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2009-09-15sched: for_each_domain() vs RCUPeter Zijlstra
for_each_domain() uses RCU to serialize the sched_domains, except it doesn't actually use rcu_read_lock() and instead relies on disabling preemption -> FAIL. XXX: audit other sched_domain code. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Weaken SD_POWERSAVINGS_BALANCEPeter Zijlstra
One of the problems of power-saving balancing is that under certain scenarios it is too slow and allows tons of real work to pile up. Avoid this by ignoring the powersave stuff when there's real work to be done. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Merge select_task_rq_fair() and sched_balance_self()Peter Zijlstra
The problem with wake_idle() is that is doesn't respect things like cpu_power, which means it doesn't deal well with SMT nor the recent RT interaction. To cure this, it needs to do what sched_balance_self() does, which leads to the possibility of merging select_task_rq_fair() and sched_balance_self(). Modify sched_balance_self() to: - update_shares() when walking up the domain tree, (it only called it for the top domain, but it should have done this anyway), which allows us to remove this ugly bit from try_to_wake_up(). - do wake_affine() on the smallest domain that contains both this (the waking) and the prev (the wakee) cpu for WAKE invocations. Then use the top-down balance steps it had to replace wake_idle(). This leads to the dissapearance of SD_WAKE_BALANCE and SD_WAKE_IDLE_FAR, with SD_WAKE_IDLE replaced with SD_BALANCE_WAKE. SD_WAKE_AFFINE needs SD_BALANCE_WAKE to be effective. Touch all topology bits to replace the old with new SD flags -- platforms might need re-tuning, enabling SD_BALANCE_WAKE conditionally on a NUMA distance seems like a good additional feature, magny-core and small nehalem systems would want this enabled, systems with slow interconnects would not. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Add TASK_WAKINGPeter Zijlstra
We're going to want to drop rq->lock in try_to_wake_up() for a longer period of time, however we also want to deal with concurrent waking of the same task, which is currently handled by holding rq->lock. So introduce a new TASK state, namely TASK_WAKING, which indicates someone is already waking the task (other wakers will fail p->state & state). We also keep preemption disabled over the whole ttwu(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Hook sched_balance_self() into sched_class::select_task_rq()Peter Zijlstra
Rather ugly patch to fully place the sched_balance_self() code inside the fair class. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Move sched_balance_self() into sched_fair.cPeter Zijlstra
Move the sched_balance_self() code into sched_fair.c This facilitates the merger of sched_balance_self() and sched_fair::select_task_rq(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Move code aroundPeter Zijlstra
In preparation to other code movement, move weighted_cpuload(), source_load() and target_load() before the class includes. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Add come comments to the sched featuresPeter Zijlstra
Add text... Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Complete buddy switchesMike Galbraith
Add a NEXT_BUDDY feature flag to aid in debugging. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Split WAKEUP_OVERLAPPeter Zijlstra
It consists of two conditions, split them out in separate toggles so we can test them independently. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15sched: Fix double_rq_lock() compile warningPeter Zijlstra
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-11Merge branch 'tracing-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (105 commits) ring-buffer: only enable ring_buffer_swap_cpu when needed ring-buffer: check for swapped buffers in start of committing tracing: report error in trace if we fail to swap latency buffer tracing: add trace_array_printk for internal tracers to use tracing: pass around ring buffer instead of tracer tracing: make tracing_reset safe for external use tracing: use timestamp to determine start of latency traces tracing: Remove mentioning of legacy latency_trace file from documentation tracing/filters: Defer pred allocation, fix memory leak tracing: remove users of tracing_reset tracing: disable buffers and synchronize_sched before resetting tracing: disable update max tracer while reading trace tracing: print out start and stop in latency traces ring-buffer: disable all cpu buffers when one finds a problem ring-buffer: do not count discarded events ring-buffer: remove ring_buffer_event_discard ring-buffer: fix ring_buffer_read crossing pages ring-buffer: remove unnecessary cpu_relax ring-buffer: do not swap buffers during a commit ring-buffer: do not reset while in a commit ...
