RE: [f2fs-dev] [PATCH 07/10] f2fs: use meta_inode cache to improve roll-forward speed

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Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx]
> Sent: Tuesday, September 23, 2014 12:47 PM
> To: Chao Yu
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx;
> linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [f2fs-dev] [PATCH 07/10] f2fs: use meta_inode cache to improve roll-forward speed
> 
> Hi Chao,
> 
> On Mon, Sep 22, 2014 at 10:36:25AM +0800, Chao Yu wrote:
> > Hi Jaegeuk,
> >
> > > -----Original Message-----
> > > From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx]
> > > Sent: Monday, September 15, 2014 6:14 AM
> > > To: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx;
> > > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> > > Cc: Jaegeuk Kim
> > > Subject: [f2fs-dev] [PATCH 07/10] f2fs: use meta_inode cache to improve roll-forward speed
> > >
> > > Previously, all the dnode pages should be read during the roll-forward recovery.
> > > Even worsely, whole the chain was traversed twice.
> > > This patch removes that redundant and costly read operations by using page cache
> > > of meta_inode and readahead function as well.
> > >
> > > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> > > ---
> > >  fs/f2fs/checkpoint.c | 11 ++++++++--
> > >  fs/f2fs/f2fs.h       |  5 +++--
> > >  fs/f2fs/recovery.c   | 59 +++++++++++++++++++++++++---------------------------
> > >  fs/f2fs/segment.h    |  5 +++--
> > >  4 files changed, 43 insertions(+), 37 deletions(-)
> > >
> > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > > index 7262d99..d1ed889 100644
> > > --- a/fs/f2fs/checkpoint.c
> > > +++ b/fs/f2fs/checkpoint.c
> > > @@ -82,6 +82,8 @@ static inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
> > >  	case META_SSA:
> > >  	case META_CP:
> > >  		return 0;
> > > +	case META_POR:
> > > +		return SM_I(sbi)->main_blkaddr + sbi->user_block_count;
> >
> > Here we will skip virtual over-provision segments, so better to use TOTAL_BLKS(sbi).
> >
> > >  	default:
> > >  		BUG();
> > >  	}
> > > @@ -90,11 +92,11 @@ static inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
> > >  /*
> > >   * Readahead CP/NAT/SIT/SSA pages
> > >   */
> > > -int ra_meta_pages(struct f2fs_sb_info *sbi, int start, int nrpages, int type)
> > > +int ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages, int type)
> > >  {
> > >  	block_t prev_blk_addr = 0;
> > >  	struct page *page;
> > > -	int blkno = start;
> > > +	block_t blkno = start;
> > >  	int max_blks = get_max_meta_blks(sbi, type);
> > >
> > >  	struct f2fs_io_info fio = {
> > > @@ -128,6 +130,11 @@ int ra_meta_pages(struct f2fs_sb_info *sbi, int start, int nrpages,
> int
> > > type)
> > >  			/* get ssa/cp block addr */
> > >  			blk_addr = blkno;
> > >  			break;
> > > +		case META_POR:
> > > +			if (unlikely(blkno >= max_blks))
> > > +				goto out;
> > > +			blk_addr = blkno;
> > > +			break;
> >
> > The real modification in patch which is merged to dev of f2fs is as following:
> >
> > - /* get ssa/cp block addr */
> > + case META_POR:
> > + if (blkno >= max_blks || blkno < min_blks)
> > + goto out;
> >
> > IMHO, it's better to verify boundary separately for META_{SSA,CP,POR} with unlikely.
> > How do you think?
> 
> Not bad.
> Could you check the v2 below?
> 
> >
> > >  		default:
> > >  			BUG();
> > >  		}
> > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > index 4f84d2a..48d7d46 100644
> > > --- a/fs/f2fs/f2fs.h
> > > +++ b/fs/f2fs/f2fs.h
> > > @@ -103,7 +103,8 @@ enum {
> > >  	META_CP,
> > >  	META_NAT,
> > >  	META_SIT,
> > > -	META_SSA
> > > +	META_SSA,
> > > +	META_POR,
