Re: [PATCH v2] virtio_ring: use alloc_pages_node for NUMA-aware allocation

[Shile Zhang]

Hi Michael & Bjorn,

Sorry for the ping,
but how about this patch/issue? any comments/suggestions?

Thanks!

On 2020/7/27 21:10, Shile Zhang wrote:
> On 2020/7/21 19:28, Shile Zhang wrote:
> > On 2020/7/21 16:18, Michael S. Tsirkin wrote:
> > > On Tue, Jul 21, 2020 at 03:00:13PM +0800, Shile Zhang wrote:
> > > > Use alloc_pages_node() allocate memory for vring queue with proper
> > > > NUMA affinity.
> > > >
> > > > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > > > Suggested-by: Jiang Liu <liuj97@xxxxxxxxx>
> > > > Signed-off-by: Shile Zhang <shile.zhang@xxxxxxxxxxxxxxxxx>
> > >
> > > Do you observe any performance gains from this patch?
> >
> > Thanks for your comments!
> > Yes, the bandwidth can boost more than doubled (from 30Gbps to 80GBps) 
> > with this changes in my test env (8 numa nodes), with netperf test.
> >
> > > I also wonder why isn't the probe code run on the correct numa node?
> > > That would fix a wide class of issues like this without need to tweak
> > > drivers.
> >
> > Good point, I'll check this, thanks!
>
> Sorry, I have no idea about how the probe code to grab the appropriate 
> NUMA node.
>
> > > Bjorn, what do you think? Was this considered?
>
> Hi Bjorn, Could you please give any comments about this issue?
> Thanks!
>
> > > > ---
> > > > Changelog
> > > > v1 -> v2:
> > > > - fixed compile warning reported by LKP.
> > > > ---
> > > >   drivers/virtio/virtio_ring.c | 10 ++++++----
> > > >   1 file changed, 6 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/virtio/virtio_ring.c 
> > > > b/drivers/virtio/virtio_ring.c
> > > > index 58b96baa8d48..d38fd6872c8c 100644
> > > > --- a/drivers/virtio/virtio_ring.c
> > > > +++ b/drivers/virtio/virtio_ring.c
> > > > @@ -276,9 +276,11 @@ static void *vring_alloc_queue(struct 
> > > > virtio_device *vdev, size_t size,
> > > >           return dma_alloc_coherent(vdev->dev.parent, size,
> > > >                         dma_handle, flag);
> > > >       } else {
> > > > -        void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag);
> > > > -
> > > > -        if (queue) {
> > > > +        void *queue = NULL;
> > > > +        struct page *page = 
> > > > alloc_pages_node(dev_to_node(vdev->dev.parent),
> > > > +                             flag, get_order(size));
> > > > +        if (page) {
> > > > +            queue = page_address(page);
> > > >               phys_addr_t phys_addr = virt_to_phys(queue);
> > > >               *dma_handle = (dma_addr_t)phys_addr;
> > > > @@ -308,7 +310,7 @@ static void vring_free_queue(struct 
> > > > virtio_device *vdev, size_t size,
> > > >       if (vring_use_dma_api(vdev))
> > > >           dma_free_coherent(vdev->dev.parent, size, queue, dma_handle);
> > > >       else
> > > > -        free_pages_exact(queue, PAGE_ALIGN(size));
> > > > +        free_pages((unsigned long)queue, get_order(size));
> > > >   }
> > > >   /*
> > > > --
> > > > 2.24.0.rc2