From patchwork Wed Feb 10 05:07:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Coly Li X-Patchwork-Id: 380862 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5902BC433DB for ; Wed, 10 Feb 2021 05:09:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A2F664E45 for ; Wed, 10 Feb 2021 05:09:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230483AbhBJFJb (ORCPT ); Wed, 10 Feb 2021 00:09:31 -0500 Received: from mx2.suse.de ([195.135.220.15]:40716 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230015AbhBJFJ0 (ORCPT ); Wed, 10 Feb 2021 00:09:26 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 33018B061; Wed, 10 Feb 2021 05:08:10 +0000 (UTC) From: Coly Li To: axboe@kernel.dk Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, Kai Krakow , Coly Li , stable@vger.kernel.org Subject: [PATCH 05/20] bcache: Move journal work to new flush wq Date: Wed, 10 Feb 2021 13:07:27 +0800 Message-Id: <20210210050742.31237-6-colyli@suse.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210210050742.31237-1-colyli@suse.de> References: <20210210050742.31237-1-colyli@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kai Krakow This is potentially long running and not latency sensitive, let's get it out of the way of other latency sensitive events. As observed in the previous commit, the `system_wq` comes easily congested by bcache, and this fixes a few more stalls I was observing every once in a while. Let's not make this `WQ_MEM_RECLAIM` as it showed to reduce performance of boot and file system operations in my tests. Also, without `WQ_MEM_RECLAIM`, I no longer see desktop stalls. This matches the previous behavior as `system_wq` also does no memory reclaim: > // workqueue.c: > system_wq = alloc_workqueue("events", 0, 0); Cc: Coly Li Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Kai Krakow Signed-off-by: Coly Li --- drivers/md/bcache/bcache.h | 1 + drivers/md/bcache/journal.c | 4 ++-- drivers/md/bcache/super.c | 16 ++++++++++++++++ 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 2b8c7dd2cfae..848dd4db1659 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -1005,6 +1005,7 @@ void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent); extern struct workqueue_struct *bcache_wq; extern struct workqueue_struct *bch_journal_wq; +extern struct workqueue_struct *bch_flush_wq; extern struct mutex bch_register_lock; extern struct list_head bch_cache_sets; diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c index aefbdb7e003b..c6613e817333 100644 --- a/drivers/md/bcache/journal.c +++ b/drivers/md/bcache/journal.c @@ -932,8 +932,8 @@ atomic_t *bch_journal(struct cache_set *c, journal_try_write(c); } else if (!w->dirty) { w->dirty = true; - schedule_delayed_work(&c->journal.work, - msecs_to_jiffies(c->journal_delay_ms)); + queue_delayed_work(bch_flush_wq, &c->journal.work, + msecs_to_jiffies(c->journal_delay_ms)); spin_unlock(&c->journal.lock); } else { spin_unlock(&c->journal.lock); diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 85a44a0cffe0..0228ccb293fc 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -49,6 +49,7 @@ static int bcache_major; static DEFINE_IDA(bcache_device_idx); static wait_queue_head_t unregister_wait; struct workqueue_struct *bcache_wq; +struct workqueue_struct *bch_flush_wq; struct workqueue_struct *bch_journal_wq; @@ -2821,6 +2822,8 @@ static void bcache_exit(void) destroy_workqueue(bcache_wq); if (bch_journal_wq) destroy_workqueue(bch_journal_wq); + if (bch_flush_wq) + destroy_workqueue(bch_flush_wq); bch_btree_exit(); if (bcache_major) @@ -2884,6 +2887,19 @@ static int __init bcache_init(void) if (!bcache_wq) goto err; + /* + * Let's not make this `WQ_MEM_RECLAIM` for the following reasons: + * + * 1. It used `system_wq` before which also does no memory reclaim. + * 2. With `WQ_MEM_RECLAIM` desktop stalls, increased boot times, and + * reduced throughput can be observed. + * + * We still want to user our own queue to not congest the `system_wq`. + */ + bch_flush_wq = alloc_workqueue("bch_flush", 0, 0); + if (!bch_flush_wq) + goto err; + bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0); if (!bch_journal_wq) goto err;