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-rw-r--r--kernel/trace/ring_buffer.c40
1 files changed, 37 insertions, 3 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 96fc3c043ad6..01b4ee5326cf 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -438,6 +438,7 @@ struct ring_buffer_per_cpu {
raw_spinlock_t reader_lock; /* serialize readers */
arch_spinlock_t lock;
struct lock_class_key lock_key;
+ struct buffer_data_page *free_page;
unsigned long nr_pages;
unsigned int current_context;
struct list_head *pages;
@@ -4377,9 +4378,25 @@ EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
*/
void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu)
{
- struct buffer_data_page *bpage;
+ struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+ struct buffer_data_page *bpage = NULL;
+ unsigned long flags;
struct page *page;
+ local_irq_save(flags);
+ arch_spin_lock(&cpu_buffer->lock);
+
+ if (cpu_buffer->free_page) {
+ bpage = cpu_buffer->free_page;
+ cpu_buffer->free_page = NULL;
+ }
+
+ arch_spin_unlock(&cpu_buffer->lock);
+ local_irq_restore(flags);
+
+ if (bpage)
+ goto out;
+
page = alloc_pages_node(cpu_to_node(cpu),
GFP_KERNEL | __GFP_NORETRY, 0);
if (!page)
@@ -4387,6 +4404,7 @@ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu)
bpage = page_address(page);
+ out:
rb_init_page(bpage);
return bpage;
@@ -4396,13 +4414,29 @@ EXPORT_SYMBOL_GPL(ring_buffer_alloc_read_page);
/**
* ring_buffer_free_read_page - free an allocated read page
* @buffer: the buffer the page was allocate for
+ * @cpu: the cpu buffer the page came from
* @data: the page to free
*
* Free a page allocated from ring_buffer_alloc_read_page.
*/
-void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
+void ring_buffer_free_read_page(struct ring_buffer *buffer, int cpu, void *data)
{
- free_page((unsigned long)data);
+ struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+ struct buffer_data_page *bpage = data;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ arch_spin_lock(&cpu_buffer->lock);
+
+ if (!cpu_buffer->free_page) {
+ cpu_buffer->free_page = bpage;
+ bpage = NULL;
+ }
+
+ arch_spin_unlock(&cpu_buffer->lock);
+ local_irq_restore(flags);
+
+ free_page((unsigned long)bpage);
}
EXPORT_SYMBOL_GPL(ring_buffer_free_read_page);