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authorTejun Heo <tj@kernel.org>2015-05-22 17:13:42 -0400
committerJens Axboe <axboe@fb.com>2015-06-02 08:33:35 -0600
commitd40f75a06dd675808eed385d490ba9468200b23f (patch)
treebe5fbf53681dbe330c4066cf3f1024f8d5fc18d1 /block
parentec8a6f2643923ee5b74d24fa8d134240379f436b (diff)
downloadblackbird-op-linux-d40f75a06dd675808eed385d490ba9468200b23f.tar.gz
blackbird-op-linux-d40f75a06dd675808eed385d490ba9468200b23f.zip
writeback, blkcg: restructure blk_{set|clear}_queue_congested()
blk_{set|clear}_queue_congested() take @q and set or clear, respectively, the congestion state of its bdi's root wb. Because bdi used to be able to handle congestion state only on the root wb, the callers of those functions tested whether the congestion is on the root blkcg and skipped if not. This is cumbersome and makes implementation of per cgroup bdi_writeback congestion state propagation difficult. This patch renames blk_{set|clear}_queue_congested() to blk_{set|clear}_congested(), and makes them take request_list instead of request_queue and test whether the specified request_list is the root one before updating bdi_writeback congestion state. This makes the tests in the callers unnecessary and simplifies them. As there are no external users of these functions, the definitions are moved from include/linux/blkdev.h to block/blk-core.c. This patch doesn't introduce any noticeable behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c62
1 files changed, 37 insertions, 25 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index c114a61590bc..f46a43ef1a94 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -63,6 +63,28 @@ struct kmem_cache *blk_requestq_cachep;
*/
static struct workqueue_struct *kblockd_workqueue;
+static void blk_clear_congested(struct request_list *rl, int sync)
+{
+ if (rl != &rl->q->root_rl)
+ return;
+#ifdef CONFIG_CGROUP_WRITEBACK
+ clear_wb_congested(rl->blkg->wb_congested, sync);
+#else
+ clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
+#endif
+}
+
+static void blk_set_congested(struct request_list *rl, int sync)
+{
+ if (rl != &rl->q->root_rl)
+ return;
+#ifdef CONFIG_CGROUP_WRITEBACK
+ set_wb_congested(rl->blkg->wb_congested, sync);
+#else
+ set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
+#endif
+}
+
void blk_queue_congestion_threshold(struct request_queue *q)
{
int nr;
@@ -842,13 +864,8 @@ static void __freed_request(struct request_list *rl, int sync)
{
struct request_queue *q = rl->q;
- /*
- * bdi isn't aware of blkcg yet. As all async IOs end up root
- * blkcg anyway, just use root blkcg state.
- */
- if (rl == &q->root_rl &&
- rl->count[sync] < queue_congestion_off_threshold(q))
- blk_clear_queue_congested(q, sync);
+ if (rl->count[sync] < queue_congestion_off_threshold(q))
+ blk_clear_congested(rl, sync);
if (rl->count[sync] + 1 <= q->nr_requests) {
if (waitqueue_active(&rl->wait[sync]))
@@ -881,25 +898,25 @@ static void freed_request(struct request_list *rl, unsigned int flags)
int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
{
struct request_list *rl;
+ int on_thresh, off_thresh;
spin_lock_irq(q->queue_lock);
q->nr_requests = nr;
blk_queue_congestion_threshold(q);
+ on_thresh = queue_congestion_on_threshold(q);
+ off_thresh = queue_congestion_off_threshold(q);
- /* congestion isn't cgroup aware and follows root blkcg for now */
- rl = &q->root_rl;
-
- if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
- blk_set_queue_congested(q, BLK_RW_SYNC);
- else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
- blk_clear_queue_congested(q, BLK_RW_SYNC);
+ blk_queue_for_each_rl(rl, q) {
+ if (rl->count[BLK_RW_SYNC] >= on_thresh)
+ blk_set_congested(rl, BLK_RW_SYNC);
+ else if (rl->count[BLK_RW_SYNC] < off_thresh)
+ blk_clear_congested(rl, BLK_RW_SYNC);
- if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
- blk_set_queue_congested(q, BLK_RW_ASYNC);
- else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
- blk_clear_queue_congested(q, BLK_RW_ASYNC);
+ if (rl->count[BLK_RW_ASYNC] >= on_thresh)
+ blk_set_congested(rl, BLK_RW_ASYNC);
+ else if (rl->count[BLK_RW_ASYNC] < off_thresh)
+ blk_clear_congested(rl, BLK_RW_ASYNC);
- blk_queue_for_each_rl(rl, q) {
if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
blk_set_rl_full(rl, BLK_RW_SYNC);
} else {
@@ -1009,12 +1026,7 @@ static struct request *__get_request(struct request_list *rl, int rw_flags,
}
}
}
- /*
- * bdi isn't aware of blkcg yet. As all async IOs end up
- * root blkcg anyway, just use root blkcg state.
- */
- if (rl == &q->root_rl)
- blk_set_queue_congested(q, is_sync);
+ blk_set_congested(rl, is_sync);
}
/*
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