| Message ID | 20211125022046.10433-1-jasowang@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] virito-balloon: process all in sgs for free_page_vq | expand |
On 25.11.21 03:20, Jason Wang wrote: > We only process the first in sg which may lead to the bitmap of the > pages belongs to following sgs were not cleared. This may result more > pages to be migrated. Fixing this by process all in sgs for > free_page_vq. > > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > hw/virtio/virtio-balloon.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > index c6962fcbfe..17de2558cb 100644 > --- a/hw/virtio/virtio-balloon.c > +++ b/hw/virtio/virtio-balloon.c > @@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon *dev) > VirtIODevice *vdev = VIRTIO_DEVICE(dev); > VirtQueue *vq = dev->free_page_vq; > bool ret = true; > + int i; > > while (dev->block_iothread) { > qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock); > @@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon *dev) > } > > if (elem->in_num && dev->free_page_hint_status == FREE_PAGE_HINT_S_START) { > - qemu_guest_free_page_hint(elem->in_sg[0].iov_base, > - elem->in_sg[0].iov_len); > + for (i = 0; i < elem->in_num; i++) { > + qemu_guest_free_page_hint(elem->in_sg[i].iov_base, > + elem->in_sg[i].iov_len); > + } > } > > out: > Yes, but: 1. Linux never used more than one 2. QEMU never consumed more than one The spec states: "(b) The driver maps a series of pages and adds them to the free_page_vq as individual scatter-gather input buffer entries." However, the spec was written by someone else (Alex) as the code was (Wei). The code was there first. I don't particularly care what to adjust (code or spec). However, to me it feels more like the spec is slightly wrong and it was intended like the code is by the original code author. But then again, I don't particularly care :)
On 11/25/21 03:20, Jason Wang wrote: > We only process the first in sg which may lead to the bitmap of the > pages belongs to following sgs were not cleared. This may result more > pages to be migrated. Fixing this by process all in sgs for > free_page_vq. > > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > hw/virtio/virtio-balloon.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) Typo "virtio" in subject.
On Thu, Nov 25, 2021 at 09:28:59AM +0100, David Hildenbrand wrote: > On 25.11.21 03:20, Jason Wang wrote: > > We only process the first in sg which may lead to the bitmap of the > > pages belongs to following sgs were not cleared. This may result more > > pages to be migrated. Fixing this by process all in sgs for > > free_page_vq. > > > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > --- > > hw/virtio/virtio-balloon.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > > index c6962fcbfe..17de2558cb 100644 > > --- a/hw/virtio/virtio-balloon.c > > +++ b/hw/virtio/virtio-balloon.c > > @@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon *dev) > > VirtIODevice *vdev = VIRTIO_DEVICE(dev); > > VirtQueue *vq = dev->free_page_vq; > > bool ret = true; > > + int i; > > > > while (dev->block_iothread) { > > qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock); > > @@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon *dev) > > } > > > > if (elem->in_num && dev->free_page_hint_status == FREE_PAGE_HINT_S_START) { > > - qemu_guest_free_page_hint(elem->in_sg[0].iov_base, > > - elem->in_sg[0].iov_len); > > + for (i = 0; i < elem->in_num; i++) { > > + qemu_guest_free_page_hint(elem->in_sg[i].iov_base, > > + elem->in_sg[i].iov_len); > > + } > > } > > > > out: > > > > Yes, but: > > 1. Linux never used more than one > 2. QEMU never consumed more than one > > The spec states: > > "(b) The driver maps a series of pages and adds them to the free_page_vq > as individual scatter-gather input buffer entries." > > However, the spec was written by someone else (Alex) as the code was > (Wei). The code was there first. > > I don't particularly care what to adjust (code or spec). However, to me > it feels more like the spec is slightly wrong and it was intended like > the code is by the original code author. > > But then again, I don't particularly care :) Original QEMU side code had several bugs so, that's another one. Given nothing too bad happens if guest submits too many S/Gs, and given the spec also has a general chapter suggesting devices are flexible in accepting a single buffer split to multiple S/Gs, I'm inclined to accept the patch. > -- > Thanks, > > David / dhildenb
On Thu, Nov 25, 2021 at 09:34:32AM +0100, Philippe Mathieu-Daudé wrote: > On 11/25/21 03:20, Jason Wang wrote: > > We only process the first in sg which may lead to the bitmap of the > > pages belongs to following sgs were not cleared. This may result more > > pages to be migrated. Fixing this by process all in sgs for > > free_page_vq. > > > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > --- > > hw/virtio/virtio-balloon.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > Typo "virtio" in subject. Yes, it's an annoyingly common typo. If using vim, I suggest: ab virito virtio in your vimrc.
