linux/kernel/events, branch v3.2.2

perf events: Fix ring_buffer_wakeup() brown paperbag bug

2011-12-14T07:44:53Z

Commit 10c6db11 ("perf: Fix loss of notification with multi-event") seems to unconditionally dereference event->rb in the wakeup handler, this is wrong, there might not be a buffer attached. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20111213152651.GP20297@mudshark.cambridge.arm.com [ minor edits ] Signed-off-by: Ingo Molnar

perf: Do no try to schedule task events if there are none

2011-12-07T15:31:22Z

perf_event_sched_in() shouldn't try to schedule task events if there are none otherwise task's ctx->is_active will be set and will not be cleared during sched_out. This will prevent newly added events from being scheduled into the task context. Fixes a boo-boo in commit 1d5f003f5a9 ("perf: Do not set task_ctx pointer in cpuctx if there are no events in the context"). Signed-off-by: Gleb Natapov Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20111122140821.GF2557@redhat.com Signed-off-by: Ingo Molnar

perf: Fix loss of notification with multi-event

2011-12-05T08:33:03Z

When you do: $ perf record -e cycles,cycles,cycles noploop 10 You expect about 10,000 samples for each event, i.e., 10s at 1000samples/sec. However, this is not what's happening. You get much fewer samples, maybe 3700 samples/event: $ perf report -D | tail -15 Aggregated stats: TOTAL events: 10998 MMAP events: 66 COMM events: 2 SAMPLE events: 10930 cycles stats: TOTAL events: 3644 SAMPLE events: 3644 cycles stats: TOTAL events: 3642 SAMPLE events: 3642 cycles stats: TOTAL events: 3644 SAMPLE events: 3644 On a Intel Nehalem or even AMD64, there are 4 counters capable of measuring cycles, so there is plenty of space to measure those events without multiplexing (even with the NMI watchdog active). And even with multiplexing, we'd expect roughly the same number of samples per event. The root of the problem was that when the event that caused the buffer to become full was not the first event passed on the cmdline, the user notification would get lost. The notification was sent to the file descriptor of the overflowed event but the perf tool was not polling on it. The perf tool aggregates all samples into a single buffer, i.e., the buffer of the first event. Consequently, it assumes notifications for any event will come via that descriptor. The seemingly straight forward solution of moving the waitq into the ringbuffer object doesn't work because of life-time issues. One could perf_event_set_output() on a fd that you're also blocking on and cause the old rb object to be freed while its waitq would still be referenced by the blocked thread -> FAIL. Therefore link all events to the ringbuffer and broadcast the wakeup from the ringbuffer object to all possible events that could be waited upon. This is rather ugly, and we're open to better solutions but it works for now. Reported-by: Stephane Eranian Finished-by: Stephane Eranian Reviewed-by: Stephane Eranian Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20111126014731.GA7030@quad Signed-off-by: Ingo Molnar

perf: Do not set task_ctx pointer in cpuctx if there are no events in the context

2011-11-14T12:01:21Z

Do not set task_ctx pointer during sched_in if there are no events associated with the context. Otherwise if during task execution total number of events in the system will become zero perf_event_context_sched_out() will not be called and cpuctx->task_ctx will be left with a stale value. Signed-off-by: Gleb Natapov Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20111023171033.GI17571@redhat.com Signed-off-by: Ingo Molnar

Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

2011-11-07T03:44:47Z

* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits) Revert "tracing: Include module.h in define_trace.h" irq: don't put module.h into irq.h for tracking irqgen modules. bluetooth: macroize two small inlines to avoid module.h ip_vs.h: fix implicit use of module_get/module_put from module.h nf_conntrack.h: fix up fallout from implicit moduleparam.h presence include: replace linux/module.h with "struct module" wherever possible include: convert various register fcns to macros to avoid include chaining crypto.h: remove unused crypto_tfm_alg_modname() inline uwb.h: fix implicit use of asm/page.h for PAGE_SIZE pm_runtime.h: explicitly requires notifier.h linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h miscdevice.h: fix up implicit use of lists and types stop_machine.h: fix implicit use of smp.h for smp_processor_id of: fix implicit use of errno.h in include/linux/of.h of_platform.h: delete needless include acpi: remove module.h include from platform/aclinux.h miscdevice.h: delete unnecessary inclusion of module.h device_cgroup.h: delete needless include net: sch_generic remove redundant use of net: inet_timewait_sock doesnt need ... Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in - drivers/media/dvb/frontends/dibx000_common.c - drivers/media/video/{mt9m111.c,ov6650.c} - drivers/mfd/ab3550-core.c - include/linux/dmaengine.h

Revert "perf: Add PM notifiers to fix CPU hotplug races"

2011-11-03T14:44:04Z

This reverts commit 144060fee07e9c22e179d00819c83c86fbcbf82c. It causes a resume regression for Andi on his Acer Aspire 1830T post 3.1. The screen just stays black after wakeup. Also, it really looks like the wrong way to suspend and resume perf events: I think they should be done as part of the CPU suspend and resume, rather than as a notifier that does smp_call_function(). Reported-by: Andi Kleen Acked-by: Ingo Molnar Cc: Peter Zijlstra Cc: Rafael J. Wysocki Signed-off-by: Linus Torvalds

mm: distinguish between mlocked and pinned pages

2011-11-01T00:30:46Z

Some kernel components pin user space memory (infiniband and perf) (by increasing the page count) and account that memory as "mlocked". The difference between mlocking and pinning is: A. mlocked pages are marked with PG_mlocked and are exempt from swapping. Page migration may move them around though. They are kept on a special LRU list. B. Pinned pages cannot be moved because something needs to directly access physical memory. They may not be on any LRU list. I recently saw an mlockalled process where mm->locked_vm became bigger than the virtual size of the process (!) because some memory was accounted for twice: Once when the page was mlocked and once when the Infiniband layer increased the refcount because it needt to pin the RDMA memory. This patch introduces a separate counter for pinned pages and accounts them seperately. Signed-off-by: Christoph Lameter Cc: Mike Marciniszyn Cc: Roland Dreier Cc: Sean Hefty Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure

2011-10-31T23:30:05Z

These files were getting via an implicit non-obvious path, but we want to crush those out of existence since they cost time during compiles of processing thousands of lines of headers for no reason. Give them the lightweight header that just contains the EXPORT_SYMBOL infrastructure. Signed-off-by: Paul Gortmaker

Merge commit 'v3.1-rc7' into perf/core

2011-09-26T10:54:28Z

Merge reason: Pick up the latest upstream fixes. Signed-off-by: Ingo Molnar

perf_event: Fix broken calc_timer_values()

2011-08-31T13:56:29Z

We detected a serious issue with PERF_SAMPLE_READ and timing information when events were being multiplexing. Samples would have time_running > time_enabled. That was easy to reproduce with a libpfm4 example (ran 3 times to cause multiplexing on Core 2): $ syst_smpl -e uops_retired:freq=1 & $ syst_smpl -e uops_retired:freq=1 & $ syst_smpl -e uops_retired:freq=1 & IIP:0x0000000040062d ... PERIOD:2355332948 ENA=40144625315 RUN=60014875184 syst_smpl: WARNING: time_running > time_enabled 63277537998 uops_retired:freq=1 , scaled The bug was not present in kernel up to (and including) 3.0. It turns out the bug was introduced by the following commit: commit c4794295917ebeda8013b6cb9c8d71ab4f74a1fa events: Move lockless timer calculation into helper function The parameters of the function got reversed yet the call sites were not updated to reflect the change. That lead to time_running and time_enabled being swapped. That had no effect when there was no multiplexing because in that case time_running = time_enabled but it would show up in any other scenario. Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110829124112.GA4828@quad Signed-off-by: Ingo Molnar