[f2fs-dev] [PATCH] f2fs: do not use AT_SSR mode in FG_GC & high urgent BG_GC

[f2fs-dev] [PATCH] f2fs: do not use AT_SSR mode in FG_GC & high urgent BG_GC

[Weichao Guo via Linux-f2fs-devel]

AT_SSR mode is introduced by age threshold based GC for better
hot/cold data seperation and avoiding free segment cost. However,
LFS write mode is preferred in the scenario of foreground or high
urgent GC, which should be finished ASAP. Let's only use AT_SSR
in background GC and not high urgent GC modes.

Signed-off-by: Weichao Guo <guoweichao@oppo.com>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
---
 fs/f2fs/gc.c      | 3 ++-
 fs/f2fs/segment.c | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 86ba8ed..0f2c34f 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1120,7 +1120,8 @@ static int move_data_block(struct inode *inode, block_t bidx,
 	block_t newaddr;
 	int err = 0;
 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
-	int type = fio.sbi->am.atgc_enabled ?
+	int type = fio.sbi->am.atgc_enabled && gc_type == BG_GC &&
+				fio.sbi->gc_mode != GC_URGENT_HIGH ?
 				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
 
 	/* do not read out */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 32b915e..81be3e9 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3264,7 +3264,9 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
 		struct inode *inode = fio->page->mapping->host;
 
 		if (is_cold_data(fio->page)) {
-			if (fio->sbi->am.atgc_enabled)
+			if (fio->sbi->am.atgc_enabled &&
+				fio->io_type == FS_DATA_IO &&
+				fio->sbi->gc_mode != GC_URGENT_HIGH)
 				return CURSEG_ALL_DATA_ATGC;
 			else
 				return CURSEG_COLD_DATA;
-- 
2.7.4



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Re: [f2fs-dev] [PATCH] f2fs: do not use AT_SSR mode in FG_GC & high urgent BG_GC

[Chao Yu]

On 2021/3/17 16:28, Weichao Guo via Linux-f2fs-devel wrote:
> AT_SSR mode is introduced by age threshold based GC for better
> hot/cold data seperation and avoiding free segment cost. However,
> LFS write mode is preferred in the scenario of foreground or high
> urgent GC, which should be finished ASAP. Let's only use AT_SSR
> in background GC and not high urgent GC modes.
> 
> Signed-off-by: Weichao Guo <guoweichao@oppo.com>
> Signed-off-by: Huang Jianan <huangjianan@oppo.com>
> ---

v2:
...

>   fs/f2fs/gc.c      | 3 ++-
>   fs/f2fs/segment.c | 4 +++-
>   2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 86ba8ed..0f2c34f 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1120,7 +1120,8 @@ static int move_data_block(struct inode *inode, block_t bidx,
>   	block_t newaddr;
>   	int err = 0;
>   	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
> -	int type = fio.sbi->am.atgc_enabled ?
> +	int type = fio.sbi->am.atgc_enabled && gc_type == BG_GC &&
> +				fio.sbi->gc_mode != GC_URGENT_HIGH ?
>   				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;

Minor thing:

.. && (gc_type == BG_GC) &&
(fio.sbi->gc_mode != GC_URGENT_HIGH)

I guess it will be better to use parenthesis to improve readability,
so that we don't need to check priority from different operators.

>   
>   	/* do not read out */
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 32b915e..81be3e9 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -3264,7 +3264,9 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
>   		struct inode *inode = fio->page->mapping->host;
>   
>   		if (is_cold_data(fio->page)) {
> -			if (fio->sbi->am.atgc_enabled)
> +			if (fio->sbi->am.atgc_enabled &&
> +				fio->io_type == FS_DATA_IO &&
> +				fio->sbi->gc_mode != GC_URGENT_HIGH)

Ditto,

Otherwise, it looks good to me, you can add below tag in next version:

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

>   				return CURSEG_ALL_DATA_ATGC;
>   			else
>   				return CURSEG_COLD_DATA;



> 


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