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Date:   Sun, 26 Jul 2020 09:05:32 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <yuchao0@huawei.com>
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, chao@kernel.org
Subject: Re: [PATCH 3/5] f2fs: inherit mtime of original block during GC
Message-ID: <20200726160532.GB2233572@google.com>
References: <20200707112128.89136-1-yuchao0@huawei.com>
 <20200707112128.89136-4-yuchao0@huawei.com>
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On 07/07, Chao Yu wrote:
> Don't let f2fs inner GC ruins original aging degree of segment.
> 
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
>  fs/f2fs/data.c    |  2 +-
>  fs/f2fs/f2fs.h    |  5 +++--
>  fs/f2fs/gc.c      |  4 ++--
>  fs/f2fs/segment.c | 55 ++++++++++++++++++++++++++++++++++++-----------
>  4 files changed, 49 insertions(+), 17 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 44645f4f914b..7f108684de1d 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1368,7 +1368,7 @@ static int __allocate_data_block(struct dnode_of_data *dn, int seg_type)
>  	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
>  	old_blkaddr = dn->data_blkaddr;
>  	f2fs_allocate_data_block(sbi, NULL, old_blkaddr, &dn->data_blkaddr,
> -					&sum, seg_type, NULL);
> +				&sum, seg_type, NULL, false);
>  	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
>  		invalidate_mapping_pages(META_MAPPING(sbi),
>  					old_blkaddr, old_blkaddr);
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index ce4305ac42dd..dcf99f1bdfe1 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -3383,7 +3383,8 @@ void f2fs_outplace_write_data(struct dnode_of_data *dn,
>  int f2fs_inplace_write_data(struct f2fs_io_info *fio);
>  void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>  			block_t old_blkaddr, block_t new_blkaddr,
> -			bool recover_curseg, bool recover_newaddr);
> +			bool recover_curseg, bool recover_newaddr,
> +			bool from_gc);
>  void f2fs_replace_block(struct f2fs_sb_info *sbi, struct dnode_of_data *dn,
>  			block_t old_addr, block_t new_addr,
>  			unsigned char version, bool recover_curseg,
> @@ -3391,7 +3392,7 @@ void f2fs_replace_block(struct f2fs_sb_info *sbi, struct dnode_of_data *dn,
>  void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
>  			block_t old_blkaddr, block_t *new_blkaddr,
>  			struct f2fs_summary *sum, int type,
> -			struct f2fs_io_info *fio);
> +			struct f2fs_io_info *fio, bool from_gc);
>  void f2fs_wait_on_page_writeback(struct page *page,
>  			enum page_type type, bool ordered, bool locked);
>  void f2fs_wait_on_block_writeback(struct inode *inode, block_t blkaddr);
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 755641047978..da187aec988f 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -877,7 +877,7 @@ static int move_data_block(struct inode *inode, block_t bidx,
>  	}
>  
>  	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
> -					&sum, CURSEG_COLD_DATA, NULL);
> +				&sum, CURSEG_COLD_DATA, NULL, true);
>  
>  	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
>  				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
> @@ -927,7 +927,7 @@ static int move_data_block(struct inode *inode, block_t bidx,
>  recover_block:
>  	if (err)
>  		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
> -								true, true);
> +							true, true, true);
>  up_out:
>  	if (lfs_mode)
>  		up_write(&fio.sbi->io_order_lock);
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 9d10285932f9..222d28c44e4f 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2149,12 +2149,28 @@ static void __set_sit_entry_type(struct f2fs_sb_info *sbi, int type,
>  	if (modified)
>  		__mark_sit_entry_dirty(sbi, segno);
>  }

Need a new line?

