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Go Back   Linux Archive > Redhat > Device-mapper Development
Reload this Page block: Only clone bio vecs that are in use

 
 
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Old 05-18-2012, 04:13 PM
Tejun Heo
 
Default block: Only clone bio vecs that are in use
On Thu, May 17, 2012 at 10:59:52PM -0400, koverstreet@google.com wrote:
> diff --git a/fs/bio.c b/fs/bio.c
> index e2c0970..de0733e 100644
> --- a/fs/bio.c
> +++ b/fs/bio.c
> @@ -435,8 +435,9 @@ EXPORT_SYMBOL(bio_phys_segments);
> */
> void __bio_clone(struct bio *bio, struct bio *bio_src)
> {
> - memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
> - bio_src->bi_max_vecs * sizeof(struct bio_vec));
> + memcpy(bio->bi_io_vec,
> + bio_iovec(bio_src),

Unnecessary line break.

> + bio_segments(bio_src) * sizeof(struct bio_vec));
>
> /*
> * most users will be overriding ->bi_bdev with a new target,
> @@ -445,10 +446,10 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
> bio->bi_sector = bio_src->bi_sector;
> bio->bi_bdev = bio_src->bi_bdev;
> bio->bi_flags |= 1 << BIO_CLONED;
> + bio->bi_flags &= ~(1 << BIO_SEG_VALID);

Can probably be conditionalized on bi_idx?

Thanks.

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Old 05-18-2012, 09:14 PM
Kent Overstreet
 
Default block: Only clone bio vecs that are in use
On Fri, May 18, 2012 at 09:13:34AM -0700, Tejun Heo wrote:
> On Thu, May 17, 2012 at 10:59:52PM -0400, koverstreet@google.com wrote:
> > diff --git a/fs/bio.c b/fs/bio.c
> > index e2c0970..de0733e 100644
> > --- a/fs/bio.c
> > +++ b/fs/bio.c
> > @@ -435,8 +435,9 @@ EXPORT_SYMBOL(bio_phys_segments);
> > */
> > void __bio_clone(struct bio *bio, struct bio *bio_src)
> > {
> > - memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
> > - bio_src->bi_max_vecs * sizeof(struct bio_vec));
> > + memcpy(bio->bi_io_vec,
> > + bio_iovec(bio_src),
>
> Unnecessary line break.
>
> > + bio_segments(bio_src) * sizeof(struct bio_vec));
> >
> > /*
> > * most users will be overriding ->bi_bdev with a new target,
> > @@ -445,10 +446,10 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
> > bio->bi_sector = bio_src->bi_sector;
> > bio->bi_bdev = bio_src->bi_bdev;
> > bio->bi_flags |= 1 << BIO_CLONED;
> > + bio->bi_flags &= ~(1 << BIO_SEG_VALID);
>
> Can probably be conditionalized on bi_idx?

I've never been that clear on the semantics of BIO_SEG_VALID. I'll defer
to you on that.

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Old 05-24-2012, 12:02 AM
Kent Overstreet
 
Default block: Only clone bio vecs that are in use
bcache creates large bios internally, and then splits them according to
the device requirements before it sends them down. If a lower level
device tries to clone the bio, and the original bio had more than
BIO_MAX_PAGES, the clone will fail unecessarily.

We can fix this by only cloning the bio vecs that are actually in use.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
---
fs/bio.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/bio.c b/fs/bio.c
index e2c0970..de0733e 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -435,8 +435,9 @@ EXPORT_SYMBOL(bio_phys_segments);
*/
void __bio_clone(struct bio *bio, struct bio *bio_src)
{
- memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
- bio_src->bi_max_vecs * sizeof(struct bio_vec));
+ memcpy(bio->bi_io_vec,
+ bio_iovec(bio_src),
+ bio_segments(bio_src) * sizeof(struct bio_vec));

/*
* most users will be overriding ->bi_bdev with a new target,
@@ -445,10 +446,10 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
bio->bi_sector = bio_src->bi_sector;
bio->bi_bdev = bio_src->bi_bdev;
bio->bi_flags |= 1 << BIO_CLONED;
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
bio->bi_rw = bio_src->bi_rw;
- bio->bi_vcnt = bio_src->bi_vcnt;
+ bio->bi_vcnt = bio_segments(bio_src);
bio->bi_size = bio_src->bi_size;
- bio->bi_idx = bio_src->bi_idx;
}
EXPORT_SYMBOL(__bio_clone);

