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Date: Fri, 14 Oct 2011 05:33:51 +0200 From: Eric Dumazet <eric.dumazet@...il.com> To: David Miller <davem@...emloft.net> Cc: netdev@...r.kernel.org Subject: Re: [PATCH net-next] niu: fix skb truesize underestimation Le jeudi 13 octobre 2011 à 22:26 -0400, David Miller a écrit : > From: Eric Dumazet <eric.dumazet@...il.com> > Date: Fri, 14 Oct 2011 00:39:27 +0200 > > > Add a 'truesize' argument to niu_rx_skb_append(), filled with rcr_size > > by the caller to properly account frag sizes in skb->truesize > > > > Signed-off-by: Eric Dumazet <eric.dumazet@...il.com> > > --- > > Please David double check this one as I am not very familiar with NIU > > code. Thanks ! > > It looks perfect! And if it's not I'll soon find out :-) > Thanks ! By the way, I noticed NIU uses a get_page() every time a chunk is attached to a skb (only the last chunk of a page is given without the get_page()) So I thought it might incur false sharing if a previous SKB using a chunk from same page is processed by another CPU. But then I see you also do in niu_rbr_add_page(), rigth after the alloc_page(), the thing I was thinking to add : (perform all needed get_page() in a single shot) atomic_add(rp->rbr_blocks_per_page - 1, &compound_head(page)->_count); So I am a bit lost here. Arent you doing too many page->_count increases ? Thanks ! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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