From patchwork Mon Nov 14 22:22:13 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shaohua Li X-Patchwork-Id: 9428537 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4ACE160755 for ; Mon, 14 Nov 2016 22:22:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4CC7C28950 for ; Mon, 14 Nov 2016 22:22:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 41A8728AE7; Mon, 14 Nov 2016 22:22:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E7BB628AE3 for ; Mon, 14 Nov 2016 22:22:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965079AbcKNWW1 (ORCPT ); Mon, 14 Nov 2016 17:22:27 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:37683 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965030AbcKNWWZ (ORCPT ); Mon, 14 Nov 2016 17:22:25 -0500 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uAEMK1sN008239 for ; Mon, 14 Nov 2016 14:22:24 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=xzLkXO/7Bpz5KbYZmAt9wmcd3CLg//Q7e+WT6aOK1Hg=; b=IFCC2ToeeYiflSVQcgIHtzn0ZllhX4jLlATDHK8Vu4o1YYE98Txxwv6o7Hln8RQsPz0J HpOQR/clfQVy3ZFDu8kkCd8qOqU3+QZqWB6GDWxHHyQ2ML5OI6TPc6bkyyRXZqm90PCt fT5Y9CfBJuOqOGFjnC6s3xQaRZo68hkrFNM= Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 26qj6dhcn4-3 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Mon, 14 Nov 2016 14:22:24 -0800 Received: from mx-out.facebook.com (192.168.52.123) by PRN-CHUB04.TheFacebook.com (192.168.16.14) with Microsoft SMTP Server (TLS) id 14.3.294.0; Mon, 14 Nov 2016 14:22:24 -0800 Received: from facebook.com (2401:db00:21:603d:face:0:19:0) by mx-out.facebook.com (10.223.100.99) with ESMTP id d0eef5eaaab811e6822c24be05956610-870e8a50 for ; Mon, 14 Nov 2016 14:22:23 -0800 Received: by devbig638.prn2.facebook.com (Postfix, from userid 11222) id 7866D42E3F52; Mon, 14 Nov 2016 14:22:22 -0800 (PST) From: Shaohua Li To: , CC: , , , Subject: [PATCH V4 06/15] blk-throttle: make sure expire time isn't too big Date: Mon, 14 Nov 2016 14:22:13 -0800 Message-ID: <9ec659c894ba328a113c4f51596175fcdbbbe571.1479161136.git.shli@fb.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-11-14_13:, , signatures=0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP cgroup could be throttled to a limit but when all cgroups cross high limit, queue enters a higher state and so the group should be throttled to a higher limit. It's possible the cgroup is sleeping because of throttle and other cgroups don't dispatch IO any more. In this case, nobody can trigger current downgrade/upgrade logic. To fix this issue, we could either set up a timer to wakeup the cgroup if other cgroups are idle or make sure this cgroup doesn't sleep too long. Setting up a timer means we must change the timer very frequently. This patch chooses the latter. Making cgroup sleep time not too big wouldn't change cgroup bps/iops, but could make it wakeup more frequently, which isn't a big issue because throtl_slice * 8 is already quite big. Signed-off-by: Shaohua Li --- block/blk-throttle.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index d177252..eff3120 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -589,6 +589,10 @@ static void throtl_dequeue_tg(struct throtl_grp *tg) static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, unsigned long expires) { + unsigned long max_expire = jiffies + 8 * throtl_slice; + + if (time_after(expires, max_expire)) + expires = max_expire; mod_timer(&sq->pending_timer, expires); throtl_log(sq, "schedule timer. delay=%lu jiffies=%lu", expires - jiffies, jiffies);