Le samedi 05 juin 2010 à 18:14 +0800, xiaohui.xin@xxxxxxxxx a écrit : > From: Xin Xiaohui <xiaohui.xin@xxxxxxxxx> > > If buffer is external, then use the callback to destruct > buffers. > > Signed-off-by: Xin Xiaohui <xiaohui.xin@xxxxxxxxx> > Signed-off-by: Zhao Yu <yzhao81new@xxxxxxxxx> > Reviewed-by: Jeff Dike <jdike@xxxxxxxxxxxxxxx> > --- > net/core/skbuff.c | 11 +++++++++++ > 1 files changed, 11 insertions(+), 0 deletions(-) > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 37587f0..418457c 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -385,6 +385,11 @@ static void skb_clone_fraglist(struct sk_buff *skb) > > static void skb_release_data(struct sk_buff *skb) > { > + /* check if the skb has external buffers, we have use destructor_arg > + * here to indicate > + */ > + struct skb_external_page *ext_page = skb_shinfo(skb)->destructor_arg; > + Oh well. This is v7 of your series, and nobody complained yet ? This is a new cache miss on a _critical_ path. > if (!skb->cloned || > !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, > &skb_shinfo(skb)->dataref)) { > @@ -397,6 +402,12 @@ static void skb_release_data(struct sk_buff *skb) > if (skb_has_frags(skb)) > skb_drop_fraglist(skb); > > + /* if the skb has external buffers, use destructor here, > + * since after that skb->head will be kfree, in case skb->head > + * from external buffer cannot use kfree to destroy. > + */ Why not deferring here the access to skb_shinfo(skb)->destructor_arg ? > + if (dev_is_mpassthru(skb->dev) && ext_page && ext_page->dtor) > + ext_page->dtor(ext_page); > kfree(skb->head); > } > } if (dev_is_mpassthru(skb->dev)) { struct skb_external_page *ext_page = skb_shinfo(skb)->destructor_arg; if (ext_page && ext_page->dtor) ext_page->dtor(ext_page); } destructor_arg should me moved before frags[] if you really want to use it. diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index bf243fc..b136d90 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -202,10 +202,11 @@ struct skb_shared_info { */ atomic_t dataref; - skb_frag_t frags[MAX_SKB_FRAGS]; /* Intermediate layers must ensure that destructor_arg * remains valid until skb destructor */ void * destructor_arg; + + skb_frag_t frags[MAX_SKB_FRAGS]; }; /* We divide dataref into two halves. The higher 16 bits hold references -- 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