Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753304AbbLIIeM (ORCPT ); Wed, 9 Dec 2015 03:34:12 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:59177 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751354AbbLIIeK (ORCPT ); Wed, 9 Dec 2015 03:34:10 -0500 Date: Wed, 9 Dec 2015 09:34:02 +0100 From: Peter Zijlstra To: zheng.z.yan@intel.com, linux-kernel@vger.kernel.org, hpa@zytor.com, kan.liang@intel.com, torvalds@linux-foundation.org, acme@kernel.org, mingo@kernel.org, paulus@samba.org, tglx@linutronix.de Cc: linux-tip-commits@vger.kernel.org Subject: Re: [tip:perf/core] perf: Add pmu specific data for perf task context Message-ID: <20151209083402.GK6356@twins.programming.kicks-ass.net> References: <1415156173-10035-6-git-send-email-kan.liang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2512 Lines: 99 On Wed, Feb 18, 2015 at 09:15:06AM -0800, tip-bot for Yan, Zheng wrote: > +find_get_context(struct pmu *pmu, struct task_struct *task, > + struct perf_event *event) > { > struct perf_event_context *ctx, *clone_ctx = NULL; > struct perf_cpu_context *cpuctx; > + void *task_ctx_data = NULL; > unsigned long flags; > int ctxn, err; > + int cpu = event->cpu; > > if (!task) { > /* Must be root to operate on a CPU event: */ > @@ -3342,11 +3354,24 @@ find_get_context(struct pmu *pmu, struct task_struct *task, int cpu) > if (ctxn < 0) > goto errout; > > + if (event->attach_state & PERF_ATTACH_TASK_DATA) { > + task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL); > + if (!task_ctx_data) { > + err = -ENOMEM; > + goto errout; > + } > + } > + > retry: > ctx = perf_lock_task_context(task, ctxn, &flags); > if (ctx) { > clone_ctx = unclone_ctx(ctx); > ++ctx->pin_count; > + > + if (task_ctx_data && !ctx->task_ctx_data) { > + ctx->task_ctx_data = task_ctx_data; > + task_ctx_data = NULL; > + } > raw_spin_unlock_irqrestore(&ctx->lock, flags); > > if (clone_ctx) > @@ -3357,6 +3382,11 @@ retry: > if (!ctx) > goto errout; > > + if (task_ctx_data) { > + ctx->task_ctx_data = task_ctx_data; > + task_ctx_data = NULL; > + } > + > err = 0; > mutex_lock(&task->perf_event_mutex); > /* > @@ -3383,9 +3413,11 @@ retry: > } > } > > + kfree(task_ctx_data); > return ctx; > > errout: > + kfree(task_ctx_data); > return ERR_PTR(err); > } diff --git a/kernel/events/core.c b/kernel/events/core.c index 36babfd..97aa610 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3508,11 +3515,6 @@ retry: if (!ctx) goto errout; - if (task_ctx_data) { - ctx->task_ctx_data = task_ctx_data; - task_ctx_data = NULL; - } - err = 0; mutex_lock(&task->perf_event_mutex); /* @@ -3526,6 +3528,10 @@ retry: else { get_ctx(ctx); ++ctx->pin_count; + if (task_ctx_data) { + ctx->task_ctx_data = task_ctx_data; + task_ctx_data = NULL; + } rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); } mutex_unlock(&task->perf_event_mutex); Does that make sense? No point in setting task_ctx_data if we're going to free the ctx and try again. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/