Previously, do_checkpoint() will call congestion_wait() for waiting the pages
(previous submitted node/meta/data pages) to be written back.
Because congestion_wait() will set a regular period (e.g. HZ / 50 ) for waiting.
For this reason, there is a situation that after the pages have been written
back, but the checkpoint thread still wait for congestion_wait to exit.
This is a problem here, especially, when sync a large number of small files or
dirs.
In order to avoid this, a wait_list is introduced, the checkpoint thread will
be dropped into the wait_list if the pages have not been written back, and will
be waked up by contrast.
Signed-off-by: Yuan Zhong <yuan.mark.zh...@samsung.com>
---
fs/f2fs/checkpoint.c | 3 +--
fs/f2fs/f2fs.h | 19 +++++++++++++++++++
fs/f2fs/segment.c | 1 +
fs/f2fs/super.c | 1 +
4 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index ca39442..5d69ae0 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -758,8 +758,7 @@ static void do_checkpoint(struct f2fs_sb_info *sbi, bool
is_umount)
f2fs_put_page(cp_page, 1);
/* wait for previous submitted node/meta pages writeback */
- while (get_pages(sbi, F2FS_WRITEBACK))
- congestion_wait(BLK_RW_ASYNC, HZ / 50);
+ f2fs_writeback_wait(sbi);
filemap_fdatawait_range(sbi->node_inode->i_mapping, 0, LONG_MAX);
filemap_fdatawait_range(sbi->meta_inode->i_mapping, 0, LONG_MAX);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 7fd99d8..4b0d70e 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -18,6 +18,8 @@
#include <linux/crc32.h>
#include <linux/magic.h>
#include <linux/kobject.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
/*
* For mount options
@@ -368,6 +370,7 @@ struct f2fs_sb_info {
struct mutex fs_lock[NR_GLOBAL_LOCKS]; /* blocking FS operations */
struct mutex node_write; /* locking node writes */
struct mutex writepages; /* mutex for writepages() */
+ wait_queue_head_t writeback_wqh; /* wait_queue for writeback */
unsigned char next_lock_num; /* round-robin global locks */
int por_doing; /* recovery is doing or not */
int on_build_free_nids; /* build_free_nids is doing */
@@ -961,6 +964,22 @@ static inline int f2fs_readonly(struct super_block *sb)
return sb->s_flags & MS_RDONLY;
}
+static inline void f2fs_writeback_wait(struct f2fs_sb_info *sbi)
+{
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&sbi->writeback_wqh, &wait, TASK_UNINTERRUPTIBLE);
+ if (get_pages(sbi, F2FS_WRITEBACK))
+ io_schedule();
+ finish_wait(&sbi->writeback_wqh, &wait);
+}
+
+static inline void f2fs_writeback_wake(struct f2fs_sb_info *sbi)
+{
+ if (!get_pages(sbi, F2FS_WRITEBACK))
+ wake_up_all(&sbi->writeback_wqh);
+}
+
/*
* file.c
*/
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index bd79bbe..0708aa9 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -597,6 +597,7 @@ static void f2fs_end_io_write(struct bio *bio, int err)
if (p->is_sync)
complete(p->wait);
+ f2fs_writeback_wake(p->sbi);
kfree(p);
bio_put(bio);
}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 094ccc6..3ac6d85 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -835,6 +835,7 @@ static int f2fs_fill_super(struct super_block *sb, void
*data, int silent)
mutex_init(&sbi->gc_mutex);
mutex_init(&sbi->writepages);
mutex_init(&sbi->cp_mutex);
+ init_waitqueue_head(&sbi->writeback_wqh);
for (i = 0; i < NR_GLOBAL_LOCKS; i++)
mutex_init(&sbi->fs_lock[i]);
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