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"Because when we call ftrace_free_rec we change the rec->ip to point to the
next record in the chain. Something is very wrong if rec->ip >= s &&
rec->ip < e and the record is already free."
"Note, use FTRACE_WARN_ON() macro. This way it shuts down ftrace if it is
hit and helps to avoid further damage later."
-- Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Empty lines separate cpus stat. After previous
fix(trace_stat: keep original order) applied, the empty lines
are displayed at incorrect position.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C9F266.2060706@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: make trace_stat files show items with the original order
trace_stat tracer reverse the items, it makes the output
looks a little ugly.
Example, when we read trace_stat/workqueues, we get cpu#7's stat.
at first, and then cpu#6... cpu#0.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C9F23F.5040307@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Fix incorrect way using seq_file's API
Use SEQ_START_TOKEN instead of calling ->stat_headers()
int seq_operation->start().
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
LKML-Reference: <49C9EAE5.5070202@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Add /** style comments around find_busiest_group(). Also add a few
explanatory comments.
This concludes the find_busiest_group() cleanup. The function is
now down to 72 lines from the original 313 lines.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: "Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>
LKML-Reference: <20090325091427.13992.18933.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Create seperate helper functions to initialize the
power-savings-balance related variables, to update them and
to check if we have a scope for performing power-savings balance.
Add no-op inline functions for the !(CONFIG_SCHED_MC || CONFIG_SCHED_SMT)
case.
This will eliminate all the #ifdef jungle in find_busiest_group() and the
other helper functions.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: "Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>
LKML-Reference: <20090325091422.13992.73616.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, micro-optimization
We don't need to perform power_savings balance if either the
cpu is NOT_IDLE or if the sched_domain doesn't contain the
SD_POWERSAVINGS_BALANCE flag set.
Currently, we check for these conditions multiple number of
times, even though these variables don't change over the scope
of find_busiest_group().
Check once, and store the value in the already exiting
"power_savings_balance" variable.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: "Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>
LKML-Reference: <20090325091417.13992.2657.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move all the imbalance calculation out of find_busiest_group()
through this helper function.
With this change, the structure of find_busiest_group() will be
as follows:
- update_sched_domain_statistics.
- check if imbalance exits.
- update imbalance and return busiest.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: "Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>
LKML-Reference: <20090325091411.13992.43293.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
We have two places in find_busiest_group() where we need to calculate
the minor imbalance before returning the busiest group. Encapsulate
this functionality into a seperate helper function.
Credit: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
LKML-Reference: <20090325091406.13992.54316.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Create a helper function named update_sd_lb_stats() to update the
various sched_domain related statistics in find_busiest_group().
With this we would have moved all the statistics computation out of
find_busiest_group().
Credit: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
LKML-Reference: <20090325091401.13992.88737.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Currently we use a lot of local variables in find_busiest_group()
to capture the various statistics related to the sched_domain.
Group them together into a single data structure.
This will help us to offload the job of updating the sched_domain
statistics to a helper function.
Credit: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
LKML-Reference: <20090325091356.13992.25970.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Create a helper function named update_sg_lb_stats() which
can be invoked to calculate the individual group's statistics
in find_busiest_group().
This reduces the lenght of find_busiest_group() considerably.
Credit: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Aked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
LKML-Reference: <20090325091351.13992.43461.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Currently a whole bunch of variables are used to store the
various statistics pertaining to the groups we iterate over
in find_busiest_group().
Group them together in a single data structure and add
appropriate comments.
This will be useful later on when we create helper functions
to calculate the sched_group statistics.
Credit: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
LKML-Reference: <20090325091345.13992.20099.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Some indentations in find_busiest_group() can minimized by using
early exits with the help of gotos. This improves readability in
a couple of cases.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: "Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>
LKML-Reference: <20090325091340.13992.45062.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Currently the load idx calculation code is in find_busiest_group().
Move that to a static inline helper function.
