Messages in this thread | | | Date | Sun, 9 May 2004 23:49:41 +0200 | From | Vincent Lefevre <> | Subject | Re: [2.4.26] overcommit_memory documentation clarification |
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On 2004-05-09 14:06:11 -0700, Paul Jackson wrote: > Vincent wrote: > > NULL == (void *) 0 and NULL == 0 must be true > Yes - NULL is compares equal to both (void *)0 and 0. > No - not necessarily the _same_ value - one could be > on a system with 32 bit ints, 64 bit pointers, for example.
And so?
> > The goal of malloc is to reserve memory. > It's up to the kernel whether sbrk (used by malloc to > obtain virtual address space) reserves memory or not.
More old_mmap than brk (BTW, I forgot to say that this was on an x86 machine, I don't know if this matters...).
> Check out: > /proc/sys/vm/overcommit_memory > Documentation/sysctl/vm.txt - overcommit_memory
But the documentation is wrong (on an official 2.4.26 kernel). It seems that there is no way to get malloc() always return 0 when there isn't enough memory, even in simple cases (see my program posted in the first message).
-- Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/> 100% validated (X)HTML - Acorn / RISC OS / ARM, free software, YP17, Championnat International des Jeux Mathématiques et Logiques, etc. Work: CR INRIA - computer arithmetic / SPACES project at LORIA - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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