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Date: Thu, 3 Feb 2022 22:53:07 +0800
From: Chao Yu <chao@...nel.org>
To: jaegeuk@...nel.org
Cc: linux-f2fs-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] f2fs: adjust readahead block number during recovery
Jaegeuk, any comments on this patch?
Thanks,
On 2022/1/29 16:21, Chao Yu wrote:
> In a fragmented image, entries in dnode block list may locate in
> incontiguous physical block address space, however, in recovery flow,
> we will always readahead BIO_MAX_VECS size blocks, so in such case,
> current readahead policy is low efficient, let's adjust readahead
> window size dynamically based on consecutiveness of dnode blocks.
>
> Signed-off-by: Chao Yu <chao@...nel.org>
> ---
> fs/f2fs/checkpoint.c | 8 ++++++--
> fs/f2fs/f2fs.h | 6 +++++-
> fs/f2fs/recovery.c | 27 ++++++++++++++++++++++++---
> 3 files changed, 35 insertions(+), 6 deletions(-)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 57a2d9164bee..203a1577942d 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -282,18 +282,22 @@ int f2fs_ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages,
> return blkno - start;
> }
>
> -void f2fs_ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index)
> +void f2fs_ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index,
> + unsigned int ra_blocks)
> {
> struct page *page;
> bool readahead = false;
>
> + if (ra_blocks == RECOVERY_MIN_RA_BLOCKS)
> + return;
> +
> page = find_get_page(META_MAPPING(sbi), index);
> if (!page || !PageUptodate(page))
> readahead = true;
> f2fs_put_page(page, 0);
>
> if (readahead)
> - f2fs_ra_meta_pages(sbi, index, BIO_MAX_VECS, META_POR, true);
> + f2fs_ra_meta_pages(sbi, index, ra_blocks, META_POR, true);
> }
>
> static int __f2fs_write_meta_page(struct page *page,
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 5af415208488..1fa6b3f98a71 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -590,6 +590,9 @@ enum {
> /* number of extent info in extent cache we try to shrink */
> #define EXTENT_CACHE_SHRINK_NUMBER 128
>
> +#define RECOVERY_MAX_RA_BLOCKS BIO_MAX_VECS
> +#define RECOVERY_MIN_RA_BLOCKS 1
> +
> struct rb_entry {
> struct rb_node rb_node; /* rb node located in rb-tree */
> union {
> @@ -3655,7 +3658,8 @@ bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi,
> block_t blkaddr, int type);
> int f2fs_ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages,
> int type, bool sync);
> -void f2fs_ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index);
> +void f2fs_ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index,
> + unsigned int ra_blocks);
> long f2fs_sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
> long nr_to_write, enum iostat_type io_type);
> void f2fs_add_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type);
> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> index f69b685fb2b2..0b88d0ce284a 100644
> --- a/fs/f2fs/recovery.c
> +++ b/fs/f2fs/recovery.c
> @@ -346,6 +346,19 @@ static int recover_inode(struct inode *inode, struct page *page)
> return 0;
> }
>
> +static unsigned int adjust_por_ra_blocks(struct f2fs_sb_info *sbi,
> + unsigned int ra_blocks, unsigned int blkaddr,
> + unsigned int next_blkaddr)
> +{
> + if (blkaddr + 1 == next_blkaddr)
> + ra_blocks = min_t(unsigned int, RECOVERY_MIN_RA_BLOCKS,
> + ra_blocks * 2);
> + else if (next_blkaddr % sbi->blocks_per_seg)
> + ra_blocks = max_t(unsigned int, RECOVERY_MAX_RA_BLOCKS,
> + ra_blocks / 2);
> + return ra_blocks;
> +}
> +
> static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
> bool check_only)
> {
> @@ -353,6 +366,7 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
> struct page *page = NULL;
> block_t blkaddr;
> unsigned int loop_cnt = 0;
> + unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS;
> unsigned int free_blocks = MAIN_SEGS(sbi) * sbi->blocks_per_seg -
> valid_user_blocks(sbi);
> int err = 0;
> @@ -427,11 +441,14 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
> break;
> }
>
> + ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, blkaddr,
> + next_blkaddr_of_node(page));
> +
> /* check next segment */
> blkaddr = next_blkaddr_of_node(page);
> f2fs_put_page(page, 1);
>
> - f2fs_ra_meta_pages_cond(sbi, blkaddr);
> + f2fs_ra_meta_pages_cond(sbi, blkaddr, ra_blocks);
> }
> return err;
> }
> @@ -707,6 +724,7 @@ static int recover_data(struct f2fs_sb_info *sbi, struct list_head *inode_list,
> struct page *page = NULL;
> int err = 0;
> block_t blkaddr;
> + unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS;
>
> /* get node pages in the current segment */
> curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);
> @@ -718,8 +736,6 @@ static int recover_data(struct f2fs_sb_info *sbi, struct list_head *inode_list,
> if (!f2fs_is_valid_blkaddr(sbi, blkaddr, META_POR))
> break;
>
> - f2fs_ra_meta_pages_cond(sbi, blkaddr);
> -
> page = f2fs_get_tmp_page(sbi, blkaddr);
> if (IS_ERR(page)) {
> err = PTR_ERR(page);
> @@ -762,9 +778,14 @@ static int recover_data(struct f2fs_sb_info *sbi, struct list_head *inode_list,
> if (entry->blkaddr == blkaddr)
> list_move_tail(&entry->list, tmp_inode_list);
> next:
> + ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, blkaddr,
> + next_blkaddr_of_node(page));
> +
> /* check next segment */
> blkaddr = next_blkaddr_of_node(page);
> f2fs_put_page(page, 1);
> +
> + f2fs_ra_meta_pages_cond(sbi, blkaddr, ra_blocks);
> }
> if (!err)
> f2fs_allocate_new_segments(sbi);
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