OK, I seem to understand what toggle_bp_task_slot() does, and
it looks equally wrong.
I think we need something like the patch below... I'll try to
recheck/test tomorrow, but I would not mind if someone who knows
this code makes the authoritative fix.
Even if this patch is right, I think this all needs more cleanups,
at least. For example, every DEFINE_PER_CPU() looks bogus. This
is not pcpu memory.
Oleg.
--- x/kernel/events/hw_breakpoint.c
+++ x/kernel/events/hw_breakpoint.c
@@ -111,7 +111,7 @@ static unsigned int max_task_bp_pinned(int cpu, enum
bp_type_idx type)
* Count the number of breakpoints of the same type and same task.
* The given event must be not on the list.
*/
-static int task_bp_pinned(int cpu, struct perf_event *bp, enum bp_type_idx
type)
+static int task_bp_pinned(struct perf_event *bp, enum bp_type_idx type)
{
struct task_struct *tsk = bp->hw.bp_target;
struct perf_event *iter;
@@ -120,7 +120,7 @@ static int task_bp_pinned(int cpu, struct perf_event *bp,
enum bp_type_idx type)
list_for_each_entry(iter, &bp_task_head, hw.bp_list) {
if (iter->hw.bp_target == tsk &&
find_slot_idx(iter) == type &&
- cpu == iter->cpu)
+ bp->cpu == iter->cpu)
count += hw_breakpoint_weight(iter);
}
@@ -137,13 +137,17 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct
perf_event *bp,
{
int cpu = bp->cpu;
struct task_struct *tsk = bp->hw.bp_target;
+ int task_pinned;
+
+ if (tsk)
+ task_pinned = task_bp_pinned(bp, type);
if (cpu >= 0) {
slots->pinned = per_cpu(nr_cpu_bp_pinned[type], cpu);
if (!tsk)
slots->pinned += max_task_bp_pinned(cpu, type);
else
- slots->pinned += task_bp_pinned(cpu, bp, type);
+ slots->pinned += task_pinned;
slots->flexible = per_cpu(nr_bp_flexible[type], cpu);
return;
@@ -156,7 +160,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct
perf_event *bp,
if (!tsk)
nr += max_task_bp_pinned(cpu, type);
else
- nr += task_bp_pinned(cpu, bp, type);
+ nr += task_pinned;
if (nr > slots->pinned)
slots->pinned = nr;
@@ -182,15 +186,13 @@ 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(int old_count, int cpu, bool enable,
enum bp_type_idx type, int weight)
{
unsigned int *tsk_pinned;
- int old_count = 0;
int old_idx = 0;
int idx = 0;
- old_count = task_bp_pinned(cpu, bp, type);
old_idx = old_count - 1;
idx = old_idx + weight;
@@ -216,6 +218,7 @@ 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;
+ int task_pinned;
/* Pinned counter cpu profiling */
if (!tsk) {
@@ -232,11 +235,13 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum
bp_type_idx type,
if (!enable)
list_del(&bp->hw.bp_list);
+ task_pinned = task_bp_pinned(bp, type);
+
if (cpu >= 0) {
- toggle_bp_task_slot(bp, cpu, enable, type, weight);
+ toggle_bp_task_slot(task_pinned, cpu, enable, type, weight);
} else {
for_each_online_cpu(cpu)
- toggle_bp_task_slot(bp, cpu, enable, type, weight);
+ toggle_bp_task_slot(task_pinned, cpu, enable, type,
weight);
}
if (enable)
--
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