Re: [f2fs-dev] [PATCH 5/7] f2fs: do FG_GC when GC boosting is required for zoned devices

[Chao Yu <chao@kernel.org>]

On 2024/8/30 5:52, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@google.com>
> 
> Under low free section count, we need to use FG_GC instead of BG_GC to
> recover free sections.
> 
> Signed-off-by: Daeho Jeong <daehojeong@google.com>
> ---
>   fs/f2fs/f2fs.h |  1 +
>   fs/f2fs/gc.c   | 24 +++++++++++++++++-------
>   2 files changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 5e4db3ba534a..ee1fafc65e95 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1294,6 +1294,7 @@ struct f2fs_gc_control {
>   	bool should_migrate_blocks;	/* should migrate blocks */
>   	bool err_gc_skipped;		/* return EAGAIN if GC skipped */

bool one_time;			/* require one time GC in one migration unit */

In order to avoid unnecessary padding for alignment.

Thanks,

>   	unsigned int nr_free_secs;	/* # of free sections to do GC */
> +	bool one_time;			/* require one time GC in one migration unit */
>   };
>   
>   /*
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index d6d71aab94f3..37b47a8d95f1 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -81,6 +81,8 @@ static int gc_thread_func(void *data)
>   			continue;
>   		}
>   
> +		gc_control.one_time = false;
> +
>   		/*
>   		 * [GC triggering condition]
>   		 * 0. GC is not conducted currently.
> @@ -126,15 +128,19 @@ static int gc_thread_func(void *data)
>   				wait_ms = gc_th->max_sleep_time;
>   		}
>   
> -		if (need_to_boost_gc(sbi))
> +		if (need_to_boost_gc(sbi)) {
>   			decrease_sleep_time(gc_th, &wait_ms);
> -		else
> +			if (f2fs_sb_has_blkzoned(sbi))
> +				gc_control.one_time = true;
> +		} else {
>   			increase_sleep_time(gc_th, &wait_ms);
> +		}
>   do_gc:
>   		stat_inc_gc_call_count(sbi, foreground ?
>   					FOREGROUND : BACKGROUND);
>   
> -		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
> +		sync_mode = (F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC) ||
> +				gc_control.one_time;
>   
>   		/* foreground GC was been triggered via f2fs_balance_fs() */
>   		if (foreground)
> @@ -1701,7 +1707,7 @@ static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
>   static int do_garbage_collect(struct f2fs_sb_info *sbi,
>   				unsigned int start_segno,
>   				struct gc_inode_list *gc_list, int gc_type,
> -				bool force_migrate)
> +				bool force_migrate, bool one_time)
>   {
>   	struct page *sum_page;
>   	struct f2fs_summary_block *sum;
> @@ -1728,7 +1734,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
>   			sec_end_segno -= SEGS_PER_SEC(sbi) -
>   					f2fs_usable_segs_in_sec(sbi, segno);
>   
> -		if (gc_type == BG_GC) {
> +		if (gc_type == BG_GC || one_time) {
>   			unsigned int migration_granularity =
>   				sbi->migration_granularity;
>   
> @@ -1908,7 +1914,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
>   	}
>   
>   	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type,
> -				gc_control->should_migrate_blocks);
> +				gc_control->should_migrate_blocks,
> +				gc_control->one_time);
>   	if (seg_freed < 0)
>   		goto stop;
>   
> @@ -1919,6 +1926,9 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
>   		total_sec_freed++;
>   	}
>   
> +	if (gc_control->one_time)
> +		goto stop;
> +
>   	if (gc_type == FG_GC) {
>   		sbi->cur_victim_sec = NULL_SEGNO;
>   
> @@ -2044,7 +2054,7 @@ int f2fs_gc_range(struct f2fs_sb_info *sbi,
>   		};
>   
>   		do_garbage_collect(sbi, segno, &gc_list, FG_GC,
> -						dry_run_sections == 0);
> +						dry_run_sections == 0, false);
>   		put_gc_inode(&gc_list);
>   
>   		if (!dry_run && get_valid_blocks(sbi, segno, true))