Messages in this thread | | | Date | Thu, 27 May 2004 09:20:42 -0300 | From | Marcelo Tosatti <> | Subject | Re: [2.4.26] overcommit_memory documentation clarification |
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On Sun, May 09, 2004 at 11:49:41PM +0200, Vincent Lefevre wrote: > 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).
Right.
We should or merge Alan's strict-overcommit patches (from RH's tree), or fix the documentation.
Marc-Christian Petersen has a patch to fixup the documentation. - 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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