigned level, struct list_head *elt) { + q->nr_elts++; list_add_tail(elt, q->qs + level); } -static void queue_remove(struct list_head *elt) +static void queue_remove(struct queue *q, struct list_head *elt) { + q->nr_elts--; list_del(elt); } @@ -197,6 +191,7 @@ static struct list_head *queue_pop(struct queue *q) struct list_head *r = queue_peek(q); if (r) { + q->nr_elts--; list_del(r); /* have we just emptied the bottom level? */ @@ -496,7 +491,11 @@ static void push(struct mq_policy *mq, struct entry *e) */ static void del(struct mq_policy *mq, struct entry *e) { - queue_remove(&e->list); + if (in_cache(mq, e)) + queue_remove(e->dirty ? &mq->cache_dirty : &mq->cache_clean, &e->list); + else + queue_remove(&mq->pre_cache, &e->list); + hash_remove(e); } |