From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1555BCD37B4 for ; Sun, 17 Sep 2023 20:07:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239569AbjIQUG6 (ORCPT ); Sun, 17 Sep 2023 16:06:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240435AbjIQUGe (ORCPT ); Sun, 17 Sep 2023 16:06:34 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61E4D97 for ; Sun, 17 Sep 2023 13:06:29 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E6B1C433C7; Sun, 17 Sep 2023 20:06:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694981189; bh=hgchqwMhRLXTa9gfy3mGsceHiNzAZzYxFMxE2Vcrp9A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KbBnMhfZ2PyrbvjixQ9mGCE+eivixauzF30dlwINIrEI34Ikj8m1KDpAKwAjY6Xup tX0RBZhlekYChXYnVisz3xettBqO4+1QFJXpiDEL3x8d1iJAKG2K+wyuJEqd7N913s C3CDZSbNwFpjisZkQJKar4wX2c4znbI+I9YO7MX4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, zhuxiaohui , Yu Kuai , Tejun Heo , Jens Axboe , Sasha Levin Subject: [PATCH 6.1 084/219] blk-throttle: consider carryover_ios/bytes in throtl_trim_slice() Date: Sun, 17 Sep 2023 21:13:31 +0200 Message-ID: <20230917191044.014858635@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230917191040.964416434@linuxfoundation.org> References: <20230917191040.964416434@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yu Kuai [ Upstream commit eead0056648cef49d7b15c07ae612fa217083165 ] Currently, 'carryover_ios/bytes' is not handled in throtl_trim_slice(), for consequence, 'carryover_ios/bytes' will be used to throttle bio multiple times, for example: 1) set iops limit to 100, and slice start is 0, slice end is 100ms; 2) current time is 0, and 10 ios are dispatched, those io won't be throttled and io_disp is 10; 3) still at current time 0, update iops limit to 1000, carryover_ios is updated to (0 - 10) = -10; 4) in this slice(0 - 100ms), io_allowed = 100 + (-10) = 90, which means only 90 ios can be dispatched without waiting; 5) assume that io is throttled in slice(0 - 100ms), and throtl_trim_slice() update silce to (100ms - 200ms). In this case, 'carryover_ios/bytes' is not cleared and still only 90 ios can be dispatched between 100ms - 200ms. Fix this problem by updating 'carryover_ios/bytes' in throtl_trim_slice(). Fixes: a880ae93e5b5 ("blk-throttle: fix io hung due to configuration updates") Reported-by: zhuxiaohui Link: https://lore.kernel.org/all/20230812072116.42321-1-zhuxiaohui.400@bytedance.com/ Signed-off-by: Yu Kuai Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20230816012708.1193747-5-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-throttle.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 931795da4d65d..1007f80278579 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -729,8 +729,9 @@ static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long jiffy_elapsed) /* Trim the used slices and adjust slice start accordingly */ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) { - unsigned long time_elapsed, io_trim; - u64 bytes_trim; + unsigned long time_elapsed; + long long bytes_trim; + int io_trim; BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); @@ -758,17 +759,21 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) return; bytes_trim = calculate_bytes_allowed(tg_bps_limit(tg, rw), - time_elapsed); - io_trim = calculate_io_allowed(tg_iops_limit(tg, rw), time_elapsed); - if (!bytes_trim && !io_trim) + time_elapsed) + + tg->carryover_bytes[rw]; + io_trim = calculate_io_allowed(tg_iops_limit(tg, rw), time_elapsed) + + tg->carryover_ios[rw]; + if (bytes_trim <= 0 && io_trim <= 0) return; - if (tg->bytes_disp[rw] >= bytes_trim) + tg->carryover_bytes[rw] = 0; + if ((long long)tg->bytes_disp[rw] >= bytes_trim) tg->bytes_disp[rw] -= bytes_trim; else tg->bytes_disp[rw] = 0; - if (tg->io_disp[rw] >= io_trim) + tg->carryover_ios[rw] = 0; + if ((int)tg->io_disp[rw] >= io_trim) tg->io_disp[rw] -= io_trim; else tg->io_disp[rw] = 0; @@ -776,7 +781,7 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) tg->slice_start[rw] += time_elapsed; throtl_log(&tg->service_queue, - "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", + "[%c] trim slice nr=%lu bytes=%lld io=%d start=%lu end=%lu jiffies=%lu", rw == READ ? 'R' : 'W', time_elapsed / tg->td->throtl_slice, bytes_trim, io_trim, tg->slice_start[rw], tg->slice_end[rw], jiffies); -- 2.40.1