Lockdep events subsystem gathers various locking related events
such as a request, release, contention or acquisition of a lock.
The name of this event subsystem is a bit of a misnomer since
these events are not quite related to lockdep but more generally
to locking, ie: these events are not reporting lock dependencies
or possible deadlock scenario but pure locking events.
Hence this rename.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <1258103194-843-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While tracing using events with perf, if one enables the
lockdep:lock_acquire event, it will infect every other perf
trace events.
Basically, you can enable whatever set of trace events through
perf but if this event is part of the set, the only result we
can get is a long list of lock_acquire events of rcu read lock,
and only that.
This is because of a recursion inside perf.
1) When a trace event is triggered, it will fill a per cpu
buffer and submit it to perf.
2) Perf will commit this event but will also protect some data
using rcu_read_lock
3) A recursion appears: rcu_read_lock triggers a lock_acquire
event that will fill the per cpu event and then submit the
buffer to perf.
4) Perf detects a recursion and ignores it
5) Perf continues its work on the previous event, but its buffer
has been overwritten by the lock_acquire event, it has then
been turned into a lock_acquire event of rcu read lock
Such scenario also happens with lock_release with
rcu_read_unlock().
We could turn the rcu_read_lock() into __rcu_read_lock() to drop
the lock debugging from perf fast path, but that would make us
lose the rcu debugging and that doesn't prevent from other
possible kind of recursion from perf in the future.
This patch adds a recursion protection based on a counter on the
perf trace per cpu buffers to solve the problem.
-v2: Fixed lost whitespace, added reviewed-by tag
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <1257477185-7838-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
tools/perf/Makefile
Merge reason:
- fix the conflict
- pick up the pr_*() infrastructure to queue up dependent patch
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now that we can filter based on fields via perf record, people
will start using filter expressions and will expect them to
be obvious.
The primary way to see which fields are available is by looking
at the trace output, such as:
gcc-18676 [000] 343.011728: irq_handler_entry: irq=0 handler=timer
cc1-18677 [000] 343.012727: irq_handler_entry: irq=0 handler=timer
cc1-18677 [000] 343.032692: irq_handler_entry: irq=0 handler=timer
cc1-18677 [000] 343.033690: irq_handler_entry: irq=0 handler=timer
cc1-18677 [000] 343.034687: irq_handler_entry: irq=0 handler=timer
cc1-18677 [000] 343.035686: irq_handler_entry: irq=0 handler=timer
cc1-18677 [000] 343.036684: irq_handler_entry: irq=0 handler=timer
While 'irq==0' filters work, the 'handler==<x>' filter expression
does not work:
$ perf record -R -f -a -e irq:irq_handler_entry --filter handler=timer sleep 1
Error: failed to set filter with 22 (Invalid argument)
The problem is that while an 'irq' field exists and is recognized
as a filter field - 'handler' does not exist - its name is 'name'
in the output.
To solve this, we need to synchronize the printout and the field
names, wherever possible.
In cases where the printout prints a non-field, we enclose
that information in square brackets, such as:
perf-1380 [013] 724.903505: softirq_exit: vec=9 [action=RCU]
perf-1380 [013] 724.904482: softirq_exit: vec=1 [action=TIMER]
This way users can use filter expressions more intuitively: all
fields that show up as 'primary' (non-bracketed) information is
filterable.
This patch harmonizes the field names for all irq, bkl, power,
sched and timer events.
We might in fact think about dropping the print format bit of
generic tracepoints altogether, and just print the fields that
are being recorded.
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge reason: to add event filter support we need the following
commits from the tracing tree:
3f6fe06: tracing/filters: Unify the regex parsing helpers
1889d20: tracing/filters: Provide basic regex support
737f453: tracing/filters: Cleanup useless headers
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Most of the syscalls metadata processing is done from arch.
But these operations are mostly generic accross archs. Especially now
that we have a common variable name that expresses the number of
syscalls supported by an arch: NR_syscalls, the only remaining bits
that need to reside in arch is the syscall nr to addr translation.
v2: Compare syscalls symbols only after the "sys" prefix so that we
avoid spurious mismatches with archs that have syscalls wrappers,
in which case syscalls symbols have "SyS" prefixed aliases.
(Reported by: Heiko Carstens)
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (41 commits)
Revert "Seperate read and write statistics of in_flight requests"
cfq-iosched: don't delay async queue if it hasn't dispatched at all
block: Topology ioctls
cfq-iosched: use assigned slice sync value, not default
cfq-iosched: rename 'desktop' sysfs entry to 'low_latency'
cfq-iosched: implement slower async initiate and queue ramp up
cfq-iosched: delay async IO dispatch, if sync IO was just done
cfq-iosched: add a knob for desktop interactiveness
Add a tracepoint for block request remapping
block: allow large discard requests
block: use normal I/O path for discard requests
swapfile: avoid NULL pointer dereference in swapon when s_bdev is NULL
fs/bio.c: move EXPORT* macros to line after function
Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs
cciss: fix build when !PROC_FS
block: Do not clamp max_hw_sectors for stacking devices
block: Set max_sectors correctly for stacking devices
cciss: cciss_host_attr_groups should be const
cciss: Dynamically allocate the drive_info_struct for each logical drive.
cciss: Add usage_count attribute to each logical drive in /sys
...
Since 2.6.31 now has request-based device-mapper, it's useful to have
a tracepoint for request-remapping as well as bio-remapping.
This patch adds a tracepoint for request-remapping, trace_block_rq_remap().
