[PATCH v23 1/5] ring-buffer: Allocate sub-buffers with __GFP_COMP

Vincent Donnefort
2024-05-10T14:04:43Z

In preparation for the ring-buffer memory mapping, allocate compound
pages for the ring-buffer sub-buffers to enable us to map them to
user-space with vm_insert_pages().

Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 25476ead681b..cc9ebe593571 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1524,7 +1524,7 @@ static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
list_add(&bpage->list, pages);

page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu),
- mflags | __GFP_ZERO,
+ mflags | __GFP_COMP | __GFP_ZERO,
cpu_buffer->buffer->subbuf_order);
if (!page)
goto free_pages;
@@ -1609,7 +1609,7 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu)

cpu_buffer->reader_page = bpage;

- page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_ZERO,
+ page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_COMP | __GFP_ZERO,
cpu_buffer->buffer->subbuf_order);
if (!page)
goto fail_free_reader;
@@ -5579,7 +5579,7 @@ ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu)
goto out;

page = alloc_pages_node(cpu_to_node(cpu),
- GFP_KERNEL | __GFP_NORETRY | __GFP_ZERO,
+ GFP_KERNEL | __GFP_NORETRY | __GFP_COMP | __GFP_ZERO,
cpu_buffer->buffer->subbuf_order);
if (!page) {
kfree(bpage);
--
2.45.0.118.g7fe29c98d7-goog