[V10,13/19] iomap & xfs: only account for new added page
diff mbox series

Message ID 20181115085306.9910-14-ming.lei@redhat.com
State New
Headers show
Series
  • block: support multi-page bvec
Related show

Commit Message

Ming Lei Nov. 15, 2018, 8:53 a.m. UTC
After multi-page is enabled, one new page may be merged to a segment
even though it is a new added page.

This patch deals with this issue by post-check in case of merge, and
only a freshly new added page need to be dealt with for iomap & xfs.

Cc: Dave Chinner <dchinner@redhat.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Shaohua Li <shli@kernel.org>
Cc: linux-raid@vger.kernel.org
Cc: linux-erofs@lists.ozlabs.org
Cc: David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: linux-xfs@vger.kernel.org
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: linux-ext4@vger.kernel.org
Cc: Coly Li <colyli@suse.de>
Cc: linux-bcache@vger.kernel.org
Cc: Boaz Harrosh <ooo@electrozaur.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: cluster-devel@redhat.com
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 fs/iomap.c          | 22 ++++++++++++++--------
 fs/xfs/xfs_aops.c   | 10 ++++++++--
 include/linux/bio.h | 11 +++++++++++
 3 files changed, 33 insertions(+), 10 deletions(-)

Comments

Omar Sandoval Nov. 16, 2018, 1:46 a.m. UTC | #1
On Thu, Nov 15, 2018 at 04:53:00PM +0800, Ming Lei wrote:
> After multi-page is enabled, one new page may be merged to a segment
> even though it is a new added page.
> 
> This patch deals with this issue by post-check in case of merge, and
> only a freshly new added page need to be dealt with for iomap & xfs.
> 
> Cc: Dave Chinner <dchinner@redhat.com>
> Cc: Kent Overstreet <kent.overstreet@gmail.com>
> Cc: Mike Snitzer <snitzer@redhat.com>
> Cc: dm-devel@redhat.com
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Cc: linux-fsdevel@vger.kernel.org
> Cc: Shaohua Li <shli@kernel.org>
> Cc: linux-raid@vger.kernel.org
> Cc: linux-erofs@lists.ozlabs.org
> Cc: David Sterba <dsterba@suse.com>
> Cc: linux-btrfs@vger.kernel.org
> Cc: Darrick J. Wong <darrick.wong@oracle.com>
> Cc: linux-xfs@vger.kernel.org
> Cc: Gao Xiang <gaoxiang25@huawei.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Theodore Ts'o <tytso@mit.edu>
> Cc: linux-ext4@vger.kernel.org
> Cc: Coly Li <colyli@suse.de>
> Cc: linux-bcache@vger.kernel.org
> Cc: Boaz Harrosh <ooo@electrozaur.com>
> Cc: Bob Peterson <rpeterso@redhat.com>
> Cc: cluster-devel@redhat.com
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
>  fs/iomap.c          | 22 ++++++++++++++--------
>  fs/xfs/xfs_aops.c   | 10 ++++++++--
>  include/linux/bio.h | 11 +++++++++++
>  3 files changed, 33 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/iomap.c b/fs/iomap.c
> index df0212560b36..a1b97a5c726a 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -288,6 +288,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>  	loff_t orig_pos = pos;
>  	unsigned poff, plen;
>  	sector_t sector;
> +	bool need_account = false;
>  
>  	if (iomap->type == IOMAP_INLINE) {
>  		WARN_ON_ONCE(pos);
> @@ -313,18 +314,15 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>  	 */
>  	sector = iomap_sector(iomap, pos);
>  	if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
> -		if (__bio_try_merge_page(ctx->bio, page, plen, poff))
> +		if (__bio_try_merge_page(ctx->bio, page, plen, poff)) {
> +			need_account = iop && bio_is_last_segment(ctx->bio,
> +					page, plen, poff);

It's redundant to make this iop && ... since you already check
iop && need_account below. Maybe rename it to added_page? Also, this
indentation is wack.