2009-09-11Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (64 commits) sched: Fix sched::sched_stat_wait tracepoint field sched: Disable NEW_FAIR_SLEEPERS for now sched: Keep kthreads at default priority sched: Re-tune the scheduler latency defaults to decrease worst-case latencies sched: Turn off child_runs_first sched: Ensure that a child can't gain time over it's parent after fork() sched: enable SD_WAKE_IDLE sched: Deal with low-load in wake_affine() sched: Remove short cut from select_task_rq_fair() sched: Turn on SD_BALANCE_NEWIDLE sched: Clean up topology.h sched: Fix dynamic power-balancing crash sched: Remove reciprocal for cpu_power sched: Try to deal with low capacity, fix update_sd_power_savings_stats() sched: Try to deal with low capacity sched: Scale down cpu_power due to RT tasks sched: Implement dynamic cpu_power sched: Add smt_gain sched: Update the cpu_power sum during load-balance sched: Add SD_PREFER_SIBLING ...
2009-09-11Merge branch 'perfcounters-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (60 commits) perf tools: Avoid unnecessary work in directory lookups perf stat: Clean up statistics calculations a bit more perf stat: More advanced variance computation perf stat: Use stddev_mean in stead of stddev perf stat: Remove the limit on repeat perf stat: Change noise calculation to use stddev x86, perf_counter, bts: Do not allow kernel BTS tracing for now x86, perf_counter, bts: Correct pointer-to-u64 casts x86, perf_counter, bts: Fail if BTS is not available perf_counter: Fix output-sharing error path perf trace: Fix read_string() perf trace: Print out in nanoseconds perf tools: Seek to the end of the header area perf trace: Fix parsing of perf.data perf trace: Sample timestamps as well perf_counter: Introduce new (non-)paranoia level to allow raw tracepoint access perf trace: Sample the CPU too perf tools: Work around strict aliasing related warnings perf tools: Clean up warnings list in the Makefile perf tools: Complete support for dynamic strings ...
2009-09-11Merge branch 'irq-threaded-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-threaded-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: genirq: Do not mask oneshot edge type interrupts genirq: Support nested threaded irq handling genirq: Add buslock support genirq: Add oneshot support
2009-09-11Merge branch 'irq-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: pci/intr_remapping: Allocate irq_iommu on node irq: Add irq_node() primitive irq: Make sure irq_desc for legacy irq get correct node setting genirq: Add prototype for handle_nested_irq() irq: Remove superfluous NULL pointer check in check_irq_resend() irq: Clean up by removing irqfixup MODULE_PARM_DESC() genirq: Fix comment describing suspend_device_irqs() genirq: Remove obsolete defines and typedefs
2009-09-11Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (28 commits) rcu: Move end of special early-boot RCU operation earlier rcu: Changes from reviews: avoid casts, fix/add warnings, improve comments rcu: Create rcutree plugins to handle hotplug CPU for multi-level trees rcu: Remove lockdep annotations from RCU's _notrace() API members rcu: Add #ifdef to suppress __rcu_offline_cpu() warning in !HOTPLUG_CPU builds rcu: Add CPU-offline processing for single-node configurations rcu: Add "notrace" to RCU function headers used by ftrace rcu: Remove CONFIG_PREEMPT_RCU rcu: Merge preemptable-RCU functionality into hierarchical RCU rcu: Simplify rcu_pending()/rcu_check_callbacks() API rcu: Use debugfs_remove_recursive() simplify code. rcu: Merge per-RCU-flavor initialization into pre-existing macro rcu: Fix online/offline indication for rcudata.csv trace file rcu: Consolidate sparse and lockdep declarations in include/linux/rcupdate.h rcu: Renamings to increase RCU clarity rcu: Move private definitions from include/linux/rcutree.h to kernel/rcutree.h rcu: Expunge lingering references to CONFIG_CLASSIC_RCU, optimize on !SMP rcu: Delay rcu_barrier() wait until beginning of next CPU-hotunplug operation. rcu: Fix typo in rcu_irq_exit() comment header rcu: Make rcupreempt_trace.c look at offline CPUs ...