> > >  };
> > >
> > >  /* for the list of ino */
> > > @@ -1291,7 +1292,7 @@ void destroy_segment_manager_caches(void);
> > >   */
> > >  struct page *grab_meta_page(struct f2fs_sb_info *, pgoff_t);
> > >  struct page *get_meta_page(struct f2fs_sb_info *, pgoff_t);
> > > -int ra_meta_pages(struct f2fs_sb_info *, int, int, int);
> > > +int ra_meta_pages(struct f2fs_sb_info *, block_t, int, int);
> > >  long sync_meta_pages(struct f2fs_sb_info *, enum page_type, long);
> > >  void add_dirty_inode(struct f2fs_sb_info *, nid_t, int type);
> > >  void remove_dirty_inode(struct f2fs_sb_info *, nid_t, int type);
> > > diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> > > index 3736728..6f7fbfa 100644
> > > --- a/fs/f2fs/recovery.c
> > > +++ b/fs/f2fs/recovery.c
> > > @@ -173,7 +173,7 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head
> > > *head)
> > >  {
> > >  	unsigned long long cp_ver = cur_cp_version(F2FS_CKPT(sbi));
> > >  	struct curseg_info *curseg;
> > > -	struct page *page;
> > > +	struct page *page = NULL;
> > >  	block_t blkaddr;
> > >  	int err = 0;
> > >
> > > @@ -181,20 +181,19 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head
> > > *head)
> > >  	curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);
> > >  	blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
> > >
> > > -	/* read node page */
> > > -	page = alloc_page(GFP_F2FS_ZERO);
> > > -	if (!page)
> > > -		return -ENOMEM;
> > > -	lock_page(page);
> > > -
> > >  	while (1) {
> > >  		struct fsync_inode_entry *entry;
> > >
> > > -		err = f2fs_submit_page_bio(sbi, page, blkaddr, READ_SYNC);
> > > -		if (err)
> > > -			return err;
> > > +		if (blkaddr < SM_I(sbi)->main_blkaddr ||
> > > +					blkaddr > TOTAL_BLKS(sbi))
> >
> > blkaddr >= TOTAL_BLKS(sbi) ?
> 
> Right.
> 
> >
> > > +			break;
> > >
> > > -		lock_page(page);
> > > +		page = get_meta_page(sbi, blkaddr);
> > > +		if (IS_ERR(page))
> > > +			return PTR_ERR(page);
> > > +
> > > +		ra_meta_pages(sbi, next_blkaddr_of_node(page),
> > > +				MAX_BIO_BLOCKS(max_hw_blocks(sbi)), META_POR);
> >
> > In first round we readahead [0,n] pages, then in second round we readahead [1,n+1] pages,
> > but as [1,n] pages is already uptodate, so we will readahead only one page, the same for the
> > following rounds. It's low efficiency.
> >
> > So how about modify in find_fsync_dnodes/recover_data like this:
> >
> > 	block_t blkaddr, ra_start_blk;
> > 	int err = 0;
> >
> > 	/* get node pages in the current segment */
> > 	curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);
> > 	blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
> > 	ra_start_blk = blkaddr;
> >
> > 	while (1) {
> > 		struct fsync_inode_entry *entry;
> >
> > 		if (blkaddr < SM_I(sbi)->main_blkaddr ||
> > 					blkaddr > TOTAL_BLKS(sbi))
> > 			return 0;
> >
> > 		if (ra_start_blk == blkaddr) {
> > 			ra_meta_pages(sbi, ra_start_blk, MAX_BIO_BLOCKS(sbi),
> > 								META_POR);
> > 			ra_start_blk += MAX_BIO_BLOCKS(sbi);
> > 		}
> >
> > 		page = get_meta_page(sbi, blkaddr);
> 
> Well. the blkaddr would not be alway able to be matched.
> How about this?
> 
> commit 1cdbd53437f32046af8d94f551505754446c9720
> Author: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> Date:   Thu Sep 11 13:49:55 2014 -0700
> 
>     f2fs: use meta_inode cache to improve roll-forward speed
> 
>     Previously, all the dnode pages should be read during the roll-forward recovery.
>     Even worsely, whole the chain was traversed twice.
>     This patch removes that redundant and costly read operations by using page cache
>     of meta_inode and readahead function as well.
> 
>     Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>

Reviewed-by: Chao Yu <chao2.yu@xxxxxxxxxxx>

> 
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index d44d287..700869c 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -72,7 +72,23 @@ out:
>  	return page;
>  }
> 
> -static inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
> +struct page *get_meta_page_ra(struct f2fs_sb_info *sbi, pgoff_t index)
> +{
> +	bool readahead = false;
> +	struct page *page;
> +
> +	page = find_get_page(META_MAPPING(sbi), index);
> +	if (!page || (page && !PageUptodate(page)))
> +		readahead = true;
> +	f2fs_put_page(page, 0);
> +
> +	if (readahead)
> +		ra_meta_pages(sbi, index,
> +				MAX_BIO_BLOCKS(max_hw_blocks(sbi)), META_POR);
> +	return get_meta_page(sbi, index);
> +}
> +
> +static inline block_t get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
>  {
>  	switch (type) {
>  	case META_NAT:
> @@ -82,6 +98,8 @@ static inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
>  	case META_SSA:
>  	case META_CP:
>  		return 0;
> +	case META_POR:
> +		return SM_I(sbi)->main_blkaddr + TOTAL_BLKS(sbi);

return SM_I(sbi)->seg0_blkaddr + TOTAL_BLKS(sbi);

>  	default:
>  		BUG();
>  	}
> @@ -90,12 +108,13 @@ static inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
>  /*
>   * Readahead CP/NAT/SIT/SSA pages
>   */
> -int ra_meta_pages(struct f2fs_sb_info *sbi, int start, int nrpages, int type)
> +int ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages, int type)
>  {
>  	block_t prev_blk_addr = 0;
>  	struct page *page;
> -	int blkno = start;
> -	int max_blks = get_max_meta_blks(sbi, type);
> +	block_t blkno = start;
> +	block_t max_blks = get_max_meta_blks(sbi, type);
> +	block_t min_blks = SM_I(sbi)->seg0_blkaddr;
> 
>  	struct f2fs_io_info fio = {
>  		.type = META,
> @@ -125,7 +144,11 @@ int ra_meta_pages(struct f2fs_sb_info *sbi, int start, int nrpages, int
> type)
>  			break;
>  		case META_SSA:
>  		case META_CP:
> -			/* get ssa/cp block addr */
> +		case META_POR:
> +			if (unlikely(blkno >= max_blks))
> +				goto out;
> +			if (unlikely(blkno < min_blks))
> +				goto out;
>  			blk_addr = blkno;
>  			break;
>  		default:
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 8efa170..b6439c3 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -103,7 +103,8 @@ enum {
>  	META_CP,
>  	META_NAT,
>  	META_SIT,
> -	META_SSA
> +	META_SSA,
> +	META_POR,
>  };
> 
>  /* for the list of ino */
> @@ -1294,7 +1295,8 @@ void destroy_segment_manager_caches(void);
>   */
>  struct page *grab_meta_page(struct f2fs_sb_info *, pgoff_t);
>  struct page *get_meta_page(struct f2fs_sb_info *, pgoff_t);
> -int ra_meta_pages(struct f2fs_sb_info *, int, int, int);
> +struct page *get_meta_page_ra(struct f2fs_sb_info *, pgoff_t);
> +int ra_meta_pages(struct f2fs_sb_info *, block_t, int, int);
>  long sync_meta_pages(struct f2fs_sb_info *, enum page_type, long);
>  void add_dirty_inode(struct f2fs_sb_info *, nid_t, int type);
>  void remove_dirty_inode(struct f2fs_sb_info *, nid_t, int type);
> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> index e587ee1..3a259a9 100644
> --- a/fs/f2fs/recovery.c
> +++ b/fs/f2fs/recovery.c
> @@ -138,7 +138,7 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head
> *head)
>  {
>  	unsigned long long cp_ver = cur_cp_version(F2FS_CKPT(sbi));
>  	struct curseg_info *curseg;
> -	struct page *page;
> +	struct page *page = NULL;
>  	block_t blkaddr;
>  	int err = 0;
> 
> @@ -146,20 +146,14 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head
> *head)
>  	curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);
>  	blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
> 
> -	/* read node page */
> -	page = alloc_page(GFP_F2FS_ZERO);
> -	if (!page)
> -		return -ENOMEM;
> -	lock_page(page);
> -
>  	while (1) {
>  		struct fsync_inode_entry *entry;
> 
> -		err = f2fs_submit_page_bio(sbi, page, blkaddr, READ_SYNC);
> -		if (err)
> -			return err;
> +		if (blkaddr < SM_I(sbi)->main_blkaddr ||
> +					blkaddr >= TOTAL_BLKS(sbi))

Here, upper boundary should be the same as value in get_max_meta_blks().

blkaddr >= SM_I(sbi)->seg0_blkaddr + TOTAL_BLKS(sbi)

> +			return 0;
> 
> -		lock_page(page);
> +		page = get_meta_page_ra(sbi, blkaddr);
> 
>  		if (cp_ver != cpver_of_node(page))
>  			break;
> @@ -202,11 +196,9 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head
> *head)
>  next:
>  		/* check next segment */
>  		blkaddr = next_blkaddr_of_node(page);
> +		f2fs_put_page(page, 1);
>  	}
> -
> -	unlock_page(page);
> -	__free_pages(page, 0);
> -
> +	f2fs_put_page(page, 1);
>  	return err;
>  }
> 
> @@ -400,7 +392,7 @@ static int recover_data(struct f2fs_sb_info *sbi,
>  {
>  	unsigned long long cp_ver = cur_cp_version(F2FS_CKPT(sbi));
>  	struct curseg_info *curseg;
> -	struct page *page;
> +	struct page *page = NULL;
>  	int err = 0;
>  	block_t blkaddr;
> 
> @@ -408,32 +400,29 @@ static int recover_data(struct f2fs_sb_info *sbi,
>  	curseg = CURSEG_I(sbi, type);
>  	blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
> 
> -	/* read node page */
> -	page = alloc_page(GFP_F2FS_ZERO);
> -	if (!page)
> -		return -ENOMEM;
> -
> -	lock_page(page);
> -
>  	while (1) {
>  		struct fsync_inode_entry *entry;
> 
> -		err = f2fs_submit_page_bio(sbi, page, blkaddr, READ_SYNC);
> -		if (err)
> -			return err;
> +		if (blkaddr < SM_I(sbi)->main_blkaddr ||
> +					blkaddr > TOTAL_BLKS(sbi))

blkaddr >= SM_I(sbi)->seg0_blkaddr + TOTAL_BLKS(sbi)

It's my mistaken that I do not reminder you to fix this in recover_data.

Thanks,
Yu

> +			break;
> 
> -		lock_page(page);
> +		page = get_meta_page_ra(sbi, blkaddr);
> 
> -		if (cp_ver != cpver_of_node(page))
> +		if (cp_ver != cpver_of_node(page)) {
> +			f2fs_put_page(page, 1);
>  			break;
> +		}
> 
>  		entry = get_fsync_inode(head, ino_of_node(page));
>  		if (!entry)
>  			goto next;
> 
>  		err = do_recover_data(sbi, entry->inode, page, blkaddr);
> -		if (err)
> +		if (err) {
> +			f2fs_put_page(page, 1);
>  			break;
> +		}
> 
>  		if (entry->blkaddr == blkaddr) {
>  			iput(entry->inode);
> @@ -443,11 +432,8 @@ static int recover_data(struct f2fs_sb_info *sbi,
>  next:
>  		/* check next segment */
>  		blkaddr = next_blkaddr_of_node(page);
> +		f2fs_put_page(page, 1);
>  	}
> -
> -	unlock_page(page);
> -	__free_pages(page, 0);
> -
>  	if (!err)
>  		allocate_new_segments(sbi);
>  	return err;
> @@ -493,6 +479,10 @@ out:
>  	destroy_fsync_dnodes(&inode_list);
>  	kmem_cache_destroy(fsync_entry_slab);
> 
> +	/* truncate meta pages to be used by the recovery */
> +	truncate_inode_pages_range(META_MAPPING(sbi),
> +		SM_I(sbi)->main_blkaddr << PAGE_CACHE_SHIFT, -1);
> +
>  	if (err) {
>  		truncate_inode_pages_final(NODE_MAPPING(sbi));
>  		truncate_inode_pages_final(META_MAPPING(sbi));
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index 013aed2..c6f37f2 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -87,6 +87,7 @@
>  	(BITS_TO_LONGS(nr) * sizeof(unsigned long))
>  #define TOTAL_SEGS(sbi)	(SM_I(sbi)->main_segments)
>  #define TOTAL_SECS(sbi)	(sbi->total_sections)
> +#define TOTAL_BLKS(sbi)	(SM_I(sbi)->segment_count << sbi->log_blocks_per_seg)
> 
>  #define SECTOR_FROM_BLOCK(sbi, blk_addr)				\
>  	(((sector_t)blk_addr) << (sbi)->log_sectors_per_block)
> @@ -553,7 +554,7 @@ static inline void check_seg_range(struct f2fs_sb_info *sbi, unsigned int
> segno)
>  static inline void verify_block_addr(struct f2fs_sb_info *sbi, block_t blk_addr)
>  {
>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
> -	block_t total_blks = sm_info->segment_count << sbi->log_blocks_per_seg;
> +	block_t total_blks = TOTAL_BLKS(sbi);
>  	block_t start_addr = sm_info->seg0_blkaddr;
>  	block_t end_addr = start_addr + total_blks - 1;
>  	BUG_ON(blk_addr < start_addr);
> @@ -606,7 +607,7 @@ static inline void check_seg_range(struct f2fs_sb_info *sbi, unsigned int
> segno)
>  static inline void verify_block_addr(struct f2fs_sb_info *sbi, block_t blk_addr)
>  {
>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
> -	block_t total_blks = sm_info->segment_count << sbi->log_blocks_per_seg;
> +	block_t total_blks = TOTAL_BLKS(sbi);
>  	block_t start_addr = sm_info->seg0_blkaddr;
>  	block_t end_addr = start_addr + total_blks - 1;
> 

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