From patchwork Mon Oct 3 21:20:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shaohua Li X-Patchwork-Id: 9360947 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 C4F38608A6 for ; Mon, 3 Oct 2016 21:21:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B93A228842 for ; Mon, 3 Oct 2016 21:21:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id ADCF628A6E; Mon, 3 Oct 2016 21:21:13 +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 5AE9C28842 for ; Mon, 3 Oct 2016 21:21:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753520AbcJCVVM (ORCPT ); Mon, 3 Oct 2016 17:21:12 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:43059 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752444AbcJCVUg (ORCPT ); Mon, 3 Oct 2016 17:20:36 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.17/8.16.0.17) with SMTP id u93LGccw024557 for ; Mon, 3 Oct 2016 14:20:35 -0700 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=jqBJPFM2U2t3fJ+guc8Gt0v4sXVQ3Xi84ttyz0B7xh4=; b=J3oDDItE+m8DkKnOozkea8lzWpCUUToPOfrQRUbilzeKt3Ufcc95YNhbqVwnywT0DBRu xIJ+qhGUMq3oUByayp4cZLUukRHQ0kwBE42wItYOiE+CKLkE5gsPMmRIwKLkqTouKU+Z UJS1wTm1R9OseRbnk/L0+ZglTw7JszbsHHQ= Received: from mail.thefacebook.com ([199.201.64.23]) by m0001303.ppops.net with ESMTP id 25t8tbef3a-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Mon, 03 Oct 2016 14:20:35 -0700 Received: from mx-out.facebook.com (192.168.52.123) by PRN-CHUB13.TheFacebook.com (192.168.16.23) with Microsoft SMTP Server (TLS) id 14.3.294.0; Mon, 3 Oct 2016 14:20:34 -0700 Received: from facebook.com (2401:db00:21:603d:face:0:19:0) by mx-out.facebook.com (10.223.100.99) with ESMTP id 37a5b54c89af11e693a824be05956610-83ffaa50 for ; Mon, 03 Oct 2016 14:20:32 -0700 Received: by devbig638.prn2.facebook.com (Postfix, from userid 11222) id 5E85D42C11A0; Mon, 3 Oct 2016 14:20:31 -0700 (PDT) From: Shaohua Li To: , CC: , , , , Subject: [PATCH v3 06/11] blk-throttle: make sure expire time isn't too big Date: Mon, 3 Oct 2016 14:20:25 -0700 Message-ID: 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=2016-10-03_12:, , 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 | 3 +++ 1 file changed, 3 insertions(+) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 41b75a3..778de0b 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -589,6 +589,9 @@ 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);