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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 735C0C55189 for ; Wed, 22 Apr 2020 10:38:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4EB8A2073A for ; Wed, 22 Apr 2020 10:38:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587551918; bh=Jkaizt38vuK3ad4xV68G+hRZiQoc5INa/ZDzkOBwnko=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SYQjgu+fnBw7Q5+yYjgXLxdr5LXvsM4PG3T3jiNyZ0SVpVc1xFjQeOuxZ25Ljex7H S5CF9doKGUd84v0BSCfh6CXSHNSX+k42/6pIslfVINdcoBqUZk1RXw4HGoGwWHdHAV HBKE2eMa9m9m8Chb3/uLY17fqqKvt/+CF6dhESEo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731005AbgDVKi2 (ORCPT ); Wed, 22 Apr 2020 06:38:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:58284 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729846AbgDVKWG (ORCPT ); Wed, 22 Apr 2020 06:22:06 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 312B620CC7; Wed, 22 Apr 2020 10:21:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587550908; bh=Jkaizt38vuK3ad4xV68G+hRZiQoc5INa/ZDzkOBwnko=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GG4gZyam3HWH9z/vBCFdzSMsYHqrZ8vMXoCAeAAi0x0UgkGSewvhID2w0AaSaStQ+ 9qdZsSPHHoaWYP9YoWlIBQzLHuB4l1as1vP2JkexhDhn+6TJ2SyuttCMR5KY5ABUIV CGMGcW/G7d6YTPdzsDYBihrD8YUfcvLtnEQkNSZY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andreas Dilger , Roman Gushchin , Theodore Tso Subject: [PATCH 5.6 006/166] ext4: use non-movable memory for superblock readahead Date: Wed, 22 Apr 2020 11:55:33 +0200 Message-Id: <20200422095048.754376835@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200422095047.669225321@linuxfoundation.org> References: <20200422095047.669225321@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Roman Gushchin commit d87f639258a6a5980183f11876c884931ad93da2 upstream. Since commit a8ac900b8163 ("ext4: use non-movable memory for the superblock") buffers for ext4 superblock were allocated using the sb_bread_unmovable() helper which allocated buffer heads out of non-movable memory blocks. It was necessarily to not block page migrations and do not cause cma allocation failures. However commit 85c8f176a611 ("ext4: preload block group descriptors") broke this by introducing pre-reading of the ext4 superblock. The problem is that __breadahead() is using __getblk() underneath, which allocates buffer heads out of movable memory. It resulted in page migration failures I've seen on a machine with an ext4 partition and a preallocated cma area. Fix this by introducing sb_breadahead_unmovable() and __breadahead_gfp() helpers which use non-movable memory for buffer head allocations and use them for the ext4 superblock readahead. Reviewed-by: Andreas Dilger Fixes: 85c8f176a611 ("ext4: preload block group descriptors") Signed-off-by: Roman Gushchin Link: https://lore.kernel.org/r/20200229001411.128010-1-guro@fb.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/buffer.c | 11 +++++++++++ fs/ext4/inode.c | 2 +- fs/ext4/super.c | 2 +- include/linux/buffer_head.h | 8 ++++++++ 4 files changed, 21 insertions(+), 2 deletions(-) --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1377,6 +1377,17 @@ void __breadahead(struct block_device *b } EXPORT_SYMBOL(__breadahead); +void __breadahead_gfp(struct block_device *bdev, sector_t block, unsigned size, + gfp_t gfp) +{ + struct buffer_head *bh = __getblk_gfp(bdev, block, size, gfp); + if (likely(bh)) { + ll_rw_block(REQ_OP_READ, REQ_RAHEAD, 1, &bh); + brelse(bh); + } +} +EXPORT_SYMBOL(__breadahead_gfp); + /** * __bread_gfp() - reads a specified block and returns the bh * @bdev: the block_device to read from --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4348,7 +4348,7 @@ make_io: if (end > table) end = table; while (b <= end) - sb_breadahead(sb, b++); + sb_breadahead_unmovable(sb, b++); } /* --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4331,7 +4331,7 @@ static int ext4_fill_super(struct super_ /* Pre-read the descriptors into the buffer cache */ for (i = 0; i < db_count; i++) { block = descriptor_loc(sb, logical_sb_block, i); - sb_breadahead(sb, block); + sb_breadahead_unmovable(sb, block); } for (i = 0; i < db_count; i++) { --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -189,6 +189,8 @@ struct buffer_head *__getblk_gfp(struct void __brelse(struct buffer_head *); void __bforget(struct buffer_head *); void __breadahead(struct block_device *, sector_t block, unsigned int size); +void __breadahead_gfp(struct block_device *, sector_t block, unsigned int size, + gfp_t gfp); struct buffer_head *__bread_gfp(struct block_device *, sector_t block, unsigned size, gfp_t gfp); void invalidate_bh_lrus(void); @@ -319,6 +321,12 @@ sb_breadahead(struct super_block *sb, se __breadahead(sb->s_bdev, block, sb->s_blocksize); } +static inline void +sb_breadahead_unmovable(struct super_block *sb, sector_t block) +{ + __breadahead_gfp(sb->s_bdev, block, sb->s_blocksize, 0); +} + static inline struct buffer_head * sb_getblk(struct super_block *sb, sector_t block) {