[PATCH 4.9 46/70] f2fs: try grabbing node page lock aggressively in sync scenario

Greg Kroah-Hartman
2018-09-17T22:59:02Z

From: Chao Yu <yuchao0@huawei.com>

[ Upstream commit 4b270a8cc5047682f0a3f3f9af3b498408dbd2bc ]

In synchronous scenario, like in checkpoint(), we are going to flush
dirty node pages to device synchronously, we can easily failed
writebacking node page due to trylock_page() failure, especially in
condition of intensive lock competition, which can cause long latency
of checkpoint(). So let's use lock_page() in synchronous scenario to
avoid this issue.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/f2fs/node.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1463,7 +1463,9 @@ next_step:
!is_cold_node(page)))
continue;
lock_node:
- if (!trylock_page(page))
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ lock_page(page);
+ else if (!trylock_page(page))
continue;

if (unlikely(page->mapping != NODE_MAPPING(sbi))) {