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hw_breakpoint: Simplify the "weight" usage in toggle_bp_slot() paths 

Change toggle_bp_slot() to make "weight" negative if !enable.
This way we can always use "+ weight" without additional "if
(enable)" check and toggle_bp_task_slot() no longer needs this
arg.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155013.GA6337@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Oleg Nesterov 2013-06-20 17:50:13 +02:00 committed by Ingo Molnar
parent e1ebe86203
commit 7ab71f3244
1 changed files with 8 additions and 12 deletions
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20
kernel/events/hw_breakpoint.c
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@ -182,7 +182,7 @@ fetch_this_slot(struct bp_busy_slots *slots, int weight)
/*
* Add a pinned breakpoint for the given task in our constraint table
*/
static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable,
static void toggle_bp_task_slot(struct perf_event *bp, int cpu,
enum bp_type_idx type, int weight)
{
/* tsk_pinned[n-1] is the number of tasks having n>0 breakpoints */
@ -190,10 +190,7 @@ static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable,
int old_idx, new_idx;
old_idx = task_bp_pinned(cpu, bp, type) - 1;
if (enable)
new_idx = old_idx + weight;
else
new_idx = old_idx - weight;
new_idx = old_idx + weight;
if (old_idx >= 0)
tsk_pinned[old_idx]--;
@ -211,22 +208,21 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
int cpu = bp->cpu;
struct task_struct *tsk = bp->hw.bp_target;
if (!enable)
weight = -weight;
/* Pinned counter cpu profiling */
if (!tsk) {
if (enable)
per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight;
else
per_cpu(nr_cpu_bp_pinned[type], bp->cpu) -= weight;
per_cpu(nr_cpu_bp_pinned[type], cpu) += weight;
return;
}
/* Pinned counter task profiling */
if (cpu >= 0) {
toggle_bp_task_slot(bp, cpu, enable, type, weight);
toggle_bp_task_slot(bp, cpu, type, weight);
} else {
for_each_possible_cpu(cpu)
toggle_bp_task_slot(bp, cpu, enable, type, weight);
toggle_bp_task_slot(bp, cpu, type, weight);
}
if (enable)