@@ -463,7 +464,7 @@ EXPORT_SYMBOL(__bio_clone);
struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
struct bio_set *bs)
{
- struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
+ struct bio *b = bio_alloc_bioset(gfp_mask, bio_segments(bio), bs);

if (!b)
return NULL;
@@ -493,7 +494,7 @@ EXPORT_SYMBOL(bio_clone);

struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
{
- struct bio *b = bio_kmalloc(gfp_mask, bio->bi_max_vecs);
+ struct bio *b = bio_kmalloc(gfp_mask, bio_segments(bio));

if (!b)
return NULL;
--
1.7.9.3.327.g2980b

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Old 05-25-2012, 08:25 PM
Kent Overstreet
 
Default block: Only clone bio vecs that are in use
bcache creates large bios internally, and then splits them according to
the device requirements before it sends them down. If a lower level
device tries to clone the bio, and the original bio had more than
BIO_MAX_PAGES, the clone will fail unecessarily.

We can fix this by only cloning the bio vecs that are actually in use.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
Change-Id: I71971827a623ce90626fa4a09b07f95f875ad890
---
drivers/block/rbd.c | 2 +-
drivers/md/dm.c | 5 ++---
fs/bio.c | 13 +++++++------
3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 11777b4..c1f8a8fe 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -729,7 +729,7 @@ static struct bio *bio_chain_clone(struct bio **old, struct bio **next,
}

while (old_chain && (total < len)) {
- tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs);
+ tmp = bio_kmalloc(gfpmask, bio_segments(old_chain));
if (!tmp)
goto err_out;

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3f3c26e..193fb19 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1057,11 +1057,10 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
{
struct bio *clone;

- clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
+ clone = bio_alloc_bioset(GFP_NOIO, bv_count, bs);
__bio_clone(clone, bio);
clone->bi_sector = sector;
- clone->bi_idx = idx;
- clone->bi_vcnt = idx + bv_count;
+ clone->bi_vcnt = bv_count;
clone->bi_size = to_bytes(len);
clone->bi_flags &= ~(1 << BIO_SEG_VALID);

diff --git a/fs/bio.c b/fs/bio.c
index a62b5b6..a85239f 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -441,8 +441,9 @@ EXPORT_SYMBOL(bio_phys_segments);
*/
void __bio_clone(struct bio *bio, struct bio *bio_src)
{
- memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
- bio_src->bi_max_vecs * sizeof(struct bio_vec));
+ memcpy(bio->bi_io_vec,
+ bio_iovec(bio_src),
+ bio_segments(bio_src) * sizeof(struct bio_vec));

/*
* most users will be overriding ->bi_bdev with a new target,
@@ -451,10 +452,10 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
bio->bi_sector = bio_src->bi_sector;
bio->bi_bdev = bio_src->bi_bdev;
bio->bi_flags |= 1 << BIO_CLONED;
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
bio->bi_rw = bio_src->bi_rw;
- bio->bi_vcnt = bio_src->bi_vcnt;
+ bio->bi_vcnt = bio_segments(bio_src);
bio->bi_size = bio_src->bi_size;
- bio->bi_idx = bio_src->bi_idx;
}
EXPORT_SYMBOL(__bio_clone);

@@ -469,7 +470,7 @@ EXPORT_SYMBOL(__bio_clone);
struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
struct bio_set *bs)
{
- struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
+ struct bio *b = bio_alloc_bioset(gfp_mask, bio_segments(bio), bs);

if (!b)
return NULL;
@@ -499,7 +500,7 @@ EXPORT_SYMBOL(bio_clone);

struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
{
- struct bio *b = bio_kmalloc(gfp_mask, bio->bi_max_vecs);
+ struct bio *b = bio_kmalloc(gfp_mask, bio_segments(bio));

if (!b)
return NULL;
--
1.7.9.3.327.g2980b

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Old 07-24-2012, 08:11 PM
Kent Overstreet
 
Default block: Only clone bio vecs that are in use
bcache creates large bios internally, and then splits them according to
the device requirements before it sends them down. If a lower level
device tries to clone the bio, and the original bio had more than
BIO_MAX_PAGES, the clone will fail unecessarily.

