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From: Nicholas Mc Guire <mcguire@lzu.edu.cn>
To: Joe <longapple@gmail.com>
Cc: Glynn Clements <glynn@gclements.plus.com>,
	linux-c-programming@vger.kernel.org
Subject: Re: strange stack limit behavior when allocating more than 2GB mem on 32bit machine
Date: Fri, 21 Aug 2009 11:37:50 +0200	[thread overview]
Message-ID: <20090821093750.GA16299@opentech.at> (raw)
In-Reply-To: <56b13acf0908210212t5b6921f5h4c224efa21d2f067@mail.gmail.com>

On Fri, 21 Aug 2009, Joe wrote:

> Hi Glynn,
> 
> Thanks for your explanation. However as you can see, I got 2GB mem and
> ~10GB swap, totally 12GB.
> 
> With ulimit -s 10240(KB), I can allocate 2.5GB, I guess these are in
> swap, right?
> With ulimit -s unlimited, as you said, kernel reserved 1GB, stack
> reserved 2GB, there are still 12-3=9GB left??
> 
> Why did malloc failed, instead of allocating this abundant swap space?
>
initializing 12GB swap will not change the address space limit unless you
enabled high-memory support in the kernel (CONFIG_HIGHMEM64G=y in your .config)
the limit is not the physical memory (RAM+swap) but the 32bit address space.

hofrat

  reply	other threads:[~2009-08-21  9:37 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-21  3:47 strange stack limit behavior when allocating more than 2GB mem on 32bit machine Joe
2009-08-21  6:58 ` Glynn Clements
2009-08-21  9:12   ` Joe
2009-08-21  9:37     ` Nicholas Mc Guire [this message]
2009-08-21 10:33       ` Michał Nazarewicz
2009-08-21  9:38     ` Michał Nazarewicz
2009-08-21 11:04       ` Joe
2009-08-21 12:21         ` Michał Nazarewicz
2009-08-22  7:44         ` Glynn Clements
2009-08-21  7:09 ` Michał Nazarewicz

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