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 <[email protected]> --- 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 bb31220..cf6b4a5 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -756,8 +756,7 @@ 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 608f0df..f8b62cc 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -18,6 +18,7 @@ #include <linux/crc32.h> #include <linux/magic.h> #include <linux/kobject.h> +#include <linux/wait.h> /* * For mount options @@ -430,6 +431,8 @@ struct f2fs_sb_info { /* For sysfs suppport */ struct kobject s_kobj; struct completion s_kobj_unregister; + + wait_queue_head_t writeback_wqh; }; /* @@ -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 09af9c7..79293fe 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 13d0a0f..b31f686 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -818,6 +818,7 @@ 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]); mutex_init(&sbi->node_write);
