netdev - Re: [PATCH][RFC] network splice receive

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Date:	Fri, 8 Jun 2007 18:57:25 +0400
From:	Evgeniy Polyakov <johnpol@....mipt.ru>
To:	Jens Axboe <jens.axboe@...cle.com>
Cc:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH][RFC] network splice receive

On Fri, Jun 08, 2007 at 04:14:52PM +0200, Jens Axboe (jens.axboe@...cle.com) wrote:
> Here's a start, for the splice side at least of storing a buf-private
> entity with the ops.

:) I tested the same implementation, but I put skb pointer into
page->private. My approach is not correct, since the same page can hold
several objects, so if there are several splicers, this will scream.
I've tested your patch on top of splice-net branch, here is a result:

[   44.798853] Slab corruption: skbuff_head_cache start=ffff81003b726668, len=192
[   44.806148] Redzone: 0x9f911029d74e35b/0x9f911029d74e35b.
[   44.811598] Last user: [<ffffffff803699fd>](kfree_skbmem+0x7a/0x7e)
[   44.818012] 0b0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b a5
[   44.824889] Prev obj: start=ffff81003b726590, len=192
[   44.829985] Redzone: 0xd84156c5635688c0/0xd84156c5635688c0.
[   44.835604] Last user: [<ffffffff8036a22c>](__alloc_skb+0x40/0x13f)
[   44.842010] 000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   44.848896] 010: 20 58 7e 3b 00 81 ff ff 00 00 00 00 00 00 00 00
[   44.855772] Next obj: start=ffff81003b726740, len=192
[   44.860868] Redzone: 0x9f911029d74e35b/0x9f911029d74e35b.
[   44.866314] Last user: [<ffffffff803699fd>](kfree_skbmem+0x7a/0x7e)
[   44.872721] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
[   44.879597] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b

I will try some things for the nearest 30-60 minutes, and then will move to
canoe trip until thuesday, so will not be able to work on this idea.

-- 
	Evgeniy Polyakov
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