From 48b5ba9cc98d676712da29d9931f1c88e5185ff2 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker <fweisbec@gmail.com> Date: Thu, 31 Dec 2009 05:53:02 +0100 Subject: [PATCH] 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 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index c223b7e895d9..d616c06e99b4 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); } /* -- 2.30.2