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 C7577ECAAD8 for ; Fri, 16 Sep 2022 18:36:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229938AbiIPSgf (ORCPT ); Fri, 16 Sep 2022 14:36:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230054AbiIPSgY (ORCPT ); Fri, 16 Sep 2022 14:36:24 -0400 Received: from ale.deltatee.com (ale.deltatee.com [204.191.154.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 824B5B6D74; Fri, 16 Sep 2022 11:36:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:In-Reply-To:From:References:Cc:To: MIME-Version:Date:Message-ID:content-disposition; bh=3p1fjf6+XUColGE3d9QDmsCLNG1nGpDvT5jgoM7KnRc=; b=POMuk+t4ekbySgv39Yia/iPs6n cy3NAyVNTyiDpXaWNCB1SlinerYYZaLPIBe+cNzi+eB9otWICfz3CZ3C9sE6DOAUFj44u6bMY7Jpr btRK1D2nOrKoX5CJ6n537MRj8/r0z/01ApkyNajDgrcrm6VwGFUk8QZDhlbFB2OLtReHL3xbvumwG 0Xz0DNi0bQVbe9k1aiWoOQGmK0Zuge2+Cgwk+YQLPBcd6o0chRUa54GwPZPOX2ZUHDSfApxtO6HTp 5NrrWbdW8qz5YPJbYkaEwOUl0n9xR93zWvO0T9tFVE9E/MS2cNhikPeHRl4eaSrYUd8OnsL6VrBuw 28QyGFzw==; Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1oZGCE-003JPP-GC; Fri, 16 Sep 2022 12:36:15 -0600 Message-ID: <641c8be0-69f6-0ab5-b174-411352ed5f94@deltatee.com> Date: Fri, 16 Sep 2022 12:36:14 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Content-Language: en-CA To: Yu Kuai , song@kernel.org, guoqing.jiang@linux.dev, pmenzel@molgen.mpg.de Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yi.zhang@huawei.com References: <20220916113428.774061-1-yukuai1@huaweicloud.com> <20220916113428.774061-4-yukuai1@huaweicloud.com> From: Logan Gunthorpe In-Reply-To: <20220916113428.774061-4-yukuai1@huaweicloud.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: yukuai1@huaweicloud.com, song@kernel.org, guoqing.jiang@linux.dev, pmenzel@molgen.mpg.de, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yi.zhang@huawei.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v3 3/5] md/raid10: prevent unnecessary calls to wake_up() in fast path X-SA-Exim-Version: 4.2.1 (built Sat, 13 Feb 2021 17:57:42 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022-09-16 05:34, Yu Kuai wrote: > From: Yu Kuai > > Currently, wake_up() is called unconditionally in fast path such as > raid10_make_request(), which will cause lock contention under high > concurrency: > > raid10_make_request > wake_up > __wake_up_common_lock > spin_lock_irqsave > > Improve performance by only call wake_up() if waitqueue is not empty > in allow_barrier() and raid10_make_request(). > > Signed-off-by: Yu Kuai Reviewed-by: Logan Gunthorpe