On 25.11.21 17:09, Michael S. Tsirkin wrote: > On Thu, Nov 25, 2021 at 09:28:59AM +0100, David Hildenbrand wrote: >> On 25.11.21 03:20, Jason Wang wrote: >>> We only process the first in sg which may lead to the bitmap of the >>> pages belongs to following sgs were not cleared. This may result more >>> pages to be migrated. Fixing this by process all in sgs for >>> free_page_vq. >>> >>> Signed-off-by: Jason Wang <jasowang@redhat.com> >>> --- >>> hw/virtio/virtio-balloon.c | 7 +++++-- >>> 1 file changed, 5 insertions(+), 2 deletions(-) >>> >>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c >>> index c6962fcbfe..17de2558cb 100644 >>> --- a/hw/virtio/virtio-balloon.c >>> +++ b/hw/virtio/virtio-balloon.c >>> @@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon *dev) >>> VirtIODevice *vdev = VIRTIO_DEVICE(dev); >>> VirtQueue *vq = dev->free_page_vq; >>> bool ret = true; >>> + int i; >>> >>> while (dev->block_iothread) { >>> qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock); >>> @@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon *dev) >>> } >>> >>> if (elem->in_num && dev->free_page_hint_status == FREE_PAGE_HINT_S_START) { >>> - qemu_guest_free_page_hint(elem->in_sg[0].iov_base, >>> - elem->in_sg[0].iov_len); >>> + for (i = 0; i < elem->in_num; i++) { >>> + qemu_guest_free_page_hint(elem->in_sg[i].iov_base, >>> + elem->in_sg[i].iov_len); >>> + } >>> } >>> >>> out: >>> >> >> Yes, but: >> >> 1. Linux never used more than one >> 2. QEMU never consumed more than one >> >> The spec states: >> >> "(b) The driver maps a series of pages and adds them to the free_page_vq >> as individual scatter-gather input buffer entries." >> >> However, the spec was written by someone else (Alex) as the code was >> (Wei). The code was there first. >> >> I don't particularly care what to adjust (code or spec). However, to me >> it feels more like the spec is slightly wrong and it was intended like >> the code is by the original code author. >> >> But then again, I don't particularly care :) > > Original QEMU side code had several bugs so, that's another one. > Given nothing too bad happens if guest submits too many S/Gs, > and given the spec also has a general chapter suggesting devices > are flexible in accepting a single buffer split to multiple S/Gs, > I'm inclined to accept the patch. Yeah, as I said, I don't particularly care. It's certainly an "easy change". Acked-by: David Hildenbrand <david@redhat.com>
On Friday, November 26, 2021 12:11 AM, David Hildenbrand wrote: > On 25.11.21 17:09, Michael S. Tsirkin wrote: > > On Thu, Nov 25, 2021 at 09:28:59AM +0100, David Hildenbrand wrote: > >> On 25.11.21 03:20, Jason Wang wrote: > >>> We only process the first in sg which may lead to the bitmap of the > >>> pages belongs to following sgs were not cleared. This may result > >>> more pages to be migrated. Fixing this by process all in sgs for > >>> free_page_vq. > >>> > >>> Signed-off-by: Jason Wang <jasowang@redhat.com> > >>> --- > >>> hw/virtio/virtio-balloon.c | 7 +++++-- > >>> 1 file changed, 5 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > >>> index c6962fcbfe..17de2558cb 100644 > >>> --- a/hw/virtio/virtio-balloon.c > >>> +++ b/hw/virtio/virtio-balloon.c > >>> @@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon > *dev) > >>> VirtIODevice *vdev = VIRTIO_DEVICE(dev); > >>> VirtQueue *vq = dev->free_page_vq; > >>> bool ret = true; > >>> + int i; > >>> > >>> while (dev->block_iothread) { > >>> qemu_cond_wait(&dev->free_page_cond, > &dev->free_page_lock); > >>> @@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon > *dev) > >>> } > >>> > >>> if (elem->in_num && dev->free_page_hint_status == > FREE_PAGE_HINT_S_START) { > >>> - qemu_guest_free_page_hint(elem->in_sg[0].iov_base, > >>> - elem->in_sg[0].iov_len); > >>> + for (i = 0; i < elem->in_num; i++) { > >>> + qemu_guest_free_page_hint(elem->in_sg[i].iov_base, > >>> + elem->in_sg[i].iov_len); > >>> + } > >>> } > >>> > >>> out: > >>> > >> > >> Yes, but: > >> > >> 1. Linux never used more than one > >> 2. QEMU never consumed more than one Yes, it works based on the fact that Linux only sends one hint each time. > >> > >> The spec states: > >> > >> "(b) The driver maps a series of pages and adds them to the > >> free_page_vq as individual scatter-gather input buffer entries." > >> > >> However, the spec was written by someone else (Alex) as the code was > >> (Wei). The code was there first. > >> > >> I don't particularly care what to adjust (code or spec). However, to > >> me it feels more like the spec is slightly wrong and it was intended > >> like the code is by the original code author. > >> > >> But then again, I don't particularly care :) > > > > Original QEMU side code had several bugs so, that's another one. > > Given nothing too bad happens if guest submits too many S/Gs, and > > given the spec also has a general chapter suggesting devices are > > flexible in accepting a single buffer split to multiple S/Gs, I'm > > inclined to accept the patch. > > Yeah, as I said, I don't particularly care. It's certainly an "easy change". > > Acked-by: David Hildenbrand <david@redhat.com> > Don’t object the change. Just in case something unexpected, it would be better if someone could help do a test. Thanks, Wei
On Fri, Nov 26, 2021 at 01:21:46AM +0000, Wang, Wei W wrote: > On Friday, November 26, 2021 12:11 AM, David Hildenbrand wrote: > > On 25.11.21 17:09, Michael S. Tsirkin wrote: > > > On Thu, Nov 25, 2021 at 09:28:59AM +0100, David Hildenbrand wrote: > > >> On 25.11.21 03:20, Jason Wang wrote: > > >>> We only process the first in sg which may lead to the bitmap of the > > >>> pages belongs to following sgs were not cleared. This may result > > >>> more pages to be migrated. Fixing this by process all in sgs for > > >>> free_page_vq. > > >>> > > >>> Signed-off-by: Jason Wang <jasowang@redhat.com> > > >>> --- > > >>> hw/virtio/virtio-balloon.c | 7 +++++-- > > >>> 1 file changed, 5 insertions(+), 2 deletions(-) > > >>> > > >>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > > >>> index c6962fcbfe..17de2558cb 100644 > > >>> --- a/hw/virtio/virtio-balloon.c > > >>> +++ b/hw/virtio/virtio-balloon.c > > >>> @@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon > > *dev) > > >>> VirtIODevice *vdev = VIRTIO_DEVICE(dev); > > >>> VirtQueue *vq = dev->free_page_vq; > > >>> bool ret = true; > > >>> + int i; > > >>> > > >>> while (dev->block_iothread) { > > >>> qemu_cond_wait(&dev->free_page_cond, > > &dev->free_page_lock); > > >>> @@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon > > *dev) > > >>> } > > >>> > > >>> if (elem->in_num && dev->free_page_hint_status == > > FREE_PAGE_HINT_S_START) { > > >>> - qemu_guest_free_page_hint(elem->in_sg[0].iov_base, > > >>> - elem->in_sg[0].iov_len); > > >>> + for (i = 0; i < elem->in_num; i++) { > > >>> + qemu_guest_free_page_hint(elem->in_sg[i].iov_base, > > >>> + elem->in_sg[i].iov_len); > > >>> + } > > >>> } > > >>> > > >>> out: > > >>> > > >> > > >> Yes, but: > > >> > > >> 1. Linux never used more than one > > >> 2. QEMU never consumed more than one > > Yes, it works based on the fact that Linux only sends one hint each time. > > > >> > > >> The spec states: > > >> > > >> "(b) The driver maps a series of pages and adds them to the > > >> free_page_vq as individual scatter-gather input buffer entries." > > >> > > >> However, the spec was written by someone else (Alex) as the code was > > >> (Wei). The code was there first. > > >> > > >> I don't particularly care what to adjust (code or spec). However, to > > >> me it feels more like the spec is slightly wrong and it was intended > > >> like the code is by the original code author. > > >> > > >> But then again, I don't particularly care :) > > > > > > Original QEMU side code had several bugs so, that's another one. > > > Given nothing too bad happens if guest submits too many S/Gs, and > > > given the spec also has a general chapter suggesting devices are > > > flexible in accepting a single buffer split to multiple S/Gs, I'm > > > inclined to accept the patch. > > > > Yeah, as I said, I don't particularly care. It's certainly an "easy change". > > > > Acked-by: David Hildenbrand <david@redhat.com> > > > > Don’t object the change. > Just in case something unexpected, it would be better if someone could help do a test. > > Thanks, > Wei Yes, the setup you used to test the original patches will do fine ...
On Fri, Nov 26, 2021 at 9:21 AM Wang, Wei W <wei.w.wang@intel.com> wrote: > > On Friday, November 26, 2021 12:11 AM, David Hildenbrand wrote: > > On 25.11.21 17:09, Michael S. Tsirkin wrote: > > > On Thu, Nov 25, 2021 at 09:28:59AM +0100, David Hildenbrand wrote: > > >> On 25.11.21 03:20, Jason Wang wrote: > > >>> We only process the first in sg which may lead to the bitmap of the > > >>> pages belongs to following sgs were not cleared. This may result > > >>> more pages to be migrated. Fixing this by process all in sgs for > > >>> free_page_vq. > > >>> > > >>> Signed-off-by: Jason Wang <jasowang@redhat.com> > > >>> --- > > >>> hw/virtio/virtio-balloon.c | 7 +++++-- > > >>> 1 file changed, 5 insertions(+), 2 deletions(-) > > >>> > > >>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > > >>> index c6962fcbfe..17de2558cb 100644 > > >>> --- a/hw/virtio/virtio-balloon.c > > >>> +++ b/hw/virtio/virtio-balloon.c > > >>> @@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon > > *dev) > > >>> VirtIODevice *vdev = VIRTIO_DEVICE(dev); > > >>> VirtQueue *vq = dev->free_page_vq; > > >>> bool ret = true; > > >>> + int i; > > >>> > > >>> while (dev->block_iothread) { > > >>> qemu_cond_wait(&dev->free_page_cond, > > &dev->free_page_lock); > > >>> @@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon > > *dev) > > >>> } > > >>> > > >>> if (elem->in_num && dev->free_page_hint_status == > > FREE_PAGE_HINT_S_START) { > > >>> - qemu_guest_free_page_hint(elem->in_sg[0].iov_base, > > >>> - elem->in_sg[0].iov_len); > > >>> + for (i = 0; i < elem->in_num; i++) { > > >>> + qemu_guest_free_page_hint(elem->in_sg[i].iov_base, > > >>> + elem->in_sg[i].iov_len); > > >>> + } > > >>> } > > >>> > > >>> out: > > >>> > > >> > > >> Yes, but: > > >> > > >> 1. Linux never used more than one > > >> 2. QEMU never consumed more than one > > Yes, it works based on the fact that Linux only sends one hint each time. > > > >> > > >> The spec states: > > >> > > >> "(b) The driver maps a series of pages and adds them to the > > >> free_page_vq as individual scatter-gather input buffer entries." > > >> > > >> However, the spec was written by someone else (Alex) as the code was > > >> (Wei). The code was there first. > > >> > > >> I don't particularly care what to adjust (code or spec). However, to > > >> me it feels more like the spec is slightly wrong and it was intended > > >> like the