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Message-ID: <bug-76821-13602-lKfKAY8hNb@https.bugzilla.kernel.org/> Date: Sat, 24 May 2014 14:42:23 +0000 From: bugzilla-daemon@...zilla.kernel.org To: linux-ext4@...r.kernel.org Subject: [Bug 76821] jbd2 write on disk each 2/3 seconds https://bugzilla.kernel.org/show_bug.cgi?id=76821 Theodore Tso <tytso@....edu> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |tytso@....edu --- Comment #2 from Theodore Tso <tytso@....edu> --- If your kernel doesn't have ftrace enabled, please enable it by enabling the following kernel config options: CONFIG_FUNCTION_TRACER CONFIG_FUNCTION_GRAPH_TRACER CONFIG_STACK_TRACER CONFIG_DYNAMIC_FTRACE Once you do that, make sure debugfs is mounted: mount -t debugfs debugfs /sys/kernel/debug Now enable the ext4_mark_inode_dirty tracepoint and start tracing: cd /sys/kernel/debug/tracing echo 1 > events/ext4/ext4_mark_inode_dirty/enable cat trace_pipe You will start seeing lines like this: kworker/u16:2-14718 [006] ...1 616239.342464: ext4_mark_inode_dirty: dev 252,0 ino 4203428 caller ext4_writepages+0x743/0x93e BrowserBlocking-5875 [006] ...1 616241.972533: ext4_mark_inode_dirty: dev 8,3 ino 3545316 caller ext4_dirty_inode+0x40/0x59 The first line indicates that process 14718, which is a kernel thread named kworking/u16:2, dirtied inode 4203428 on device 252,0, which is /dev/dm-0 (which on my system has major number 252, minor 0, which you can see by the command ls -l /dev/dm-0). This is probably dirty inode writeback, so that doesn't help tell you who dirtied the file. You can find the filename using debugfs: debugfs /dev/dm-0 debugfs: ncheck 4203428 Inode Pathname 4203428 /build/e2fsprogs-maint/tests/f_eofblocks.1.log (and since /dev/dm-0 is mounted on /u1, I know the filename is /u1/build/e2fsprogs-maint/....) The second line indicates the task id was 5875, and with a name like BrowserBlocking, it's almost certainly one of the Chrome threads. The ps program won't show individual threads by default, but you can also use the inode number to find which process has the file open by using lsof: lsof | grep 3545316 Once you're done, don't forget to disable the tracing to save a bit on CPU and battery life: cat /dev/null > /sys/kernel/debug/tracing/set_event Anyway, I hope this helps. -- You are receiving this mail because: You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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