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authorKemeng Shi <shikemeng@huaweicloud.com>2023-01-16 12:51:46 +0300
committerJens Axboe <axboe@kernel.dk>2023-01-30 06:03:49 +0300
commit0c3e09e8854bcd3f7c45de85007ed283342b3464 (patch)
tree7f1fe22e232ad6fec5adfa713a19fbc7a9203dd3 /block/bfq-iosched.c
parentb5fcf7871acb7f9a3a8ed341a68bd86aba3e254a (diff)
downloadlinux-0c3e09e8854bcd3f7c45de85007ed283342b3464.tar.xz
block, bfq: correctly raise inject limit in bfq_choose_bfqq_for_injection
Function bfq_choose_bfqq_for_injection may temporarily raise inject limit to one request if current inject_limit is 0 before search of the source queue for injection. However the search below will reset inject limit to bfqd->in_service_queue which is zero for raised inject limit. Then the temporarily raised inject limit never works as expected. Assigment limit to bfqd->in_service_queue in search is needed as limit maybe overwriten to min_t(unsigned int, 1, limit) for condition that a large in-flight request is on non-rotational devices in found queue. So we need to reset limit to bfqd->in_service_queue for normal case. Actually, we have already make sure bfqd->rq_in_driver is < limit before search, then -Limit is >= 1 as bfqd->rq_in_driver is >= 0. Then min_t(unsigned int, 1, limit) is always 1. So we can simply check bfqd->rq_in_driver with 1 instead of result of min_t(unsigned int, 1, limit) for larget request in non-rotational device case to avoid overwritting limit and the bug is gone. -For normal case, we have already check bfqd->rq_in_driver is < limit, so we can return found bfqq unconditionally to remove unncessary check. Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20230116095153.3810101-2-shikemeng@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/bfq-iosched.c')
-rw-r--r--block/bfq-iosched.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 815b884d6c5a..8836221a2673 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4730,12 +4730,10 @@ bfq_choose_bfqq_for_injection(struct bfq_data *bfqd)
*/
if (blk_queue_nonrot(bfqd->queue) &&
blk_rq_sectors(bfqq->next_rq) >=
- BFQQ_SECT_THR_NONROT)
- limit = min_t(unsigned int, 1, limit);
- else
- limit = in_serv_bfqq->inject_limit;
-
- if (bfqd->tot_rq_in_driver < limit) {
+ BFQQ_SECT_THR_NONROT &&
+ bfqd->tot_rq_in_driver >= 1)
+ continue;
+ else {
bfqd->rqs_injected = true;
return bfqq;
}