From patchwork Fri Jan 9 20:24:52 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 17588 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id ADC95DE490 for ; Sat, 10 Jan 2009 07:25:25 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754556AbZAIUZY (ORCPT ); Fri, 9 Jan 2009 15:25:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754415AbZAIUZX (ORCPT ); Fri, 9 Jan 2009 15:25:23 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:37422 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754262AbZAIUZW (ORCPT ); Fri, 9 Jan 2009 15:25:22 -0500 Received: from imap1.linux-foundation.org (imap1.linux-foundation.org [140.211.169.55]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id n09KOrVm022356 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 9 Jan 2009 12:24:54 -0800 Received: from localhost.localdomain (localhost [127.0.0.1]) by imap1.linux-foundation.org (8.13.5.20060308/8.13.5/Debian-3ubuntu1.1) with ESMTP id n09KOqq8021734; Fri, 9 Jan 2009 12:24:52 -0800 Message-Id: <200901092024.n09KOqq8021734@imap1.linux-foundation.org> Subject: [patch 1/3] ext4: allocate ->s_blockgroup_lock separately To: tytso@mit.edu Cc: linux-ext4@vger.kernel.org, akpm@linux-foundation.org, penberg@cs.helsinki.fi, adilger@sun.com From: akpm@linux-foundation.org Date: Fri, 09 Jan 2009 12:24:52 -0800 X-Spam-Status: No, hits=-3.412 required=5 tests=AWL, BAYES_00, OSDL_HEADER_SUBJECT_BRACKETED X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.13 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Pekka Enberg As spotted by kmemtrace, struct ext4_sb_info is 17664 bytes on 64-bit which makes it a very bad fit for SLAB allocators. The culprit of the wasted memory is ->s_blockgroup_lock which can be as big as 16 KB when NR_CPUS >= 32. To fix that, allocate ->s_blockgroup_lock, which fits nicely in a order 2 page in the worst case, separately. This shinks down struct ext4_sb_info enough to fit a 2 KB slab cache so now we allocate 16 KB + 2 KB instead of 32 KB saving 14 KB of memory. Acked-by: Andreas Dilger Signed-off-by: Pekka Enberg Cc: Signed-off-by: Andrew Morton --- fs/ext4/ext4_sb.h | 4 ++-- fs/ext4/super.c | 10 +++++++++- 2 files changed, 11 insertions(+), 3 deletions(-) diff -puN fs/ext4/ext4_sb.h~ext4-allocate-s_blockgroup_lock-separately fs/ext4/ext4_sb.h --- a/fs/ext4/ext4_sb.h~ext4-allocate-s_blockgroup_lock-separately +++ a/fs/ext4/ext4_sb.h @@ -62,7 +62,7 @@ struct ext4_sb_info { struct percpu_counter s_freeinodes_counter; struct percpu_counter s_dirs_counter; struct percpu_counter s_dirtyblocks_counter; - struct blockgroup_lock s_blockgroup_lock; + struct blockgroup_lock *s_blockgroup_lock; struct proc_dir_entry *s_proc; /* root of the per fs reservation window tree */ @@ -153,7 +153,7 @@ struct ext4_sb_info { static inline spinlock_t * sb_bgl_lock(struct ext4_sb_info *sbi, unsigned int block_group) { - return bgl_lock_ptr(&sbi->s_blockgroup_lock, block_group); + return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group); } #endif /* _EXT4_SB */ diff -puN fs/ext4/super.c~ext4-allocate-s_blockgroup_lock-separately fs/ext4/super.c --- a/fs/ext4/super.c~ext4-allocate-s_blockgroup_lock-separately +++ a/fs/ext4/super.c @@ -615,6 +615,7 @@ static void ext4_put_super(struct super_ ext4_blkdev_remove(sbi); } sb->s_fs_info = NULL; + kfree(sbi->s_blockgroup_lock); kfree(sbi); return; } @@ -2019,6 +2020,13 @@ static int ext4_fill_super(struct super_ sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); if (!sbi) return -ENOMEM; + + sbi->s_blockgroup_lock = + kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL); + if (!sbi->s_blockgroup_lock) { + kfree(sbi); + return -ENOMEM; + } sb->s_fs_info = sbi; sbi->s_mount_opt = 0; sbi->s_resuid = EXT4_DEF_RESUID; @@ -2330,7 +2338,7 @@ static int ext4_fill_super(struct super_ &sbi->s_inode_readahead_blks); #endif - bgl_lock_init(&sbi->s_blockgroup_lock); + bgl_lock_init(sbi->s_blockgroup_lock); for (i = 0; i < db_count; i++) { block = descriptor_loc(sb, logical_sb_block, i);