some BIOS like to use continus MTRR layout, and X driver can not add
WB entries for graphical cards when 4g or more RAM installed.
the patch will change MTRR to discrete.
mtrr_chunk_size= could be used to have smaller continuous block to hold holes.
default is 256m, could be set according to size of graphics card memory.
mtrr_gran_size= could be used to send smallest mtrr block to avoid run out of MTRRs
v2: fix -1 for UC checking
v3: default to disable, and need use enable_mtrr_cleanup to enable this feature
skip the var state change warning.
remove next_basek in range_to_mtrr()
v4: correct warning mask.
v5: CONFIG_MTRR_SANITIZER
v6: fix 1g, 2g, 512 aligment with extra hole
v7: gran_sizek to prevent running out of MTRRs.
v8: fix hole_basek caculation caused when removing next_basek
gran_sizek using when basek is 0.
need to apply
[PATCH] x86: fix trimming e820 with MTRR holes.
right after this one.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
mtrr.h was included everywhere needed. Fixes the following sparse
warnings. Also, the return types in the extern definitions were
incorrect.
arch/x86/kernel/cpu/mtrr/amd.c:113:12: warning: symbol 'amd_init_mtrr' was not declared. Should it be static?
arch/x86/kernel/cpu/mtrr/cyrix.c:268:12: warning: symbol 'cyrix_init_mtrr' was not declared. Should it be static?
arch/x86/kernel/cpu/mtrr/centaur.c:218:12: warning: symbol 'centaur_init_mtrr' was not declared. Should it be static?
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
On some machines, buggy BIOSes don't properly setup WB MTRRs to cover all
available RAM, meaning the last few megs (or even gigs) of memory will be
marked uncached. Since Linux tends to allocate from high memory addresses
first, this causes the machine to be unusably slow as soon as the kernel
starts really using memory (i.e. right around init time).
This patch works around the problem by scanning the MTRRs at boot and
figuring out whether the current end_pfn value (setup by early e820 code)
goes beyond the highest WB MTRR range, and if so, trimming it to match. A
fairly obnoxious KERN_WARNING is printed too, letting the user know that
not all of their memory is available due to a likely BIOS bug.
Something similar could be done on i386 if needed, but the boot ordering
would be slightly different, since the MTRR code on i386 depends on the
boot_cpu_data structure being setup.
This patch fixes a bug in the last patch that caused the code to run on
non-Intel machines (AMD machines apparently don't need it and it's untested
on other non-Intel machines, so best keep it off).
Further enhancements and fixes from:
Yinghai Lu <Yinghai.Lu@Sun.COM>
Andi Kleen <ak@suse.de>
Signed-off-by: Jesse Barnes <jesse.barnes@intel.com>
Tested-by: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This is a janitorish patch to 1) remove private TRUE/FALSE #def's in
favor of using the standard enum from linux/stddef.h and 2) switch the
variables holding those values to type 'bool' (from linux/types.h)
since it both seems more appropriate and allows for potentially better
optimization.
As a truly minor aside, I removed a couple of comments documenting
a 'do_safe' parameter that seems to no longer exist.
Signed-off-by: Paul Jimenez <pj@place.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