>  			goto done;
> +		}
>  		is_contig = true;
>  	}
>  
> -	/*
> -	 * If we start a new segment we need to increase the read count, and we
> -	 * need to do so before submitting any previous full bio to make sure
> -	 * that we don't prematurely unlock the page.
> -	 */
> -	if (iop)
> -		atomic_inc(&iop->read_count);
> +	need_account = true;
>  
>  	if (!ctx->bio || !is_contig || bio_full(ctx->bio)) {
>  		gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
> @@ -347,6 +345,14 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>  	__bio_add_page(ctx->bio, page, plen, poff);
>  done:
>  	/*
> +	 * If we add a new page we need to increase the read count, and we
> +	 * need to do so before submitting any previous full bio to make sure
> +	 * that we don't prematurely unlock the page.
> +	 */
> +	if (iop && need_account)
> +		atomic_inc(&iop->read_count);
> +
> +	/*
>  	 * Move the caller beyond our range so that it keeps making progress.
>  	 * For that we have to include any leading non-uptodate ranges, but
>  	 * we can skip trailing ones as they will be handled in the next
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 1f1829e506e8..d8e9cc9f751a 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -603,6 +603,7 @@ xfs_add_to_ioend(
>  	unsigned		len = i_blocksize(inode);
>  	unsigned		poff = offset & (PAGE_SIZE - 1);
>  	sector_t		sector;
> +	bool			need_account;
>  
>  	sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
>  		((offset - XFS_FSB_TO_B(mp, wpc->imap.br_startoff)) >> 9);
> @@ -617,13 +618,18 @@ xfs_add_to_ioend(
>  	}
>  
>  	if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff)) {
> -		if (iop)
> -			atomic_inc(&iop->write_count);
> +		need_account = true;
>  		if (bio_full(wpc->ioend->io_bio))
>  			xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
>  		__bio_add_page(wpc->ioend->io_bio, page, len, poff);
> +	} else {
> +		need_account = iop && bio_is_last_segment(wpc->ioend->io_bio,
> +				page, len, poff);

Same here, no need for iop &&, rename it added_page, indentation is off.

>  	}
>  
> +	if (iop && need_account)
> +		atomic_inc(&iop->write_count);
> +
>  	wpc->ioend->io_size += len;
>  }
>  
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index 1a2430a8b89d..5040e9a2eb09 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -341,6 +341,17 @@ static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
>  	return &bio->bi_io_vec[bio->bi_vcnt - 1];
>  }
>  
> +/* iomap needs this helper to deal with sub-pagesize bvec */
> +static inline bool bio_is_last_segment(struct bio *bio, struct page *page,
> +		unsigned int len, unsigned int off)

Indentation.

> +{
> +	struct bio_vec bv;
> +
> +	bvec_last_segment(bio_last_bvec_all(bio), &bv);
> +
> +	return bv.bv_page == page && bv.bv_len == len && bv.bv_offset == off;
> +}
> +
>  enum bip_flags {
>  	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
>  	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */
> -- 
> 2.9.5
>
Christoph Hellwig Nov. 16, 2018, 1:49 p.m. UTC | #2
I'd much rather have __bio_try_merge_page only do merges in
the same page, and have a new __bio_try_merge_segment that does
multi-page merges.  This will keep the accounting a lot simpler.
Ming Lei Nov. 19, 2018, 8:35 a.m. UTC | #3
On Thu, Nov 15, 2018 at 05:46:58PM -0800, Omar Sandoval wrote:
> On Thu, Nov 15, 2018 at 04:53:00PM +0800, Ming Lei wrote:
> > After multi-page is enabled, one new page may be merged to a segment
> > even though it is a new added page.
> > 
> > This patch deals with this issue by post-check in case of merge, and
> > only a freshly new added page need to be dealt with for iomap & xfs.
> > 
> > Cc: Dave Chinner <dchinner@redhat.com>
> > Cc: Kent Overstreet <kent.overstreet@gmail.com>
> > Cc: Mike Snitzer <snitzer@redhat.com>
> > Cc: dm-devel@redhat.com
> > Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> > Cc: linux-fsdevel@vger.kernel.org
> > Cc: Shaohua Li <shli@kernel.org>
> > Cc: linux-raid@vger.kernel.org
> > Cc: linux-erofs@lists.ozlabs.org
> > Cc: David Sterba <dsterba@suse.com>
> > Cc: linux-btrfs@vger.kernel.org
> > Cc: Darrick J. Wong <darrick.wong@oracle.com>
> > Cc: linux-xfs@vger.kernel.org
> > Cc: Gao Xiang <gaoxiang25@huawei.com>
> > Cc: Christoph Hellwig <hch@lst.de>
> > Cc: Theodore Ts'o <tytso@mit.edu>
> > Cc: linux-ext4@vger.kernel.org
> > Cc: Coly Li <colyli@suse.de>
> > Cc: linux-bcache@vger.kernel.org
> > Cc: Boaz Harrosh <ooo@electrozaur.com>
> > Cc: Bob Peterson <rpeterso@redhat.com>
> > Cc: cluster-devel@redhat.com
> > Signed-off-by: Ming Lei <ming.lei@redhat.com>
> > ---
> >  fs/iomap.c          | 22 ++++++++++++++--------
> >  fs/xfs/xfs_aops.c   | 10 ++++++++--
> >  include/linux/bio.h | 11 +++++++++++
> >  3 files changed, 33 insertions(+), 10 deletions(-)
> > 
> > diff --git a/fs/iomap.c b/fs/iomap.c
> > index df0212560b36..a1b97a5c726a 100644
> > --- a/fs/iomap.c
> > +++ b/fs/iomap.c
> > @@ -288,6 +288,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> >  	loff_t orig_pos = pos;
> >  	unsigned poff, plen;
> >  	sector_t sector;
> > +	bool need_account = false;
> >  
> >  	if (iomap->type == IOMAP_INLINE) {
> >  		WARN_ON_ONCE(pos);
> > @@ -313,18 +314,15 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> >  	 */
> >  	sector = iomap_sector(iomap, pos);
> >  	if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
> > -		if (__bio_try_merge_page(ctx->bio, page, plen, poff))
> > +		if (__bio_try_merge_page(ctx->bio, page, plen, poff)) {
> > +			need_account = iop && bio_is_last_segment(ctx->bio,
> > +					page, plen, poff);
> 
> It's redundant to make this iop && ... since you already check
> iop && need_account below. Maybe rename it to added_page? Also, this
> indentation is wack.

