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authorTheodore Ts'o <tytso@mit.edu>2013-02-09 03:59:22 +0100
committerTheodore Ts'o <tytso@mit.edu>2013-02-09 03:59:22 +0100
commit9924a92a8c217576bd2a2b1bbbb854462f1a00ae (patch)
tree5c4eaee350e38cd2854fd6029da9f2a822ee184e /fs/ext4/ext4_jbd2.c
parentext4: move the jbd2 wrapper functions out of super.c (diff)
downloadlinux-9924a92a8c217576bd2a2b1bbbb854462f1a00ae.tar.xz
linux-9924a92a8c217576bd2a2b1bbbb854462f1a00ae.zip
ext4: pass context information to jbd2__journal_start()
So we can better understand what bits of ext4 are responsible for long-running jbd2 handles, use jbd2__journal_start() so we can pass context information for logging purposes. The recommended way for finding the longer-running handles is: T=/sys/kernel/debug/tracing EVENT=$T/events/jbd2/jbd2_handle_stats echo "interval > 5" > $EVENT/filter echo 1 > $EVENT/enable ./run-my-fs-benchmark cat $T/trace > /tmp/problem-handles This will list handles that were active for longer than 20ms. Having longer-running handles is bad, because a commit started at the wrong time could stall for those 20+ milliseconds, which could delay an fsync() or an O_SYNC operation. Here is an example line from the trace file describing a handle which lived on for 311 jiffies, or over 1.2 seconds: postmark-2917 [000] .... 196.435786: jbd2_handle_stats: dev 254,32 tid 570 type 2 line_no 2541 interval 311 sync 0 requested_blocks 1 dirtied_blocks 0 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/ext4_jbd2.c')
-rw-r--r--fs/ext4/ext4_jbd2.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index 6f6114525535..7058975e3a55 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -38,7 +38,8 @@ static void ext4_put_nojournal(handle_t *handle)
/*
* Wrappers for jbd2_journal_start/end.
*/
-handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
+handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
+ int type, int nblocks)
{
journal_t *journal;
@@ -59,7 +60,7 @@ handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
ext4_abort(sb, "Detected aborted journal");
return ERR_PTR(-EROFS);
}
- return jbd2_journal_start(journal, nblocks);
+ return jbd2__journal_start(journal, nblocks, GFP_NOFS, type, line);
}
int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)