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Message-ID: <20230612093541.454144142@infradead.org>
Date: Mon, 12 Jun 2023 11:08:07 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: torvalds@...ux-foundation.org, keescook@...omium.org,
gregkh@...uxfoundation.org, pbonzini@...hat.com
Cc: masahiroy@...nel.org, nathan@...nel.org, ndesaulniers@...gle.com,
nicolas@...sle.eu, catalin.marinas@....com, will@...nel.org,
vkoul@...nel.org, trix@...hat.com, ojeda@...nel.org,
peterz@...radead.org, mingo@...hat.com, longman@...hat.com,
boqun.feng@...il.com, dennis@...nel.org, tj@...nel.org,
cl@...ux.com, acme@...nel.org, mark.rutland@....com,
alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
namhyung@...nel.org, irogers@...gle.com, adrian.hunter@...el.com,
juri.lelli@...hat.com, vincent.guittot@...aro.org,
dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
mgorman@...e.de, bristot@...hat.com, vschneid@...hat.com,
paulmck@...nel.org, frederic@...nel.org, quic_neeraju@...cinc.com,
joel@...lfernandes.org, josh@...htriplett.org,
mathieu.desnoyers@...icios.com, jiangshanlai@...il.com,
rientjes@...gle.com, vbabka@...e.cz, roman.gushchin@...ux.dev,
42.hyeyoo@...il.com, apw@...onical.com, joe@...ches.com,
dwaipayanray1@...il.com, lukas.bulwahn@...il.com,
john.johansen@...onical.com, paul@...l-moore.com,
jmorris@...ei.org, serge@...lyn.com, linux-kbuild@...r.kernel.org,
linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org,
llvm@...ts.linux.dev, linux-perf-users@...r.kernel.org,
rcu@...r.kernel.org, linux-security-module@...r.kernel.org,
tglx@...utronix.de, ravi.bangoria@....com, error27@...il.com,
luc.vanoostenryck@...il.com
Subject: [PATCH v3 54/57] perf: Misc cleanups
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
kernel/events/core.c | 64 +++++++++++++++++++--------------------------------
1 file changed, 25 insertions(+), 39 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1274,13 +1274,11 @@ perf_event_ctx_lock_nested(struct perf_e
struct perf_event_context *ctx;
again:
- rcu_read_lock();
- ctx = READ_ONCE(event->ctx);
- if (!refcount_inc_not_zero(&ctx->refcount)) {
- rcu_read_unlock();
- goto again;
+ scoped_guard (rcu) {
+ ctx = READ_ONCE(event->ctx);
+ if (!refcount_inc_not_zero(&ctx->refcount))
+ goto again;
}
- rcu_read_unlock();
mutex_lock_nested(&ctx->mutex, nesting);
if (event->ctx != ctx) {
@@ -2254,7 +2252,7 @@ event_sched_out(struct perf_event *event
*/
list_del_init(&event->active_list);
- perf_pmu_disable(event->pmu);
+ guard(perf_pmu_disable)(event->pmu);
event->pmu->del(event, 0);
event->oncpu = -1;
@@ -2288,8 +2286,6 @@ event_sched_out(struct perf_event *event
ctx->nr_freq--;
if (event->attr.exclusive || !cpc->active_oncpu)
cpc->exclusive = 0;
-
- perf_pmu_enable(event->pmu);
}
static void
@@ -3219,7 +3215,8 @@ static void __pmu_ctx_sched_out(struct p
if (!event_type)
return;
- perf_pmu_disable(pmu);
+ guard(perf_pmu_disable)(pmu);
+
if (event_type & EVENT_PINNED) {
list_for_each_entry_safe(event, tmp,
&pmu_ctx->pinned_active,
@@ -3239,7 +3236,6 @@ static void __pmu_ctx_sched_out(struct p
*/
pmu_ctx->rotate_necessary = 0;
}
- perf_pmu_enable(pmu);
}
static void
@@ -3586,13 +3582,10 @@ static void __perf_pmu_sched_task(struct
if (WARN_ON_ONCE(!pmu->sched_task))
return;
- perf_ctx_lock(cpuctx, cpuctx->task_ctx);
- perf_pmu_disable(pmu);
+ guard(perf_ctx_lock)(cpuctx, cpuctx->task_ctx);
+ guard(perf_pmu_disable)(pmu);
pmu->sched_task(cpc->task_epc, sched_in);
-
- perf_pmu_enable(pmu);
- perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
}
static void perf_pmu_sched_task(struct task_struct *prev,
@@ -12655,8 +12648,6 @@ static void __perf_pmu_install_event(str
struct perf_event_context *ctx,
int cpu, struct perf_event *event)
{
- struct perf_event_pmu_context *epc;
-
/*
* Now that the events are unused, put their old ctx and grab a
* reference on the new context.
@@ -12665,8 +12656,7 @@ static void __perf_pmu_install_event(str
get_ctx(ctx);
event->cpu = cpu;
- epc = find_get_pmu_context(pmu, ctx, event);
- event->pmu_ctx = epc;
+ event->pmu_ctx = find_get_pmu_context(pmu, ctx, event);
if (event->state >= PERF_EVENT_STATE_OFF)
event->state = PERF_EVENT_STATE_INACTIVE;
@@ -12815,12 +12805,12 @@ perf_event_exit_event(struct perf_event
static void perf_event_exit_task_context(struct task_struct *child)
{
- struct perf_event_context *child_ctx, *clone_ctx = NULL;
+ struct perf_event_context *clone_ctx = NULL;
struct perf_event *child_event, *next;
WARN_ON_ONCE(child != current);
- child_ctx = perf_pin_task_context(child);
+ CLASS(pin_task_ctx, child_ctx)(child);
if (!child_ctx)
return;
@@ -12834,27 +12824,27 @@ static void perf_event_exit_task_context
* without ctx::mutex (it cannot because of the move_group double mutex
* lock thing). See the comments in perf_install_in_context().
*/
- mutex_lock(&child_ctx->mutex);
+ guard(mutex)(&child_ctx->mutex);
/*
* In a single ctx::lock section, de-schedule the events and detach the
* context from the task such that we cannot ever get it scheduled back
* in.
*/
- raw_spin_lock_irq(&child_ctx->lock);
- task_ctx_sched_out(child_ctx, EVENT_ALL);
+ scoped_guard (raw_spinlock_irq, &child_ctx->lock) {
+ task_ctx_sched_out(child_ctx, EVENT_ALL);
- /*
- * Now that the context is inactive, destroy the task <-> ctx relation
- * and mark the context dead.
- */
- RCU_INIT_POINTER(child->perf_event_ctxp, NULL);
- put_ctx(child_ctx); /* cannot be last */
- WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
- put_task_struct(current); /* cannot be last */
+ /*
+ * Now that the context is inactive, destroy the task <-> ctx
+ * relation and mark the context dead.
+ */
+ RCU_INIT_POINTER(child->perf_event_ctxp, NULL);
+ put_ctx(child_ctx); /* cannot be last */
+ WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
+ put_task_struct(current); /* cannot be last */
- clone_ctx = unclone_ctx(child_ctx);
- raw_spin_unlock_irq(&child_ctx->lock);
+ clone_ctx = unclone_ctx(child_ctx);
+ }
if (clone_ctx)
put_ctx(clone_ctx);
@@ -12868,10 +12858,6 @@ static void perf_event_exit_task_context
list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
perf_event_exit_event(child_event, child_ctx);
-
- mutex_unlock(&child_ctx->mutex);
-
- put_ctx(child_ctx);
}
/*
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