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hw_breakpoint: Introduce "struct bp_cpuinfo"

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This patch simply moves all per-cpu variables into the new
single per-cpu "struct bp_cpuinfo".

To me this looks more logical and clean, but this can also
simplify the further potential changes. In particular, I do not
think this memory should be per-cpu, it is never used "locally".
After this change it is trivial to turn it into, say,
bootmem[nr_cpu_ids].

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/20130620155020.GA6350@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Oleg Nesterov 2013-06-20 17:50:20 +02:00 committed by Ingo Molnar
parent e12cbc10cb
commit bde96030f4
1 changed files with 36 additions and 33 deletions
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69
kernel/events/hw_breakpoint.c
View file

@ -46,23 +46,26 @@
#include <linux/smp.h> #include <linux/smp.h>
#include <linux/hw_breakpoint.h> #include <linux/hw_breakpoint.h>
/* /*
* Constraints data * Constraints data
*/ */
struct bp_cpuinfo {
/* Number of pinned cpu breakpoints in a cpu */
unsigned int cpu_pinned;
/* tsk_pinned[n] is the number of tasks having n+1 breakpoints */
unsigned int *tsk_pinned;
/* Number of non-pinned cpu/task breakpoints in a cpu */
unsigned int flexible; /* XXX: placeholder, see fetch_this_slot() */
};
/* Number of pinned cpu breakpoints in a cpu */ static DEFINE_PER_CPU(struct bp_cpuinfo, bp_cpuinfo[TYPE_MAX]);
static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned[TYPE_MAX]);
/* Number of pinned task breakpoints in a cpu */
static DEFINE_PER_CPU(unsigned int *, nr_task_bp_pinned[TYPE_MAX]);
/* Number of non-pinned cpu/task breakpoints in a cpu */
static DEFINE_PER_CPU(unsigned int, nr_bp_flexible[TYPE_MAX]);
static int nr_slots[TYPE_MAX]; static int nr_slots[TYPE_MAX];
static struct bp_cpuinfo *get_bp_info(int cpu, enum bp_type_idx type)
{
return per_cpu_ptr(bp_cpuinfo + type, cpu);
}
/* Keep track of the breakpoints attached to tasks */ /* Keep track of the breakpoints attached to tasks */
static LIST_HEAD(bp_task_head); static LIST_HEAD(bp_task_head);
@ -96,8 +99,8 @@ static inline enum bp_type_idx find_slot_idx(struct perf_event *bp)
*/ */
static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type) static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type)
{ {
unsigned int *tsk_pinned = get_bp_info(cpu, type)->tsk_pinned;
int i; int i;
unsigned int *tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu);
for (i = nr_slots[type] - 1; i >= 0; i--) { for (i = nr_slots[type] - 1; i >= 0; i--) {
if (tsk_pinned[i] > 0) if (tsk_pinned[i] > 0)
@ -146,8 +149,10 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
int cpu; int cpu;
for_each_cpu(cpu, cpumask) { for_each_cpu(cpu, cpumask) {
unsigned int nr = per_cpu(nr_cpu_bp_pinned[type], cpu); struct bp_cpuinfo *info = get_bp_info(cpu, type);
int nr;
nr = info->cpu_pinned;
if (!bp->hw.bp_target) if (!bp->hw.bp_target)
nr += max_task_bp_pinned(cpu, type); nr += max_task_bp_pinned(cpu, type);
else else
@ -156,8 +161,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
if (nr > slots->pinned) if (nr > slots->pinned)
slots->pinned = nr; slots->pinned = nr;
nr = per_cpu(nr_bp_flexible[type], cpu); nr = info->flexible;
if (nr > slots->flexible) if (nr > slots->flexible)
slots->flexible = nr; slots->flexible = nr;
} }
@ -180,8 +184,7 @@ fetch_this_slot(struct bp_busy_slots *slots, int weight)
static void toggle_bp_task_slot(struct perf_event *bp, int cpu, static void toggle_bp_task_slot(struct perf_event *bp, int cpu,
enum bp_type_idx type, int weight) enum bp_type_idx type, int weight)
{ {
/* tsk_pinned[n-1] is the number of tasks having n>0 breakpoints */ unsigned int *tsk_pinned = get_bp_info(cpu, type)->tsk_pinned;
unsigned int *tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu);
int old_idx, new_idx; int old_idx, new_idx;
