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| author | Zheng Liu | 2012-08-17 15:54:17 +0200 |
|---|---|---|
| committer | Theodore Ts'o | 2012-08-17 15:54:17 +0200 |
| commit | 67a5da564f97f31c4054d358e00b34d7ee570da5 (patch) | |
| tree | 525f256d46cfac4be0b0acd90cc2bad5fcdb1b77 /fs/ext4/ext4.h | |
| parent | ext4: add missing space to trace message (diff) | |
| download | kernel-qcow2-linux-67a5da564f97f31c4054d358e00b34d7ee570da5.tar.gz kernel-qcow2-linux-67a5da564f97f31c4054d358e00b34d7ee570da5.tar.xz kernel-qcow2-linux-67a5da564f97f31c4054d358e00b34d7ee570da5.zip | |
ext4: make the zero-out chunk size tunable
Currently in ext4 the length of zero-out chunk is set to 7 file system
blocks. But if an inode has uninitailized extents from using
fallocate to preallocate space, and the workload issues many random
writes, this can cause a fragmented extent tree that will
unnecessarily grow the extent tree.
So create a new sysfs tunable, extent_max_zeroout_kb, which controls
the maximum size where blocks will be zeroed out instead of creating a
new uninitialized extent. The default of this has been sent to 32kb.
CC: Zach Brown <zab@zabbo.net>
CC: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/ext4.h')
| -rw-r--r-- | fs/ext4/ext4.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 7c0841ecde6c..0df5ee102b61 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1271,6 +1271,9 @@ struct ext4_sb_info { unsigned long s_sectors_written_start; u64 s_kbytes_written; + /* the size of zero-out chunk */ + unsigned int s_extent_max_zeroout_kb; + unsigned int s_log_groups_per_flex; struct flex_groups *s_flex_groups; |