2009-09-11Merge branch 'core-printk-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: printk: Fix "printk: Enable the use of more than one CON_BOOT (early console)" printk: Restore previous console_loglevel when re-enabling logging printk: Ensure that "console enabled" messages are printed on the console printk: Enable the use of more than one CON_BOOT (early console)
2009-09-11Merge branch 'core-locking-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (32 commits) locking, m68k/asm-offsets: Rename signal defines locking: Inline spinlock code for all locking variants on s390 locking: Simplify spinlock inlining locking: Allow arch-inlined spinlocks locking: Move spinlock function bodies to header file locking, m68k: Calculate thread_info offset with asm offset locking, m68k/asm-offsets: Rename pt_regs offset defines locking, sparc: Rename __spin_try_lock() and friends locking, powerpc: Rename __spin_try_lock() and friends lockdep: Remove recursion stattistics lockdep: Simplify lock_stat seqfile code lockdep: Simplify lockdep_chains seqfile code lockdep: Simplify lockdep seqfile code lockdep: Fix missing entries in /proc/lock_chains lockdep: Fix missing entry in /proc/lock_stat lockdep: Fix memory usage info of BFS lockdep: Reintroduce generation count to make BFS faster lockdep: Deal with many similar locks lockdep: Introduce lockdep_assert_held() lockdep: Fix style nits ...
2009-09-11Merge branch 'core-futexes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-futexes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Detect mismatched requeue targets futex: Correct futex_wait_requeue_pi() commentary
2009-09-11Merge branch 'core-debug-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: debug lockups: Improve lockup detection, fix generic arch fallback debug lockups: Improve lockup detection
2009-09-11Merge branch 'core-cleanups-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: workqueues: Improve schedule_work() documentation
2009-09-11Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'writeback' of git://git.kernel.dk/linux-2.6-block: writeback: check for registered bdi in flusher add and inode dirty writeback: add name to backing_dev_info writeback: add some debug inode list counters to bdi stats writeback: get rid of pdflush completely writeback: switch to per-bdi threads for flushing data writeback: move dirty inodes from super_block to backing_dev_info writeback: get rid of generic_sync_sb_inodes() export
2009-09-11writeback: add name to backing_dev_infoJens Axboe
This enables us to track who does what and print info. Its main use is catching dirty inodes on the default_backing_dev_info, so we can fix that up. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11Merge branch 'next' into for-linusJames Morris
2009-09-10sched: Fix sched::sched_stat_wait tracepoint fieldIngo Molnar
This weird perf trace output: cc1-9943 [001] 2802.059479616: sched_stat_wait: task: as:9944 wait: 2801938766276 [ns] Is caused by setting one component field of the delta to zero a bit too early. Move it to later. ( Note, this does not affect the NEW_FAIR_SLEEPERS interactivity bug, it's just a reporting bug in essence. ) Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nikos Chantziaras <realnc@arcor.de> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <4AA93D34.8040500@arcor.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-10sched: Disable NEW_FAIR_SLEEPERS for nowIngo Molnar
Nikos Chantziaras and Jens Axboe reported that turning off NEW_FAIR_SLEEPERS improves desktop interactivity visibly. Nikos described his experiences the following way: " With this setting, I can do "nice -n 19 make -j20" and still have a very smooth desktop and watch a movie at the same time. Various other annoyances (like the "logout/shutdown/restart" dialog of KDE not appearing at all until the background fade-out effect has finished) are also gone. So this seems to be the single most important setting that vastly improves desktop behavior, at least here. " Jens described it the following way, referring to a 10-seconds xmodmap scheduling delay he was trying to debug: " Then I tried switching NO_NEW_FAIR_SLEEPERS on, and then I get: Performance counter stats for 'xmodmap .xmodmap-carl': 9.009137 task-clock-msecs # 0.447 CPUs 18 context-switches # 0.002 M/sec 1 CPU-migrations # 0.000 M/sec 315 page-faults # 0.035 M/sec 0.020167093 seconds time elapsed Woot! " So disable it for now. In perf trace output i can see weird delta timestamps: cc1-9943 [001] 2802.059479616: sched_stat_wait: task: as:9944 wait: 2801938766276 [ns] That nsec field is not supposed to be that large. More digging is needed - but lets turn it off while the real bug is found. Reported-by: Nikos Chantziaras <realnc@arcor.de> Tested-by: Nikos Chantziaras <realnc@arcor.de> Reported-by: Jens Axboe <jens.axboe@oracle.com> Tested-by: Jens Axboe <jens.axboe@oracle.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <4AA93D34.8040500@arcor.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-09sched: Keep kthreads at default priorityMike Galbraith
Removes kthread/workqueue priority boost, they increase worst-case desktop latencies. Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1252486344.28645.18.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-09sched: Re-tune the scheduler latency defaults to decrease worst-case latenciesMike Galbraith
