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 <[email protected]>
---
  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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