From: Arun Sharma <asharma@fb.com>
Date: Fri, 20 Apr 2012 22:41:34 +0000 (-0700)
Subject: perf: Limit callchains to 127
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0b0d9cf6ec7bab91977da2d71c09157f110f7c2e;p=linux-beck.git

perf: Limit callchains to 127

Stack depth of 255 seems excessive, given that copy_from_user_nmi()
could be slow.

Signed-off-by: Arun Sharma <asharma@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1334961696-19580-3-git-send-email-asharma@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 1817d4015e5f..45db49f64bb4 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -555,7 +555,7 @@ enum perf_event_type {
 	PERF_RECORD_MAX,			/* non-ABI */
 };
 
-#define PERF_MAX_STACK_DEPTH		255
+#define PERF_MAX_STACK_DEPTH		127
 
 enum perf_callchain_context {
 	PERF_CONTEXT_HV			= (__u64)-32,