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: Fix time encoding with extra epoch bits
ext4: Add a stub for mpage_da_data in the trace header
jbd2: Use tracepoints for history file
ext4: Use tracepoints for mb_history trace file
ext4, jbd2: Drop unneeded printks at mount and unmount time
ext4: Handle nested ext4_journal_start/stop calls without a journal
ext4: Make sure ext4_dirty_inode() updates the inode in no journal mode
ext4: Avoid updating the inode table bh twice in no journal mode
ext4: EXT4_IOC_MOVE_EXT: Check for different original and donor inodes first
ext4: async direct IO for holes and fallocate support
ext4: Use end_io callback to avoid direct I/O fallback to buffered I/O
ext4: Split uninitialized extents for direct I/O
ext4: release reserved quota when block reservation for delalloc retry
ext4: Adjust ext4_da_writepages() to write out larger contiguous chunks
ext4: Fix hueristic which avoids group preallocation for closed files
ext4: Use ext4_msg() for ext4_da_writepage() errors
ext4: Update documentation about quota mount options
The tracepoint ext4_da_write_pages has a struct mpage_da_data*
parameter, but that struct is only defined in fs/ext4/ext4.h. This
patch adds a forward declaration for that struct, so this tracepoint
header can still be used by tools like SystemTap.
This is a continuation of the fix in commit 3661d286.
http://sourceware.org/bugzilla/show_bug.cgi?id=10703
Signed-off-by: Josh Stone <jistone@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The /proc/fs/jbd2/<dev>/history was maintained manually; by using
tracepoints, we can get all of the existing functionality of the /proc
file plus extra capabilities thanks to the ftrace infrastructure. We
save memory as a bonus.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The /proc/fs/ext4/<dev>/mb_history was maintained manually, and had a
number of problems: it required a largish amount of memory to be
allocated for each ext4 filesystem, and the s_mb_history_lock
introduced a CPU contention problem.
By ripping out the mb_history code and replacing it with ftrace
tracepoints, and we get more functionality: timestamps, event
filtering, the ability to correlate mballoc history with other ext4
tracepoints, etc.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Work around problems in the writeback code to force out writebacks in
larger chunks than just 4mb, which is just too small. This also works
around limitations in the ext4 block allocator, which can't allocate
more than 2048 blocks at a time. So we need to defeat the round-robin
characteristics of the writeback code and try to write out as many
blocks in one inode before allowing the writeback code to move on to
another inode. We add a a new per-filesystem tunable,
max_writeback_mb_bump, which caps this to a default of 128mb per
inode.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
modules, tracing: Remove stale struct marker signature from module_layout()
tracing/workqueue: Use %pf in workqueue trace events
tracing: Fix a comment and a trivial format issue in tracepoint.h
tracing: Fix failure path in ftrace_regex_open()
tracing: Fix failure path in ftrace_graph_write()
tracing: Check the return value of trace_get_user()
tracing: Fix off-by-one in trace_get_user()
Add two events lock_kernel and unlock_kernel() to trace the bkl uses.
This opens the door for userspace tools to perform statistics about
the callsites that use it, dependencies with other locks (by pairing
the trace with lock events), use with recursivity and so on...
The {__reacquire,release}_kernel_lock() events are not traced because
these are called from schedule, thus the sched events are sufficient
to trace them.
Example of a trace:
hald-addon-stor-4152 [000] 165.875501: unlock_kernel: depth: 0, fs/block_dev.c:1358 __blkdev_put()
hald-addon-stor-4152 [000] 167.832974: lock_kernel: depth: 0, fs/block_dev.c:1167 __blkdev_get()
How to get the callsites that acquire it recursively:
cd /debug/tracing/events/bkl
echo "lock_depth > 0" > filter
firefox-4951 [001] 206.276967: unlock_kernel: depth: 1, fs/reiserfs/super.c:575 reiserfs_dirty_inode()
You can also filter by file and/or line.
v2: Use of FILTER_PTR_STRING attribute for files and lines fields to
make them traceable.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
The page allocation trace event reports that a page was successfully
allocated but it does not specify where it came from. When analysing
performance, it can be important to distinguish between pages coming from
the per-cpu allocator and pages coming from the buddy lists as the latter
requires the zone lock to the taken and more data structures to be
examined.
This patch adds a trace event for __rmqueue reporting when a page is being
allocated from the buddy lists. It distinguishes between being called to
refill the per-cpu lists or whether it is a high-order allocation.
Similarly, this patch adds an event to catch when the PCP lists are being
drained a little and pages are going back to the buddy lists.
This is trickier to draw conclusions from but high activity on those
events could explain why there were a large number of cache misses on a
page-allocator-intensive workload. The coalescing and splitting of
buddies involves a lot of writing of page metadata and cache line bounces
not to mention the acquisition of an interrupt-safe lock necessary to
enter this path.
[akpm@linux-foundation.org: fix build]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Ming Chun <macli@brc.ubc.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fragmentation avoidance depends on being able to use free pages from lists
of the appropriate migrate type. In the event this is not possible,
__rmqueue_fallback() selects a different list and in some circumstances
change the migratetype of the pageblock. Simplistically, the more times
this event occurs, the more likely that fragmentation will be a problem
later for hugepage allocation at least but there are other considerations
such as the order of page being split to satisfy the allocation.
This patch adds a trace event for __rmqueue_fallback() that reports what
page is being used for the fallback, the orders of relevant pages, the
desired migratetype and the migratetype of the lists being used, whether
the pageblock changed type and whether this event is important with
respect to fragmentation avoidance or not. This information can be used
to help analyse fragmentation avoidance and help decide whether
min_free_kbytes should be increased or not.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Ming Chun <macli@brc.ubc.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
