linux-kernel - Re: [PATCH v2 1/2] perf/core: add perf_ctx

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Message-ID: <20190415154537.GH12232@hirez.programming.kicks-ass.net>
Date:   Mon, 15 Apr 2019 17:45:37 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Stephane Eranian <eranian@...gle.com>
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de,
        ak@...ux.intel.com, kan.liang@...el.com, mingo@...e.hu,
        nelson.dsouza@...el.com, jolsa@...hat.com, tonyj@...e.com
Subject: Re: [PATCH v2 1/2] perf/core: add perf_ctx_resched() as global
 function

On Mon, Apr 08, 2019 at 10:32:51AM -0700, Stephane Eranian wrote:
> This patch add perf_ctx_resched() a global function that can be called
> to force rescheduling of events based on event types. The function locks
> both cpuctx and task_ctx internally. This will be used by a subsequent patch.

I took out the task_ctx and event_type arguments.

---
Subject: perf/core: Add perf_ctx_resched() as global function
From: Stephane Eranian <eranian@...gle.com>
Date: Mon, 8 Apr 2019 10:32:51 -0700

This patch add perf_ctx_resched() a global function that can be called
to force rescheduling of events. The function locks both cpuctx and
task_ctx internally. This will be used by a subsequent patch.

Cc: mingo@...e.hu
Cc: ak@...ux.intel.com
Cc: jolsa@...hat.com
Cc: tglx@...utronix.de
Cc: kan.liang@...el.com
Cc: nelson.dsouza@...el.com
Cc: tonyj@...e.com
Signed-off-by: Stephane Eranian <eranian@...gle.com>
[peterz: simplified calling convention]
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lkml.kernel.org/r/20190408173252.37932-2-eranian@google.com
---
 include/linux/perf_event.h |    3 +++
 kernel/events/core.c       |    9 +++++++++
 2 files changed, 12 insertions(+)

--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -888,6 +888,9 @@ extern void perf_sched_cb_dec(struct pmu
 extern void perf_sched_cb_inc(struct pmu *pmu);
 extern int perf_event_task_disable(void);
 extern int perf_event_task_enable(void);
+
+extern void perf_ctx_resched(struct perf_cpu_context *cpuctx);
+
 extern int perf_event_refresh(struct perf_event *event, int refresh);
 extern void perf_event_update_userpage(struct perf_event *event);
 extern int perf_event_release_kernel(struct perf_event *event);
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2478,6 +2478,15 @@ static void ctx_resched(struct perf_cpu_
 	perf_pmu_enable(cpuctx->ctx.pmu);
 }
 
+void perf_ctx_resched(struct perf_cpu_context *cpuctx)
+{
+	struct perf_event_context *task_ctx = cpuctx->task_ctx;
+
+	perf_ctx_lock(cpuctx, task_ctx);
+	ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
+	perf_ctx_unlock(cpuctx, task_ctx);
+}
+
 /*
  * Cross CPU call to install and enable a performance event
  *