[PATCH 2/5] perf_counter: Export various perf helpers for external users

Frederic Weisbecker
2009-09-10T08:29:41Z

Export various perf helpers that initialize, destroy, attach and detach
a perf counter for future external users like the hardware breakpoint api.

The allocation and initialization of a perf counter have been split up
so that an external user can first allocate and then prefill the
counter before initialize it properly.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
---
include/linux/perf_counter.h | 31 +++++++++++++++++
kernel/perf_counter.c | 74 +++++++++++++++++++++++++-----------------
2 files changed, 75 insertions(+), 30 deletions(-)

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index f557483..1181c24 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -692,9 +692,23 @@ extern int perf_max_counters;

extern const struct pmu *hw_perf_counter_init(struct perf_counter *counter);

+extern int
+__perf_counter_init(struct perf_counter *counter,
+ struct perf_counter_attr *attr,
+ int cpu,
+ struct perf_counter_context *ctx,
+ struct perf_counter *group_leader,
+ struct perf_counter *parent_counter);
+extern void free_counter(struct perf_counter *counter);
+extern void put_ctx(struct perf_counter_context *ctx);
extern void perf_counter_task_sched_in(struct task_struct *task, int cpu);
extern void perf_counter_task_sched_out(struct task_struct *task,
struct task_struct *next, int cpu);
+extern struct perf_counter_context *find_get_context(pid_t pid, int cpu);
+extern void perf_install_in_context(struct perf_counter_context *ctx,
+ struct perf_counter *counter,
+ int cpu);
+extern void perf_counter_remove_from_context(struct perf_counter *counter);
extern void perf_counter_task_tick(struct task_struct *task, int cpu);
extern int perf_counter_init_task(struct task_struct *child);
extern void perf_counter_exit_task(struct task_struct *child);
@@ -799,6 +813,23 @@ static inline void perf_counter_mmap(struct vm_area_struct *vma) { }
static inline void perf_counter_comm(struct task_struct *tsk) { }
static inline void perf_counter_fork(struct task_struct *tsk) { }
static inline void perf_counter_init(void) { }
+static inline int
+__perf_counter_init(struct perf_counter *counter,
+ struct perf_counter_attr *attr,
+ int cpu,
+ struct perf_counter_context *ctx,
+ struct perf_counter *group_leader,
+ struct perf_counter *parent_counter) { return NULL; }
+static inline void free_counter(struct perf_counter *counter) { }
+static inline void put_ctx(struct perf_counter_context *ctx) { }
+static inline struct perf_counter_context *
+find_get_context(pid_t pid, int cpu) { return NULL; }
+static inline void perf_install_in_context(struct perf_counter_context *ctx,
+ struct perf_counter *counter,
+ int cpu) { }
+static inline void
+perf_counter_remove_from_context(struct perf_counter *counter) { }
+
#endif

#endif /* __KERNEL__ */
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 400ccf6..de62fab 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -137,7 +137,7 @@ static void free_ctx(struct rcu_head *head)
kfree(ctx);
}

-static void put_ctx(struct perf_counter_context *ctx)
+void put_ctx(struct perf_counter_context *ctx)
{
if (atomic_dec_and_test(&ctx->refcount)) {
if (ctx->parent_ctx)
@@ -405,7 +405,7 @@ static void __perf_counter_remove_from_context(void *info)
* When called from perf_counter_exit_task, it's OK because the
* context has been detached from its task.
*/
-static void perf_counter_remove_from_context(struct perf_counter *counter)
+void perf_counter_remove_from_context(struct perf_counter *counter)
{
struct perf_counter_context *ctx = counter->ctx;
struct task_struct *task = ctx->task;
@@ -810,10 +810,9 @@ static void __perf_install_in_context(void *info)
*
* Must be called with ctx->mutex held.
*/
-static void
-perf_install_in_context(struct perf_counter_context *ctx,
- struct perf_counter *counter,
- int cpu)
+void perf_install_in_context(struct perf_counter_context *ctx,
+ struct perf_counter *counter,
+ int cpu)
{
struct task_struct *task = ctx->task;

@@ -1558,7 +1557,7 @@ __perf_counter_init_context(struct perf_counter_context *ctx,
ctx->task = task;
}

-static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
+struct perf_counter_context *find_get_context(pid_t pid, int cpu)
{
struct perf_counter_context *ctx;
struct perf_cpu_context *cpuctx;
@@ -1661,7 +1660,7 @@ static void free_counter_rcu(struct rcu_head *head)

static void perf_pending_sync(struct perf_counter *counter);

-static void free_counter(struct perf_counter *counter)
+void free_counter(struct perf_counter *counter)
{
perf_pending_sync(counter);

@@ -1676,8 +1675,7 @@ static void free_counter(struct perf_counter *counter)
}

if (counter->pmu->close)
- if (counter->state != PERF_COUNTER_STATE_UNOPENED)
- counter->pmu->close(counter);
+ counter->pmu->close(counter);

if (counter->destroy)
counter->destroy(counter);
@@ -4010,26 +4008,18 @@ static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
return pmu;
}

-/*
- * Allocate and initialize a counter structure
- */
-static struct perf_counter *
-perf_counter_alloc(struct perf_counter_attr *attr,
- int cpu,
- struct perf_counter_context *ctx,
- struct perf_counter *group_leader,
- struct perf_counter *parent_counter,
- gfp_t gfpflags)
+
+int __perf_counter_init(struct perf_counter *counter,
+ struct perf_counter_attr *attr,
+ int cpu,
+ struct perf_counter_context *ctx,
+ struct perf_counter *group_leader,
+ struct perf_counter *parent_counter)
{
const struct pmu *pmu;
- struct perf_counter *counter;
struct hw_perf_counter *hwc;
long err;

- counter = kzalloc(sizeof(*counter), gfpflags);
- if (!counter)
- return ERR_PTR(-ENOMEM);
-
/*
* Single counters are their own group leaders, with an
* empty sibling list:
@@ -4112,10 +4102,8 @@ done:

if (pmu->open) {
err = pmu->open(counter);
- if (err) {
- counter->state = PERF_COUNTER_STATE_UNOPENED;
+ if (err)
goto fail;
- }
}

if (!counter->parent) {
@@ -4128,14 +4116,40 @@ done:
atomic_inc(&nr_task_counters);
}

- return counter;
+ return 0;

fail:
if (counter->ns)
put_pid_ns(counter->ns);
kfree(counter);

- return ERR_PTR(err);
+ return err;
+}
+
+/*
+ * Allocate and initialize a counter structure
+ */
+static struct perf_counter *
+perf_counter_alloc(struct perf_counter_attr *attr,
+ int cpu,
+ struct perf_counter_context *ctx,
+ struct perf_counter *group_leader,
+ struct perf_counter *parent_counter,
+ gfp_t gfpflags)
+{
+ int err;
+ struct perf_counter *counter;
+
+ counter = kzalloc(sizeof(*counter), gfpflags);
+ if (!counter)
+ return ERR_PTR(-ENOMEM);
+
+ err = __perf_counter_init(counter, attr, cpu, ctx, group_leader,
+ parent_counter);
+ if (err)
+ return ERR_PTR(err);
+
+ return counter;
}

static int perf_copy_attr(struct perf_counter_attr __user *uattr,
--
1.6.2.3