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 X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 8D8A9C433DB for ; Fri, 29 Jan 2021 16:43:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49BF060C3D for ; Fri, 29 Jan 2021 16:43:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231184AbhA2QnP (ORCPT ); Fri, 29 Jan 2021 11:43:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231459AbhA2Qmj (ORCPT ); Fri, 29 Jan 2021 11:42:39 -0500 Received: from mail-ed1-x52f.google.com (mail-ed1-x52f.google.com [IPv6:2a00:1450:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17987C0617AA for ; Fri, 29 Jan 2021 08:40:58 -0800 (PST) Received: by mail-ed1-x52f.google.com with SMTP id j13so11287743edp.2 for ; Fri, 29 Jan 2021 08:40:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kaishome.de; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=LhPAB63wWMLQ/c42n+YNR2BSOGoLuye0ZVC0bKgjkvk=; b=EeveDW7adIPOXf1NfNrcHWWHQi+cdKNE1jHOJ8dq4aU/NSKCbxGoeidtJj69eXwZUE ocoPCiUFbr6oFeqBnxGNVjWiQol8vgUWasR5cVzc+J3/1bFz5HlWSRTgjFFSGiA7JuiT RgXp2GKuS0Zy3V8AyvEfoE0DMV+q5wEzFtvqo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=LhPAB63wWMLQ/c42n+YNR2BSOGoLuye0ZVC0bKgjkvk=; b=NxU/gch1vAy/mTB+47xfUdbx5qB9SYfPnDw5zsZjpz6HcJRFfJIRlthNwlNTWMn76u ZBKh+Kdv4bY4z+m43RXT5PzDN+EFQ0W6R5UsEpWCjGNYSt0Yk7eJ87nliVrYnVaMisA4 g904LgE3nlp8xulDQsyxK92vIIWrlVZDPSLtcfpIVgDFVXk/AiwCE58c/3mXgLhr4WJu FpmnZuplabsAGc5r6Op+cVn0K8eoGb46rgBfIXPQnZR/a+Vg70aJzX7ki/JiM5spvQeV OMnyiIWd7XyfR3deQx3Iki8p7g57l0fFgeUcXQlYcVDKSfq+iWu2Bckgcas5RXP1+hSM tkwg== X-Gm-Message-State: AOAM530fG2okGEpA1b9FuXn9JD1N0/w4ip4wSF0VHK1tTWkR13lesNtP 14edmtuHLzeVTah6o7ZOnVnMs53LXrUcUQ== X-Google-Smtp-Source: ABdhPJwV3YoIBw/7vZUs1sX9LwVpkhL8qywav1l4IJm7HbS6zR/cQIAF4mkPo2h1J9eDrZRtX5AGJg== X-Received: by 2002:a50:d6dc:: with SMTP id l28mr6054002edj.105.1611938441471; Fri, 29 Jan 2021 08:40:41 -0800 (PST) Received: from jupiter.sol.kaishome.de ([2a02:8109:c40:9200::1a2]) by smtp.gmail.com with ESMTPSA id g2sm4050533ejk.108.2021.01.29.08.40.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Jan 2021 08:40:40 -0800 (PST) Received: (nullmailer pid 188535 invoked by uid 500); Fri, 29 Jan 2021 16:40:37 -0000 From: Kai Krakow To: linux-bcache@vger.kernel.org Cc: Kai Krakow , Coly Li Subject: [PATCH v4 1/3] Revert "bcache: Kill btree_io_wq" Date: Fri, 29 Jan 2021 17:40:05 +0100 Message-Id: <20210129164007.188468-1-kai@kaishome.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210127132350.557935-1-kai@kaishome.de> References: <20210127132350.557935-1-kai@kaishome.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org This reverts commit 56b30770b27d54d68ad51eccc6d888282b568cee. With the btree using the `system_wq`, I seem to see a lot more desktop latency than I should. After some more investigation, it looks like the original assumption of 56b3077 no longer is true, and bcache has a very high potential of congesting the `system_wq`. In turn, this introduces laggy desktop performance, IO stalls (at least with btrfs), and input events may be delayed. So let's revert this. It's important to note that the semantics of using `system_wq` previously mean that `btree_io_wq` should be created before and destroyed after other bcache wqs to keep the same assumptions. Cc: Coly Li Signed-off-by: Kai Krakow --- drivers/md/bcache/bcache.h | 2 ++ drivers/md/bcache/btree.c | 21 +++++++++++++++++++-- drivers/md/bcache/super.c | 4 ++++ 3 files changed, 25 insertions(+), 2 deletions(-) diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 1d57f48307e66..b1ed16c7a5341 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -1042,5 +1042,7 @@ void bch_debug_exit(void); void bch_debug_init(void); void bch_request_exit(void); int bch_request_init(void); +void bch_btree_exit(void); +int bch_btree_init(void); #endif /* _BCACHE_H */ diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 910df242c83df..952f022db5a5f 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -99,6 +99,8 @@ #define PTR_HASH(c, k) \ (((k)->ptr[0] >> c->bucket_bits) | PTR_GEN(k, 0)) +static struct workqueue_struct *btree_io_wq; + #define insert_lock(s, b) ((b)->level <= (s)->lock) @@ -308,7 +310,7 @@ static void __btree_node_write_done(struct closure *cl) btree_complete_write(b, w); if (btree_node_dirty(b)) - schedule_delayed_work(&b->work, 30 * HZ); + queue_delayed_work(btree_io_wq, &b->work, 30 * HZ); closure_return_with_destructor(cl, btree_node_write_unlock); } @@ -481,7 +483,7 @@ static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref) BUG_ON(!i->keys); if (!btree_node_dirty(b)) - schedule_delayed_work(&b->work, 30 * HZ); + queue_delayed_work(btree_io_wq, &b->work, 30 * HZ); set_btree_node_dirty(b); @@ -2764,3 +2766,18 @@ void bch_keybuf_init(struct keybuf *buf) spin_lock_init(&buf->lock); array_allocator_init(&buf->freelist); } + +void bch_btree_exit(void) +{ + if (btree_io_wq) + destroy_workqueue(btree_io_wq); +} + +int __init bch_btree_init(void) +{ + btree_io_wq = create_singlethread_workqueue("bch_btree_io"); + if (!btree_io_wq) + return -ENOMEM; + + return 0; +} diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 2047a9cccdb5d..77c5d8b6d4316 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -2821,6 +2821,7 @@ static void bcache_exit(void) destroy_workqueue(bcache_wq); if (bch_journal_wq) destroy_workqueue(bch_journal_wq); + bch_btree_exit(); if (bcache_major) unregister_blkdev(bcache_major, "bcache"); @@ -2876,6 +2877,9 @@ static int __init bcache_init(void) return bcache_major; } + if (bch_btree_init()) + goto err; + bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); if (!bcache_wq) goto err; -- 2.26.2