1 files changed, 37 insertions, 3 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index ca47a4fa2986..4ae268e687fe 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;
@@ -4389,9 +4390,25 @@ 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)
@@ -4399,6 +4416,7 @@ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu)
 
         bpage = page_address(page);
 
+ out:
         rb_init_page(bpage);
 
         return bpage;
@@ -4408,13 +4426,29 @@ 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);