Re: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
It causes NULL pointer error without f2fs_bug_on(), so I don't think we
need to add this.
Thanks,
2013-12-02 (월), 16:59 +0800, Chao Yu:
> Hi Kim,
>
> > -Original Message-
> > From: Jaegeuk Kim [mailto:jaegeuk@samsung.com]
> > Sent: Monday, December 02, 2013 4:15 PM
> > To: Chao Yu
> > Cc: linux-fsde...@vger.kernel.org; linux-ker...@vger.kernel.org;
> > linux-f2fs-devel@lists.sourceforge.net; 谭姝
> > Subject: RE: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
> >
> > 2013-12-02 (월), 14:14 +0800, Chao Yu:
> > > Hi Kim,
> > >
> > > > -Original Message-
> > > > From: Jaegeuk Kim [mailto:jaegeuk@samsung.com]
> > > > Sent: Saturday, November 30, 2013 9:48 AM
> > > > Cc: linux-fsde...@vger.kernel.org; linux-ker...@vger.kernel.org;
> > > > linux-f2fs-devel@lists.sourceforge.net
> > > > Subject: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
> > > >
> > > > Previously f2fs allocates its own bi_private data structure all the
> > > > time even
> > > > though we don't use it. But, can we remove this bi_private allocation?
> > > >
> > > > This patch removes such the additional bi_private allocation.
> > > >
> > > > 1. Retrieve f2fs_sb_info from its page->mapping->host->i_sb.
> > > > - This removes the usecases of bi_private in end_io.
> > > >
> > > > 2. Use bi_private only when we really need it.
> > > > - The bi_private is used only when the checkpoint procedure is
> > > > conducted.
> > > > - When conducting the checkpoint, f2fs submits a META_FLUSH bio to
> > > > wait its bio
> > > > completion.
> > > > - Since we have no dependancies to remove bi_private now, let's just
> > > > use
> > > > bi_private pointer as the completion pointer.
> > > >
> > > > Signed-off-by: Jaegeuk Kim
> > > > ---
> > > > fs/f2fs/segment.c | 43 ---
> > > > fs/f2fs/segment.h | 7 ---
> > > > 2 files changed, 16 insertions(+), 34 deletions(-)
> > > >
> > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > index 0387863..0db4027 100644
> > > > --- a/fs/f2fs/segment.c
> > > > +++ b/fs/f2fs/segment.c
> > > > @@ -791,7 +791,7 @@ static void f2fs_end_io_write(struct bio *bio, int
> > > > err)
> > > > {
> > > > const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
> > > > struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
> > > > - struct bio_private *p = bio->bi_private;
>
> f2fs_bug_on(unlikely(!bvec->bv_page->mapping));
>
> > > > + struct f2fs_sb_info *sbi =
> > > > F2FS_SB(bvec->bv_page->mapping->host->i_sb);
> > >
> > > I'm not sure whether bvec->bv_page->mapping will be set to NULL in the
> > > flow
> > > where may not check WRITEBACK flag of page. Is it possible?
> >
> > The mapping should be not NULL cause it is a writebacking page.
> > Otherwise, it's a bug.
>
> If so, should we add additional code as above?
>
> Regards,
> Yu
>
> > Thanks,
> >
> > --
> > Jaegeuk Kim
> > Samsung
>
> --
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--
Jaegeuk Kim
Samsung
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Re: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
Hi Kim,
> -Original Message-
> From: Jaegeuk Kim [mailto:jaegeuk@samsung.com]
> Sent: Monday, December 02, 2013 4:15 PM
> To: Chao Yu
> Cc: linux-fsde...@vger.kernel.org; linux-ker...@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net; 谭姝
> Subject: RE: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
>
> 2013-12-02 (월), 14:14 +0800, Chao Yu:
> > Hi Kim,
> >
> > > -Original Message-
> > > From: Jaegeuk Kim [mailto:jaegeuk@samsung.com]
> > > Sent: Saturday, November 30, 2013 9:48 AM
> > > Cc: linux-fsde...@vger.kernel.org; linux-ker...@vger.kernel.org;
> > > linux-f2fs-devel@lists.sourceforge.net
> > > Subject: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
> > >
> > > Previously f2fs allocates its own bi_private data structure all the time
> > > even
> > > though we don't use it. But, can we remove this bi_private allocation?
> > >
> > > This patch removes such the additional bi_private allocation.
> > >
> > > 1. Retrieve f2fs_sb_info from its page->mapping->host->i_sb.
> > > - This removes the usecases of bi_private in end_io.
