Re: [f2fs-dev] [PATCH] f2fs: set *_data_age_threshold according to user_block_count

[qixiaoyu]

On Tue, Jan 17, 2023 at 06:30:42PM +0800, Yangtao Li via Linux-f2fs-devel wrote:
> Commit 71644dff4811 ("f2fs: add block_age-based extent cache")
> introduce age extent cache, which experimental data is based on
> a 128G storage device, and hot and warm data age threshold are
> set to 1G and 10G respectively. But it is unreasonable to set
> this value to 1G or 10G by default, which varies depending on
> the environment. For small storage devices, some storage devices
> do not even have 10G.
> 
> Let's change hot and warm data age threshold to 1% and 10% of
> user_block_count respectively.
> 

Hi Yangtao,

Thanks for your patch.

The block age here refers to total data blocks allocated of filesystem
between two consecutive updates. So, it has nothing to do with storage
size.

> Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
> ---
>  Documentation/ABI/testing/sysfs-fs-f2fs | 6 ++----
>  fs/f2fs/extent_cache.c                  | 2 --
>  fs/f2fs/f2fs.h                          | 9 +++++----
>  fs/f2fs/super.c                         | 2 ++
>  4 files changed, 9 insertions(+), 10 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> index 75420c242cc4..c7952f1baf59 100644
> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> @@ -660,15 +660,13 @@ What:		/sys/fs/f2fs/<disk>/hot_data_age_threshold
>  Date:		November 2022
>  Contact:	"Ping Xiong" <xiongping1@xxxxxxxxxx>
>  Description:	When DATA SEPARATION is on, it controls the age threshold to indicate
> -		the data blocks as hot. By default it was initialized as 262144 blocks
> -		(equals to 1GB).
> +		the data blocks as hot. By default it was initialized as 1% of user_block_count.
>  
>  What:		/sys/fs/f2fs/<disk>/warm_data_age_threshold
>  Date:		November 2022
>  Contact:	"Ping Xiong" <xiongping1@xxxxxxxxxx>
>  Description:	When DATA SEPARATION is on, it controls the age threshold to indicate
> -		the data blocks as warm. By default it was initialized as 2621440 blocks
> -		(equals to 10GB).
> +		the data blocks as warm. By default it was initialized as 10% of user_block_count.
>  
>  What:		/sys/fs/f2fs/<disk>/fault_rate
>  Date:		May 2016
> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
> index 1daf8c88c09b..9c7e304d5660 100644
> --- a/fs/f2fs/extent_cache.c
> +++ b/fs/f2fs/extent_cache.c
> @@ -1235,8 +1235,6 @@ void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi)
>  
>  	/* initialize for block age extents */
>  	atomic64_set(&sbi->allocated_data_blocks, 0);
> -	sbi->hot_data_age_threshold = DEF_HOT_DATA_AGE_THRESHOLD;
> -	sbi->warm_data_age_threshold = DEF_WARM_DATA_AGE_THRESHOLD;
>  }
>  
>  int __init f2fs_create_extent_cache(void)
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index f3c5f7740c1a..3b853c302a43 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -615,11 +615,12 @@ enum {
>  #define SAME_AGE_REGION			1024
>  
>  /*
> - * Define data block with age less than 1GB as hot data
> - * define data block with age less than 10GB but more than 1GB as warm data
> + * Define data block with age less than 1% of user_block_count as hot data
> + * Define data block with age less than 10% of user_block_count but more
> + * than 1% of user_block_count as warm data
>   */
> -#define DEF_HOT_DATA_AGE_THRESHOLD	262144
> -#define DEF_WARM_DATA_AGE_THRESHOLD	2621440
> +#define DEF_HOT_DATA_AGE_THRESHOLD	1
> +#define DEF_WARM_DATA_AGE_THRESHOLD	10
>  
>  /* extent cache type */
>  enum extent_type {
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 5fc83771042d..8333ea5b8ffd 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -4088,6 +4088,8 @@ static void f2fs_tuning_parameters(struct f2fs_sb_info *sbi)
>  					BIT(F2FS_IPU_HONOR_OPU_WRITE);
>  	}
>  
> +	sbi->hot_data_age_threshold = sbi->user_block_count * DEF_HOT_DATA_AGE_THRESHOLD / 100;
> +	sbi->warm_data_age_threshold = sbi->user_block_count * DEF_WARM_DATA_AGE_THRESHOLD / 100;
>  	sbi->readdir_ra = true;
>  }
>  
> -- 
> 2.25.1
> 
> 
> 
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