From: Eric Dumazet <eric.dumazet@gmail.com>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Govindarajulu Varadarajan <_govind@gmx.com>,
Alexander Duyck <alexander.h.duyck@redhat.com>,
davem@davemloft.net, netdev@vger.kernel.org, ssujith@cisco.com,
benve@cisco.com
Subject: Re: [PATCH net-next v3 1/2] net: implement dma cache skb allocator
Date: Wed, 11 Mar 2015 08:42:40 -0700 [thread overview]
Message-ID: <1426088560.11398.44.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <5500496E.1060701@gmail.com>
On Wed, 2015-03-11 at 06:55 -0700, Alexander Duyck wrote:
> That definitely helps but still leaves you open since a 257 byte packet
> would be consuming 9K in that case. Also standard flows with frames of
> 1514 still take a hard hit with a receive buffer size of 9K.
One possible way to deal with this would be to try to use order-2 pages,
(but not compound pages) but break them.
split_page(page, 2);
struct page *page0 = page;
struct page *page1 = page + 1;
struct page *page2 = page + 2;
struct page *page3 = page + 3;
if frame length <= 4096, attach page0 as skb first frag, and free
page[1-3]
If frame length <= 8192 bytes, driver can attach page0 & page1 to the
skb, and free page[2-3]
Otherwise, attach page[0-2] to skb and free page3
Not sure if buddy allocator will be pleased, but worth trying ?
next prev parent reply other threads:[~2015-03-11 15:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-10 17:43 [PATCH net-next v3 0/2] introduce dma frag allocation and reduce dma mapping Govindarajulu Varadarajan
2015-03-10 17:43 ` [PATCH net-next v3 1/2] net: implement dma cache skb allocator Govindarajulu Varadarajan
2015-03-10 20:33 ` Alexander Duyck
2015-03-11 8:57 ` Govindarajulu Varadarajan
2015-03-11 13:55 ` Alexander Duyck
2015-03-11 15:42 ` Eric Dumazet [this message]
2015-03-11 17:06 ` David Laight
2015-03-14 20:08 ` Ben Hutchings
2015-03-10 17:43 ` [PATCH net-next v3 2/2] enic: use netdev_dma_alloc Govindarajulu Varadarajan
2015-03-10 20:14 ` Alexander Duyck
2015-03-11 9:27 ` Govindarajulu Varadarajan
2015-03-11 14:00 ` Alexander Duyck
2015-03-11 17:34 ` David Laight
2015-03-11 17:51 ` Alexander Duyck
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