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authorTheodore Ts'o <tytso@mit.edu>2013-04-21 16:47:54 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-04-21 16:47:54 -0400
commitf783f091e49ce4896e6b026af82d76e0537c6089 (patch)
tree0ff78a05254d4b996bb027d9fac9969d1d6e0b07 /include/trace
parent13fca323e9a8b63c08de7a4e05d3c702516b535d (diff)
jbd2: trace when lock_buffer in do_get_write_access takes a long time
While investigating interactivity problems it was clear that processes sometimes stall for long periods of times if an attempt is made to lock a buffer which is undergoing writeback. It would stall in a trace looking something like [<ffffffff811a39de>] __lock_buffer+0x2e/0x30 [<ffffffff8123a60f>] do_get_write_access+0x43f/0x4b0 [<ffffffff8123a7cb>] jbd2_journal_get_write_access+0x2b/0x50 [<ffffffff81220f79>] __ext4_journal_get_write_access+0x39/0x80 [<ffffffff811f3198>] ext4_reserve_inode_write+0x78/0xa0 [<ffffffff811f3209>] ext4_mark_inode_dirty+0x49/0x220 [<ffffffff811f57d1>] ext4_dirty_inode+0x41/0x60 [<ffffffff8119ac3e>] __mark_inode_dirty+0x4e/0x2d0 [<ffffffff8118b9b9>] update_time+0x79/0xc0 [<ffffffff8118ba98>] file_update_time+0x98/0x100 [<ffffffff81110ffc>] __generic_file_aio_write+0x17c/0x3b0 [<ffffffff811112aa>] generic_file_aio_write+0x7a/0xf0 [<ffffffff811ea853>] ext4_file_write+0x83/0xd0 [<ffffffff81172b23>] do_sync_write+0xa3/0xe0 [<ffffffff811731ae>] vfs_write+0xae/0x180 [<ffffffff8117361d>] sys_write+0x4d/0x90 [<ffffffff8159d62d>] system_call_fastpath+0x1a/0x1f [<ffffffffffffffff>] 0xffffffffffffffff Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/events/jbd2.h21
1 files changed, 21 insertions, 0 deletions
diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h
index 070df49e4a1..c1d1f3eb242 100644
--- a/include/trace/events/jbd2.h
+++ b/include/trace/events/jbd2.h
@@ -358,6 +358,27 @@ TRACE_EVENT(jbd2_write_superblock,
MINOR(__entry->dev), __entry->write_op)
);
+TRACE_EVENT(jbd2_lock_buffer_stall,
+
+ TP_PROTO(dev_t dev, unsigned long stall_ms),
+
+ TP_ARGS(dev, stall_ms),
+
+ TP_STRUCT__entry(
+ __field( dev_t, dev )
+ __field(unsigned long, stall_ms )
+ ),
+
+ TP_fast_assign(
+ __entry->dev = dev;
+ __entry->stall_ms = stall_ms;
+ ),
+
+ TP_printk("dev %d,%d stall_ms %lu",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->stall_ms)
+);
+
#endif /* _TRACE_JBD2_H */
/* This part must be outside protection */