Bug 9893 (HIMEM4G)

Summary:	When CONFIG_HIMEM4G is set, the kernel only identifies 2GB of the 4GB the bios identifies
Product:	Memory Management	Reporter:	Andrew J Barbaccia III (andrew)
Component:	MTTR	Assignee:	Andrew Morton (akpm)
Status:	REJECTED DOCUMENTED
Severity:	normal	CC:	protasnb
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.24	Subsystem:
Regression:	---	Bisected commit-id:
Attachments:	dmesg /proc/mtrr

Description Andrew J Barbaccia III 2008-02-05 07:43:27 UTC

Latest working kernel version: None
Earliest failing kernel version: All
Distribution: Ubuntu Hardy
Hardware Environment: 4GB RAM, Intel Core2 6600
Software Environment: 
Problem Description: /proc/meminfo only displays 2GB of mem while it should show the full 4GB. When compiled with CONFIG_HIMEM64G=y, the full 4GB of mem is displayed.

Steps to reproduce: Compile the kernel with CONFIG_HIMEM4G=y on a system with 4GB of ram.

Comment 1 Natalie Protasevich 2008-05-03 17:06:30 UTC

Can you attach your dmesg and /proc/mtrr please.

Comment 2 Andrew J Barbaccia III 2008-05-03 17:32:16 UTC

Created attachment 16015 [details]
dmesg

Comment 3 Andrew J Barbaccia III 2008-05-03 17:32:29 UTC

Created attachment 16016 [details]
/proc/mtrr

Comment 4 Natalie Protasevich 2008-06-01 20:54:37 UTC

OK, this was with HIGHMEM64 support, how about the same without it for comparison. It would also help to have /proc/meminfo for both cases.

Comment 5 Alan 2008-09-25 08:02:12 UTC

Your bios is mapping 2GB of your RAM above the 4GB boundary so this is expected behaviour.