We may avoid to call bio_is_last_segment() in case of !iop, and will
fix the indentation.

Looks added_page is one better name.

> 
> >  			goto done;
> > +		}
> >  		is_contig = true;
> >  	}
> >  
> > -	/*
> > -	 * If we start a new segment we need to increase the read count, and we
> > -	 * need to do so before submitting any previous full bio to make sure
> > -	 * that we don't prematurely unlock the page.
> > -	 */
> > -	if (iop)
> > -		atomic_inc(&iop->read_count);
> > +	need_account = true;
> >  
> >  	if (!ctx->bio || !is_contig || bio_full(ctx->bio)) {
> >  		gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
> > @@ -347,6 +345,14 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> >  	__bio_add_page(ctx->bio, page, plen, poff);
> >  done:
> >  	/*
> > +	 * If we add a new page we need to increase the read count, and we
> > +	 * need to do so before submitting any previous full bio to make sure
> > +	 * that we don't prematurely unlock the page.
> > +	 */
> > +	if (iop && need_account)
> > +		atomic_inc(&iop->read_count);
> > +
> > +	/*
> >  	 * Move the caller beyond our range so that it keeps making progress.
> >  	 * For that we have to include any leading non-uptodate ranges, but
> >  	 * we can skip trailing ones as they will be handled in the next
> > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> > index 1f1829e506e8..d8e9cc9f751a 100644
> > --- a/fs/xfs/xfs_aops.c
> > +++ b/fs/xfs/xfs_aops.c
> > @@ -603,6 +603,7 @@ xfs_add_to_ioend(
> >  	unsigned		len = i_blocksize(inode);
> >  	unsigned		poff = offset & (PAGE_SIZE - 1);
> >  	sector_t		sector;
> > +	bool			need_account;
> >  
> >  	sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
> >  		((offset - XFS_FSB_TO_B(mp, wpc->imap.br_startoff)) >> 9);
> > @@ -617,13 +618,18 @@ xfs_add_to_ioend(
> >  	}
> >  
> >  	if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff)) {
> > -		if (iop)
> > -			atomic_inc(&iop->write_count);
> > +		need_account = true;
> >  		if (bio_full(wpc->ioend->io_bio))
> >  			xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
> >  		__bio_add_page(wpc->ioend->io_bio, page, len, poff);
> > +	} else {
> > +		need_account = iop && bio_is_last_segment(wpc->ioend->io_bio,
> > +				page, len, poff);
> 
> Same here, no need for iop &&, rename it added_page, indentation is off.
> 
> >  	}
> >  
> > +	if (iop && need_account)
> > +		atomic_inc(&iop->write_count);
> > +
> >  	wpc->ioend->io_size += len;
> >  }
> >  
> > diff --git a/include/linux/bio.h b/include/linux/bio.h
> > index 1a2430a8b89d..5040e9a2eb09 100644
> > --- a/include/linux/bio.h
> > +++ b/include/linux/bio.h
> > @@ -341,6 +341,17 @@ static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
> >  	return &bio->bi_io_vec[bio->bi_vcnt - 1];
> >  }
> >  
> > +/* iomap needs this helper to deal with sub-pagesize bvec */
> > +static inline bool bio_is_last_segment(struct bio *bio, struct page *page,
> > +		unsigned int len, unsigned int off)
> 
> Indentation.

