linux-kernel - [tip:perf/core] perf/core: Remove perf_cpu_context::unique

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Date:   Mon, 30 Jan 2017 03:58:04 -0800
From:   tip-bot for David Carrillo-Cisneros <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     acme@...hat.com, mark.rutland@....com,
        torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org,
        peterz@...radead.org, tglx@...utronix.de,
        dave.hansen@...ux.intel.com, srinivas.pandruvada@...ux.intel.com,
        acme@...nel.org, eranian@...gle.com, hpa@...or.com, bp@...e.de,
        vince@...ter.net, vincent.weaver@...ne.edu, davidcc@...gle.com,
        pjt@...gle.com, mingo@...nel.org, jolsa@...hat.com,
        vikas.shivappa@...ux.intel.com, alexander.shishkin@...ux.intel.com,
        kan.liang@...el.com
Subject: [tip:perf/core] perf/core: Remove perf_cpu_context::unique_pmu

Commit-ID:  1fd7e416995401ec082fc0fe6090a223969beda5
Gitweb:     http://git.kernel.org/tip/1fd7e416995401ec082fc0fe6090a223969beda5
Author:     David Carrillo-Cisneros <davidcc@...gle.com>
AuthorDate: Wed, 18 Jan 2017 11:24:54 -0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Mon, 30 Jan 2017 12:01:14 +0100

perf/core: Remove perf_cpu_context::unique_pmu

cpuctx->unique_pmu was originally introduced as a way to identify cpuctxs
with shared pmus in order to avoid visiting the same cpuctx more than once
in a for_each_pmu loop.

cpuctx->unique_pmu == cpuctx->pmu in non-software task contexts since they
have only one pmu per cpuctx. Since perf_pmu_sched_task() is only called in
hw contexts, this patch replaces cpuctx->unique_pmu by cpuctx->pmu in it.

The change above, together with the previous patch in this series, removed
the remaining uses of cpuctx->unique_pmu, so we remove it altogether.

Signed-off-by: David Carrillo-Cisneros <davidcc@...gle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Acked-by: Mark Rutland <mark.rutland@....com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Kan Liang <kan.liang@...el.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Paul Turner <pjt@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
Cc: Vince Weaver <vince@...ter.net>
Cc: Vince Weaver <vincent.weaver@...ne.edu>
Link: http://lkml.kernel.org/r/20170118192454.58008-3-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 include/linux/perf_event.h |  1 -
 kernel/events/core.c       | 31 +------------------------------
 2 files changed, 1 insertion(+), 31 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index dfa7257..5c58e93 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -785,7 +785,6 @@ struct perf_cpu_context {
 	ktime_t				hrtimer_interval;
 	unsigned int			hrtimer_active;
 
-	struct pmu			*unique_pmu;
 #ifdef CONFIG_CGROUP_PERF
 	struct perf_cgroup		*cgrp;
 	struct list_head		cgrp_cpuctx_entry;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 928a818..d92c7ad 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2932,7 +2932,7 @@ static void perf_pmu_sched_task(struct task_struct *prev,
 		return;
 
 	list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
-		pmu = cpuctx->unique_pmu; /* software PMUs will not have sched_task */
+		pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
 
 		if (WARN_ON_ONCE(!pmu->sched_task))
 			continue;
@@ -8636,37 +8636,10 @@ static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
 	return NULL;
 }
 
-static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
-{
-	int cpu;
-
-	for_each_possible_cpu(cpu) {
-		struct perf_cpu_context *cpuctx;
-
-		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
-
-		if (cpuctx->unique_pmu == old_pmu)
-			cpuctx->unique_pmu = pmu;
-	}
-}
-
 static void free_pmu_context(struct pmu *pmu)
 {
-	struct pmu *i;
-
 	mutex_lock(&pmus_lock);
-	/*
-	 * Like a real lame refcount.
-	 */
-	list_for_each_entry(i, &pmus, entry) {
-		if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
-			update_pmu_context(i, pmu);
-			goto out;
-		}
-	}
-
 	free_percpu(pmu->pmu_cpu_context);
-out:
 	mutex_unlock(&pmus_lock);
 }
 
@@ -8870,8 +8843,6 @@ skip_type:
 		cpuctx->ctx.pmu = pmu;
 
 		__perf_mux_hrtimer_init(cpuctx, cpu);
-
-		cpuctx->unique_pmu = pmu;
 	}
 
 got_cpu_context: