From: Michal Hocko <mhocko@xxxxxxxx> b92b1b89a33c ("virtio: force vring descriptors to be allocated from lowmem") tried to exclude highmem pages for descriptors so it cleared __GFP_HIGHMEM from a given gfp mask. The patch also cleared __GFP_HIGH which doesn't make much sense for this fix because __GFP_HIGH only controls access to memory reserves and it doesn't have any influence on the zone selection. Some of the call paths use GFP_ATOMIC and dropping __GFP_HIGH will reduce their changes for success because the lack of access to memory reserves. Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> --- Hi, I have stumbled over this code while looking at other issue [1]. I think that using __GFP_HIGH simply got there because of its confusing name. It doesn't have anything to do with the highmem zone. The patch is based on the current linux-next. I think that clearing __GFP_HIGHMEM is bogus in the current code because all code paths either use GFP_KERNEL or GFP_ATOMIC and those do not fall back to the highmem zone but I have kept it because clearing the flag cannot be harmful. [1] http://lkml.kernel.org/r/87h9k4kzcv.fsf%40yhuang-dev.intel.com drivers/virtio/virtio_ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 14e7ce9b3e96..734de927c89d 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -110,7 +110,7 @@ static struct vring_desc *alloc_indirect(struct virtqueue *_vq, * otherwise virt_to_phys will give us bogus addresses in the * virtqueue. */ - gfp &= ~(__GFP_HIGHMEM | __GFP_HIGH); + gfp &= ~__GFP_HIGHMEM; desc = kmalloc(total_sg * sizeof(struct vring_desc), gfp); if (!desc) -- 2.6.2 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization