linux-kernel - [for-next][PATCH 1/6] ring-buffer: Allocate sub-buffers with __GFP

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Date: Tue, 14 May 2024 12:15:59 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
 Mark Rutland <mark.rutland@....com>,
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 David Hildenbrand <david@...hat.com>,
 Vincent Donnefort <vdonnefort@...gle.com>
Subject: [for-next][PATCH 1/6] ring-buffer: Allocate sub-buffers with __GFP_COMP

From: Vincent Donnefort <vdonnefort@...gle.com>

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().

Link: https://lore.kernel.org/linux-trace-kernel/20240510140435.3550353-2-vdonnefort@google.com

Acked-by: David Hildenbrand <david@...hat.com>
Signed-off-by: Vincent Donnefort <vdonnefort@...gle.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
 kernel/trace/ring_buffer.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 6511dc3a00da..a1e011733f6a 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);
-- 
2.43.0