From patchwork Wed Jun 21 10:57:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 13286594 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 45746EB64D7 for ; Wed, 21 Jun 2023 02:59:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229885AbjFUC7E (ORCPT ); Tue, 20 Jun 2023 22:59:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbjFUC7D (ORCPT ); Tue, 20 Jun 2023 22:59:03 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98889170A; Tue, 20 Jun 2023 19:59:01 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Qm7W554TTz4f3tY4; Wed, 21 Jun 2023 10:58:57 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgAHvbBvZ5Jk68yyMA--.20696S4; Wed, 21 Jun 2023 10:58:57 +0800 (CST) From: Yu Kuai To: pmenzel@molgen.mpg.de, song@kernel.org Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com Subject: [PATCH v2] raid10: avoid spin_lock from fastpath from raid10_unplug() Date: Wed, 21 Jun 2023 18:57:28 +0800 Message-Id: <20230621105728.1268542-1-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 X-CM-TRANSID: gCh0CgAHvbBvZ5Jk68yyMA--.20696S4 X-Coremail-Antispam: 1UD129KBjvJXoW7uFWrWF1xAw1Dur45JFWkWFg_yoW8tw1fp3 y5KFWFvFWUAryjq3yDWa17Za4Yga1vq3yI9rZ8C3s8ZF15WFWYqw4YyFW8WrWUZrs3Ca43 ZF45KrW8Gr4jvaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvF14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2jI8I6cxK62vIxIIY0VWUZVW8XwA2ocxC64kIII 0Yj41l84x0c7CEw4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xv wVC0I7IYx2IY6xkF7I0E14v26r4UJVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4 x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG 64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r 1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAq YI8I648v4I1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4 xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43 MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I 0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWrJr0_WFyUJwCI42IY6I8E87Iv67AK xVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvj TRNgAwUUUUU X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org From: Yu Kuai Commit 0c0be98bbe67 ("md/raid10: prevent unnecessary calls to wake_up() in fast path") missed one place, for example, with: fio -direct=1 -rw=write/randwrite -iodepth=1 ... Plug and unplug are called for each io, then wake_up() from raid10_unplug() will cause lock contention as well. Avoid this contention by using wake_up_barrier() instead of wake_up(), where spin_lock is not held if waitqueue is empty. Fio test script: [global] name=random reads and writes ioengine=libaio direct=1 readwrite=randrw rwmixread=70 iodepth=64 buffered=0 filename=/dev/md0 size=1G runtime=30 time_based randrepeat=0 norandommap refill_buffers ramp_time=10 bs=4k numjobs=400 group_reporting=1 [job1] Test result with ramdisk raid10(By Ali): Before this patch With this patch READ IOPS=2033k IOPS=3642k WRITE IOPS=871k IOPS=1561K By the way, in this scenario, blk_plug_cb() will be allocated and freed for each io, this seems need to be optimized as well. Reported-and-tested-by: Ali Gholami Rudi Closes: https://lore.kernel.org/all/20231606122233@laper.mirepesht/ Signed-off-by: Yu Kuai --- Changes in v2: - update commit message; drivers/md/raid10.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index d0de8c9fb3cf..fbaaa5e05edc 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1118,7 +1118,7 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule) spin_lock_irq(&conf->device_lock); bio_list_merge(&conf->pending_bio_list, &plug->pending); spin_unlock_irq(&conf->device_lock); - wake_up(&conf->wait_barrier); + wake_up_barrier(conf); md_wakeup_thread(mddev->thread); kfree(plug); return; @@ -1127,7 +1127,7 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule) /* we aren't scheduling, so we can do the write-out directly. */ bio = bio_list_get(&plug->pending); raid1_prepare_flush_writes(mddev->bitmap); - wake_up(&conf->wait_barrier); + wake_up_barrier(conf); while (bio) { /* submit pending writes */ struct bio *next = bio->bi_next;