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=-18.7 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 93DFFC433DB for ; Thu, 28 Jan 2021 23:29:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46B5D64DFA for ; Thu, 28 Jan 2021 23:29:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231394AbhA1X3Q (ORCPT ); Thu, 28 Jan 2021 18:29:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231310AbhA1X3O (ORCPT ); Thu, 28 Jan 2021 18:29:14 -0500 Received: from mail-ej1-x630.google.com (mail-ej1-x630.google.com [IPv6:2a00:1450:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 815B6C061573 for ; Thu, 28 Jan 2021 15:28:34 -0800 (PST) Received: by mail-ej1-x630.google.com with SMTP id kg20so10336610ejc.4 for ; Thu, 28 Jan 2021 15:28:34 -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=aNEaA+JdqKHrg9/w7ysfiFWKM7c70ra6DYa8OEhcmJAANwrux67A04eo6kv732y4P2 409f28pwyoWjYh7kn4/p1Zb+cvAKLOG0nact4l7MMEcmwxNDtE/TQZ7wN3r31nKTvZCH P8nVmVaJVpJpAXX3vY/jKnCeNVIuOKUjOd8cg= 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=XClmvKsIzWfUDkANnEwj9TZtXTDstBGGG4ngzPUUsjqeVY3HhDytW3FRJ66iDVpj+0 HDhf5VYomGeWXvR3sLrE9lI9pCHFpG2+x8HoWrGpxd9s4Kdz8dQvt8qomY15PooQPAzq aI4lDznP+2yZwoZMdomdmDvyudg26QzFd2bOimamBDPTiPCwZDg9OqYVVww/l17sVyh3 LScp1SSQNpweXbqrTsdvqRzjxm5YcCXUZLRakjBbWuDrnbs2Qz3cmWbDMyQfdTHdc5ga gWvQe5rHSPPmt5UKu+VBQoho4SX37fmgMIIzFLeAlijNY+a7fRuNNf9efZXr956Hty8i bsTQ== X-Gm-Message-State: AOAM531CdXlMKaTRZZVRcIs/J9vyS5PyjvEYTa2U4Ez7B3PE1J3LXzr7 hQjl8/R11D1i4+bzF3H/buKVe4T/ZEyR5A== X-Google-Smtp-Source: ABdhPJzbe7Y6ObOFLZ3B34GdwIQIyLtQvKMYnO9lS/3TSnNCofWJUQMP485F4qIYaTqrgNuuJ7kuMg== X-Received: by 2002:a17:906:804c:: with SMTP id x12mr1846398ejw.42.1611876512871; Thu, 28 Jan 2021 15:28:32 -0800 (PST) Received: from jupiter.sol.kaishome.de ([2a02:8109:c40:9200::1a2]) by smtp.gmail.com with ESMTPSA id i18sm3609883edt.68.2021.01.28.15.28.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Jan 2021 15:28:32 -0800 (PST) Received: (nullmailer pid 20720 invoked by uid 500); Thu, 28 Jan 2021 23:28:29 -0000 From: Kai Krakow To: linux-bcache@vger.kernel.org Cc: Kai Krakow , Coly Li Subject: [PATCH v3 1/3] Revert "bcache: Kill btree_io_wq" Date: Fri, 29 Jan 2021 00:28:23 +0100 Message-Id: <20210128232825.18719-1-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