Messages in this thread Patch in this message | | | Date | Thu, 31 Dec 2009 14:30:33 GMT | From | tip-bot for Frederic Weisbecker <> | Subject | [tip:perf/urgent] perf: Pass appropriate frame pointer to dump_trace() |
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Commit-ID: 48b5ba9cc98d676712da29d9931f1c88e5185ff2 Gitweb: http://git.kernel.org/tip/48b5ba9cc98d676712da29d9931f1c88e5185ff2 Author: Frederic Weisbecker <fweisbec@gmail.com> AuthorDate: Thu, 31 Dec 2009 05:53:02 +0100 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Thu, 31 Dec 2009 13:11:31 +0100
perf: Pass appropriate frame pointer to dump_trace()
Pass the frame pointer from the regs of the interrupted path to dump_trace() while processing the stack trace.
Currently, dump_trace() takes the current bp and starts the callchain from dump_trace() itself. This is wasteful because we need to walk through the entire NMI/DEBUG stack before retrieving the interrupted point.
We can fix that by just using the frame pointer from the captured regs. It points exactly where we want to start.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1262235183-5320-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> --- arch/x86/kernel/cpu/perf_event.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index c223b7e..d616c06 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -2347,7 +2347,7 @@ perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry) callchain_store(entry, PERF_CONTEXT_KERNEL); callchain_store(entry, regs->ip); - dump_trace(NULL, regs, NULL, 0, &backtrace_ops, entry); + dump_trace(NULL, regs, NULL, regs->bp, &backtrace_ops, entry); } /*
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