> > >
> > > 2. Use bi_private only when we really need it.
> > > - The bi_private is used only when the checkpoint procedure is conducted.
> > > - When conducting the checkpoint, f2fs submits a META_FLUSH bio to wait
> > > its bio
> > > completion.
> > > - Since we have no dependancies to remove bi_private now, let's just use
> > > bi_private pointer as the completion pointer.
> > >
> > > Signed-off-by: Jaegeuk Kim
> > > ---
> > > fs/f2fs/segment.c | 43 ---
> > > fs/f2fs/segment.h | 7 ---
> > > 2 files changed, 16 insertions(+), 34 deletions(-)
> > >
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index 0387863..0db4027 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -791,7 +791,7 @@ static void f2fs_end_io_write(struct bio *bio, int
> > > err)
> > > {
> > > const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
> > > struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
> > > - struct bio_private *p = bio->bi_private;
f2fs_bug_on(unlikely(!bvec->bv_page->mapping));
> > > + struct f2fs_sb_info *sbi = F2FS_SB(bvec->bv_page->mapping->host->i_sb);
> >
> > I'm not sure whether bvec->bv_page->mapping will be set to NULL in the flow
> > where may not check WRITEBACK flag of page. Is it possible?
>
> The mapping should be not NULL cause it is a writebacking page.
> Otherwise, it's a bug.
If so, should we add additional code as above?
Regards,
Yu
> Thanks,
>
> --
> Jaegeuk Kim
> Samsung
--
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Re: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
2013-12-02 (월), 14:14 +0800, Chao Yu:
> Hi Kim,
>
> > -Original Message-
> > From: Jaegeuk Kim [mailto:jaegeuk@samsung.com]
> > Sent: Saturday, November 30, 2013 9:48 AM
> > Cc: linux-fsde...@vger.kernel.org; linux-ker...@vger.kernel.org;
> > linux-f2fs-devel@lists.sourceforge.net
> > Subject: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
> >
> > Previously f2fs allocates its own bi_private data structure all the time
> > even
> > though we don't use it. But, can we remove this bi_private allocation?
> >
> > This patch removes such the additional bi_private allocation.
> >
> > 1. Retrieve f2fs_sb_info from its page->mapping->host->i_sb.
> > - This removes the usecases of bi_private in end_io.
> >
> > 2. Use bi_private only when we really need it.
> > - The bi_private is used only when the checkpoint procedure is conducted.
> > - When conducting the checkpoint, f2fs submits a META_FLUSH bio to wait
> > its bio
> > completion.
> > - Since we have no dependancies to remove bi_private now, let's just use
> > bi_private pointer as the completion pointer.
> >
> > Signed-off-by: Jaegeuk Kim
> > ---
> > fs/f2fs/segment.c | 43 ---
> > fs/f2fs/segment.h | 7 ---
> > 2 files changed, 16 insertions(+), 34 deletions(-)
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 0387863..0db4027 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -791,7 +791,7 @@ static void f2fs_end_io_write(struct bio *bio, int err)
> > {
> > const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
> > struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
> > - struct bio_private *p = bio->bi_private;
> > + struct f2fs_sb_info *sbi = F2FS_SB(bvec->bv_page->mapping->host->i_sb);
>
> I'm not sure whether bvec->bv_page->mapping will be set to NULL in the flow
> where may not check WRITEBACK flag of page. Is it possible?
The mapping should be not NULL cause it is a writebacking page.
Otherwise, it's a bug.
Thanks,
--
Jaegeuk Kim
Samsung
--
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organizations don't have a clear picture of how application performance
affects their revenue. With AppDynamics, you get 100% visibility into your
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Re: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
Hi Kim,
> -Original Message-
> From: Jaegeuk Kim [mailto:jaegeuk@samsung.com]
> Sent: Saturday, November 30, 2013 9:48 AM
> Cc: linux-fsde...@vger.kernel.org; linux-ker...@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
>
> Previously f2fs allocates its own bi_private data structure all the time even
> though we don't use it. But, can we remove this bi_private allocation?
>
> This patch removes such the additional bi_private allocation.
>
> 1. Retrieve f2fs_sb_info from its page->mapping->host->i_sb.
> - This removes the usecases of bi_private in end_io.
>
> 2. Use bi_private only when we really need it.
> - The bi_private is used only when the checkpoint procedure is conducted.
> - When conducting the checkpoint, f2fs submits a META_FLUSH bio to wait its
> bio
> completion.
> - Since we have no dependancies to remove bi_private now, let's just use
> bi_private pointer as the completion pointer.
