From: "Yan, Zheng" <zheng.z....@intel.com>
The x86 special perf event context is named x86_perf_event_context,
We can enlarge it later to store PMU special data.
Signed-off-by: Yan, Zheng <zheng.z....@intel.com>
---
arch/x86/kernel/cpu/perf_event.c | 12 ++++++++++++
arch/x86/kernel/cpu/perf_event.h | 4 ++++
include/linux/perf_event.h | 5 +++++
kernel/events/core.c | 28 ++++++++++++++++++----------
4 files changed, 39 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index afc2413..b2eada9 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1768,6 +1768,17 @@ static int x86_pmu_event_idx(struct perf_event *event)
return idx + 1;
}
+static void *x86_pmu_event_context_alloc(struct perf_event_context *parent_ctx)
+{
+ struct perf_event_context *ctx;
+
+ ctx = kzalloc(sizeof(struct x86_perf_event_context), GFP_KERNEL);
+ if (!ctx)
+ return ERR_PTR(-ENOMEM);
+
+ return ctx;
+}
+
static ssize_t get_attr_rdpmc(struct device *cdev,
struct device_attribute *attr,
char *buf)
@@ -1855,6 +1866,7 @@ static struct pmu pmu = {
.event_idx = x86_pmu_event_idx,
.flush_branch_stack = x86_pmu_flush_branch_stack,
+ .event_context_alloc = x86_pmu_event_context_alloc,
};
void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index e14c963..08469de 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -454,6 +454,10 @@ enum {
PERF_SAMPLE_BRANCH_CALL_STACK = 1U <<
PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT,
};
+struct x86_perf_event_context {
+ struct perf_event_context ctx;
+};
+
#define x86_add_quirk(func_) \
do { \
static struct x86_pmu_quirk __quirk __initdata = { \
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 50b3efd..f6d1d59 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -274,6 +274,11 @@ struct pmu {
* flush branch stack on context-switches (needed in cpu-wide mode)
*/
void (*flush_branch_stack) (void);
+
+ /*
+ * Allocate PMU special perf event context
+ */
+ void *(*event_context_alloc) (struct perf_event_context *parent_ctx);
};
/**
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1db3af9..3aececc 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2961,13 +2961,20 @@ static void __perf_event_init_context(struct
perf_event_context *ctx)
}
static struct perf_event_context *
-alloc_perf_context(struct pmu *pmu, struct task_struct *task)
+alloc_perf_context(struct pmu *pmu, struct task_struct *task,
+ struct perf_event_context *parent_ctx)
{
struct perf_event_context *ctx;
- ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
- if (!ctx)
- return NULL;
+ if (pmu->event_context_alloc) {
+ ctx = pmu->event_context_alloc(parent_ctx);
+ if (IS_ERR(ctx))
+ return ctx;
+ } else {
+ ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
+ if (!ctx)
+ return ERR_PTR(-ENOMEM);
+ }
__perf_event_init_context(ctx);
if (task) {
@@ -3053,10 +3060,11 @@ retry:
++ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
} else {
- ctx = alloc_perf_context(pmu, task);
- err = -ENOMEM;
- if (!ctx)
+ ctx = alloc_perf_context(pmu, task, NULL);
+ if (IS_ERR(ctx)) {
+ err = PTR_ERR(ctx);
goto errout;
+ }
err = 0;
mutex_lock(&task->perf_event_mutex);
@@ -7465,9 +7473,9 @@ inherit_task_group(struct perf_event *event, struct
task_struct *parent,
* child.
*/
- child_ctx = alloc_perf_context(event->pmu, child);
- if (!child_ctx)
- return -ENOMEM;
+ child_ctx = alloc_perf_context(event->pmu, child, parent_ctx);
+ if (IS_ERR(child_ctx))
+ return PTR_ERR(child_ctx);
child->perf_event_ctxp[ctxn] = child_ctx;
}
--
1.8.1.4
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