linux/include/trace/events/writeback.h, branch v3.4.1

Merge tag 'device-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

2012-03-24T17:41:37Z

Pull avoidance patches from Paul Gortmaker: "Nearly every subsystem has some kind of header with a proto like: void foo(struct device *dev); and yet there is no reason for most of these guys to care about the sub fields within the device struct. This allows us to significantly reduce the scope of headers including headers. For this instance, a reduction of about 40% is achieved by replacing the include with the simple fact that the device is some kind of a struct. Unlike the much larger module.h cleanup, this one is simply two commits. One to fix the implicit users, and then one to delete the device.h includes from the linux/include/ dir wherever possible." * tag 'device-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: device.h: audit and cleanup users in main include dir device.h: cleanup users outside of linux/include (C files)

device.h: audit and cleanup users in main include dir

2012-03-16T14:38:24Z

The header includes a lot of stuff, and it in turn gets a lot of use just for the basic "struct device" which appears so often. Clean up the users as follows: 1) For those headers only needing "struct device" as a pointer in fcn args, replace the include with exactly that. 2) For headers not really using anything from device.h, simply delete the include altogether. 3) For headers relying on getting device.h implicitly before being included themselves, now explicitly include device.h 4) For files in which doing #1 or #2 uncovers an implicit dependency on some other header, fix by explicitly adding the required header(s). Any C files that were implicitly relying on device.h to be present have already been dealt with in advance. Total removals from #1 and #2: 51. Total additions coming from #3: 9. Total other implicit dependencies from #4: 7. As of 3.3-rc1, there were 110, so a net removal of 42 gives about a 38% reduction in device.h presence in include/* Signed-off-by: Paul Gortmaker

writeback: fix dereferencing NULL bdi->dev on trace_writeback_queue

2012-02-06T03:17:25Z

When a SD card is hot removed without umount, del_gendisk() will call bdi_unregister() without destroying/freeing it. This leaves the bdi in the bdi->dev = NULL, bdi->wb.task = NULL, bdi->bdi_list removed state. When sync(2) gets the bdi before bdi_unregister() and calls bdi_queue_work() after the unregister, trace_writeback_queue will be dereferencing the NULL bdi->dev. Fix it with a simple test for NULL. LKML-reference: http://lkml.org/lkml/2012/1/18/346 Cc: stable@kernel.org Reported-by: Rabin Vincent Tested-by: Namjae Jeon Signed-off-by: Wu Fengguang

writeback: fix NULL bdi->dev in trace writeback_single_inode

2012-02-01T08:53:40Z

bdi_prune_sb() resets sb->s_bdi to default_backing_dev_info when the tearing down the original bdi. Fix trace_writeback_single_inode to use sb->s_bdi=default_backing_dev_info rather than bdi->dev=NULL for a teared down bdi. Cc: Reported-by: Rabin Vincent Tested-by: Rabin Vincent Signed-off-by: Wu Fengguang

writeback: dirty ratelimit - think time compensation

2011-12-18T06:20:27Z

Compensate the task's think time when computing the final pause time, so that ->dirty_ratelimit can be executed accurately. think time := time spend outside of balance_dirty_pages() In the rare case that the task slept longer than the 200ms period time (result in negative pause time), the sleep time will be compensated in the following periods, too, if it's less than 1 second. Accumulated errors are carefully avoided as long as the max pause area is not hitted. Pseudo code: period = pages_dirtied / task_ratelimit; think = jiffies - dirty_paused_when; pause = period - think; 1) normal case: period > think pause = period - think dirty_paused_when = jiffies + pause nr_dirtied = 0 period time |===============================>| think time pause time |===============>|==============>| ------|----------------|---------------|------------------------ dirty_paused_when jiffies 2) no pause case: period <= think don't pause; reduce future pause time by: dirty_paused_when += period nr_dirtied = 0 period time |===============================>| think time |===================================================>| ------|--------------------------------+-------------------|---- dirty_paused_when jiffies Acked-by: Jan Kara Acked-by: Peter Zijlstra Signed-off-by: Wu Fengguang

writeback: show writeback reason with __print_symbolic

2011-12-18T06:20:17Z

This makes the binary trace understandable by trace-cmd. CC: Dave Chinner CC: Curt Wohlgemuth CC: Steven Rostedt Signed-off-by: Wu Fengguang

writeback: Add a 'reason' to wb_writeback_work

2011-10-30T16:33:36Z

This creates a new 'reason' field in a wb_writeback_work structure, which unambiguously identifies who initiates writeback activity. A 'wb_reason' enumeration has been added to writeback.h, to enumerate the possible reasons. The 'writeback_work_class' and tracepoint event class and 'writeback_queue_io' tracepoints are updated to include the symbolic 'reason' in all trace events. And the 'writeback_inodes_sbXXX' family of routines has had a wb_stats parameter added to them, so callers can specify why writeback is being started. Acked-by: Jan Kara Signed-off-by: Curt Wohlgemuth Signed-off-by: Wu Fengguang

writeback: send work item to queue_io, move_expired_inodes

2011-10-30T16:33:27Z

Instead of sending ->older_than_this to queue_io() and move_expired_inodes(), send the entire wb_writeback_work structure. There are other fields of a work item that are useful in these routines and in tracepoints. Acked-by: Jan Kara Signed-off-by: Curt Wohlgemuth Signed-off-by: Wu Fengguang

writeback: trace event balance_dirty_pages

2011-10-30T16:29:38Z

Useful for analyzing the dynamics of the throttling algorithms and debugging user reported problems. Signed-off-by: Wu Fengguang

writeback: trace event bdi_dirty_ratelimit

2011-10-30T16:29:21Z

It helps understand how various throttle bandwidths are updated. Signed-off-by: Wu Fengguang