>
> Signed-off-by: Jaegeuk Kim
> ---
> fs/f2fs/segment.c | 43 ---
> fs/f2fs/segment.h | 7 ---
> 2 files changed, 16 insertions(+), 34 deletions(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 0387863..0db4027 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -791,7 +791,7 @@ static void f2fs_end_io_write(struct bio *bio, int err)
> {
> const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
> struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
> - struct bio_private *p = bio->bi_private;
> + struct f2fs_sb_info *sbi = F2FS_SB(bvec->bv_page->mapping->host->i_sb);
I'm not sure whether bvec->bv_page->mapping will be set to NULL in the flow
where may not check WRITEBACK flag of page. Is it possible?
>
> do {
> struct page *page = bvec->bv_page;
> @@ -802,21 +802,21 @@ static void f2fs_end_io_write(struct bio *bio, int err)
> SetPageError(page);
> if (page->mapping)
> set_bit(AS_EIO, &page->mapping->flags);
> - set_ckpt_flags(p->sbi->ckpt, CP_ERROR_FLAG);
> - p->sbi->sb->s_flags |= MS_RDONLY;
> +
> + set_ckpt_flags(sbi->ckpt, CP_ERROR_FLAG);
> + sbi->sb->s_flags |= MS_RDONLY;
> }
> end_page_writeback(page);
> - dec_page_count(p->sbi, F2FS_WRITEBACK);
> + dec_page_count(sbi, F2FS_WRITEBACK);
> } while (bvec >= bio->bi_io_vec);
>
> - if (p->is_sync)
> - complete(p->wait);
> + if (bio->bi_private)
> + complete(bio->bi_private);
>
> - if (!get_pages(p->sbi, F2FS_WRITEBACK) &&
> - !list_empty(&p->sbi->cp_wait.task_list))
> - wake_up(&p->sbi->cp_wait);
> + if (!get_pages(sbi, F2FS_WRITEBACK) &&
> + !list_empty(&sbi->cp_wait.task_list))
> + wake_up(&sbi->cp_wait);
>
> - kfree(p);
> bio_put(bio);
> }
>
> @@ -838,7 +838,6 @@ static void do_submit_bio(struct f2fs_sb_info *sbi,
> int rw = sync ? WRITE_SYNC : WRITE;
> enum page_type btype = PAGE_TYPE_OF_BIO(type);
> struct f2fs_bio_info *io = &sbi->write_io[btype];
> - struct bio_private *p;
>
> if (!io->bio)
> return;
> @@ -851,18 +850,16 @@ static void do_submit_bio(struct f2fs_sb_info *sbi,
>
> trace_f2fs_submit_write_bio(sbi->sb, rw, btype, io->bio);
>
> - p = io->bio->bi_private;
> - p->sbi = sbi;
> - io->bio->bi_end_io = f2fs_end_io_write;
> -
> + /*
> + * META_FLUSH is only from the checkpoint procedure, and we should wait
> + * this metadata bio for FS consistency.
> + */
> if (type == META_FLUSH) {
> DECLARE_COMPLETION_ONSTACK(wait);
> - p->is_sync = true;
> - p->wait = &wait;
> + io->bio->bi_private = &wait;
> submit_bio(rw, io->bio);
> wait_for_completion(&wait);
> } else {
> - p->is_sync = false;
> submit_bio(rw, io->bio);
> }
> io->bio = NULL;
> @@ -897,18 +894,10 @@ static void submit_write_page(struct f2fs_sb_info *sbi,
> struct page *page,
> do_submit_bio(sbi, type, false);
> alloc_new:
> if (io->bio == NULL) {
> - struct bio_private *priv;
> -retry:
> - priv = kmalloc(sizeof(struct bio_private), GFP_NOFS);
> - if (!priv) {
> - cond_resched();
> - goto retry;
> - }
> -
> bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
> io->bio = f2fs_bio_alloc(bdev, bio_blocks);
> io->bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
> - io->bio->bi_private = priv;
> + io->bio->bi_end_io = f2fs_end_io_write;
> /*
>
Re: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
On 11/30/2013 09:48 AM, Jaegeuk Kim wrote:
> Previously f2fs allocates its own bi_private data structure all the time even
> though we don't use it. But, can we remove this bi_private allocation?
>
> This patch removes such the additional bi_private allocation.
>
> 1. Retrieve f2fs_sb_info from its page->mapping->host->i_sb.
> - This removes the usecases of bi_private in end_io.
>
> 2. Use bi_private only when we really need it.