Reduce the latency target from 20 msecs to 5 msecs. Why? Larger latencies increase spread, which is good for scaling, but bad for worst case latency. We still have the ilog(nr_cpus) rule to scale up on bigger server boxes. Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1252486344.28645.18.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-09sched: Turn off child_runs_firstMike Galbraith
Set child_runs_first default to off. It hurts 'optimal' make -j<NR_CPUS> workloads as make jobs get preempted by child tasks, reducing parallelism. Note, this patch might make existing races in user applications more prominent than before - so breakages might be bisected to this commit. Child-runs-first is broken on SMP to begin with, and we already had it off briefly in v2.6.23 so most of the offenders ought to be fixed. Would be nice not to revert this commit but fix those apps finally ... Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1252486344.28645.18.camel@marge.simson.net> [ made the sysctl independent of CONFIG_SCHED_DEBUG, in case people want to work around broken apps. ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-08sched: Ensure that a child can't gain time over it's parent after fork()Mike Galbraith
A fork/exec load is usually "pass the baton", so the child should never be placed behind the parent. With START_DEBIT we make room for the new task, but with child_runs_first, that room comes out of the _parent's_ hide. There's nothing to say that the parent wasn't ahead of min_vruntime at fork() time, which means that the "baton carrier", who is essentially the parent in drag, can gain time and increase scheduling latencies for waiters. With NEW_FAIR_SLEEPERS + START_DEBIT + child_runs_first enabled, we essentially pass the sleeper fairness off to the child, which is fine, but if we don't base placement on the parent's updated vruntime, we can end up compounding latency woes if the child itself then does fork/exec. The debit incurred at fork doesn't hurt the parent who is then going to sleep and maybe exit, but the child who acquires the error harms all comers. This improves latencies of make -j<n> kernel build workloads. Reported-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-07sched: Deal with low-load in wake_affine()Peter Zijlstra
wake_affine() would always fail under low-load situations where both prev and this were idle, because adding a single task will always be a significant imbalance, even if there's nothing around that could balance it. Deal with this by allowing imbalance when there's nothing you can do about it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-07sched: Remove short cut from select_task_rq_fair()Peter Zijlstra
select_task_rq_fair() incorrectly skips the wake_affine() logic, remove this. When prev_cpu == this_cpu, the code jumps straight to the wake_idle() logic, this doesn't give the wake_affine() logic the chance to pin the task to this cpu. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-07Security/SELinux: includecheck fix kernel/sysctl.cJaswinder Singh Rajput
fix the following 'make includecheck' warning: kernel/sysctl.c: linux/security.h is included more than once. Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-09-06Merge branch 'tracing/core' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into tracing/core
2009-09-06Merge commit 'v2.6.31-rc9' into tracing/coreIngo Molnar
Merge reason: move from -rc5 to -rc9. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-05Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf_counter/powerpc: Fix cache event codes for POWER7 perf_counter: Fix /0 bug in swcounters perf_counters: Increase paranoia level
2009-09-04ring-buffer: only enable ring_buffer_swap_cpu when neededSteven Rostedt
Since the ability to swap the cpu buffers adds a small overhead to the recording of a trace, we only want to add it when needed. Only the irqsoff and preemptoff tracers use this feature, and both are not recommended for production kernels. This patch disables its use when neither irqsoff nor preemptoff is configured. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04ring-buffer: check for swapped buffers in start of committingSteven Rostedt
Because the irqsoff tracer can swap an internal CPU buffer, it is possible that a swap happens between the start of the write and before the committing bit is set (the committing bit will disable swapping). This patch adds a check for this and will fail the write if it detects it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: report error in trace if we fail to swap latency bufferSteven Rostedt
The irqsoff tracer will fail to swap the cpu buffer with the max buffer if it preempts a commit. Instead of ignoring this, this patch makes the tracer report it if the last max latency failed due to preempting a current commit. The output of the latency tracer will look like this: # tracer: irqsoff # # irqsoff latency trace v1.1.5 on 2.6.31-rc5 # -------------------------------------------------------------------- # latency: 112 us, #1/1, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -4281 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # => started at: save_args # => ended at: __do_softirq # # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / bash-4281 1d.s6 265us : update_max_tr_single: Failed to swap buffers due to commit in progress Note the latency time and the functions that disabled the irqs or preemption will still be listed. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: add trace_array_printk for internal tracers to useSteven Rostedt
