On 2025/7/21 10:13, Chao Yu wrote:
This patch supports to readahead more blocks in erofs_readdir(), it can enhance readdir performance in large direcotry. readdir test in a large directory which contains 12000 sub-files. files_per_second Before: 926385.54 After: 2380435.562 Meanwhile, let's introduces a new sysfs entry to control readahead bytes to provide more flexible policy for readahead of readdir(). - location: /sys/fs/erofs/<disk>/dir_ra_bytes - default value: 16384 - disable readahead: set the value to 0 Signed-off-by: Chao Yu <c...@kernel.org> --- v4: - clean up codes and comments Documentation/ABI/testing/sysfs-fs-erofs | 8 ++++++++ fs/erofs/dir.c | 14 ++++++++++++++ fs/erofs/internal.h | 4 ++++ fs/erofs/super.c | 2 ++ fs/erofs/sysfs.c | 2 ++ 5 files changed, 30 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-fs-erofs b/Documentation/ABI/testing/sysfs-fs-erofs index bf3b6299c15e..85fa56ca092c 100644 --- a/Documentation/ABI/testing/sysfs-fs-erofs +++ b/Documentation/ABI/testing/sysfs-fs-erofs @@ -35,3 +35,11 @@ Description: Used to set or show hardware accelerators in effect and multiple accelerators are separated by '\n'. Supported accelerator(s): qat_deflate. Disable all accelerators with an empty string (echo > accel). + +What: /sys/fs/erofs/<disk>/dir_ra_bytes +Date: July 2025 +Contact: "Chao Yu" <c...@kernel.org> +Description: Used to set or show readahead bytes during readdir(), by + default the value is 16384. + + - 0: disable readahead. diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c index 3e4b38bec0aa..99745c272b60 100644 --- a/fs/erofs/dir.c +++ b/fs/erofs/dir.c @@ -47,8 +47,12 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx) struct inode *dir = file_inode(f); struct erofs_buf buf = __EROFS_BUF_INITIALIZER; struct super_block *sb = dir->i_sb; + struct file_ra_state *ra = &f->f_ra; unsigned long bsz = sb->s_blocksize; unsigned int ofs = erofs_blkoff(sb, ctx->pos); + pgoff_t ra_pages = DIV_ROUND_UP_POW2( + EROFS_I_SB(dir)->dir_ra_bytes, PAGE_SIZE); + pgoff_t nr_pages = DIV_ROUND_UP_POW2(dir->i_size, PAGE_SIZE); int err = 0; bool initial = true;@@ -63,6 +67,16 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)break; }+ /* readahead blocks to enhance performance in large directory */+ if (ra_pages) { + pgoff_t idx = DIV_ROUND_UP(ctx->pos, PAGE_SIZE);
Can we use DIV_ROUND_UP_POW2 here too? If it's okay, I will update the patch manually when applied. Otherwise it looks good to me, Reviewed-by: Gao Xiang <hsiang...@linux.alibaba.com> Thanks, Gao Xiang
