Re: [PATCH]f2fs: avoid congestion_wait when do_checkpoint for better performance

Re: [PATCH]f2fs: avoid congestion_wait when do_checkpoint for better performance

[Jaegeuk Kim]

Hi,

Please do checkpatch.pl before sending a patch.
Thanks,

2013-09-30 (월), 18:28 +0800, yuan zhong:
> 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.zhong@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 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);
> 

-- 
Jaegeuk Kim
Samsung



------------------------------------------------------------------------------
October Webinars: Code for Performance
Free Intel webinars can help you accelerate application performance.
Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from 
the latest Intel processors and coprocessors. See abstracts and register >
http://pubads.g.doubleclick.net/gampad/clk?id=60134791&iu=/4140/ostg.clktrk
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel