From: Matthew Wilcox <willy@infradead.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: davem@davemloft.net, hch@lst.de, netdev@vger.kernel.org
Subject: Re: [PATCH 0/5] Beginnings of skb_frag -> bio_vec conversion
Date: Wed, 1 May 2019 02:44:37 -0700 [thread overview]
Message-ID: <20190501094437.GA3698@bombadil.infradead.org> (raw)
In-Reply-To: <639880c6-5703-857c-8a70-82fbb5a90238@gmail.com>
On Wed, May 01, 2019 at 04:14:41AM -0400, Eric Dumazet wrote:
> On 4/30/19 9:17 PM, Matthew Wilcox wrote:
> > It turns out there's a lot of accessors for the skb_frag, which would
> > make this conversion really easy if some drivers didn't bypass them.
> > This is what I've done so far; my laptop's not really beefy enough to
> > cope with changing skbuff.h too often ;-)
>
> I guess the missing part here is the "why" all this is done ?
>
> 32 bit hosts will have bigger skb_shared_info and this impacts sk_rcvbuf and sk_sndbuf limits.
>
> 17 * 4 are 68 extra bytes per skb.
Right. The plan is to replace get_user_pages() with get_user_bvec(). If
userspace has physically consecutive pages (and often it will, even when
not using THP), we can reduce the number of elements in the array at the
start. So each skb_frag_t is larger, but you'll have fewer of them for a
large I/O. Obviously this particularly benefits THP.
prev parent reply other threads:[~2019-05-01 9:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-01 4:17 [PATCH 0/5] Beginnings of skb_frag -> bio_vec conversion Matthew Wilcox
2019-05-01 4:17 ` [PATCH 1/5] net: Increase the size of skb_frag_t Matthew Wilcox
2019-05-01 4:17 ` [PATCH 2/5] net: Reorder the contents " Matthew Wilcox
2019-05-01 4:17 ` [PATCH 3/5] net: Include bvec.h in skbuff.h Matthew Wilcox
2019-05-01 4:17 ` [PATCH 4/5] net: Use skb accessors for skb->page Matthew Wilcox
2019-05-02 10:21 ` kbuild test robot
2019-05-01 4:17 ` [PATCH 5/5] net: Rename skb_frag page to bv_page Matthew Wilcox
2019-05-01 8:14 ` [PATCH 0/5] Beginnings of skb_frag -> bio_vec conversion Eric Dumazet
2019-05-01 9:44 ` Matthew Wilcox [this message]
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