Similary, to find the first cpu of a sched_group we use
cpumask_first(sched_group_cpus(group))
Use a helper to that. It improves readability in some cases.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: "Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>
LKML-Reference: <20090325091335.13992.55424.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch combines Greg Bank's dprintk() work with the existing dynamic
printk patchset, we are now calling it 'dynamic debug'.
The new feature of this patchset is a richer /debugfs control file interface,
(an example output from my system is at the bottom), which allows fined grained
control over the the debug output. The output can be controlled by function,
file, module, format string, and line number.
for example, enabled all debug messages in module 'nf_conntrack':
echo -n 'module nf_conntrack +p' > /mnt/debugfs/dynamic_debug/control
to disable them:
echo -n 'module nf_conntrack -p' > /mnt/debugfs/dynamic_debug/control
A further explanation can be found in the documentation patch.
Signed-off-by: Greg Banks <gnb@sgi.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Impact: cleanup, new schedstat ABI
Since they are used on in statistics and are always set to zero, the
following fields from struct rq have been removed: yld_exp_empty,
yld_act_empty and yld_both_empty.
Both Sched Debug and SCHEDSTAT_VERSION versions has also been
incremented since ABIs have been changed.
The schedtop tool has been updated to properly handle new version of
schedstat:
http://rt.wiki.kernel.org/index.php/Schedtop_utility
Signed-off-by: Luis Henriques <henrix@sapo.pt>
Acked-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20090324221002.GA10061@hades.domain.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
struct dyn_ftrace::ip has different usages in his lifecycle,
we use union for it. And also for struct dyn_ftrace::flags.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C871BE.3080405@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix PID output under namespaces
When current namespace is not the global namespace,
pid read from set_ftrace_pid is no correct.
# ~/newpid_namespace_run bash
# echo $$
1
# echo 1 > set_ftrace_pid
# cat set_ftrace_pid
3756
Since we write virtual PID to set_ftrace_pid, we need get
virtual PID when we read it.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C84D65.9050606@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: give user a choice to show times spent while sleeping
The user may want to see the time a function spent sleeping.
This patch adds the trace option "sleep-time" to allow that.
The "sleep-time" option is default on.
echo sleep-time > /debug/tracing/trace_options
produces:
------------------------------------------
2) avahi-d-3428 => <idle>-0
------------------------------------------
2) | finish_task_switch() {
2) 0.621 us | _spin_unlock_irq();
2) 2.202 us | }
2) ! 1002.197 us | }
2) ! 1003.521 us | }
where as,
echo nosleep-time > /debug/tracing/trace_options
produces:
0) <idle>-0 => yum-upd-3416
------------------------------------------
0) | finish_task_switch() {
0) 0.643 us | _spin_unlock_irq();
0) 2.342 us | }
0) + 41.302 us | }
0) + 42.453 us | }
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: more accurate timings
The current method of function graph tracing does not take into
account the time spent when a task is not running. This shows functions
that call schedule have increased costs:
3) + 18.664 us | }
------------------------------------------
3) <idle>-0 => kblockd-123
------------------------------------------
3) | finish_task_switch() {
3) 1.441 us | _spin_unlock_irq();
3) 3.966 us | }
3) ! 2959.433 us | }
3) ! 2961.465 us | }
This patch uses the tracepoint in the scheduling context switch to
account for time that has elapsed while a task is scheduled out.
Now we see:
------------------------------------------
3) <idle>-0 => edac-po-1067
------------------------------------------
3) | finish_task_switch() {
3) 0.685 us | _spin_unlock_irq();
3) 2.331 us | }
3) + 41.439 us | }
3) + 42.663 us | }
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: prevent crash due to multiple function graph tracers
The function graph tracer can currently only handle a single tracer
being registered. If another tracer registers with the function
graph tracer it can crash the system.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch move the timestamp from happening in the arch specific
code into the general code. This allows for better control by the tracer
to time manipulation.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
If the function profiler does not have any items recorded and one were
to cat the function stat file, the kernel would take a BUG with a NULL
pointer dereference.
