From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Jianchao Wang To: axboe@kernel.dk, shli@fb.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] blk-throttle: only update last_low_overflow_time when LIMIT_MAX Date: Mon, 9 Apr 2018 14:16:02 +0800 Message-Id: <1523254562-2006-1-git-send-email-jianchao.w.wang@oracle.com> List-ID: Currently, last_low_overflow_time will be updated whenever bios are throttled and queued. This is true when LIMIT_MAX, but not for LIMIT_LOW. what last_low_overflow_time indicates is dispatching not submitting. When LIMIT_LOW, the dispatch bps/iops should never be above the low limit, we should not update last_low_overflow_time at the moment. Otherwise, it will be hard to upgrade limit_index when there is always bios to be submitted. Signed-off-by: Jianchao Wang --- block/blk-throttle.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 851aa16..b5ba845 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2214,7 +2214,8 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, /* if above limits, break to queue */ if (!tg_may_dispatch(tg, bio, NULL)) { - tg->last_low_overflow_time[rw] = jiffies; + if (td->limit_index == LIMIT_MAX) + tg->last_low_overflow_time[rw] = jiffies; if (throtl_can_upgrade(td, tg)) { throtl_upgrade_state(td); goto again; @@ -2258,7 +2259,8 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, tg->io_disp[rw], tg_iops_limit(tg, rw), sq->nr_queued[READ], sq->nr_queued[WRITE]); - tg->last_low_overflow_time[rw] = jiffies; + if (td->limit_index == LIMIT_MAX) + tg->last_low_overflow_time[rw] = jiffies; td->nr_queued[rw]++; throtl_add_bio_tg(bio, qn, tg); -- 2.7.4