block/block-backend.c | 6 ++++++ block/file-posix.c | 2 +- block/io.c | 1 + hw/scsi/scsi-generic.c | 2 +- include/block/block_int.h | 7 +++++++ include/sysemu/block-backend.h | 1 + 6 files changed, 17 insertions(+), 2 deletions(-)
Linux limits the size of iovecs to 1024 (UIO_MAXIOV in the kernel
sources, IOV_MAX in POSIX). Because of this, on some host adapters
requests with many iovecs are rejected with -EINVAL by the
io_submit() or readv()/writev() system calls.
In fact, the same limit applies to SG_IO as well. To fix both the
EINVAL and the possible performance issues from using fewer iovecs
than allowed by Linux (some HBAs have max_segments as low as 128),
introduce a separate entry in BlockLimits to hold the max_segments
value from sysfs. This new limit is used only for SG_IO and clamped
to bs->bl.max_iov anyway, just like max_hw_transfer is clamped to
bs->bl.max_transfer.
Reported-by: Halil Pasic <pasic@linux.ibm.com>
Cc: Hanna Reitz <hreitz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-block@nongnu.org
Fixes: 18473467d5 ("file-posix: try BLKSECTGET on block devices too, do not round to power of 2", 2021-06-25)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
block/block-backend.c | 6 ++++++
block/file-posix.c | 2 +-
block/io.c | 1 +
hw/scsi/scsi-generic.c | 2 +-
include/block/block_int.h | 7 +++++++
include/sysemu/block-backend.h | 1 +
6 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/block/block-backend.c b/block/block-backend.c
index 6140d133e2..ba2b5ebb10 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1986,6 +1986,12 @@ uint32_t blk_get_max_transfer(BlockBackend *blk)
return ROUND_DOWN(max, blk_get_request_alignment(blk));
}
+int blk_get_max_hw_iov(BlockBackend *blk)
+{
+ return MIN_NON_ZERO(blk->root->bs->bl.max_hw_iov,
+ blk->root->bs->bl.max_iov);
+}
+
int blk_get_max_iov(BlockBackend *blk)
{
return blk->root->bs->bl.max_iov;
diff --git a/block/file-posix.c b/block/file-posix.c
index cb9bffe047..1567edb3d5 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1273,7 +1273,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
ret = hdev_get_max_segments(s->fd, &st);
if (ret > 0) {
- bs->bl.max_iov = ret;
+ bs->bl.max_hw_iov = ret;
}
}
}
diff --git a/block/io.c b/block/io.c
index a19942718b..f38e7f81d8 100644
--- a/block/io.c
+++ b/block/io.c
@@ -136,6 +136,7 @@ static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src)
dst->min_mem_alignment = MAX(dst->min_mem_alignment,
src->min_mem_alignment);
dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov);
+ dst->max_hw_iov = MIN_NON_ZERO(dst->max_hw_iov, src->max_hw_iov);
}
typedef struct BdrvRefreshLimitsState {
diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 665baf900e..0306ccc7b1 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -180,7 +180,7 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len)
page = r->req.cmd.buf[2];
if (page == 0xb0) {
uint64_t max_transfer = blk_get_max_hw_transfer(s->conf.blk);
- uint32_t max_iov = blk_get_max_iov(s->conf.blk);
+ uint32_t max_iov = blk_get_max_hw_iov(s->conf.blk);
assert(max_transfer);
max_transfer = MIN_NON_ZERO(max_transfer, max_iov * qemu_real_host_page_size)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index f1a54db0f8..c31cbd034a 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -702,6 +702,13 @@ typedef struct BlockLimits {
*/
uint64_t max_hw_transfer;
+ /* Maximal number of scatter/gather elements allowed by the hardware.
+ * Applies whenever transfers to the device bypass the kernel I/O
+ * scheduler, for example with SG_IO. If larger than max_iov
+ * or if zero, blk_get_max_hw_iov will fall back to max_iov.
