diff options
| -rw-r--r-- | block/cfq-iosched.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 94f53a1f467..64df3fa303b 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1165,6 +1165,8 @@ static void cfq_free_io_context(struct io_context *ioc) struct rb_node *n; int freed = 0; + ioc->ioc_data = NULL; + while ((n = rb_first(&ioc->cic_root)) != NULL) { __cic = rb_entry(n, struct cfq_io_context, rb_node); rb_erase(&__cic->rb_node, &ioc->cic_root); @@ -1228,10 +1230,11 @@ static void cfq_exit_io_context(struct io_context *ioc) struct cfq_io_context *__cic; struct rb_node *n; + ioc->ioc_data = NULL; + /* * put the reference this task is holding to the various queues */ - n = rb_first(&ioc->cic_root); while (n != NULL) { __cic = rb_entry(n, struct cfq_io_context, rb_node); @@ -1415,6 +1418,10 @@ static void cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic) { WARN_ON(!list_empty(&cic->queue_list)); + + if (ioc->ioc_data == cic) + ioc->ioc_data = NULL; + rb_erase(&cic->rb_node, &ioc->cic_root); kmem_cache_free(cfq_ioc_pool, cic); elv_ioc_count_dec(ioc_count); @@ -1430,6 +1437,13 @@ cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc) if (unlikely(!ioc)) return NULL; + /* + * we maintain a last-hit cache, to avoid browsing over the tree + */ + cic = ioc->ioc_data; + if (cic && cic->key == cfqd) + return cic; + restart: n = ioc->cic_root.rb_node; while (n) { @@ -1445,8 +1459,10 @@ restart: n = n->rb_left; else if (key > k) n = n->rb_right; - else + else { + ioc->ioc_data = cic; return cic; + } } return NULL; |