Messages in this thread | | | Date | Wed, 26 Nov 2003 14:20:58 +0100 | From | "Ihar 'Philips' Filipau" <> | Subject | Re: 2.2/2.4/2.6 VMs: do malloc() ever return NULL? |
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Richard B. Johnson wrote: > >> May I ask you one question? Did you were ever doing once graceful >>failure of application under memory pressure? Looks like not. >> > > Yes. I'm in the business of making embedded systems that cannot > fail. And they do not fail. They allocate memory once during > startup and they never fail or exit. They also do not use malloc() > but that's not an issue. >
So what do you use then in user space to reliably allocate memory?
As to me - memory is a resource. Is it virtual or is it physical - it is still resource. And I need to allocate part of this resource.
malloc() uses brk() inside. But brk() is "implementation details". I honestly do not care about them - I just want to be sure that what ever resource I have allocated - I can use it afterwards until I shall free it. POSIX even doesn't mention brk() BTW.
If you can hint me any other method to allocate memory without surprises - I will really appreciate.
> > >> Memory pools used by applications exactly to make grace error >>handling under memory pressure - but it looks like this stuff under >>Linux gets no testing at all. And default settings could make from >>simple bug complete disaster. >> > > Wrong. It is up to the application to allocate and deallocate > dynamic memory properly. FYI, you can always look at /proc/meminfo > yourself instead of expecting malloc() to do it for you. You only > need to look at swap. >
Embedded? with swap?!? What you have smoken?! - take me to your dealer!-)))
And btw Rik already gave me answer - 2.6 kernels + /proc/sys/vm/overcommit_memory == 2. Work charmfully ;-) Enjoy.
-- 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
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