[tip:perf/core] perf/core: Remove perf_cpu_context::unique_pmu

tip-bot for David Carrillo-Cisneros
2017-01-30T11:59:21Z

Commit-ID: 1fd7e416995401ec082fc0fe6090a223969beda5
Gitweb: http://git.kernel.org/tip/1fd7e416995401ec082fc0fe6090a223969beda5
Author: David Carrillo-Cisneros <davidcc@google.com>
AuthorDate: Wed, 18 Jan 2017 11:24:54 -0800
Committer: Ingo Molnar <mingo@kernel.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@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20170118192454.58008-3-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.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;
}