From nobody Fri Apr 3 05:40:36 2026 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 5A7B3C6FA8B for ; Fri, 16 Sep 2022 11:23:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231311AbiIPLXt (ORCPT ); Fri, 16 Sep 2022 07:23:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229861AbiIPLXi (ORCPT ); Fri, 16 Sep 2022 07:23:38 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA7706B662; Fri, 16 Sep 2022 04:23:35 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4MTWqm4tFKzlCjt; Fri, 16 Sep 2022 19:21:56 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.127.227]) by APP2 (Coremail) with SMTP id Syh0CgDXKXOzXCRjdyK5Aw--.60594S7; Fri, 16 Sep 2022 19:23:34 +0800 (CST) From: Yu Kuai To: song@kernel.org, logang@deltatee.com, guoqing.jiang@linux.dev, pmenzel@molgen.mpg.de Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com Subject: [PATCH v3 3/5] md/raid10: prevent unnecessary calls to wake_up() in fast path Date: Fri, 16 Sep 2022 19:34:26 +0800 Message-Id: <20220916113428.774061-4-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220916113428.774061-1-yukuai1@huaweicloud.com> References: <20220916113428.774061-1-yukuai1@huaweicloud.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: Syh0CgDXKXOzXCRjdyK5Aw--.60594S7 X-Coremail-Antispam: 1UD129KBjvJXoW7ZFyDKw1xCFyxWryfWrykXwb_yoW8Wr1fpw sFgFyFvry5AF98tw4UJFWUuas8K34ktayIkFZ2k3s7ZFn8tF9akF1UJa4qkryjgrZ3uryU ZFn0krW3Aw4UtFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9l14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JrWl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCF04k20xvY0x0EwIxGrwCFx2 IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v2 6r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67 AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IY s7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr 1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjfUojjgUUUUU X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 Acked-by: Guoqing Jiang Reviewed-by: Logan Gunthorpe --- drivers/md/raid10.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index df435d693637..cf452c25e1e5 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -274,6 +274,12 @@ static void put_buf(struct r10bio *r10_bio) lower_barrier(conf); } =20 +static void wake_up_barrier(struct r10conf *conf) +{ + if (wq_has_sleeper(&conf->wait_barrier)) + wake_up(&conf->wait_barrier); +} + static void reschedule_retry(struct r10bio *r10_bio) { unsigned long flags; @@ -1015,7 +1021,7 @@ static void allow_barrier(struct r10conf *conf) { if ((atomic_dec_and_test(&conf->nr_pending)) || (conf->array_freeze_pending)) - wake_up(&conf->wait_barrier); + wake_up_barrier(conf); } =20 static void freeze_array(struct r10conf *conf, int extra) @@ -1891,7 +1897,7 @@ static bool raid10_make_request(struct mddev *mddev, = struct bio *bio) __make_request(mddev, bio, sectors); =20 /* In case raid10d snuck in to freeze_array */ - wake_up(&conf->wait_barrier); + wake_up_barrier(conf); return true; } =20 --=20 2.31.1