From: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue, 27 Oct 2020 23:25:38 +0000 (+0000)
Subject: io_uring: rearrange io_kiocb fields for better caching
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0415767e7f0542b3cd1ab270c2e61e90e87aafa2;p=linux.git

io_uring: rearrange io_kiocb fields for better caching

We've got extra 8 bytes in the 2nd cacheline, put ->fixed_file_refs
there, so inline execution path mostly doesn't touch the 3rd cacheline
for fixed_file requests as well.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a0a6d13c0c166..b651d6e6d6099 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -713,14 +713,13 @@ struct io_kiocb {
 	u64				user_data;
 
 	struct io_kiocb			*link;
+	struct percpu_ref		*fixed_file_refs;
 
 	/*
 	 * 1. used with ctx->iopoll_list with reads/writes
 	 * 2. to track reqs with ->files (see io_op_def::file_table)
 	 */
 	struct list_head		inflight_entry;
-
-	struct percpu_ref		*fixed_file_refs;
 	struct callback_head		task_work;
 	/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
 	struct hlist_node		hash_node;