MESSAGE
| DATE | 2014-09-21 |
| FROM | Ruben Safir
|
| SUBJECT | Subject: [NYLXS - HANGOUT] Fwd: Re: realloc limitations
|
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Path: reader1.panix.com!panix!not-for-mail
From: ruben safir
Newsgroups: comp.lang.c
Subject: Re: realloc limitations
Date: Sun, 21 Sep 2014 04:00:46 +0000 (UTC)
Organization: PANIX Public Access Internet and UNIX, NYC
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On Wed, 17 Sep 2014 09:15:46 +0200, Noob wrote:
> On 10/09/2014 23:15, Keith Thompson wrote:
>
>> On some systems, both realloc and malloc can allocate address space
>> without allocationg physical memory, resulting in a failure later when
>> you try to access the memory that you *think* you've already allocated.
>
> [Straying off-topic]
>
> As an example, cf. the Linux man page for malloc:
>
> http://man7.org/linux/man-pages/man3/malloc.3.html
>
> By default, Linux follows an optimistic memory allocation strategy.
> This means that when malloc() returns non-NULL there is no guarantee
> that the memory really is available. In case it turns out that the
> system is out of memory, one or more processes will be killed by the
> OOM killer. For more information, see the description of
> /proc/sys/vm/overcommit_memory and /proc/sys/vm/oom_adj in proc(5),
> and the Linux kernel source file
> Documentation/vm/overcommit-accounting.
>
> http://man7.org/linux/man-pages/man5/proc.5.html
> http://lxr.free-electrons.com/source/Documentation/vm/overcommit-
accounting
>
> I disable overcommit on every system I come in contact with.
> I wish 'disabled' were the default.
>
> Regards.
thankyou for this very insightful and useful writeup
Ruben
--
The Coin Hangout: http://www.coinhangout.com/home
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