> +static inline unsigned long long get_segment_mtime(struct f2fs_sb_info *sbi,
> +								block_t blkaddr)
> +{
> +	unsigned int segno = GET_SEGNO(sbi, blkaddr);
> +
> +	if (segno == NULL_SEGNO)
> +		return 0;
> +	return get_seg_entry(sbi, segno)->mtime;
> +}
>  
> -static void update_segment_mtime(struct f2fs_sb_info *sbi, block_t blkaddr)
> +static void update_segment_mtime(struct f2fs_sb_info *sbi, block_t blkaddr,
> +						unsigned long long old_mtime)
>  {
> +	struct seg_entry *se;
>  	unsigned int segno = GET_SEGNO(sbi, blkaddr);
> -	struct seg_entry *se = get_seg_entry(sbi, segno);
> -	unsigned long long mtime = get_mtime(sbi, false);
> +	unsigned long long ctime = get_mtime(sbi, false);
> +	unsigned long long mtime = old_mtime ? old_mtime : ctime;
> +
> +	if (segno == NULL_SEGNO)
> +		return;
> +
> +	se = get_seg_entry(sbi, segno);
>  
>  	if (!se->mtime)
>  		se->mtime = mtime;
> @@ -2162,8 +2178,8 @@ static void update_segment_mtime(struct f2fs_sb_info *sbi, block_t blkaddr)
>  		se->mtime = div_u64(se->mtime * se->valid_blocks + mtime,
>  						se->valid_blocks + 1);
>  
> -	if (mtime > SIT_I(sbi)->max_mtime)
> -		SIT_I(sbi)->max_mtime = mtime;
> +	if (ctime > SIT_I(sbi)->max_mtime)
> +		SIT_I(sbi)->max_mtime = ctime;
>  }
>  
>  static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
> @@ -2185,8 +2201,6 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
>  	f2fs_bug_on(sbi, (new_vblocks >> (sizeof(unsigned short) << 3) ||
>  				(new_vblocks > sbi->blocks_per_seg)));
>  
> -	update_segment_mtime(sbi, blkaddr);
> -
>  	se->valid_blocks = new_vblocks;
>  
>  	/* Update valid block bitmap */
> @@ -2280,6 +2294,7 @@ void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr)
>  	/* add it into sit main buffer */
>  	down_write(&sit_i->sentry_lock);
>  
> +	update_segment_mtime(sbi, addr, 0);
>  	update_sit_entry(sbi, addr, -1);
>  
>  	/* add it into dirty seglist */
> @@ -3188,10 +3203,11 @@ static int __get_segment_type(struct f2fs_io_info *fio)
>  void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
>  		block_t old_blkaddr, block_t *new_blkaddr,
>  		struct f2fs_summary *sum, int type,
> -		struct f2fs_io_info *fio)
> +		struct f2fs_io_info *fio, bool from_gc)
>  {
>  	struct sit_info *sit_i = SIT_I(sbi);
>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
> +	unsigned long long old_mtime;
>  
>  	down_read(&SM_I(sbi)->curseg_lock);
>  
> @@ -3213,6 +3229,14 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
>  
>  	stat_inc_block_count(sbi, curseg);
>  
> +	if (from_gc) {
> +		old_mtime = get_segment_mtime(sbi, old_blkaddr);
> +	} else {
> +		update_segment_mtime(sbi, old_blkaddr, 0);
> +		old_mtime = 0;
> +	}
> +	update_segment_mtime(sbi, *new_blkaddr, old_mtime);
> +
>  	/*
>  	 * SIT information should be updated before segment allocation,
>  	 * since SSR needs latest valid block information.
> @@ -3289,7 +3313,8 @@ static void do_write_page(struct f2fs_summary *sum, struct f2fs_io_info *fio)
>  		down_read(&fio->sbi->io_order_lock);
>  reallocate:
>  	f2fs_allocate_data_block(fio->sbi, fio->page, fio->old_blkaddr,
> -			&fio->new_blkaddr, sum, type, fio);
> +			&fio->new_blkaddr, sum, type, fio,
> +			is_cold_data(fio->page));
>  	if (GET_SEGNO(fio->sbi, fio->old_blkaddr) != NULL_SEGNO)
>  		invalidate_mapping_pages(META_MAPPING(fio->sbi),
>  					fio->old_blkaddr, fio->old_blkaddr);
> @@ -3405,7 +3430,8 @@ static inline int __f2fs_get_curseg(struct f2fs_sb_info *sbi,
>  
>  void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>  				block_t old_blkaddr, block_t new_blkaddr,
> -				bool recover_curseg, bool recover_newaddr)
> +				bool recover_curseg, bool recover_newaddr,
> +				bool from_gc)
>  {
>  	struct sit_info *sit_i = SIT_I(sbi);
>  	struct curseg_info *curseg;
> @@ -3456,11 +3482,16 @@ void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>  	curseg->next_blkoff = GET_BLKOFF_FROM_SEG0(sbi, new_blkaddr);
>  	__add_sum_entry(sbi, type, sum);
>  
> -	if (!recover_curseg || recover_newaddr)
> +	if (!recover_curseg || recover_newaddr) {
> +		if (!from_gc)
> +			update_segment_mtime(sbi, new_blkaddr, 0);
>  		update_sit_entry(sbi, new_blkaddr, 1);
> +	}
>  	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO) {
>  		invalidate_mapping_pages(META_MAPPING(sbi),
>  					old_blkaddr, old_blkaddr);
> +		if (!from_gc)
> +			update_segment_mtime(sbi, old_blkaddr, 0);
>  		update_sit_entry(sbi, old_blkaddr, -1);
>  	}
>  
> @@ -3492,7 +3523,7 @@ void f2fs_replace_block(struct f2fs_sb_info *sbi, struct dnode_of_data *dn,
>  	set_summary(&sum, dn->nid, dn->ofs_in_node, version);
>  
>  	f2fs_do_replace_block(sbi, &sum, old_addr, new_addr,
> -					recover_curseg, recover_newaddr);
> +					recover_curseg, recover_newaddr, false);
>  
>  	f2fs_update_data_blkaddr(dn, new_addr);
>  }
> -- 
> 2.26.2