> - The bi_private is used only when the checkpoint procedure is conducted.
> - When conducting the checkpoint, f2fs submits a META_FLUSH bio to wait its
> bio
> completion.
> - Since we have no dependancies to remove bi_private now, let's just use
> bi_private pointer as the completion pointer.
Cool, looks good to me.:)
>
> Signed-off-by: Jaegeuk Kim
Reviewed-by: Gu Zheng
> ---
> fs/f2fs/segment.c | 43 ---
> fs/f2fs/segment.h | 7 ---
> 2 files changed, 16 insertions(+), 34 deletions(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 0387863..0db4027 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -791,7 +791,7 @@ static void f2fs_end_io_write(struct bio *bio, int err)
> {
> const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
> struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
> - struct bio_private *p = bio->bi_private;
> + struct f2fs_sb_info *sbi = F2FS_SB(bvec->bv_page->mapping->host->i_sb);
>
> do {
> struct page *page = bvec->bv_page;
> @@ -802,21 +802,21 @@ static void f2fs_end_io_write(struct bio *bio, int err)
> SetPageError(page);
> if (page->mapping)
> set_bit(AS_EIO, &page->mapping->flags);
> - set_ckpt_flags(p->sbi->ckpt, CP_ERROR_FLAG);
> - p->sbi->sb->s_flags |= MS_RDONLY;
> +
> + set_ckpt_flags(sbi->ckpt, CP_ERROR_FLAG);
> + sbi->sb->s_flags |= MS_RDONLY;
> }
> end_page_writeback(page);
> - dec_page_count(p->sbi, F2FS_WRITEBACK);
> + dec_page_count(sbi, F2FS_WRITEBACK);
> } while (bvec >= bio->bi_io_vec);
>
> - if (p->is_sync)
> - complete(p->wait);
> + if (bio->bi_private)
> + complete(bio->bi_private);
>
> - if (!get_pages(p->sbi, F2FS_WRITEBACK) &&
> - !list_empty(&p->sbi->cp_wait.task_list))
> - wake_up(&p->sbi->cp_wait);
> + if (!get_pages(sbi, F2FS_WRITEBACK) &&
> + !list_empty(&sbi->cp_wait.task_list))
> + wake_up(&sbi->cp_wait);
>
> - kfree(p);
> bio_put(bio);
> }
>
> @@ -838,7 +838,6 @@ static void do_submit_bio(struct f2fs_sb_info *sbi,
> int rw = sync ? WRITE_SYNC : WRITE;
> enum page_type btype = PAGE_TYPE_OF_BIO(type);
> struct f2fs_bio_info *io = &sbi->write_io[btype];
> - struct bio_private *p;
>
> if (!io->bio)
> return;
> @@ -851,18 +850,16 @@ static void do_submit_bio(struct f2fs_sb_info *sbi,
>
> trace_f2fs_submit_write_bio(sbi->sb, rw, btype, io->bio);
>
> - p = io->bio->bi_private;
> - p->sbi = sbi;
> - io->bio->bi_end_io = f2fs_end_io_write;
> -
> + /*
> + * META_FLUSH is only from the checkpoint procedure, and we should wait
> + * this metadata bio for FS consistency.
> + */
> if (type == META_FLUSH) {
> DECLARE_COMPLETION_ONSTACK(wait);
> - p->is_sync = true;
> - p->wait = &wait;
> + io->bio->bi_private = &wait;
> submit_bio(rw, io->bio);
> wait_for_completion(&wait);
> } else {
> - p->is_sync = false;
> submit_bio(rw, io->bio);
> }
> io->bio = NULL;
> @@ -897,18 +894,10 @@ static void submit_write_page(struct f2fs_sb_info *sbi,
> struct page *page,
> do_submit_bio(sbi, type, false);
> alloc_new:
> if (io->bio == NULL) {
> - struct bio_private *priv;
> -retry:
> - priv = kmalloc(sizeof(struct bio_private), GFP_NOFS);
> - if (!priv) {
> - cond_resched();
> - goto retry;
> - }
> -
> bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
> io->bio = f2fs_bio_alloc(bdev, bio_blocks);
> io->bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
> - io->bio->bi_private = priv;
> + io->bio->bi_end_io = f2fs_end_io_write;
> /*
>* The end_io will be assigned at the sumbission phase.
>* Until then, let bio_add_page() merge consecutive IOs as much
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index 7fea2ee..26812fc 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -92,13 +92,6 @@
> #define MAX_BIO_BLOCKS(max_hw_blocks)
