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 9F90AC433EF for ; Tue, 7 Jun 2022 19:19:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355036AbiFGTTI (ORCPT ); Tue, 7 Jun 2022 15:19:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356063AbiFGTRz (ORCPT ); Tue, 7 Jun 2022 15:17:55 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 110212B19B; Tue, 7 Jun 2022 11:08:06 -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 sin.source.kernel.org (Postfix) with ESMTPS id F4160CE240B; Tue, 7 Jun 2022 18:08:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BF64C385A5; Tue, 7 Jun 2022 18:08:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654625283; bh=wEN67JUF7h90gFRJYEPgOYbXPQQrDcNRic4aTK3LJmM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=muGAnfOqPhCVNMAZ1Utg+JK0a4sr/V6sohjV3AuA9GMnSomeDGYGnRuisuLmo166o +QTlYicamGN0Jc4oy73E/PKEgYaOw0piE+ZFtQxV90NnPGV739TB9RMFENnFbOgbmn UwkITDlc1WOIQshHdnA6VSWyJ9ojIhgiHrJKcf3g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Coly Li , Jens Axboe Subject: [PATCH 5.15 631/667] bcache: remove incremental dirty sector counting for bch_sectors_dirty_init() Date: Tue, 7 Jun 2022 19:04:56 +0200 Message-Id: <20220607164953.591587744@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607164934.766888869@linuxfoundation.org> References: <20220607164934.766888869@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 80db4e4707e78cb22287da7d058d7274bd4cb370 upstream. After making bch_sectors_dirty_init() being multithreaded, the existing incremental dirty sector counting in bch_root_node_dirty_init() doesn't release btree occupation after iterating 500000 (INIT_KEYS_EACH_TIME) bkeys. Because a read lock is added on btree root node to prevent the btree to be split during the dirty sectors counting, other I/O requester has no chance to gain the write lock even restart bcache_btree(). That is to say, the incremental dirty sectors counting is incompatible to the multhreaded bch_sectors_dirty_init(). We have to choose one and drop another one. In my testing, with 512 bytes random writes, I generate 1.2T dirty data and a btree with 400K nodes. With single thread and incremental dirty sectors counting, it takes 30+ minites to register the backing device. And with multithreaded dirty sectors counting, the backing device registration can be accomplished within 2 minutes. The 30+ minutes V.S. 2- minutes difference makes me decide to keep multithreaded bch_sectors_dirty_init() and drop the incremental dirty sectors counting. This is what this patch does. But INIT_KEYS_EACH_TIME is kept, in sectors_dirty_init_fn() the CPU will be released by cond_resched() after every INIT_KEYS_EACH_TIME keys iterated. This is to avoid the watchdog reports a bogus soft lockup warning. Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded") Signed-off-by: Coly Li Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220524102336.10684-4-colyli@suse.de Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/md/bcache/writeback.c | 39 ++++++++++++--------------------------- 1 file changed, 12 insertions(+), 27 deletions(-) --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -802,13 +802,11 @@ static int bch_writeback_thread(void *ar /* Init */ #define INIT_KEYS_EACH_TIME 500000 -#define INIT_KEYS_SLEEP_MS 100 struct sectors_dirty_init { struct btree_op op; unsigned int inode; size_t count; - struct bkey start; }; static int sectors_dirty_init_fn(struct btree_op *_op, struct btree *b, @@ -824,11 +822,8 @@ static int sectors_dirty_init_fn(struct KEY_START(k), KEY_SIZE(k)); op->count++; - if (atomic_read(&b->c->search_inflight) && - !(op->count % INIT_KEYS_EACH_TIME)) { - bkey_copy_key(&op->start, k); - return -EAGAIN; - } + if (!(op->count % INIT_KEYS_EACH_TIME)) + cond_resched(); return MAP_CONTINUE; } @@ -843,24 +838,16 @@ static int bch_root_node_dirty_init(stru bch_btree_op_init(&op.op, -1); op.inode = d->id; op.count = 0; - op.start = KEY(op.inode, 0, 0); - do { - ret = bcache_btree(map_keys_recurse, - k, - c->root, - &op.op, - &op.start, - sectors_dirty_init_fn, - 0); - if (ret == -EAGAIN) - schedule_timeout_interruptible( - msecs_to_jiffies(INIT_KEYS_SLEEP_MS)); - else if (ret < 0) { - pr_warn("sectors dirty init failed, ret=%d!\n", ret); - break; - } - } while (ret == -EAGAIN); + ret = bcache_btree(map_keys_recurse, + k, + c->root, + &op.op, + &KEY(op.inode, 0, 0), + sectors_dirty_init_fn, + 0); + if (ret < 0) + pr_warn("sectors dirty init failed, ret=%d!\n", ret); return ret; } @@ -904,7 +891,6 @@ static int bch_dirty_init_thread(void *a goto out; } skip_nr--; - cond_resched(); } if (p) { @@ -914,7 +900,6 @@ static int bch_dirty_init_thread(void *a p = NULL; prev_idx = cur_idx; - cond_resched(); } out: @@ -953,11 +938,11 @@ void bch_sectors_dirty_init(struct bcach bch_btree_op_init(&op.op, -1); op.inode = d->id; op.count = 0; - op.start = KEY(op.inode, 0, 0); for_each_key_filter(&c->root->keys, k, &iter, bch_ptr_invalid) sectors_dirty_init_fn(&op.op, c->root, k); + rw_unlock(0, c->root); return; }