From patchwork Tue Oct 18 11:12:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kemeng Shi X-Patchwork-Id: 13010272 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 78E81C4332F for ; Tue, 18 Oct 2022 11:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230018AbiJRLMw (ORCPT ); Tue, 18 Oct 2022 07:12:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229956AbiJRLMv (ORCPT ); Tue, 18 Oct 2022 07:12:51 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 021C4B6038; Tue, 18 Oct 2022 04:12:46 -0700 (PDT) Received: from kwepemi500016.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MsB150GBLzVhxN; Tue, 18 Oct 2022 19:08:09 +0800 (CST) Received: from huawei.com (10.174.178.129) by kwepemi500016.china.huawei.com (7.221.188.220) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 18 Oct 2022 19:12:44 +0800 From: Kemeng Shi To: , , CC: , , , Subject: [PATCH v2 2/3] block: Correct comment for scale_cookie_change Date: Tue, 18 Oct 2022 19:12:39 +0800 Message-ID: <20221018111240.22612-3-shikemeng@huawei.com> X-Mailer: git-send-email 2.14.1.windows.1 In-Reply-To: <20221018111240.22612-1-shikemeng@huawei.com> References: <20221018111240.22612-1-shikemeng@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.178.129] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemi500016.china.huawei.com (7.221.188.220) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Default queue depth of iolatency_grp is unlimited, so we scale down quickly(once by half) in scale_cookie_change. Remove the "subtract 1/16th" part which is not the truth and add the actual way we scale down. Signed-off-by: Kemeng Shi Reviewed-by: Josef Bacik --- block/blk-iolatency.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c index b24d7b788ba3..2c574f98c8d1 100644 --- a/block/blk-iolatency.c +++ b/block/blk-iolatency.c @@ -364,9 +364,11 @@ static void scale_cookie_change(struct blk_iolatency *blkiolat, } /* - * Change the queue depth of the iolatency_grp. We add/subtract 1/16th of the + * Change the queue depth of the iolatency_grp. We add 1/16th of the * queue depth at a time so we don't get wild swings and hopefully dial in to - * fairer distribution of the overall queue depth. + * fairer distribution of the overall queue depth. We halve the queue depth + * at a time so we can scale down queue depth quickly from default unlimited + * to target. */ static void scale_change(struct iolatency_grp *iolat, bool up) {