code is by the original code author. > > >> > > >> But then again, I don't particularly care :) > > > > > > Original QEMU side code had several bugs so, that's another one. > > > Given nothing too bad happens if guest submits too many S/Gs, and > > > given the spec also has a general chapter suggesting devices are > > > flexible in accepting a single buffer split to multiple S/Gs, I'm > > > inclined to accept the patch. Yes, and it's probably too late to change the spec even if we want to change. > > > > Yeah, as I said, I don't particularly care. It's certainly an "easy change". > > > > Acked-by: David Hildenbrand <david@redhat.com> > > Thanks > > Don’t object the change. > Just in case something unexpected, it would be better if someone could help do a test. I've tested the code with migration before sending the patches, I see the hint works fine. Thanks > > Thanks, > Wei
On Friday, November 26, 2021 10:31 AM, Jason Wang wrote: > > I've tested the code with migration before sending the patches, I see the hint > works fine. > That's great (assume you saw great reduction in the migration time as well). Reviewed-by: Wei Wang <wei.w.wang@intel.com> Thanks, Wei
On Fri, Nov 26, 2021 at 12:10 AM Michael S. Tsirkin <mst@redhat.com> wrote: > > On Thu, Nov 25, 2021 at 09:34:32AM +0100, Philippe Mathieu-Daudé wrote: > > On 11/25/21 03:20, Jason Wang wrote: > > > We only process the first in sg which may lead to the bitmap of the > > > pages belongs to following sgs were not cleared. This may result more > > > pages to be migrated. Fixing this by process all in sgs for > > > free_page_vq. > > > > > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > > --- > > > hw/virtio/virtio-balloon.c | 7 +++++-- > > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > Typo "virtio" in subject. > > Yes, it's an annoyingly common typo. If using vim, I suggest: > > ab virito virtio > > in your vimrc. Right, actually I'm using flyspell with emacs. I will add a dedicated detection like this if it's possible. Will fix it. Thanks > > -- > MST >
On Fri, Nov 26, 2021 at 10:40 AM Wang, Wei W <wei.w.wang@intel.com> wrote: > > On Friday, November 26, 2021 10:31 AM, Jason Wang wrote: > > > > I've tested the code with migration before sending the patches, I see the hint > > works fine. > > > > That's great (assume you saw great reduction in the migration time as well). > Reviewed-by: Wei Wang <wei.w.wang@intel.com> I don't measure that. But it should be sufficient to see the hint considering we don't modify any logic at dirty bitmap layer. Thanks > > Thanks, > Wei
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index c6962fcbfe..17de2558cb 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon *dev) VirtIODevice *vdev = VIRTIO_DEVICE(dev); VirtQueue *vq = dev->free_page_vq; bool ret = true; + int i; while (dev->block_iothread) { qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock); @@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon *dev) } if (elem->in_num && dev->free_page_hint_status == FREE_PAGE_HINT_S_START) { - qemu_guest_free_page_hint(elem->in_sg[0].iov_base, - elem->in_sg[0].iov_len); + for (i = 0; i < elem->in_num; i++) { + qemu_guest_free_page_hint(elem->in_sg[i].iov_base, + elem->in_sg[i].iov_len); + } } out:
We only process the first in sg which may lead to the bitmap of the pages belongs to following sgs were not cleared. This may result more pages to be migrated. Fixing this by process all in sgs for free_page_vq. Signed-off-by: Jason Wang <jasowang@redhat.com> --- hw/virtio/virtio-balloon.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)