linux-kernel - [PATCH AUTOSEL 4.9 31/62] f2fs: try grabbing node page lock aggressively in sync scenario

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Message-ID: <20180902131411.183978-21-alexander.levin@microsoft.com>
Date:   Sun, 2 Sep 2018 13:14:43 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Chao Yu <yuchao0@...wei.com>, Yunlei He <heyunlei@...wei.com>,
        Jaegeuk Kim <jaegeuk@...nel.org>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.9 31/62] f2fs: try grabbing node page lock
 aggressively in sync scenario

From: Chao Yu <yuchao0@...wei.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@...wei.com>
Signed-off-by: Chao Yu <yuchao0@...wei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 fs/f2fs/node.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 01177ecdeab8..addff6a3b176 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1463,7 +1463,9 @@ int sync_node_pages(struct f2fs_sb_info *sbi, struct writeback_control *wbc)
 						!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))) {
-- 
2.17.1