We can fix this by only cloning the bio vecs that are actually in use.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
---
drivers/block/rbd.c | 2 +-
drivers/md/dm.c | 5 ++---
fs/bio.c | 13 +++++++------
3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 692cf05..21edfe5 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -714,7 +714,7 @@ static struct bio *bio_chain_clone(struct bio **old, struct bio **next,
}

while (old_chain && (total < len)) {
- tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs);
+ tmp = bio_kmalloc(gfpmask, bio_segments(old_chain));
if (!tmp)
goto err_out;

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3f3c26e..193fb19 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1057,11 +1057,10 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
{
struct bio *clone;

- clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
+ clone = bio_alloc_bioset(GFP_NOIO, bv_count, bs);
__bio_clone(clone, bio);
clone->bi_sector = sector;
- clone->bi_idx = idx;
- clone->bi_vcnt = idx + bv_count;
+ clone->bi_vcnt = bv_count;
clone->bi_size = to_bytes(len);
clone->bi_flags &= ~(1 << BIO_SEG_VALID);

diff --git a/fs/bio.c b/fs/bio.c
index 7a0801d..ec6a357 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -451,8 +451,9 @@ EXPORT_SYMBOL(bio_phys_segments);
*/
void __bio_clone(struct bio *bio, struct bio *bio_src)
{
- memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
- bio_src->bi_max_vecs * sizeof(struct bio_vec));
+ memcpy(bio->bi_io_vec,
+ bio_iovec(bio_src),
+ bio_segments(bio_src) * sizeof(struct bio_vec));

/*
* most users will be overriding ->bi_bdev with a new target,
@@ -461,10 +462,10 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
bio->bi_sector = bio_src->bi_sector;
bio->bi_bdev = bio_src->bi_bdev;
bio->bi_flags |= 1 << BIO_CLONED;
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
bio->bi_rw = bio_src->bi_rw;
- bio->bi_vcnt = bio_src->bi_vcnt;
+ bio->bi_vcnt = bio_segments(bio_src);
bio->bi_size = bio_src->bi_size;
- bio->bi_idx = bio_src->bi_idx;
}
EXPORT_SYMBOL(__bio_clone);

@@ -479,7 +480,7 @@ EXPORT_SYMBOL(__bio_clone);
struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
struct bio_set *bs)
{
- struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
+ struct bio *b = bio_alloc_bioset(gfp_mask, bio_segments(bio), bs);

if (!b)
return NULL;
@@ -509,7 +510,7 @@ EXPORT_SYMBOL(bio_clone);

struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
{
- struct bio *b = bio_kmalloc(gfp_mask, bio->bi_max_vecs);
+ struct bio *b = bio_kmalloc(gfp_mask, bio_segments(bio));

if (!b)
return NULL;
--
1.7.7.3

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Old 08-06-2012, 10:08 PM
Kent Overstreet
 
Default block: Only clone bio vecs that are in use
bcache creates large bios internally, and then splits them according to
the device requirements before it sends them down. If a lower level
device tries to clone the bio, and the original bio had more than
BIO_MAX_PAGES, the clone will fail unecessarily.

We can fix this by only cloning the bio vecs that are actually in use.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
---
drivers/block/rbd.c | 2 +-
drivers/md/dm.c | 5 ++---
fs/bio.c | 13 +++++++------
3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 692cf05..21edfe5 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -714,7 +714,7 @@ static struct bio *bio_chain_clone(struct bio **old, struct bio **next,
}

while (old_chain && (total < len)) {
- tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs);
+ tmp = bio_kmalloc(gfpmask, bio_segments(old_chain));
if (!tmp)
goto err_out;

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3f3c26e..193fb19 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1057,11 +1057,10 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
{
struct bio *clone;

- clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
+ clone = bio_alloc_bioset(GFP_NOIO, bv_count, bs);
__bio_clone(clone, bio);
clone->bi_sector = sector;
- clone->bi_idx = idx;
- clone->bi_vcnt = idx + bv_count;
+ clone->bi_vcnt = bv_count;
clone->bi_size = to_bytes(len);
clone->bi_flags &= ~(1 << BIO_SEG_VALID);

diff --git a/fs/bio.c b/fs/bio.c
index 38ad026..631c67e 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -449,8 +449,9 @@ EXPORT_SYMBOL(bio_phys_segments);
*/
void __bio_clone(struct bio *bio, struct bio *bio_src)
{
- memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
- bio_src->bi_max_vecs * sizeof(struct bio_vec));
+ memcpy(bio->bi_io_vec,
+ bio_iovec(bio_src),
+ bio_segments(bio_src) * sizeof(struct bio_vec));

