From: Masami Hiramatsu Date: Thu, 9 Aug 2012 12:31:10 +0000 (+0900) Subject: ftrace: Allow stealing pages from pipe buffer X-Git-Tag: firefly_0821_release~3680^2~1902^2~20 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d55cb6cf143ae16eaa415baab520b8eaf4a1012f;p=firefly-linux-kernel-4.4.55.git ftrace: Allow stealing pages from pipe buffer Use generic steal operation on pipe buffer to allow stealing ring buffer's read page from pipe buffer. Note that this could reduce the performance of splice on the splice_write side operation without affinity setting. Since the ring buffer's read pages are allocated on the tracing-node, but the splice user does not always execute splice write side operation on the same node. In this case, the page will be accessed from the another node. Thus, it is strongly recommended to assign the splicing thread to corresponding node. Signed-off-by: Masami Hiramatsu Acked-by: Steven Rostedt Signed-off-by: Rusty Russell --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 5c38c81496ce..adde0994911e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4195,12 +4195,6 @@ static void buffer_pipe_buf_release(struct pipe_inode_info *pipe, buf->private = 0; } -static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe, - struct pipe_buffer *buf) -{ - return 1; -} - static void buffer_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { @@ -4216,7 +4210,7 @@ static const struct pipe_buf_operations buffer_pipe_buf_ops = { .unmap = generic_pipe_buf_unmap, .confirm = generic_pipe_buf_confirm, .release = buffer_pipe_buf_release, - .steal = buffer_pipe_buf_steal, + .steal = generic_pipe_buf_steal, .get = buffer_pipe_buf_get, };