linux-kernel - Re: Pipe buffers' limit of 16 * 4K

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Date:	Thu, 29 May 2008 12:46:56 -0300
From:	"Fausto Richetti Blanco" <fausto.blanco@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	miquels@...tron.nl, riel@...hat.com, jengelh@...ozas.de,
	fausto.blanco@...il.com
Subject: Re: Pipe buffers' limit of 16 * 4K

On Thu, May 29, 2008 at 11:36 AM, Jan Engelhardt <jengelh@...ozas.de> wrote:
>
> On Thursday 2008-05-29 15:19, Miquel van Smoorenburg wrote:
>>On Thu, 2008-05-29 at 10:00 -0300, Fausto Richetti Blanco wrote:
>>
>>Why not use a socketpair() instead of a pipe(). You can adjust the size
>>with setsockopt SO_SNDBUF/SO_RCVBUF (see man socket(7))
>
> Nah, if there's lots of POST requests, and a large buffer for
> each of it, you may end up running into allocation failures.

Well, I think it's an alternative.. A good one, indeed :)

However, I implemented it and run into the limit of /proc/sys/net/core/wmem_max

Do you guys think it's a big impact to change this to a higher value ?
It's meant to only affect the MAX window size, right ? Does it have
any other way of changing this limit (by process or by user, for
exemple) ?

The strange thing here is that setsockopt doesn't fail if I change the
size of the buffer to anything higher than
/proc/sys/net/core/wmem_max. It doesn't work either :)

The implementation with socketpair, adjusting
/proc/sys/net/core/wmem_max, seems good to me. However, I still think
dynamic buffers for pipes a good idea.
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