Could you please share some trends of relation between has_enough_free_blocks()
vs. has_enough_dirty_blocks()? I'm wondering whethere there's a missing case
where has_enough_free_blocks() is not enough.

On 09/09, Liao Yuanhong wrote:
> Incorporate a check using has_enough_dirty_blocks() to prevent redundant
> background GC in Zoned UFS. When there are insufficient dirty segments,
> continuous execution of background GC should be avoided, as it results in
> unnecessary write operations and impacts device lifespan. The initial
> threshold is set to 3 * section size (since f2fs data uses three write
> pointers).
> 
> Signed-off-by: Liao Yuanhong <[email protected]>
> ---
>  fs/f2fs/gc.c |  8 ++++++--
>  fs/f2fs/gc.h | 10 +++++++++-
>  2 files changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index ed3acbfc83ca..4a8c08f970e3 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -120,7 +120,9 @@ static int gc_thread_func(void *data)
>  
>               if (f2fs_sb_has_blkzoned(sbi)) {
>                       if (has_enough_free_blocks(sbi,
> -                             gc_th->no_zoned_gc_percent)) {
> +                             gc_th->no_zoned_gc_percent) ||
> +                             !has_enough_dirty_blocks(sbi,
> +                             LIMIT_GC_DIRTY_SECTION_NUM)) {
>                               wait_ms = gc_th->no_gc_sleep_time;
>                               f2fs_up_write(&sbi->gc_lock);
>                               goto next;
> @@ -1750,7 +1752,9 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
>  
>                       if (f2fs_sb_has_blkzoned(sbi) &&
>                                       !has_enough_free_blocks(sbi,
> -                                     sbi->gc_thread->boost_zoned_gc_percent))
> +                                     sbi->gc_thread->boost_zoned_gc_percent) 
> &&
> +                                     has_enough_dirty_blocks(sbi,
> +                                     LIMIT_GC_DIRTY_SECTION_NUM))
>                               window_granularity *=
>                                       sbi->gc_thread->boost_gc_multiple;
>  
> diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
> index 24e8b1c27acc..1ef234c2702b 100644
> --- a/fs/f2fs/gc.h
> +++ b/fs/f2fs/gc.h
> @@ -36,6 +36,7 @@
>  #define DEF_MIGRATION_WINDOW_GRANULARITY_ZONED       3
>  #define BOOST_GC_MULTIPLE    5
>  #define ZONED_PIN_SEC_REQUIRED_COUNT 1
> +#define LIMIT_GC_DIRTY_SECTION_NUM   3
>  
>  #define DEF_GC_FAILED_PINNED_FILES   2048
>  #define MAX_GC_FAILED_PINNED_FILES   USHRT_MAX
> @@ -177,6 +178,12 @@ static inline bool has_enough_free_blocks(struct 
> f2fs_sb_info *sbi,
>       return free_sections(sbi) > ((sbi->total_sections * limit_perc) / 100);
>  }
>  
> +static inline bool has_enough_dirty_blocks(struct f2fs_sb_info *sbi,
> +                                             unsigned int limit_num)
> +{
> +     return dirty_segments(sbi) > limit_num * SEGS_PER_SEC(sbi);
> +}
> +
>  static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
>  {
>       block_t user_block_count = sbi->user_block_count;
> @@ -197,6 +204,7 @@ static inline bool need_to_boost_gc(struct f2fs_sb_info 
> *sbi)
>  {
>       if (f2fs_sb_has_blkzoned(sbi))
>               return !has_enough_free_blocks(sbi,
> -                             sbi->gc_thread->boost_zoned_gc_percent);
> +                             sbi->gc_thread->boost_zoned_gc_percent) &&
> +                             has_enough_dirty_blocks(sbi, 
> LIMIT_GC_DIRTY_SECTION_NUM);
>       return has_enough_invalid_blocks(sbi);
>  }
> -- 
> 2.34.1


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