* [tip:perf/core] hw_breakpoint: Use cpu_possible_mask in {reserve, release}_bp_slot()
[not found] <20130620155009.GA6327@redhat.com>
@ 2013-06-20 16:18 ` tip-bot for Oleg Nesterov
0 siblings, 0 replies; only message in thread
From: tip-bot for Oleg Nesterov @ 2013-06-20 16:18 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, stable, vincent.weaver, fweisbec, tglx, oleg
Commit-ID: c790b0ad23f427c7522ffed264706238c57c007e
Gitweb: http://git.kernel.org/tip/c790b0ad23f427c7522ffed264706238c57c007e
Author: Oleg Nesterov <oleg@redhat.com>
AuthorDate: Thu, 20 Jun 2013 17:50:09 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 20 Jun 2013 17:57:01 +0200
hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()
fetch_bp_busy_slots() and toggle_bp_slot() use
for_each_online_cpu(), this is obviously wrong wrt cpu_up() or
cpu_down(), we can over/under account the per-cpu numbers.
For example:
# echo 0 >> /sys/devices/system/cpu/cpu1/online
# perf record -e mem:0x10 -p 1 &
# echo 1 >> /sys/devices/system/cpu/cpu1/online
# perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a &
# taskset -p 0x2 1
triggers the same WARN_ONCE("Can't find any breakpoint slot") in
arch_install_hw_breakpoint().
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/events/hw_breakpoint.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index a853dea..20185ea 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -149,7 +149,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
return;
}
- for_each_online_cpu(cpu) {
+ for_each_possible_cpu(cpu) {
unsigned int nr;
nr = per_cpu(nr_cpu_bp_pinned[type], cpu);
@@ -235,7 +235,7 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
if (cpu >= 0) {
toggle_bp_task_slot(bp, cpu, enable, type, weight);
} else {
- for_each_online_cpu(cpu)
+ for_each_possible_cpu(cpu)
toggle_bp_task_slot(bp, cpu, enable, type, weight);
}
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2013-06-20 16:18 ` [tip:perf/core] hw_breakpoint: Use cpu_possible_mask in {reserve, release}_bp_slot() tip-bot for Oleg Nesterov
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