Messages in this thread | | | Subject | Re: [kernel-reviewers] a small code review (2414483) Automated g4 rollback of changelist 2396062. | From | Andi Kleen <> | Date | 26 Apr 2006 20:24:13 +0200 |
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Martin Bligh <mbligh@google.com> writes:
> Tim Hockin wrote: > > On Wed, Apr 26, 2006 at 10:12:14AM -0700, Ken Harrenstien wrote: > > > >>That doesn't work because IIRC it only reports the amount of memory > >>the kernel has been told (eg via "mem=") to manage in a certain sense, > >>not how much is actually physically available. > >> > >>The I2 netboot kernel would really REALLY like some exported /proc > >>values that accurately report physical memory (if nothing else, the > >>number of DIMMs and their sizes). It has to figure this out in order > >>to install the proper kernel with proper LILO command-line args. > > The kernel can't really know how much memory is in the system without > > getting chipset-specific. > > MTRR is a good way to hazard a guess, and will probably be right, > > but as > > you indicated, BIOS vendors have historically been REALLY bad about > > MTRRs. Better now, but bad a few years ago. > > SMBIOS (on our boards) *does* accurately report the number of DIMMS > > and > > their sizes (and more!). But it only works on Google BIOS.
Actually quite a lot of SMBIOS report DIMMs more or less correct. It works even on my laptop.
I implemented support for it in the latest mcelog (--dmi). Not all and a few big names screw it up (in particular the mappings from address range to interleave set). But overall it looks surprisingly good so far.
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