Re: [PATCH][RFC] splice support

From: Jens Axboe
Date: Thu Mar 30 2006 - 09:35:05 EST


On Thu, Mar 30 2006, KAMEZAWA Hiroyuki wrote:
> On Thu, 30 Mar 2006 15:53:46 +0200
> Jens Axboe <axboe@xxxxxxx> wrote:
>
> > > I don't know about sendfile() but this looks client can hold server's
> > > memory, when server uses sendfile() 64k/conn.
> >
> > You mean when the server uses splice, 64kb (well 16 pages actually) /
> > connection? That's a correct observation, I wouldn't think that pinning
> > that small a number of pages is likely to cause any issues. At least I
> > can think of much worse pinning by just doing IO :-)
> >
> My point is consumer can sleep forever and pages are pinnded forever.
> And people who use splice() will not notice they are pinning pages.
>
> But as you say, it's not problem in usual situation.
> Maybe I'm too pessimistic how my cusomers play with Linux ;)

It's a valid concern, however as mentioned there's a number of ways in
which a user can pin memory already. Perhaps this general problem should
be capped elsewhere?

--
Jens Axboe

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