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Date: Wed, 8 Jan 2020 07:03:08 -0800
From: kan.liang@...ux.intel.com
To: peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
tglx@...utronix.de, bp@...en8.de, linux-kernel@...r.kernel.org
Cc: eranian@...gle.com, alexey.budankov@...ux.intel.com,
vitaly.slobodskoy@...el.com, ak@...ux.intel.com,
Kan Liang <kan.liang@...ux.intel.com>
Subject: [RFC PATCH V3 6/7] perf: Clean up pmu specific data
From: Kan Liang <kan.liang@...ux.intel.com>
The pmu specific data is saved in task_struct now. Remove it from event
context structure.
Remove swap_task_ctx() as well.
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
---
No changes since V2
include/linux/perf_event.h | 11 ----------
kernel/events/core.c | 53 ++--------------------------------------------
2 files changed, 2 insertions(+), 62 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index f271595..364b0d0 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -413,16 +413,6 @@ struct pmu {
size_t task_ctx_size;
/*
- * PMU specific parts of task perf event context (i.e. ctx->task_ctx_data)
- * can be synchronized using this function. See Intel LBR callstack support
- * implementation and Perf core context switch handling callbacks for usage
- * examples.
- */
- void (*swap_task_ctx) (struct perf_event_context *prev,
- struct perf_event_context *next);
- /* optional */
-
- /*
* Set up pmu-private data structures for an AUX area
*/
void *(*setup_aux) (struct perf_event *event, void **pages,
@@ -817,7 +807,6 @@ struct perf_event_context {
#ifdef CONFIG_CGROUP_PERF
int nr_cgroups; /* cgroup evts */
#endif
- void *task_ctx_data; /* pmu specific data */
struct rcu_head rcu_head;
};
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1835d9b..23db381 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1214,7 +1214,6 @@ static void free_ctx(struct rcu_head *head)
struct perf_event_context *ctx;
ctx = container_of(head, struct perf_event_context, rcu_head);
- kfree(ctx->task_ctx_data);
kfree(ctx);
}
@@ -3272,28 +3271,14 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
raw_spin_lock(&ctx->lock);
raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
if (context_equiv(ctx, next_ctx)) {
- struct pmu *pmu = ctx->pmu;
-
WRITE_ONCE(ctx->task, next);
WRITE_ONCE(next_ctx->task, task);
/*
- * PMU specific parts of task perf context can require
- * additional synchronization. As an example of such
- * synchronization see implementation details of Intel
- * LBR call stack data profiling;
- */
- if (pmu->swap_task_ctx)
- pmu->swap_task_ctx(ctx, next_ctx);
- else
- swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
-
- /*
* RCU_INIT_POINTER here is safe because we've not
* modified the ctx and the above modification of
- * ctx->task and ctx->task_ctx_data are immaterial
- * since those values are always verified under
- * ctx->lock which we're now holding.
+ * ctx->task is immaterial since this value is always
+ * verified under ctx->lock which we're now holding.
*/
RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
@@ -4301,7 +4286,6 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
{
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;
@@ -4325,24 +4309,12 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
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)
@@ -4353,11 +4325,6 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
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);
/*
@@ -4384,11 +4351,9 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
}
}
- kfree(task_ctx_data);
return ctx;
errout:
- kfree(task_ctx_data);
return ERR_PTR(err);
}
@@ -12416,19 +12381,6 @@ inherit_event(struct perf_event *parent_event,
if (IS_ERR(child_event))
return child_event;
-
- if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
- !child_ctx->task_ctx_data) {
- struct pmu *pmu = child_event->pmu;
-
- child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
- GFP_KERNEL);
- if (!child_ctx->task_ctx_data) {
- free_event(child_event);
- return ERR_PTR(-ENOMEM);
- }
- }
-
/*
* is_orphaned_event() and list_add_tail(&parent_event->child_list)
* must be under the same lock in order to serialize against
@@ -12439,7 +12391,6 @@ inherit_event(struct perf_event *parent_event,
if (is_orphaned_event(parent_event) ||
!atomic_long_inc_not_zero(&parent_event->refcount)) {
mutex_unlock(&parent_event->child_mutex);
- /* task_ctx_data is freed with child_ctx */
free_event(child_event);
return NULL;
}
--
2.7.4
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