From: Benjamin LaHaise Subject: [PATCH] ext4: add noorlov parameter to avoid spreading of directory inodes Date: Tue, 1 Oct 2013 12:08:17 -0400 Message-ID: <20131001160817.GA2295@kvack.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Theodore Ts'o , Andreas Dilger Return-path: Received: from kanga.kvack.org ([205.233.56.17]:44715 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750704Ab3JAQIR (ORCPT ); Tue, 1 Oct 2013 12:08:17 -0400 Content-Disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: While investigating a performance regression during migration of the Solace product from an older kernel running ext3 to a 3.x kernel running ext4, the change in allocation policies between ext3 and ext4 were found to have caused a 10-50% decrease (depending on the test) in I/O throughput. In order to extract more parallelism from the filesystem, this particular use-case has 100 subdirectories off of the root directory of an ext4 filesystem in which files are created in a round-robin fashion. The subdirectories are used in order to increase the number of metadata operations that can occur in parallel. With the older setup on ext3, files were created sequentially, while using ext4 resulted in the files being spread out across block groups. To avoid this change in allocation policies, introduce the noorlov mount parameter to ext4. This parameter changes allocation policy such that new subdirectories in the filesystem are allocated in the same block group as the parent subdirectory. With the subdirectories in the same block group, the allocation policy once again results in files being laid out sequentially on disk, restoring performance. Signed-off-by: Benjamin LaHaise Signed-off-by: Benjamin LaHaise diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index af815ea..3894ab0 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -985,6 +985,8 @@ struct ext4_inode_info { #define EXT4_MOUNT2_STD_GROUP_SIZE 0x00000002 /* We have standard group size of blocksize * 8 blocks */ +#define EXT4_MOUNT2_NO_ORLOV 0x00000004 /* Disable orlov for inode + allocation */ #define clear_opt(sb, opt) EXT4_SB(sb)->s_mount_opt &= \ ~EXT4_MOUNT_##opt diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 137193f..2b1b4ee 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -745,7 +745,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir, goto got_group; } - if (S_ISDIR(mode)) + if (!test_opt2(sb, NO_ORLOV) && S_ISDIR(mode)) ret2 = find_group_orlov(sb, dir, &group, mode, qstr); else ret2 = find_group_other(sb, dir, &group, mode); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 2c2e6cb..d0bdcd7 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1143,7 +1143,7 @@ enum { Opt_inode_readahead_blks, Opt_journal_ioprio, Opt_dioread_nolock, Opt_dioread_lock, Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable, - Opt_max_dir_size_kb, + Opt_max_dir_size_kb, Opt_noorlov, }; static const match_table_t tokens = { @@ -1163,6 +1163,7 @@ static const match_table_t tokens = { {Opt_debug, "debug"}, {Opt_removed, "oldalloc"}, {Opt_removed, "orlov"}, + {Opt_noorlov, "noorlov"}, {Opt_user_xattr, "user_xattr"}, {Opt_nouser_xattr, "nouser_xattr"}, {Opt_acl, "acl"}, @@ -1341,6 +1342,7 @@ static const struct mount_opts { int token; int mount_opt; int flags; + int mount_opt2; } ext4_mount_opts[] = { {Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET}, {Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR}, @@ -1417,6 +1419,7 @@ static const struct mount_opts { {Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT}, {Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT}, {Opt_max_dir_size_kb, 0, MOPT_GTE0}, + {Opt_noorlov, 0, MOPT_SET, EXT4_MOUNT2_NO_ORLOV}, {Opt_err, 0, 0} }; @@ -1601,6 +1604,7 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, } else { clear_opt(sb, DATA_FLAGS); sbi->s_mount_opt |= m->mount_opt; + sbi->s_mount_opt2 |= m->mount_opt2; } #ifdef CONFIG_QUOTA } else if (m->flags & MOPT_QFMT) { @@ -1630,10 +1634,13 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, WARN_ON(1); return -1; } - if (arg != 0) + if (arg != 0) { sbi->s_mount_opt |= m->mount_opt; - else + sbi->s_mount_opt2 |= m->mount_opt2; + } else { sbi->s_mount_opt &= ~m->mount_opt; + sbi->s_mount_opt2 &= ~m->mount_opt2; + } } return 1; } @@ -1777,11 +1784,15 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb, if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) || (m->flags & MOPT_CLEAR_ERR)) continue; - if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt))) + if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)) && + !(m->mount_opt2 & sbi->s_mount_opt2)) continue; /* skip if same as the default */ - if ((want_set && - (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) || - (!want_set && (sbi->s_mount_opt & m->mount_opt))) + if (want_set && + (((sbi->s_mount_opt & m->mount_opt) != m->mount_opt) || + ((sbi->s_mount_opt2 & m->mount_opt2) != m->mount_opt2))) + continue; /* select Opt_noFoo vs Opt_Foo */ + if (!want_set && ((sbi->s_mount_opt & m->mount_opt) || + (sbi->s_mount_opt2 & m->mount_opt2))) continue; /* select Opt_noFoo vs Opt_Foo */ SEQ_OPTS_PRINT("%s", token2str(m->token)); }