2015-08-19 11:11:07

by Chao Yu

[permalink] [raw]
Subject: [PATCH 2/9] f2fs: avoid unneeded initializing when converting inline dentry

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 <[email protected]>
---
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);
+ /*
+ * 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


2015-08-20 17:17:40

by Jaegeuk Kim

[permalink] [raw]
Subject: Re: [PATCH 2/9] f2fs: avoid unneeded initializing when converting inline dentry

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 <[email protected]>
> ---
> 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

2015-08-21 12:59:32

by Chao Yu

[permalink] [raw]
Subject: RE: [PATCH 2/9] f2fs: avoid unneeded initializing when converting inline dentry

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:[email protected]]
> Sent: Friday, August 21, 2015 1:17 AM
> To: Chao Yu
> Cc: [email protected]; [email protected]
> Subject: Re: [PATCH 2/9] f2fs: avoid unneeded initializing when converting inline dentry
>
> 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 <[email protected]>
> > ---
> > 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.

Oh, you're right, I will fix it. :)

Thanks