Looking further into this, I found that returning NULL from stat_start
did not stop the stat logic, and would later call stat_next. This breaks
from the way seq_file works, so I looked into fixing the stat code.
This is where I noticed that the last next_entry is never freed.
It is allocated, and if the stat_next returns NULL, the code breaks out
of the loop, unlocks the mutex and exits. We never link the next_entry
nor do we free it. Thus it is a real memory leak.
This patch rearranges the code a bit to not only fix the memory leak,
but also to act more like seq_file where nothing is printed if there
is nothing to print. That is, stat_start returns NULL.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: new feature, allow symbolic values in /debug/tracing/act_mask
Print stringified act_mask instead of hex value:
# cat act_mask
read,write,barrier,sync,queue,requeue,issue,complete,fs,pc,ahead,meta,
discard,drv_data
# echo "meta,write" > act_mask
# cat act_mask
write,meta
Also:
- make act_mask accept "ahead", "meta", "discard" and "drv_data"
- use strsep() instead of strchr() to parse user input
- return -EINVAL if a token is not found in the mask map
- fix a bug that 'value' is unsigned, so it can < 0
- propagate error value of blk_trace_mask2str() to userspace, but not
always return -ENXIO.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <49C8AB42.1000802@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix the output of IO type category characters
Trace categories are the upper 16 bits, not the lower 16 bits.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <49C89432.8010805@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix filter use boundary condition / crash
Make sure filters for string fields don't use integer values and vice
versa. Getting it wrong can crash the system or produce bogus
results.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237878882.8339.61.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Instead of just using the trace_seq buffer to print the filters, use
trace_seq_printf() as it was intended to be used.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237878871.8339.59.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix (small) per trace filter modification memory leak
Free the current pred when clearing the filters via the filter files.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237878851.8339.58.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
No need to use the safe version here, so use list_for_each_entry instead
of list_for_each_entry_safe in find_event_field().
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237878841.8339.57.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix traces output
Sometimes one can observe an imbalance in the traces between function
calls and function return traces:
func1() {
}
}
The curly brace inside func1() is the return of another function nested
inside func1. The return trace have been inserted in the buffer but not
the entry.
We are storing a return address on the function traces stack while we
haven't inserted its entry on the buffer, hence the imbalance on the
traces.
This is because the tracers doesn't check all failures that can happen
on buffer insertion.
This patch reports the tracing recursion failures and the ring buffer
failures. In such cases, we now restore the original return address for
the function, giving up its return trace.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237843021-11695-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
commit 40ada30f9621fbd831ac2437b9a2a399aa ("tracing: clean up menu"),
despite the "clean up" in its purpose, introduced a behavioural
change for Kconfig symbols: we no longer able to select tracing
support on PPC32 (because IRQFLAGS_SUPPORT isn't yet implemented).
The IRQFLAGS_SUPPORT is not mandatory for most tracers, tracing core
has a special case for platforms w/o irqflags (which, by the way, has
become useless as of the commit above).
Though according to Ingo Molnar, there was periodic build failures on
weird, unmaintained architectures that had no irqflags-tracing support
and hence didn't know the raw_irqs_save/restore primitives. Thus we'd
better not enable irqflags-less tracing for all architectures.
This patch restores the old behaviour for PPC32, and thus brings the
tracing back. Other architectures can either add themselves to the
exception list or (better) implement TRACE_IRQFLAGS_SUPPORT.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-b: Steven Rostedt <rostedt@goodmis.org>
Cc: linuxppc-dev@ozlabs.org
LKML-Reference: <20090323220724.GA9851@oksana.dev.rtsoft.ru>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
See http://bugzilla.kernel.org/show_bug.cgi?id=12911
copy_signal() copies signal->rlim, but RLIMIT_CPU is "lost". Because
posix_cpu_timers_init_group() sets cputime_expires.prof_exp = 0 and thus
fastpath_timer_check() returns false unless we have other cpu timers.