This patch adds a trace_array_printk to allow a tracer to use the trace_printk on its own trace array. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: pass around ring buffer instead of tracerSteven Rostedt
The latency tracers (irqsoff and wakeup) can swap trace buffers on the fly. If an event is happening and has reserved data on one of the buffers, and the latency tracer swaps the global buffer with the max buffer, the result is that the event may commit the data to the wrong buffer. This patch changes the API to the trace recording to be recieve the buffer that was used to reserve a commit. Then this buffer can be passed in to the commit. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: make tracing_reset safe for external useSteven Rostedt
Reseting the trace buffer without first disabling the buffer and waiting for any writers to complete, can corrupt the ring buffer. This patch makes the external version of tracing_reset safe from corruption by disabling the ring buffer and calling synchronize_sched. This version can no longer be called from interrupt context. But all those callers have been removed. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: use timestamp to determine start of latency tracesSteven Rostedt
Currently the latency tracers reset the ring buffer. Unfortunately if a commit is in process (due to a trace event), this can corrupt the ring buffer. When this happens, the ring buffer will detect the corruption and then permanently disable the ring buffer. The bug does not crash the system, but it does prevent further tracing after the bug is hit. Instead of reseting the trace buffers, the timestamp of the start of the trace is used instead. The buffers will still contain the previous data, but the output will not count any data that is before the timestamp of the trace. Note, this only affects the static trace output (trace) and not the runtime trace output (trace_pipe). The runtime trace output does not make sense for the latency tracers anyway. Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing/filters: Defer pred allocation, fix memory leakLi Zefan
The predicates of an event and their filter structure are allocated when we create an event filter for the first time. These objects must be created once but each time we come with a new filter, we overwrite such pre-existing allocation, if any. Thus, this patch checks if the filter has already been allocated before going ahead. Spotted-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> LKML-Reference: <4A9CB1BA.3060402@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-04tracing: remove users of tracing_resetSteven Rostedt
The function tracing_reset is deprecated for outside use of trace.c. The new function to reset the the buffers is tracing_reset_online_cpus. The reason for this is that resetting the buffers while the event trace points are active can corrupt the buffers, because they may be writing at the time of reset. The tracing_reset_online_cpus disables writes and waits for current writers to finish. This patch replaces all users of tracing_reset except for the latency tracers. Those changes require more work and will be removed in the following patches. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: disable buffers and synchronize_sched before resettingSteven Rostedt
Resetting the ring buffers while traces are happening can corrupt the ring buffer and disable it (no kernel crash to worry about). The safest thing to do is disable the ring buffers, call synchronize_sched() to wait for all current writers to finish and then reset the buffer. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: disable update max tracer while reading traceSteven Rostedt
When reading the tracer from the trace file, updating the max latency may corrupt the output. This patch disables the tracing of the max latency while reading the trace file. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: print out start and stop in latency tracesSteven Rostedt
During development of the tracer, we would copy information from the live tracer to the max tracer with one memcpy. Since then we added a generic ring buffer and we handle the copies differently now. Unfortunately, we never copied the critical section information, and we lost the output: # => started at: kmem_cache_alloc # => ended at: kmem_cache_alloc This patch adds back the critical start and end copying as well as removes the unused "trace_idx" and "overrun" fields of the trace_array_cpu structure. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04ring-buffer: disable all cpu buffers when one finds a problemSteven Rostedt
Currently the way RB_WARN_ON works, is to disable either the current CPU buffer or all CPU buffers, depending on whether a ring_buffer or ring_buffer_per_cpu struct was passed into the macro. Most users of the RB_WARN_ON pass in the CPU buffer, so only the one CPU buffer gets disabled but the rest are still active. This may confuse users even though a warning is sent to the console. This patch changes the macro to disable the entire buffer even if the CPU buffer is passed in. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>