From 1bce63d1a2a2c8929442b79acd4eab2e3db10a0b Mon Sep 17 00:00:00 2001
From: Shaohua Li <shaohua.li@intel.com>
Date: Tue, 18 Oct 2011 10:55:51 -0400
Subject: [PATCH] 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>
---
fs/ext4/inode.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4863238c3754d..081bb25a9ad3c 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -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;
--
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