When vm.overcommit_memory = 2 and there appears to be about 2M of memory readily available and about 12M of memory allocated to pagecache (this is info gathered from /proc/meminfo) , a call to malloc(5000000) returns NULL. I would have expected that somehow, the call to malloc(5000000) would request the memory in pagecache to be released for use by the app.
-----Original Message----- From: Robert Hancock [mailto:[EMAIL PROTECTED] Sent: Tuesday, April 10, 2007 10:15 AM To: Mouawad, Tony Cc: linux-kernel@vger.kernel.org Subject: Re: Help Understanding Linux memory management Mouawad, Tony wrote: > Hello, > > I've been a MS Windows based programmer for a very long time and was > recently tossed in an environment where I am developing embedded apps on > the m68k / Linux platform. That makes me a Linux newbie. I started > asking a few questions on various IRC channels and was directed to this > group. So, I will start asking: > > These are questions derived from observations on the MCF 5475 CPU > running Linux 2.6.10 built for the m68k platform. Disk swapping is > disabled. > > 1) When physical memory runs low, the memory manager will try to use > memory currently allocated to the pagecache. Is this true? Yes. > 2) When vm.overcommit_memory = 2 (overcommit disabled), and memory runs > low, it appears that the memory manager does not try to use memory > currently allocated to pagecache. Is this true? Shouldn't be, what makes you think this is happening? > 3) Is it possible to disable the pagecache? Not as far as I know, it's unlikely this would be of any benefit. -- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from [EMAIL PROTECTED] Home Page: http://www.roberthancock.com/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