/*
* most users will be overriding ->bi_bdev with a new target,
@@ -459,10 +460,10 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
bio->bi_sector = bio_src->bi_sector;
bio->bi_bdev = bio_src->bi_bdev;
bio->bi_flags |= 1 << BIO_CLONED;
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
bio->bi_rw = bio_src->bi_rw;
- bio->bi_vcnt = bio_src->bi_vcnt;
+ bio->bi_vcnt = bio_segments(bio_src);
bio->bi_size = bio_src->bi_size;
- bio->bi_idx = bio_src->bi_idx;
}
EXPORT_SYMBOL(__bio_clone);

@@ -477,7 +478,7 @@ EXPORT_SYMBOL(__bio_clone);
struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
struct bio_set *bs)
{
- struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
+ struct bio *b = bio_alloc_bioset(gfp_mask, bio_segments(bio), bs);

if (!b)
return NULL;
@@ -507,7 +508,7 @@ EXPORT_SYMBOL(bio_clone);

struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
{
- struct bio *b = bio_kmalloc(gfp_mask, bio->bi_max_vecs);
+ struct bio *b = bio_kmalloc(gfp_mask, bio_segments(bio));

if (!b)
return NULL;
--
1.7.7.3

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Old 08-22-2012, 05:04 PM
Kent Overstreet
 
Default block: Only clone bio vecs that are in use
bcache creates large bios internally, and then splits them according to
the device requirements before it sends them down. If a lower level
device tries to clone the bio, and the original bio had more than
BIO_MAX_PAGES, the clone will fail unecessarily.

We can fix this by only cloning the bio vecs that are actually in use.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Alasdair Kergon <agk@redhat.com>
CC: Sage Weil <sage@inktank.com>
---
drivers/block/rbd.c | 2 +-
drivers/md/dm.c | 5 ++---
fs/bio.c | 15 ++++++++++-----
3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 63e5852..5c3457f 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -734,7 +734,7 @@ static struct bio *bio_chain_clone(struct bio **old, struct bio **next,
}

while (old_chain && (total < len)) {
- tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs);
+ tmp = bio_kmalloc(gfpmask, bio_segments(old_chain));
if (!tmp)
goto err_out;

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a3c38b9..3aeb108 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1080,11 +1080,10 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
{
struct bio *clone;

- clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
+ clone = bio_alloc_bioset(GFP_NOIO, bv_count, bs);
__bio_clone(clone, bio);
clone->bi_sector = sector;
- clone->bi_idx = idx;
- clone->bi_vcnt = idx + bv_count;
+ clone->bi_vcnt = bv_count;
clone->bi_size = to_bytes(len);
clone->bi_flags &= ~(1 << BIO_SEG_VALID);

diff --git a/fs/bio.c b/fs/bio.c
index a58c3c6..3f43e50 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -450,11 +450,16 @@ EXPORT_SYMBOL(bio_phys_segments);
* Clone a &bio. Caller will own the returned bio, but not
* the actual data it points to. Reference count of returned
* bio will be one.
+ *
+ * We don't clone the entire bvec, just the part from bi_idx to b_vcnt
+ * (i.e. what the bio currently points to, so the new bio is still
+ * equivalent to the old bio).
*/
void __bio_clone(struct bio *bio, struct bio *bio_src)
{
- memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
- bio_src->bi_max_vecs * sizeof(struct bio_vec));
+ memcpy(bio->bi_io_vec,
+ bio_iovec(bio_src),
+ bio_segments(bio_src) * sizeof(struct bio_vec));

/*
* most users will be overriding ->bi_bdev with a new target,
@@ -463,10 +468,10 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
bio->bi_sector = bio_src->bi_sector;
bio->bi_bdev = bio_src->bi_bdev;
bio->bi_flags |= 1 << BIO_CLONED;
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
bio->bi_rw = bio_src->bi_rw;
- bio->bi_vcnt = bio_src->bi_vcnt;
+ bio->bi_vcnt = bio_segments(bio_src);
bio->bi_size = bio_src->bi_size;
- bio->bi_idx = bio_src->bi_idx;
}
EXPORT_SYMBOL(__bio_clone);

@@ -483,7 +488,7 @@ struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
{
struct bio *b;

- b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
+ b = bio_alloc_bioset(gfp_mask, bio_segments(bio), bs);
if (!b)
return NULL;

--
1.7.12

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