Messages in this thread | | | From | Jason Wang <> | Subject | Re: [PATCH] vhost-net: fall back to vmalloc if high-order allocation fails | Date | Fri, 25 Jan 2013 13:15:51 +0800 |
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On Friday, January 25, 2013 03:03:13 AM Cong Wang wrote: > ["Followup-To:" header set to gmane.linux.network.] > > On Wed, 23 Jan 2013 at 20:46 GMT, Romain Francoise <romain@orebokech.com> wrote: > > Creating a vhost-net device allocates an object large enough (34320 bytes > > on x86-64) to trigger an order-4 allocation, which may fail if memory if > > > > fragmented: > > libvirtd: page allocation failure: order:4, mode:0x2000d0 > > ... > > SLAB: Unable to allocate memory on node 0 (gfp=0xd0) > > > > cache: size-65536, object size: 65536, order: 4 > > node 0: slabs: 8/8, objs: 8/8, free: 0 > > > > In that situation, rather than forcing the caller to use regular > > virtio-net, try to allocate the descriptor with vmalloc(). > > The real problem is vhost_net struct is really big, it > should be reduced rather than workarounded like this. >
Looks like iov in vhost_virtqueue is a little big:
struct iovec iov[UIO_MAXIOV];
Maybe we can use pointer and allocate it like indirect in vhost_dev_alloc_iovecs().
> > +static void vhost_net_kvfree(void *addr) > > +{ > > + if (is_vmalloc_addr(addr)) > > + vfree(addr); > > + else > > + kfree(addr); > > +} > > + > > This kind of stuff should really go to mm, not netdev. > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
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