From: Nicolas Pitre <nico@fluxnic.net>
Date: Tue, 05 Oct 2010 19:06:05 GMT
Subject: Re: large files and low memory
Message-ID: <alpine.LFD.2.00.1010051504530.3107@xanadu.home>
In-Reply-To: <20101005005003.GA2768@nibiru.local>

On Tue, 5 Oct 2010, Enrico Weigelt wrote:

> * Shawn Pearce <spearce@spearce.org> wrote:
> 
> > The mmap() isn't the problem.  Its the allocation of a buffer that is
> > larger than the file in order to hold the result of deflating the file
> > before it gets written to disk.  
> > When the file is bigger than physical memory, the kernel has to
> > page in parts of the file as well as swap in and out parts of
> > that allocated buffer to hold the deflated file.
> 
> What are the access pattern of these memory areas ?

Perfectly linear.

> Perhaps madvise() could help ?

Perhaps.


Nicolas