+ */
+ int max_hw_iov;
+
/* memory alignment, in bytes so that no bounce buffer is needed */
size_t min_mem_alignment;
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 29d4fdbf63..82bae55161 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -211,6 +211,7 @@ uint32_t blk_get_request_alignment(BlockBackend *blk);
uint32_t blk_get_max_transfer(BlockBackend *blk);
uint64_t blk_get_max_hw_transfer(BlockBackend *blk);
int blk_get_max_iov(BlockBackend *blk);
+int blk_get_max_hw_iov(BlockBackend *blk);
void blk_set_guest_block_size(BlockBackend *blk, int align);
void *blk_try_blockalign(BlockBackend *blk, size_t size);
void *blk_blockalign(BlockBackend *blk, size_t size);
--
2.27.0
On Thu, 23 Sep 2021 09:04:36 -0400 Paolo Bonzini <pbonzini@redhat.com> wrote: > Linux limits the size of iovecs to 1024 (UIO_MAXIOV in the kernel > sources, IOV_MAX in POSIX). Because of this, on some host adapters > requests with many iovecs are rejected with -EINVAL by the > io_submit() or readv()/writev() system calls. > > In fact, the same limit applies to SG_IO as well. To fix both the > EINVAL and the possible performance issues from using fewer iovecs > than allowed by Linux (some HBAs have max_segments as low as 128), > introduce a separate entry in BlockLimits to hold the max_segments > value from sysfs. This new limit is used only for SG_IO and clamped > to bs->bl.max_iov anyway, just like max_hw_transfer is clamped to > bs->bl.max_transfer. Doesn't this patch render bs->bl.max_iov a constant? $ git grep -p -e 'bl\(.\|->\)max_iov' block/block-backend.c=int blk_get_max_iov(BlockBackend *blk) block/block-backend.c: return blk->root->bs->bl.max_iov; block/file-posix.c=static void raw_refresh_limits(BlockDriverState *bs, Error **errp) block/file-posix.c: bs->bl.max_iov = ret; block/io.c=void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp) block/io.c: bs->bl.max_iov = IOV_MAX; block/mirror.c=static int coroutine_fn mirror_run(Job *job, Error **errp) block/mirror.c: s->max_iov = MIN(bs->bl.max_iov, target_bs->bl.max_iov); Can't we use some of the established constants instead of hard coding a qemu specific IOV_MAX? POSIX.1 seems to guarantee the availability of IOV_MAX in <limits.h> according to: https://man7.org/linux/man-pages/man2/readv.2.html and <sys/uio.h> may have UIO_MAXIOV defined. > > Reported-by: Halil Pasic <pasic@linux.ibm.com> > Cc: Hanna Reitz <hreitz@redhat.com> > Cc: Kevin Wolf <kwolf@redhat.com> > Cc: qemu-block@nongnu.org > Fixes: 18473467d5 ("file-posix: try BLKSECTGET on block devices too, do not round to power of 2", 2021-06-25) > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > block/block-backend.c | 6 ++++++ > block/file-posix.c | 2 +- > block/io.c | 1 + > hw/scsi/scsi-generic.c | 2 +- > include/block/block_int.h | 7 +++++++ > include/sysemu/block-backend.h | 1 + > 6 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/block/block-backend.c b/block/block-backend.c > index 6140d133e2..ba2b5ebb10 100644 > --- a/block/block-backend.c > +++ b/block/block-backend.c > @@ -1986,6 +1986,12 @@ uint32_t blk_get_max_transfer(BlockBackend *blk) > return ROUND_DOWN(max, blk_get_request_alignment(blk)); > } > > +int blk_get_max_hw_iov(BlockBackend *blk) > +{ > + return MIN_NON_ZERO(blk->root->bs->bl.max_hw_iov, > + blk->root->bs->bl.max_iov); > +} > + > int blk_get_max_iov(BlockBackend *blk) > { > return blk->root->bs->bl.max_iov; > diff --git a/block/file-posix.c b/block/file-posix.c > index cb9bffe047..1567edb3d5 100644 > --- a/block/file-posix.c > +++ b/block/file-posix.c > @@ -1273,7 +1273,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp) > > ret = hdev_get_max_segments(s->fd, &st); > if (ret > 0) { > - bs->bl.max_iov = ret; > + bs->bl.max_hw_iov = ret; > } > } > } > diff --git a/block/io.c b/block/io.c > index a19942718b..f38e7f81d8 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -136,6 +136,7 @@ static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) > dst->min_mem_alignment = MAX(dst->min_mem_alignment, > src->min_mem_alignment); > dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); > + dst->max_hw_iov = MIN_NON_ZERO(dst->max_hw_iov, src->max_hw_iov); > } > > typedef struct BdrvRefreshLimitsState { > diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c > index 665baf900e..0306ccc7b1 100644 > --- a/hw/scsi/scsi-generic.c > +++ b/hw/scsi/scsi-generic.c > @@ -180,7 +180,7 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len) > page = r->req.cmd.buf[2]; > if (page == 0xb0) { > uint64_t max_transfer = blk_get_max_hw_transfer(s->conf.blk); > - uint32_t max_iov = blk_get_max_iov(s->conf.blk); > + uint32_t max_iov = blk_get_max_hw_iov(s->conf.blk); > > assert(max_transfer); > max_transfer = MIN_NON_ZERO(max_transfer, max_iov * qemu_real_host_page_size) > diff --git a/include/block/block_int.h b/include/block/block_int.h > index f1a54db0f8..c31cbd034a 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -702,6 +702,13 @@ typedef struct BlockLimits { > */ > uint64_t max_hw_transfer; > > + /* Maximal number of scatter/gather elements allowed by the hardware. > + * Applies whenever transfers to the device bypass the kernel I/O > + * scheduler, for example with SG_IO. If larger than max_iov > + * or if zero, blk_get_max_hw_iov will fall back to max_iov. > + */ > + int max_hw_iov; > + > /* memory alignment, in bytes so that no bounce buffer is needed */ > size_t min_mem_alignment; > > diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h > index 29d4fdbf63..82bae55161 100644 > --- a/include/sysemu/block-backend.h > +++ b/include/sysemu/block-backend.h > @@ -211,6 +211,7 @@ uint32_t blk_get_request_alignment(BlockBackend *blk); > uint32_t blk_get_max_transfer(BlockBackend *blk); > uint64_t blk_get_max_hw_transfer(BlockBackend *blk); > int blk_get_max_iov(BlockBackend *blk); > +int blk_get_max_hw_iov(BlockBackend *blk); > void blk_set_guest_block_size(BlockBackend *blk, int align); > void *blk_try_blockalign(BlockBackend *blk, size_t size); > void *blk_blockalign(BlockBackend *blk, size_t size);
On Thu, 23 Sep 2021 16:28:11 +0200 Halil Pasic <pasic@linux.ibm.com> wrote: > Can't we use some of the established constants instead of hard coding a > qemu specific IOV_MAX? > > POSIX.1 seems to guarantee the availability of IOV_MAX in <limits.h> > according to: https://man7.org/linux/man-pages/man2/readv.2.html > and <sys/uio.h> may have UIO_MAXIOV defined. Never mind, the #define IOV_MAX 1024 in osdep.h is conditional and I guess we already use IOV_MAX from limit when CONFIG_IOVEC is defined, i.e. when we don't emulate the interface. Sorry for the noise. Regards, Halil
Am 23.09.21 um 15:04 schrieb Paolo Bonzini: > Linux limits the size of iovecs to 1024 (UIO_MAXIOV in the kernel > sources, IOV_MAX in POSIX). Because of this, on some host adapters > requests with many iovecs are rejected with -EINVAL by the > io_submit() or readv()/writev() system calls. > > In fact, the same limit applies to SG_IO as well. To fix both the > EINVAL and the possible performance issues from using fewer iovecs > than allowed by Linux (some HBAs have max_segments as low as 128), > introduce a separate entry in BlockLimits to hold the max_segments > value from sysfs. This new limit is used only for SG_IO and clamped > to bs->bl.max_iov anyway, just like max_hw_transfer is clamped to > bs->bl.max_transfer. > > Reported-by: Halil Pasic <pasic@linux.ibm.com> > Cc: Hanna Reitz <hreitz@redhat.com> > Cc: Kevin Wolf <kwolf@redhat.com> > Cc: qemu-block@nongnu.org > Fixes: 18473467d5 ("file-posix: try BLKSECTGET on block devices too, do not round to power of 2", 2021-06-25) This sneaked in shortly before the 6.1 release (between rc0 and rc1 I think). Shouldnt that go to stable in cass this still exist? > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > block/block-backend.c | 6 ++++++ > block/file-posix.c | 2 +- > block/io.c | 1 + > hw/scsi/scsi-generic.c | 2 +- > include/block/block_int.h | 7 +++++++ > include/sysemu/block-backend.h | 1 + > 6 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/block/block-backend.c b/block/block-backend.c > index 