Herbert, That's why I have sent you the patch for guest virtio-net driver. I reserved 512 bytes in each page, then I can always have the space to copy and avoid the backend memory used up issue. Thanks Xiaohui >-----Original Message----- >From: Herbert Xu [mailto:herbert@xxxxxxxxxxxxxxxxxxx] >Sent: Thursday, June 24, 2010 6:09 PM >To: Dong, Eddie >Cc: Xin, Xiaohui; Stephen Hemminger; netdev@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; >linux-kernel@xxxxxxxxxxxxxxx; mst@xxxxxxxxxx; mingo@xxxxxxx; davem@xxxxxxxxxxxxx; >jdike@xxxxxxxxxxxxxxx >Subject: Re: [RFC PATCH v7 01/19] Add a new structure for skb buffer from external. > >On Wed, Jun 23, 2010 at 06:05:41PM +0800, Dong, Eddie wrote: >> >> I mean once the frontend side driver post the buffers to the backend driver, the backend >driver will "immediately" use that buffers to compose skb or gro_frags and post them to the >assigned host NIC driver as receive buffers. In that case, if the backend driver recieves a >packet from the NIC that requires to do copy, it may be unable to find additional free guest >buffer because all of them are already used by the NIC driver. We have to reserve some guest >buffers for the possible copy even if the buffer address is not identified by original skb :( > >OK I see what you mean. Can you tell me how does Xiaohui's >previous patch-set deal with this problem? > >Thanks, >-- >Visit Openswan at http://www.openswan.org/ >Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx> >Home Page: http://gondor.apana.org.au/~herbert/ >PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