old_idx = task_bp_pinned(cpu, bp, type) - 1; old_idx = task_bp_pinned(cpu, bp, type) - 1;
@ -208,7 +211,7 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
/* Pinned counter cpu profiling */ /* Pinned counter cpu profiling */
if (!bp->hw.bp_target) { if (!bp->hw.bp_target) {
per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight; get_bp_info(bp->cpu, type)->cpu_pinned += weight;
return; return;
} }
@ -240,8 +243,8 @@ __weak void arch_unregister_hw_breakpoint(struct perf_event *bp)
* *
* - If attached to a single cpu, check: * - If attached to a single cpu, check:
* *
* (per_cpu(nr_bp_flexible, cpu) || (per_cpu(nr_cpu_bp_pinned, cpu) * (per_cpu(info->flexible, cpu) || (per_cpu(info->cpu_pinned, cpu)
* + max(per_cpu(nr_task_bp_pinned, cpu)))) < HBP_NUM * + max(per_cpu(info->tsk_pinned, cpu)))) < HBP_NUM
* *
* -> If there are already non-pinned counters in this cpu, it means * -> If there are already non-pinned counters in this cpu, it means
* there is already a free slot for them. * there is already a free slot for them.
@ -251,8 +254,8 @@ __weak void arch_unregister_hw_breakpoint(struct perf_event *bp)
* *
* - If attached to every cpus, check: * - If attached to every cpus, check:
* *
* (per_cpu(nr_bp_flexible, *) || (max(per_cpu(nr_cpu_bp_pinned, *)) * (per_cpu(info->flexible, *) || (max(per_cpu(info->cpu_pinned, *))
* + max(per_cpu(nr_task_bp_pinned, *)))) < HBP_NUM * + max(per_cpu(info->tsk_pinned, *)))) < HBP_NUM
* *
* -> This is roughly the same, except we check the number of per cpu * -> This is roughly the same, except we check the number of per cpu
* bp for every cpu and we keep the max one. Same for the per tasks * bp for every cpu and we keep the max one. Same for the per tasks
@ -263,16 +266,16 @@ __weak void arch_unregister_hw_breakpoint(struct perf_event *bp)
* *
* - If attached to a single cpu, check: * - If attached to a single cpu, check:
* *
* ((per_cpu(nr_bp_flexible, cpu) > 1) + per_cpu(nr_cpu_bp_pinned, cpu) * ((per_cpu(info->flexible, cpu) > 1) + per_cpu(info->cpu_pinned, cpu)
* + max(per_cpu(nr_task_bp_pinned, cpu))) < HBP_NUM * + max(per_cpu(info->tsk_pinned, cpu))) < HBP_NUM
* *
* -> Same checks as before. But now the nr_bp_flexible, if any, must keep * -> Same checks as before. But now the info->flexible, if any, must keep
* one register at least (or they will never be fed). * one register at least (or they will never be fed).
* *
* - If attached to every cpus, check: * - If attached to every cpus, check:
* *
* ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *)) * ((per_cpu(info->flexible, *) > 1) + max(per_cpu(info->cpu_pinned, *))
* + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM * + max(per_cpu(info->tsk_pinned, *))) < HBP_NUM
*/ */
static int __reserve_bp_slot(struct perf_event *bp) static int __reserve_bp_slot(struct perf_event *bp)
{ {
@ -622,7 +625,6 @@ static struct pmu perf_breakpoint = {
int __init init_hw_breakpoint(void) int __init init_hw_breakpoint(void)
{ {
unsigned int **task_bp_pinned;
int cpu, err_cpu; int cpu, err_cpu;
int i; int i;
@ -631,10 +633,11 @@ int __init init_hw_breakpoint(void)
for_each_possible_cpu(cpu) { for_each_possible_cpu(cpu) {
for (i = 0; i < TYPE_MAX; i++) { for (i = 0; i < TYPE_MAX; i++) {
task_bp_pinned = &per_cpu(nr_task_bp_pinned[i], cpu); struct bp_cpuinfo *info = get_bp_info(cpu, i);
*task_bp_pinned = kzalloc(sizeof(int) * nr_slots[i],
GFP_KERNEL); info->tsk_pinned = kcalloc(nr_slots[i], sizeof(int),
if (!*task_bp_pinned) GFP_KERNEL);
if (!info->tsk_pinned)
goto err_alloc; goto err_alloc;
} }
} }
@ -648,7 +651,7 @@ int __init init_hw_breakpoint(void)
err_alloc: err_alloc:
for_each_possible_cpu(err_cpu) { for_each_possible_cpu(err_cpu) {
for (i = 0; i < TYPE_MAX; i++) for (i = 0; i < TYPE_MAX; i++)
kfree(per_cpu(nr_task_bp_pinned[i], err_cpu)); kfree(get_bp_info(err_cpu, i)->tsk_pinned);
if (err_cpu == cpu) if (err_cpu == cpu)
break; break;
} }