6140d133e2..ba2b5ebb10 100644 > --- a/block/block-backend.c > +++ b/block/block-backend.c > @@ -1986,6 +1986,12 @@ uint32_t blk_get_max_transfer(BlockBackend *blk) > return ROUND_DOWN(max, blk_get_request_alignment(blk)); > } > > +int blk_get_max_hw_iov(BlockBackend *blk) > +{ > + return MIN_NON_ZERO(blk->root->bs->bl.max_hw_iov, > + blk->root->bs->bl.max_iov); > +} > + > int blk_get_max_iov(BlockBackend *blk) > { > return blk->root->bs->bl.max_iov; > diff --git a/block/file-posix.c b/block/file-posix.c > index cb9bffe047..1567edb3d5 100644 > --- a/block/file-posix.c > +++ b/block/file-posix.c > @@ -1273,7 +1273,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp) > > ret = hdev_get_max_segments(s->fd, &st); > if (ret > 0) { > - bs->bl.max_iov = ret; > + bs->bl.max_hw_iov = ret; > } > } > } > diff --git a/block/io.c b/block/io.c > index a19942718b..f38e7f81d8 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -136,6 +136,7 @@ static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) > dst->min_mem_alignment = MAX(dst->min_mem_alignment, > src->min_mem_alignment); > dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); > + dst->max_hw_iov = MIN_NON_ZERO(dst->max_hw_iov, src->max_hw_iov); > } > > typedef struct BdrvRefreshLimitsState { > diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c > index 665baf900e..0306ccc7b1 100644 > --- a/hw/scsi/scsi-generic.c > +++ b/hw/scsi/scsi-generic.c > @@ -180,7 +180,7 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len) > page = r->req.cmd.buf[2]; > if (page == 0xb0) { > uint64_t max_transfer = blk_get_max_hw_transfer(s->conf.blk); > - uint32_t max_iov = blk_get_max_iov(s->conf.blk); > + uint32_t max_iov = blk_get_max_hw_iov(s->conf.blk); > > assert(max_transfer); > max_transfer = MIN_NON_ZERO(max_transfer, max_iov * qemu_real_host_page_size) > diff --git a/include/block/block_int.h b/include/block/block_int.h > index f1a54db0f8..c31cbd034a 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -702,6 +702,13 @@ typedef struct BlockLimits { > */ > uint64_t max_hw_transfer; > > + /* Maximal number of scatter/gather elements allowed by the hardware. > + * Applies whenever transfers to the device bypass the kernel I/O > + * scheduler, for example with SG_IO. If larger than max_iov > + * or if zero, blk_get_max_hw_iov will fall back to max_iov. > + */ > + int max_hw_iov; > + > /* memory alignment, in bytes so that no bounce buffer is needed */ > size_t min_mem_alignment; > > diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h > index 29d4fdbf63..82bae55161 100644 > --- a/include/sysemu/block-backend.h > +++ b/include/sysemu/block-backend.h > @@ -211,6 +211,7 @@ uint32_t blk_get_request_alignment(BlockBackend *blk); > uint32_t blk_get_max_transfer(BlockBackend *blk); > uint64_t blk_get_max_hw_transfer(BlockBackend *blk); > int blk_get_max_iov(BlockBackend *blk); > +int blk_get_max_hw_iov(BlockBackend *blk); > void blk_set_guest_block_size(BlockBackend *blk, int align); > void *blk_try_blockalign(BlockBackend *blk, size_t size); > void *blk_blockalign(BlockBackend *blk, size_t size); >
Yes, the question is whether it still exists... Paolo El jue., 23 sept. 2021 16:48, Christian Borntraeger <borntraeger@de.ibm.com> escribió: > > > Am 23.09.21 um 15:04 schrieb Paolo Bonzini: > > Linux limits the size of iovecs to 1024 (UIO_MAXIOV in the kernel > > sources, IOV_MAX in POSIX). Because of this, on some host adapters > > requests with many iovecs are rejected with -EINVAL by the > > io_submit() or readv()/writev() system calls. > > > > In fact, the same limit applies to SG_IO as well. To fix both the > > EINVAL and the possible performance issues from using fewer iovecs > > than allowed by Linux (some HBAs have max_segments as low as 128), > > introduce a separate entry in BlockLimits to hold the max_segments > > value from sysfs. This new limit is used only for SG_IO and clamped > > to bs->bl.max_iov anyway, just like max_hw_transfer is clamped to > > bs->bl.max_transfer. > > > > Reported-by: Halil Pasic <pasic@linux.ibm.com> > > Cc: Hanna