On Mon, 2013-12-23 at 16:12 +0800, Jason Wang wrote: > On 12/17/2013 08:16 AM, Michael Dalton wrote: > > The virtio-net driver currently uses netdev_alloc_frag() for GFP_ATOMIC > > mergeable rx buffer allocations. This commit migrates virtio-net to use > > per-receive queue page frags for GFP_ATOMIC allocation. This change unifies > > mergeable rx buffer memory allocation, which now will use skb_refill_frag() > > for both atomic and GFP-WAIT buffer allocations. > > > > To address fragmentation concerns, if after buffer allocation there > > is too little space left in the page frag to allocate a subsequent > > buffer, the remaining space is added to the current allocated buffer > > so that the remaining space can be used to store packet data. > > > > Signed-off-by: Michael Dalton <[email protected]> > > --- > > drivers/net/virtio_net.c | 69 > > ++++++++++++++++++++++++++---------------------- > > 1 file changed, 38 insertions(+), 31 deletions(-) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index c51a988..d38d130 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -78,6 +78,9 @@ struct receive_queue { > > /* Chain pages by the private ptr. */ > > struct page *pages; > > > > + /* Page frag for GFP_ATOMIC packet buffer allocation. */ > > + struct page_frag atomic_frag; > > + > > /* RX: fragments + linear part + virtio header */ > > struct scatterlist sg[MAX_SKB_FRAGS + 2]; > > > > @@ -127,9 +130,9 @@ struct virtnet_info { > > struct mutex config_lock; > > > > /* Page_frag for GFP_KERNEL packet buffer allocation when we run > > - * low on memory. > > + * low on memory. May sleep. > > */ > > - struct page_frag alloc_frag; > > + struct page_frag sleep_frag; > > Any reason to use two different page_frag consider only > skb_page_frag_refill() is used?
One is used under process context, where preemption and GFP_KERNEL are allowed. One is used from softirq context and GFP_ATOMIC. You cant share a common page_frag. Acked-by: Eric Dumazet <[email protected]> _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
