Re: [PATCH 2/9] f2fs: avoid unneeded initializing when converting inline dentry
From: Jaegeuk Kim
Date: Thu Aug 20 2015 - 13:17:43 EST
Hi Chao,
On Wed, Aug 19, 2015 at 07:10:19PM +0800, Chao Yu wrote:
> When converting inline dentry, we will zero out target dentry page before
> duplicating data of inline dentry into target page, it become overhead
> since inline dentry size is not small.
>
> So this patch tries to remove unneeded initializing in the space of target
> dentry page.
>
> Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
> ---
> fs/f2fs/inline.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> index 79d18d5..e4da0d7 100644
> --- a/fs/f2fs/inline.c
> +++ b/fs/f2fs/inline.c
> @@ -384,17 +384,30 @@ static int f2fs_convert_inline_dir(struct inode *dir, struct page *ipage,
> goto out;
>
> f2fs_wait_on_page_writeback(page, DATA);
> - zero_user_segment(page, 0, PAGE_CACHE_SIZE);
> + zero_user_segment(page, MAX_INLINE_DATA, PAGE_CACHE_SIZE);
>
> dentry_blk = kmap_atomic(page);
>
> /* copy data from inline dentry block to new dentry block */
> memcpy(dentry_blk->dentry_bitmap, inline_dentry->dentry_bitmap,
> INLINE_DENTRY_BITMAP_SIZE);
> + memset(dentry_blk->dentry_bitmap + INLINE_DENTRY_BITMAP_SIZE, 0,
> + SIZE_OF_DENTRY_BITMAP - INLINE_DENTRY_BITMAP_SIZE);
Setting zeros for bitmap would be enough.
It doesn't need to copy or set zeros for reserved, dentries, and filename slots.
Thanks,
> + /*
> + * reserved space size of inline dentry is larger than the one of
> + * regular dentry, here we just copy with the size of reserved space
> + * in regular dentry.
> + */
> + memcpy(dentry_blk->reserved, inline_dentry->reserved, SIZE_OF_RESERVED);
> memcpy(dentry_blk->dentry, inline_dentry->dentry,
> sizeof(struct f2fs_dir_entry) * NR_INLINE_DENTRY);
> + memset(dentry_blk->dentry + NR_INLINE_DENTRY, 0,
> + sizeof (struct f2fs_dir_entry) *
> + (NR_DENTRY_IN_BLOCK - NR_INLINE_DENTRY));
> memcpy(dentry_blk->filename, inline_dentry->filename,
> NR_INLINE_DENTRY * F2FS_SLOT_LEN);
> + memset(&dentry_blk->filename[NR_INLINE_DENTRY][0], 0,
> + F2FS_SLOT_LEN * (NR_DENTRY_IN_BLOCK - NR_INLINE_DENTRY));
>
> kunmap_atomic(dentry_blk);
> SetPageUptodate(page);
> --
> 2.4.2
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