Reitz <hreitz@redhat.com> > > Cc: Kevin Wolf <kwolf@redhat.com> > > Cc: qemu-block@nongnu.org > > Fixes: 18473467d5 ("file-posix: try BLKSECTGET on block devices too, do > not round to power of 2", 2021-06-25) > > This sneaked in shortly before the 6.1 release (between rc0 and rc1 I > think). > Shouldnt that go to stable in cass this still exist? > > > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > > --- > > block/block-backend.c | 6 ++++++ > > block/file-posix.c | 2 +- > > block/io.c | 1 + > > hw/scsi/scsi-generic.c | 2 +- > > include/block/block_int.h | 7 +++++++ > > include/sysemu/block-backend.h | 1 + > > 6 files changed, 17 insertions(+), 2 deletions(-) > > > > diff --git a/block/block-backend.c b/block/block-backend.c > > index 6140d133e2..ba2b5ebb10 100644 > > --- a/block/block-backend.c > > +++ b/block/block-backend.c > > @@ -1986,6 +1986,12 @@ uint32_t blk_get_max_transfer(BlockBackend *blk) > > return ROUND_DOWN(max, blk_get_request_alignment(blk)); > > } > > > > +int blk_get_max_hw_iov(BlockBackend *blk) > > +{ > > + return MIN_NON_ZERO(blk->root->bs->bl.max_hw_iov, > > + blk->root->bs->bl.max_iov); > > +} > > + > > int blk_get_max_iov(BlockBackend *blk) > > { > > return blk->root->bs->bl.max_iov; > > diff --git a/block/file-posix.c b/block/file-posix.c > > index cb9bffe047..1567edb3d5 100644 > > --- a/block/file-posix.c > > +++ b/block/file-posix.c > > @@ -1273,7 +1273,7 @@ static void raw_refresh_limits(BlockDriverState > *bs, Error **errp) > > > > ret = hdev_get_max_segments(s->fd, &st); > > if (ret > 0) { > > - bs->bl.max_iov = ret; > > + bs->bl.max_hw_iov = ret; > > } > > } > > } > > diff --git a/block/io.c b/block/io.c > > index a19942718b..f38e7f81d8 100644 > > --- a/block/io.c > > +++ b/block/io.c > > @@ -136,6 +136,7 @@ static void bdrv_merge_limits(BlockLimits *dst, > const BlockLimits *src) > > dst->min_mem_alignment = MAX(dst->min_mem_alignment, > > src->min_mem_alignment); > > dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); > > + dst->max_hw_iov = MIN_NON_ZERO(dst->max_hw_iov, src->max_hw_iov); > > } > > > > typedef struct BdrvRefreshLimitsState { > > diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c > > index 665baf900e..0306ccc7b1 100644 > > --- a/hw/scsi/scsi-generic.c > > +++ b/hw/scsi/scsi-generic.c > > @@ -180,7 +180,7 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq > *r, SCSIDevice *s, int len) > > page = r->req.cmd.buf[2]; > > if (page == 0xb0) { > > uint64_t max_transfer = > blk_get_max_hw_transfer(s->conf.blk); > > - uint32_t max_iov = blk_get_max_iov(s->conf.blk); > > + uint32_t max_iov = blk_get_max_hw_iov(s->conf.blk); > > > > assert(max_transfer); > > max_transfer = MIN_NON_ZERO(max_transfer, max_iov * > qemu_real_host_page_size) > > diff --git a/include/block/block_int.h b/include/block/block_int.h > > index f1a54db0f8..c31cbd034a 100644 > > --- a/include/block/block_int.h > > +++ b/include/block/block_int.h > > @@ -702,6 +702,13 @@ typedef struct BlockLimits { > > */ > > uint64_t max_hw_transfer; > > > > + /* Maximal number of scatter/gather elements allowed by the > hardware. > > + * Applies whenever transfers to the device bypass the kernel I/O > > + * scheduler, for example with SG_IO. If larger than max_iov > > + * or if zero, blk_get_max_hw_iov will fall back to max_iov. > > + */ > > + int max_hw_iov; > > + > > /* memory alignment, in bytes so that no bounce buffer is needed */ > > size_t min_mem_alignment; > > > > diff --git a/include/sysemu/block-backend.h > b/include/sysemu/block-backend.h > > index 29d4fdbf63..82bae55161 100644 > > --- a/include/sysemu/block-backend.h > > +++ b/include/sysemu/block-backend.h > > @@ -211,6 +211,7 @@ uint32_t blk_get_request_alignment(BlockBackend > *blk); > > uint32_t blk_get_max_transfer(BlockBackend *blk); > > uint64_t blk_get_max_hw_transfer(BlockBackend *blk); > > int blk_get_max_iov(BlockBackend *blk); > > +int blk_get_max_hw_iov(BlockBackend *blk); > > void blk_set_guest_block_size(BlockBackend *blk, int align); > > void *blk_try_blockalign(BlockBackend *blk, size_t size); > > void *blk_blockalign(BlockBackend *blk, size_t size); > > > >
Peter, Michael, do we still do stable releases for QEMU or has this stopped? Am 24.09.21 um 07:27 schrieb Paolo Bonzini: > Yes, the question is whether it still exists... Paolo El jue., 23 sept. 2021 16:48, Christian Borntraeger <borntraeger@de.ibm.com> escribió: Am 23.09.21 um 15:04 schrieb Paolo Bonzini: > Linux limits the size of iovecs to 1024 (UIO_MAXIOV ZjQcmQRYFpfptBannerStart > This Message Is From an External Sender > This message came from outside your organization. > ZjQcmQRYFpfptBannerEnd > Yes, the question is whether it still exists... > > Paolo > > El jue., 23 sept. 2021 16:48, Christian Borntraeger <borntraeger@de.ibm.com <mailto:borntraeger@de.ibm.com>> escribió: > > > > Am 23.09.21 um 15:04 schrieb Paolo Bonzini: > > Linux limits the size of iovecs to 1024 (UIO_MAXIOV in the kernel > > sources, IOV_MAX in POSIX). Because of this, on some host adapters > > requests with many iovecs are rejected with -EINVAL by the > > io_submit() or readv()/writev() system calls. > > > > In fact, the same limit applies to SG_IO as well. To fix both the > > EINVAL and the possible performance issues from using fewer iovecs > > than allowed by Linux (some HBAs have max_segments as low as 128), > > introduce a separate entry in BlockLimits to hold the max_segments > > value from sysfs. This new limit is used only for SG_IO and clamped > > to bs->bl.max_iov anyway, just like max_hw_transfer is clamped to > > bs->bl.max_transfer. > > > > Reported-by: Halil Pasic <pasic@linux.ibm.com <mailto:pasic@linux.ibm.com>> > > Cc: Hanna Reitz <hreitz@redhat.com <mailto:hreitz@redhat.com>> > > Cc: Kevin Wolf <kwolf@redhat.com <mailto:kwolf@redhat.com>> > > Cc: qemu-block@nongnu.org <mailto:qemu-block@nongnu.org> > > Fixes: 18473467d5 ("file-posix: try BLKSECTGET on block devices too, do not round to power of 2", 2021-06-25) > > This sneaked in shortly before the 6.1 release (between rc0 and rc1 I think). > Shouldnt that go to stable in cass this still exist? > > > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com <mailto:pbonzini@redhat.com>> > > --- > > block/block-backend.c | 6 ++++++ > > block/file-posix.c | 2 +- > > block/io.c | 1 + > > hw/scsi/scsi-generic.c | 2 +- > > include/block/block_int.h | 7 +++++++ > > include/sysemu/block-backend.h | 1 + > > 6 files changed, 17 insertions(+), 2 deletions(-) > > > > diff --git a/block/block-backend.c b/block/block-backend.c > > index 6140d133e2..ba2b5ebb10 100644 > > --- a/block/block-backend.c > > +++ b/block/block-backend.c > > @@ -1986,6 +1986,12 @@ uint32_t blk_get_max_transfer(BlockBackend *blk) > > return ROUND_DOWN(max, blk_get_request_alignment(blk)); > > } > > > > +int blk_get_max_hw_iov(BlockBackend *blk) > > +{ > > + return MIN_NON_ZERO(blk->root->bs->bl.max_hw_iov, > > + blk->root->bs->bl.max_iov); > > +} > > + > > int blk_get_max_iov(BlockBackend *blk) > > { > > return blk->root->bs->bl.max_iov; > > diff --git a/block/file-posix.c b/block/file-posix.c > > index cb9bffe047..1567edb3d5 100644 > > --- a/block/file-posix.c > > +++ b/block/file-posix.c > > @@ -1273,7 +1273,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp) > > > > ret = hdev_get_max_segments(s->fd, &st); > > if (ret > 0) { > > - bs->bl.max_iov = ret; > > + bs->bl.max_hw_iov = ret; > > } > > } > > } > > diff --git a/block/io.c b/block/io.c > > index a19942718b..f38e7f81d8 100644 > > --- a/block/io.c > > +++ b/block/io.c > > @@ -136,6 +136,7 @@ static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) > > dst->min_mem_alignment = MAX(dst->min_mem_alignment, > > src->min_mem_alignment); > > dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); > > + dst->max_hw_iov = MIN_NON_ZERO(dst->max_hw_iov, src->max_hw_iov); > > } > > > > typedef struct BdrvRefreshLimitsState { > > diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c > > index 665baf900e..0306ccc7b1 100644 > > --- a/hw/scsi/scsi-generic.c > > +++ b/hw/scsi/scsi-generic.c > > @@ -180,7 +180,7 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len) > > page = r->req.cmd.buf[2]; > > if (page == 0xb0) { > > uint64_t max_transfer = blk_get_max_hw_transfer(s->conf.blk); > > - uint32_t max_iov = blk_get_max_iov(s->conf.blk); > > + uint32_t max_iov = blk_get_max_hw_iov(s->conf.blk); > > > > assert(max_transfer); > > max_transfer = MIN_NON_ZERO(max_transfer, max_iov * qemu_real_host_page_size) > > diff --git a/include/block/block_int.h b/include/block/block_int.h > > index f1a54db0f8..c31cbd034a 100644 > > --- a/include/block/block_int.h > > +++ b/include/block/block_int.h > > @@ -702,6 +702,13 @@ typedef struct BlockLimits { > > */ > > uint64_t max_hw_transfer; > > > > + /* Maximal number of scatter/gather elements allowed by the hardware. > > + * Applies whenever transfers to the device bypass the kernel I/O > > + * scheduler, for example with SG_IO. If larger than max_iov > > + * or if zero, blk_get_max_hw_iov will fall back to max_iov. > > + */ > > + int max_hw_iov; > > + > > /* memory alignment, in bytes so that no bounce buffer is needed */ > > size_t min_mem_alignment; > > > > diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h > > index 29d4fdbf63..82bae55161 100644 > > --- a/include/sysemu/block-backend.h > > +++ b/include/sysemu/block-backend.h > > @@ -211,6 +211,7 @@ uint32_t blk_get_request_alignment(BlockBackend *blk); > > uint32_t blk_get_max_transfer(BlockBackend *blk); > > uint64_t blk_get_max_hw_transfer(BlockBackend *blk); > > int blk_get_max_iov(BlockBackend *blk); > > +int blk_get_max_hw_iov(BlockBackend *blk); > > void blk_set_guest_block_size(BlockBackend *blk, int align); > > void *blk_try_blockalign(BlockBackend *blk, size_t size); > > void *blk_blockalign(BlockBackend *blk, size_t size); > > >
On Fri, Sep 24, 2021 at 08:50:05AM +0200, Christian Borntraeger wrote: > Peter, Michael, > > do we still do stable releases for QEMU or has this stopped? Hi Christian, Yes, it's just been a perfect storm of job moves / bad timing / much-needed testing rework. I plan to restart the stable releases starting with 6.0.1 and 6.1.1 shortly after. I'll get the release schedules posted on the release wiki week. Sorry for the delays on this. -Mike > > Am 24.09.21 um 07:27 schrieb Paolo Bonzini: > > Yes, the question is whether it still exists... Paolo El jue., 23 sept. 2021 16:48, Christian Borntraeger <borntraeger@de.ibm.com> escribió: Am 23.09.21 um 15:04 schrieb Paolo Bonzini: > Linux limits the size of iovecs to 1024 (UIO_MAXIOV ZjQcmQRYFpfptBannerStart > > This Message Is From an External Sender > > This message came from outside your organization. > > ZjQcmQRYFpfptBannerEnd > > Yes, the question is whether it still exists... > > > > Paolo > > > > El jue., 23 sept. 2021 16:48, Christian Borntraeger <borntraeger@de.ibm.com <mailto:borntraeger@de.ibm.com>> escribió: > > > > > > > > Am 23.09.21 um 15:04 schrieb Paolo Bonzini: > > > Linux limits the size of iovecs to 1024 (UIO_MAXIOV in the kernel > > > sources, IOV_MAX in POSIX). Because of this, on some host adapters > > > requests with many iovecs are rejected with -EINVAL by the > > > io_submit() or readv()/writev() system calls. > > > > > > In fact, the same limit applies to SG_IO as well. To fix both the > > > EINVAL and the possible performance issues from using fewer iovecs > > > than allowed by Linux (some HBAs have max_segments as low as 128), > > > introduce a separate entry in BlockLimits to hold the max_segments > > > value from sysfs. This new limit is used only for SG_IO and clamped > > > to bs->bl.max_iov anyway, just like max_hw_transfer is clamped to > > > bs->bl.max_transfer. > > > > > > Reported-by: Halil Pasic <pasic@linux.ibm.com <mailto:pasic@linux.ibm.com>> > > > Cc: Hanna Reitz <hreitz@redhat.com <mailto:hreitz@redhat.com>> > > > Cc: Kevin Wolf <kwolf@redhat.com <mailto:kwolf@redhat.com>> > > > Cc: qemu-block@nongnu.org <mailto:qemu-block@nongnu.org> > > > Fixes: 18473467d5 ("file-posix: try BLKSECTGET on block devices too, do not round to power of 2", 2021-06-25) > > > > This sneaked in shortly before the 6.1 release (between