This patch fix hungtask problem which can be reproduced as follow:
Thread 0~3:
while true
do
touch /xxx/test/file_xxx
done
Thread 4 write a new checkpoint every three seconds.
In the meantime, fio start 16 threads for randwrite.
With my debug info, cycles num will exceed 1000 in function
f2fs_sync_dirty_inodes, and most of cycle will be dropped
into congestion_wait() and sleep more than 20ms. Cycles num
reduced to 3 with this patch.
Signed-off-by: Yunlei He <[email protected]>
---
fs/f2fs/checkpoint.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 9624a8f..1a1a0a2 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -979,12 +979,10 @@ int f2fs_sync_dirty_inodes(struct f2fs_sb_info *sbi, enum
inode_type type)
iput(inode);
/* We need to give cpu to another writers. */
- if (ino == cur_ino) {
- congestion_wait(BLK_RW_ASYNC, HZ/50);
+ if (ino == cur_ino)
cond_resched();
- } else {
+ else
ino = cur_ino;
- }
} else {
/*
* We should submit bio, since it exists several
--
1.9.1
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