ext4: add block plug for .writepages

Add block plug for ext4 .writepages. Though ext4 .writepages
already handles request merge very well, block plug is still
helpful to reduce block lock contention.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Shaohua Li 2011-10-18 10:55:51 -04:00 committed by Theodore Ts'o
parent f6f96fdb8c
commit 1bce63d1a2

View File

@ -2160,6 +2160,7 @@ static int ext4_da_writepages(struct address_space *mapping,
struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
pgoff_t done_index = 0;
pgoff_t end;
struct blk_plug plug;
trace_ext4_da_writepages(inode, wbc);
@ -2238,6 +2239,7 @@ static int ext4_da_writepages(struct address_space *mapping,
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag_pages_for_writeback(mapping, index, end);
blk_start_plug(&plug);
while (!ret && wbc->nr_to_write > 0) {
/*
@ -2302,6 +2304,7 @@ static int ext4_da_writepages(struct address_space *mapping,
*/
break;
}
blk_finish_plug(&plug);
if (!io_done && !cycled) {
cycled = 1;
index = 0;