[PATCH] tracing/branch-tracer: PROFILE_BRANCHES_PER_CPU must depend on SMP

[Frederic Weisbecker]

While enabling the per cpu branch tracing in a non SMP config,
we get the following build failure:

kernel/trace/trace_branch.c: In function âbranch_profilerâ:
kernel/trace/trace_branch.c:353: error: implicit declaration of function âSHIFT_PERCPU_PTRâ
kernel/trace/trace_branch.c:353: error: implicit declaration of function âper_cpu_offsetâ
kernel/trace/trace_branch.c:353: error: invalid type argument of â->â (have âintâ)
kernel/trace/trace_branch.c: In function âcalculate_statâ:
kernel/trace/trace_branch.c:364: error: invalid type argument of âunary *â (have âintâ)
kernel/trace/trace_branch.c:366: error: invalid type argument of â->â (have âintâ)
kernel/trace/trace_branch.c:367: error: invalid type argument of â->â (have âintâ)

This is because the branch tracer uses per cpu internals that are not
supported on !CONFIG_SMP case.

To fix it we just need to disable the per cpu branch tracing in
!CONFIG_SMP case.

[ Impact: fix a build failure with the branch tracer ]

Reported-by: Ingo Molnar <mingo@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
---
 kernel/trace/Kconfig |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 309a264..0efbcc5 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -285,7 +285,7 @@ endchoice
 
 config PROFILE_BRANCHES_PER_CPU
 	bool "Profile branches on a per cpu basis"
-	depends on PROFILE_ALL_BRANCHES
+	depends on PROFILE_ALL_BRANCHES && SMP
 	help
 	  When profiling all branches, the system can take a big cache line
 	  bouncing hit. On boxes with lots of CPUs, this can slow the system
-- 
1.6.2.3

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