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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DCE4EC433EF for ; Tue, 7 Jun 2022 22:32:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380738AbiFGWcQ (ORCPT ); Tue, 7 Jun 2022 18:32:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1383847AbiFGWbA (ORCPT ); Tue, 7 Jun 2022 18:31:00 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4AF4DF06; Tue, 7 Jun 2022 12:24:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 300F0B823CA; Tue, 7 Jun 2022 19:24:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A2C2C385A2; Tue, 7 Jun 2022 19:24:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654629852; bh=MNGbb0y6lx7BzfYUSDabvaF+OEPYHabK0nbEfAzr7mo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FCiiG9nYlyF9+IsMSeAJ/rePXDTwn9TW35ST2NzQKV5xfvtD6GZVOKKEER6efKPe1 HxUWlJ8ZXX236Ow5rPpppJbOwDQmf++2XN3iHmhflaMXnahaIEQ/RjXIzyvFPwlC8R znqhaetkCl2qdQwzZx2uLXa+opWu3EKJcjk+hCn8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Coly Li , Jens Axboe Subject: [PATCH 5.18 839/879] bcache: improve multithreaded bch_btree_check() Date: Tue, 7 Jun 2022 19:05:57 +0200 Message-Id: <20220607165027.207360448@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607165002.659942637@linuxfoundation.org> References: <20220607165002.659942637@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Coly Li commit 622536443b6731ec82c563aae7807165adbe9178 upstream. Commit 8e7102273f59 ("bcache: make bch_btree_check() to be multithreaded") makes bch_btree_check() to be much faster when checking all btree nodes during cache device registration. But it isn't in ideal shap yet, still can be improved. This patch does the following thing to improve current parallel btree nodes check by multiple threads in bch_btree_check(), - Add read lock to root node while checking all the btree nodes with multiple threads. Although currently it is not mandatory but it is good to have a read lock in code logic. - Remove local variable 'char name[32]', and generate kernel thread name string directly when calling kthread_run(). - Allocate local variable "struct btree_check_state check_state" on the stack and avoid unnecessary dynamic memory allocation for it. - Reduce BCH_BTR_CHKTHREAD_MAX from 64 to 12 which is enough indeed. - Increase check_state->started to count created kernel thread after it succeeds to create. - When wait for all checking kernel threads to finish, use wait_event() to replace wait_event_interruptible(). With this change, the code is more clear, and some potential error conditions are avoided. Fixes: 8e7102273f59 ("bcache: make bch_btree_check() to be multithreaded") Signed-off-by: Coly Li Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220524102336.10684-2-colyli@suse.de Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/md/bcache/btree.c | 58 ++++++++++++++++++++-------------------------- drivers/md/bcache/btree.h | 2 - 2 files changed, 27 insertions(+), 33 deletions(-) --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -2006,8 +2006,7 @@ int bch_btree_check(struct cache_set *c) int i; struct bkey *k = NULL; struct btree_iter iter; - struct btree_check_state *check_state; - char name[32]; + struct btree_check_state check_state; /* check and mark root node keys */ for_each_key_filter(&c->root->keys, k, &iter, bch_ptr_invalid) @@ -2018,63 +2017,58 @@ int bch_btree_check(struct cache_set *c) if (c->root->level == 0) return 0; - check_state = kzalloc(sizeof(struct btree_check_state), GFP_KERNEL); - if (!check_state) - return -ENOMEM; - - check_state->c = c; - check_state->total_threads = bch_btree_chkthread_nr(); - check_state->key_idx = 0; - spin_lock_init(&check_state->idx_lock); - atomic_set(&check_state->started, 0); - atomic_set(&check_state->enough, 0); - init_waitqueue_head(&check_state->wait); + check_state.c = c; + check_state.total_threads = bch_btree_chkthread_nr(); + check_state.key_idx = 0; + spin_lock_init(&check_state.idx_lock); + atomic_set(&check_state.started, 0); + atomic_set(&check_state.enough, 0); + init_waitqueue_head(&check_state.wait); + rw_lock(0, c->root, c->root->level); /* * Run multiple threads to check btree nodes in parallel, - * if check_state->enough is non-zero, it means current + * if check_state.enough is non-zero, it means current * running check threads are enough, unncessary to create * more. */ - for (i = 0; i < check_state->total_threads; i++) { - /* fetch latest check_state->enough earlier */ + for (i = 0; i < check_state.total_threads; i++) { + /* fetch latest check_state.enough earlier */ smp_mb__before_atomic(); - if (atomic_read(&check_state->enough)) + if (atomic_read(&check_state.enough)) break; - check_state->infos[i].result = 0; - check_state->infos[i].state = check_state; - snprintf(name, sizeof(name), "bch_btrchk[%u]", i); - atomic_inc(&check_state->started); + check_state.infos[i].result = 0; + check_state.infos[i].state = &check_state; - check_state->infos[i].thread = + check_state.infos[i].thread = kthread_run(bch_btree_check_thread, - &check_state->infos[i], - name); - if (IS_ERR(check_state->infos[i].thread)) { + &check_state.infos[i], + "bch_btrchk[%d]", i); + if (IS_ERR(check_state.infos[i].thread)) { pr_err("fails to run thread bch_btrchk[%d]\n", i); for (--i; i >= 0; i--) - kthread_stop(check_state->infos[i].thread); + kthread_stop(check_state.infos[i].thread); ret = -ENOMEM; goto out; } + atomic_inc(&check_state.started); } /* * Must wait for all threads to stop. */ - wait_event_interruptible(check_state->wait, - atomic_read(&check_state->started) == 0); + wait_event(check_state.wait, atomic_read(&check_state.started) == 0); - for (i = 0; i < check_state->total_threads; i++) { - if (check_state->infos[i].result) { - ret = check_state->infos[i].result; + for (i = 0; i < check_state.total_threads; i++) { + if (check_state.infos[i].result) { + ret = check_state.infos[i].result; goto out; } } out: - kfree(check_state); + rw_unlock(0, c->root); return ret; } --- a/drivers/md/bcache/btree.h +++ b/drivers/md/bcache/btree.h @@ -226,7 +226,7 @@ struct btree_check_info { int result; }; -#define BCH_BTR_CHKTHREAD_MAX 64 +#define BCH_BTR_CHKTHREAD_MAX 12 struct btree_check_state { struct cache_set *c; int total_threads;