Messages in this thread Patch in this message | | | Date | Wed, 6 Jul 2011 21:24:55 +0400 | From | Cyrill Gorcunov <> | Subject | [PATCH -tip/perf/core] perf, x86: P4 PMU - Drop redundant WARN_ON_ONCE |
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This WARN_ON_ONCE triggers a false alarm on SMP because nmi-watchdog uses a single global 'wd_hw_attr' variable to serve perf event attributes and once p4_hw_watchdog_set_attr has modified it subsequent calls on the rest cpus trigger the warning.
It is safe to simply drop it since we know the caller may pass already altered type and config.
Repoted-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> --- arch/x86/kernel/cpu/perf_event_p4.c | 3 --- 1 file changed, 3 deletions(-)
Index: linux-2.6.git/arch/x86/kernel/cpu/perf_event_p4.c =================================================================== --- linux-2.6.git.orig/arch/x86/kernel/cpu/perf_event_p4.c +++ linux-2.6.git/arch/x86/kernel/cpu/perf_event_p4.c @@ -726,9 +726,6 @@ static void p4_hw_watchdog_set_attr(stru * that named "non-sleeping" ticks as recommended * by Intel SDM Vol3b. */ - WARN_ON_ONCE(wd_attr->type != PERF_TYPE_HARDWARE || - wd_attr->config != PERF_COUNT_HW_CPU_CYCLES); - wd_attr->type = PERF_TYPE_RAW; wd_attr->config = p4_config_pack_escr(P4_ESCR_EVENT(P4_EVENT_EXECUTION_EVENT) |
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