This is the minimal fix for 2.6.29 (tested) and 2.6.28. The patch is not
optimal, we need further cleanups here. With this patch update_rlimit_cpu()
is not really needed, but I don't think it should be removed.
The proper fix (I think) is:
- set_process_cpu_timer() should just start the cputimer->running
logic (it does), no need to change cputime_expires.xxx_exp
- posix_cpu_timers_init_group() should set ->running when needed
- fastpath_timer_check() can check ->running instead of
task_cputime_zero(signal->cputime_expires)
Reported-by: Peter Lojkin <ia6432@inbox.ru>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: <stable@kernel.org> [for 2.6.29.x]
LKML-Reference: <20090323193411.GA17514@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch fixes bug #12208:
Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12208
Subject : uml is very slow on 2.6.28 host
This turned out to be not a scheduler regression, but an already
existing problem in ptrace being triggered by subtle scheduler
changes.
The problem is this:
- task A is ptracing task B
- task B stops on a trace event
- task A is woken up and preempts task B
- task A calls ptrace on task B, which does ptrace_check_attach()
- this calls wait_task_inactive(), which sees that task B is still on the runq
- task A goes to sleep for a jiffy
- ...
Since UML does lots of the above sequences, those jiffies quickly add
up to make it slow as hell.
This patch solves this by not rescheduling in read_unlock() after
ptrace_stop() has woken up the tracer.
Thanks to Oleg Nesterov and Ingo Molnar for the feedback.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: fix a crash with ftrace={nop,boot} parameter
If the nop or initcall tracers are launched as boot tracers,
they will attempt to create their option directory and files.
But these tracers are registered very early and then assigned
as "boot tracers" very early if asked to.
Since they do this before debugfs has been registered (core initcall),
a crash is triggered.
Another early tracers could also come later. So we fix it by
checking if debugfs is initialized before creating the root
tracing directory.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237759847-21025-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, memory leak fix
This patch cleans up filter_add_subsystem_pred():
- searches for the field before creating a copy of the pred
- fixes memory leak in the case a predicate isn't applied
- if -ENOMEM, makes sure there's no longer a reference to the
pred so the caller can free the half-finished filter
- changes the confusing i == MAX_FILTER_PRED - 1 comparison
previously remarked upon
This affects only per-subsystem event filtering.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237796808.7527.40.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix potential crash on subsystem filter expression freeing
When making a copy of the predicate, pred->field_name needs to be
duplicated in the copy as well, otherwise bad things can happen due to
later multiple frees of the same string.
This affects only per-subsystem event filtering.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237796802.7527.39.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we want to filter an event, the filter test is done after
the event is commited to the ring-buffer to be discarded later if
needed.
But a reader could be reading this event while we are trying to discard
it. Other kind of racy events can even happen because the event is
commited and can be read and/or consumed.
What we want is to discard the event before committing it.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1237763919-21505-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: display events when they arrive
Now that the events don't use wake_up() anymore, we need the nop
tracer to poll waiting for events on the pipe. Especially because
nop is useful to look at orphan traces types (traces types that
don't rely on specific tracers) because it doesn't produce traces
itself.
And unlike other tracers that trigger specific traces periodically,
nop triggers no traces by itself that can wake him.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237759847-21025-5-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix hard-lockup with sched switch events
Some ftrace events, such as sched wakeup, can be traced
while the runqueue lock is hold. Since they are using
trace_current_buffer_unlock_commit(), they call wake_up()
which can try to grab the runqueue lock too, resulting in
a deadlock.
Now for all event, we call a new helper:
trace_nowake_buffer_unlock_commit() which do pretty the same than
trace_current_buffer_unlock_commit() except than it doesn't call
trace_wake_up().
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237759847-21025-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We need the filter files to be writable, the current
filter file permissions are only set readable.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1237759847-21025-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix potential kfree of random data in (rare) failure path
Zero-initialize the field structure.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1237710639.7703.46.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
