diff options
Diffstat (limited to 'kernel/perf_event.c')
| -rw-r--r-- | kernel/perf_event.c | 41 |
1 files changed, 26 insertions, 15 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index dae0e2f3029..13d98d75634 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1959,9 +1959,7 @@ exit_put: /* * Initialize the perf_event context in a task_struct: */ -static void -__perf_event_init_context(struct perf_event_context *ctx, - struct task_struct *task) +static void __perf_event_init_context(struct perf_event_context *ctx) { raw_spin_lock_init(&ctx->lock); mutex_init(&ctx->mutex); @@ -1969,7 +1967,25 @@ __perf_event_init_context(struct perf_event_context *ctx, INIT_LIST_HEAD(&ctx->flexible_groups); INIT_LIST_HEAD(&ctx->event_list); atomic_set(&ctx->refcount, 1); - ctx->task = task; +} + +static struct perf_event_context * +alloc_perf_context(struct pmu *pmu, struct task_struct *task) +{ + struct perf_event_context *ctx; + + ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); + if (!ctx) + return NULL; + + __perf_event_init_context(ctx); + if (task) { + ctx->task = task; + get_task_struct(task); + } + ctx->pmu = pmu; + + return ctx; } static struct perf_event_context * @@ -2036,22 +2052,22 @@ retry: } if (!ctx) { - ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); + ctx = alloc_perf_context(pmu, task); err = -ENOMEM; if (!ctx) goto errout; - __perf_event_init_context(ctx, task); - ctx->pmu = pmu; + get_ctx(ctx); + if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) { /* * We raced with some other task; use * the context they set. */ + put_task_struct(task); kfree(ctx); goto retry; } - get_task_struct(task); } put_task_struct(task); @@ -5044,7 +5060,7 @@ int perf_pmu_register(struct pmu *pmu) struct perf_cpu_context *cpuctx; cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); - __perf_event_init_context(&cpuctx->ctx, NULL); + __perf_event_init_context(&cpuctx->ctx); cpuctx->ctx.pmu = pmu; cpuctx->timer_interval = TICK_NSEC; hrtimer_init(&cpuctx->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); @@ -5866,15 +5882,11 @@ inherit_task_group(struct perf_event *event, struct task_struct *parent, * child. */ - child_ctx = kzalloc(sizeof(struct perf_event_context), - GFP_KERNEL); + child_ctx = alloc_perf_context(event->pmu, child); if (!child_ctx) return -ENOMEM; - __perf_event_init_context(child_ctx, child); - child_ctx->pmu = event->pmu; child->perf_event_ctxp = child_ctx; - get_task_struct(child); } ret = inherit_group(event, parent, parent_ctx, @@ -5886,7 +5898,6 @@ inherit_task_group(struct perf_event *event, struct task_struct *parent, return ret; } - /* * Initialize the perf_event context in task_struct */ |