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Subject[PATCH 2/3] 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.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/events/hw_breakpoint.c | 20 ++++++++------------
1 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index 21a3c88..2f4d7c4 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -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)
--
1.5.5.1



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