From c24cda9aa902775e4e23575b758f009e9fae4640 Mon Sep 17 00:00:00 2001
From: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Date: Fri, 19 Mar 2021 08:48:18 +0300
Subject: [PATCH] io_uring: completely disable io_should_merge logic

io_should_merge logic is wierd and prone to latency spikes because of slow neighbors.

Signed-off-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 478df7e..a4fb3a7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1288,7 +1288,7 @@ static ssize_t io_import_iovec(struct io_ring_ctx *ctx, int rw,
 
 static inline bool io_should_merge(struct async_list *al, struct kiocb *kiocb)
 {
-	if (al->file == kiocb->ki_filp) {
+	if (al->file == kiocb->ki_filp && 0) {
 		off_t start, end;
 
 		/*
-- 
2.7.4