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authorJens Axboe <axboe@kernel.dk>2018-05-09 15:26:55 -0600
committerJens Axboe <axboe@kernel.dk>2018-05-10 11:27:41 -0600
commit483b7bf2e40233657713279b6f98a9225ea0ff84 (patch)
tree7a44b55e40bf1ab35188980009eaa40661ff2616 /block/bfq-iosched.c
parenta327553965dede92587e6ccbe7df98dba36edcea (diff)
downloadlinux-0-day-483b7bf2e40233657713279b6f98a9225ea0ff84.tar.gz
bfq-iosched: update shallow depth to smallest one used
If our shallow depth is smaller than the wake batching of sbitmap, we can introduce hangs. Ensure that sbitmap knows how low we'll go. Acked-by: Paolo Valente <paolo.valente@linaro.org> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/bfq-iosched.c')
-rw-r--r--block/bfq-iosched.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 1029412..b622e73 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5081,10 +5081,13 @@ void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg)
/*
* See the comments on bfq_limit_depth for the purpose of
- * the depths set in the function.
+ * the depths set in the function. Return minimum shallow depth we'll use.
*/
-static void bfq_update_depths(struct bfq_data *bfqd, struct sbitmap_queue *bt)
+static unsigned int bfq_update_depths(struct bfq_data *bfqd,
+ struct sbitmap_queue *bt)
{
+ unsigned int i, j, min_shallow = UINT_MAX;
+
/*
* In-word depths if no bfq_queue is being weight-raised:
* leaving 25% of tags only for sync reads.
@@ -5115,14 +5118,22 @@ static void bfq_update_depths(struct bfq_data *bfqd, struct sbitmap_queue *bt)
bfqd->word_depths[1][0] = max(((1U << bt->sb.shift) * 3) >> 4, 1U);
/* no more than ~37% of tags for sync writes (~20% extra tags) */
bfqd->word_depths[1][1] = max(((1U << bt->sb.shift) * 6) >> 4, 1U);
+
+ for (i = 0; i < 2; i++)
+ for (j = 0; j < 2; j++)
+ min_shallow = min(min_shallow, bfqd->word_depths[i][j]);
+
+ return min_shallow;
}
static int bfq_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int index)
{
struct bfq_data *bfqd = hctx->queue->elevator->elevator_data;
struct blk_mq_tags *tags = hctx->sched_tags;
+ unsigned int min_shallow;
- bfq_update_depths(bfqd, &tags->bitmap_tags);
+ min_shallow = bfq_update_depths(bfqd, &tags->bitmap_tags);
+ sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, min_shallow);
return 0;
}