Re: 2.2/2.4/2.6 VMs: do malloc() ever return NULL?

Ihar 'Philips' Filipau
2003-11-26T10:30:31Z

Rik van Riel wrote:
> On Tue, 25 Nov 2003, Ihar 'Philips' Filipau wrote:
>
>
>>># echo 2 > /proc/sys/vm/overcommit_memory
>>>
>>>Then try again.
>>
>> What do you know what is not said in docs?
>> What '2' means?
>
> Strict non-overcommit mode. You can allocate as much
> non-file-backed virtual memory as will fit in swap,
> plus /proc/sys/vm/overcommit_percentage worth of memory.
>

[ s/overcommit_percentage/overcommit_ratio/ ]

Thanks! On 2.6 it works as expected. Test with two concurrent memory
allocations took some time, but both apps stops exactly when memory was
depleted. Great.

Did rmap has something todo with this?
As I see from implementation of do_mmap_pgoff() - it changed from 2.4
to 2.6 - but there are a lot of common things.
If I will do dumb back port of this check to 2.4 - do you think it
will work? 2.4->2.6 memory accounting changed?
I didn't found this check in your rmap patches for 2.4.22. (btw
thanks for keeping them up-to-date).

--
Ihar 'Philips' Filipau / with best regards from Saarbruecken.
-- _ _ _
Because the kernel depends on it existing. "init" |_|*|_|
literally _is_ special from a kernel standpoint, |_|_|*|
because its' the "reaper of zombies" (and, may I add, |*|*|*|
that would be a great name for a rock band).
-- Linus Torvalds