Messages in this thread | | | Date | Tue, 15 Jan 2013 18:28:49 -0800 | From | "H. Peter Anvin" <> | Subject | Re: Use of memmap= to forcibly recover memory in 3GB-4GB range - is this safe? |
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On 01/15/2013 05:47 PM, Alex Villacís Lasso wrote: > > The system boots, apparently normally, and I can see the additional > "memory" in all system reports. However, I cannot quite shake the > feeling that this "memory" might be in fact an illusion, and an attempt > to use it will wrap around to the bottom of the memory and corrupt > anything there. Or worse. > > Some tests that I have tried: > 1) I have tried to occupy as much memory as possible, by starting two > virtual machines, plus one instance of eclipse, a browser, and a > bittorrent client, while running the graphical desktop. I have seen the > free memory (as reported by "top") fall to under 200 Mb with no apparent > instability, so this should prove that the extra memory is real, right? > 2) I have recompiled the kernel to support the memtest parameter. When > using it, the extra memory segment appears to be as healthy as other > areas of memory. However this might only mean that it is wrapping into > healthy low RAM. > > Is my reasoning sane? Is there a way to know, once and for all, whether > the extra "memory" is real and safe to use or not?
Maybe you can get memtest86+ to test this phantom memory? But yes, it does sound like a BIOS bug.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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