mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

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>
This commit is contained in:
Jens Axboe 2018-05-09 15:26:55 -06:00
parent a327553965
commit 483b7bf2e4
1 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
block/bfq-iosched.c
View File

@ -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;
}