rc0 and rc1 I think). > > Shouldnt that go to stable in cass this still exist? > > > > > > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com <mailto:pbonzini@redhat.com>> > > > --- > > > block/block-backend.c | 6 ++++++ > > > block/file-posix.c | 2 +- > > > block/io.c | 1 + > > > hw/scsi/scsi-generic.c | 2 +- > > > include/block/block_int.h | 7 +++++++ > > > include/sysemu/block-backend.h | 1 + > > > 6 files changed, 17 insertions(+), 2 deletions(-) > > > > > > diff --git a/block/block-backend.c b/block/block-backend.c > > > index 6140d133e2..ba2b5ebb10 100644 > > > --- a/block/block-backend.c > > > +++ b/block/block-backend.c > > > @@ -1986,6 +1986,12 @@ uint32_t blk_get_max_transfer(BlockBackend *blk) > > > return ROUND_DOWN(max, blk_get_request_alignment(blk)); > > > } > > > > > > +int blk_get_max_hw_iov(BlockBackend *blk) > > > +{ > > > + return MIN_NON_ZERO(blk->root->bs->bl.max_hw_iov, > > > + blk->root->bs->bl.max_iov); > > > +} > > > + > > > int blk_get_max_iov(BlockBackend *blk) > > > { > > > return blk->root->bs->bl.max_iov; > > > diff --git a/block/file-posix.c b/block/file-posix.c > > > index cb9bffe047..1567edb3d5 100644 > > > --- a/block/file-posix.c > > > +++ b/block/file-posix.c > > > @@ -1273,7 +1273,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp) > > > > > > ret = hdev_get_max_segments(s->fd, &st); > > > if (ret > 0) { > > > - bs->bl.max_iov = ret; > > > + bs->bl.max_hw_iov = ret; > > > } > > > } > > > } > > > diff --git a/block/io.c b/block/io.c > > > index a19942718b..f38e7f81d8 100644 > > > --- a/block/io.c > > > +++ b/block/io.c > > > @@ -136,6 +136,7 @@ static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) > > > dst->min_mem_alignment = MAX(dst->min_mem_alignment, > > > src->min_mem_alignment); > > > dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); > > > + dst->max_hw_iov = MIN_NON_ZERO(dst->max_hw_iov, src->max_hw_iov); > > > } > > > > > > typedef struct BdrvRefreshLimitsState { > > > diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c > > > index 665baf900e..0306ccc7b1 100644 > > > --- a/hw/scsi/scsi-generic.c > > > +++ b/hw/scsi/scsi-generic.c > > > @@ -180,7 +180,7 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len) > > > page = r->req.cmd.buf[2]; > > > if (page == 0xb0) { > > > uint64_t max_transfer = blk_get_max_hw_transfer(s->conf.blk); > > > - uint32_t max_iov = blk_get_max_iov(s->conf.blk); > > > + uint32_t max_iov = blk_get_max_hw_iov(s->conf.blk); > > > > > > assert(max_transfer); > > > max_transfer = MIN_NON_ZERO(max_transfer, max_iov * qemu_real_host_page_size) > > > diff --git a/include/block/block_int.h b/include/block/block_int.h > > > index f1a54db0f8..c31cbd034a 100644 > > > --- a/include/block/block_int.h > > > +++ b/include/block/block_int.h > > > @@ -702,6 +702,13 @@ typedef struct BlockLimits { > > > */ > > > uint64_t max_hw_transfer; > > > > > > + /* Maximal number of scatter/gather elements allowed by the hardware. > > > + * Applies whenever transfers to the device bypass the kernel I/O > > > + * scheduler, for example with SG_IO. If larger than max_iov > > > + * or if zero, blk_get_max_hw_iov will fall back to max_iov. > > > + */ > > > + int max_hw_iov; > > > + > > > /* memory alignment, in bytes so that no bounce buffer is needed */ > > > size_t min_mem_alignment; > > > > > > diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h > > > index 29d4fdbf63..82bae55161 100644 > > > --- a/include/sysemu/block-backend.h > > > +++ b/include/sysemu/block-backend.h > > > @@ -211,6 +211,7 @@ uint32_t blk_get_request_alignment(BlockBackend *blk); > > > uint32_t blk_get_max_transfer(BlockBackend *blk); > > > uint64_t blk_get_max_hw_transfer(BlockBackend *blk); > > > int blk_get_max_iov(BlockBackend *blk); > > > +int blk_get_max_hw_iov(BlockBackend *blk); > > > void blk_set_guest_block_size(BlockBackend *blk, int align); > > > void *blk_try_blockalign(BlockBackend *blk, size_t size); > > > void *blk_blockalign(BlockBackend *blk, size_t size); > > > > >
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