OK.

Thanks,
Ming
Ming Lei Nov. 19, 2018, 8:39 a.m. UTC | #4
On Fri, Nov 16, 2018 at 02:49:36PM +0100, Christoph Hellwig wrote:
> I'd much rather have __bio_try_merge_page only do merges in
> the same page, and have a new __bio_try_merge_segment that does
> multi-page merges.  This will keep the accounting a lot simpler.

Looks this way is clever, will do it in next version.

Thanks,
Ming

Patch
diff mbox series

diff --git a/fs/iomap.c b/fs/iomap.c
index df0212560b36..a1b97a5c726a 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -288,6 +288,7 @@  iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	loff_t orig_pos = pos;
 	unsigned poff, plen;
 	sector_t sector;
+	bool need_account = false;
 
 	if (iomap->type == IOMAP_INLINE) {
 		WARN_ON_ONCE(pos);
@@ -313,18 +314,15 @@  iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	 */
 	sector = iomap_sector(iomap, pos);
 	if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
-		if (__bio_try_merge_page(ctx->bio, page, plen, poff))
+		if (__bio_try_merge_page(ctx->bio, page, plen, poff)) {
+			need_account = iop && bio_is_last_segment(ctx->bio,
+					page, plen, poff);
 			goto done;
+		}
 		is_contig = true;
 	}
 
-	/*
-	 * If we start a new segment we need to increase the read count, and we
-	 * need to do so before submitting any previous full bio to make sure
-	 * that we don't prematurely unlock the page.
-	 */
-	if (iop)
-		atomic_inc(&iop->read_count);
+	need_account = true;
 
 	if (!ctx->bio || !is_contig || bio_full(ctx->bio)) {
 		gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
@@ -347,6 +345,14 @@  iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	__bio_add_page(ctx->bio, page, plen, poff);
 done:
 	/*
+	 * If we add a new page we need to increase the read count, and we
+	 * need to do so before submitting any previous full bio to make sure
+	 * that we don't prematurely unlock the page.
+	 */
+	if (iop && need_account)
+		atomic_inc(&iop->read_count);
+
+	/*
 	 * Move the caller beyond our range so that it keeps making progress.
 	 * For that we have to include any leading non-uptodate ranges, but
 	 * we can skip trailing ones as they will be handled in the next
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 1f1829e506e8..d8e9cc9f751a 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -603,6 +603,7 @@  xfs_add_to_ioend(
 	unsigned		len = i_blocksize(inode);
 	unsigned		poff = offset & (PAGE_SIZE - 1);
 	sector_t		sector;
+	bool			need_account;
 
 	sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
 		((offset - XFS_FSB_TO_B(mp, wpc->imap.br_startoff)) >> 9);
@@ -617,13 +618,18 @@  xfs_add_to_ioend(
 	}
 
 	if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff)) {
-		if (iop)
-			atomic_inc(&iop->write_count);
+		need_account = true;
 		if (bio_full(wpc->ioend->io_bio))
 			xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
 		__bio_add_page(wpc->ioend->io_bio, page, len, poff);
+	} else {
+		need_account = iop && bio_is_last_segment(wpc->ioend->io_bio,
+				page, len, poff);
 	}
 
+	if (iop && need_account)
+		atomic_inc(&iop->write_count);
+
 	wpc->ioend->io_size += len;
 }
 
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 1a2430a8b89d..5040e9a2eb09 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -341,6 +341,17 @@  static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
 	return &bio->bi_io_vec[bio->bi_vcnt - 1];
 }
 
+/* iomap needs this helper to deal with sub-pagesize bvec */
+static inline bool bio_is_last_segment(struct bio *bio, struct page *page,
+		unsigned int len, unsigned int off)
+{
+	struct bio_vec bv;
+
+	bvec_last_segment(bio_last_bvec_all(bio), &bv);
+
+	return bv.bv_page == page && bv.bv_len == len && bv.bv_offset == off;
+}
+
 enum bip_flags {
 	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
 	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */