diff options
| author | Cyrill Gorcunov <gorcunov@openvz.org> | 2010-05-08 15:25:52 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-05-08 16:17:53 +0400 |
| commit | 137351e0feeb9f25d99488ee1afc1c79f5499a9a (patch) | |
| tree | 4507ec07bbf4ac9c5bb6361f90d0be3a5e989f20 /arch | |
| parent | de902d967feb96f2dfddfbe9dbd69dc22fd5ebcb (diff) | |
| download | linux-137351e0feeb9f25d99488ee1afc1c79f5499a9a.tar.xz | |
x86, perf: P4 PMU -- protect sensible procedures from preemption
Steven reported:
|
| I'm getting:
|
| Pid: 3477, comm: perf Not tainted 2.6.34-rc6 #2727
| Call Trace:
| [<ffffffff811c7565>] debug_smp_processor_id+0xd5/0xf0
| [<ffffffff81019874>] p4_hw_config+0x2b/0x15c
| [<ffffffff8107acbc>] ? trace_hardirqs_on_caller+0x12b/0x14f
| [<ffffffff81019143>] hw_perf_event_init+0x468/0x7be
| [<ffffffff810782fd>] ? debug_mutex_init+0x31/0x3c
| [<ffffffff810c68b2>] T.850+0x273/0x42e
| [<ffffffff810c6cab>] sys_perf_event_open+0x23e/0x3f1
| [<ffffffff81009e6a>] ? sysret_check+0x2e/0x69
| [<ffffffff81009e32>] system_call_fastpath+0x16/0x1b
|
| When running perf record in latest tip/perf/core
|
Due to the fact that p4 counters are shared between HT threads
we synthetically divide the whole set of counters into two
non-intersected subsets. And while we're "borrowing" counters
from these subsets we should not be preempted (well, strictly
speaking in p4_hw_config we just pre-set reference to the
subset which allow to save some cycles in schedule routine
if it happens on the same cpu). So use get_cpu/put_cpu pair.
Also p4_pmu_schedule_events should use smp_processor_id rather
than raw_ version. This allow us to catch up preemption issue
(if there will ever be).
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
LKML-Reference: <20100508112716.963478928@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_p4.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c index b1f532d1d36f..ca40180c41d4 100644 --- a/arch/x86/kernel/cpu/perf_event_p4.c +++ b/arch/x86/kernel/cpu/perf_event_p4.c @@ -421,7 +421,8 @@ static u64 p4_pmu_event_map(int hw_event) static int p4_hw_config(struct perf_event *event) { - int cpu = raw_smp_processor_id(); + int cpu = get_cpu(); + int rc = 0; u32 escr, cccr; /* @@ -454,7 +455,10 @@ static int p4_hw_config(struct perf_event *event) p4_config_pack_cccr(P4_CCCR_MASK_HT)); } - return x86_setup_perfctr(event); + rc = x86_setup_perfctr(event); + put_cpu(); + + return rc; } static inline void p4_pmu_clear_cccr_ovf(struct hw_perf_event *hwc) |