diff options
| author | Eric Anholt <eric@anholt.net> | 2009-01-23 14:14:21 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-01-26 11:14:27 +0100 |
| commit | ef5fa0ab24b87646c7bc98645acbb4b51fc2acd4 (patch) | |
| tree | 212ee811a6271eb77e887d4f63817c01606ae8a2 /arch/x86/kernel/cpu | |
| parent | e1b4d1143651fb3838be1117785b6e0386fa151f (diff) | |
x86: work around PAGE_KERNEL_WC not getting WC in iomap_atomic_prot_pfn.
In the absence of PAT, PAGE_KERNEL_WC ends up mapping to a memory type that
gets UC behavior even in the presence of a WC MTRR covering the area in
question. By swapping to PAGE_KERNEL_UC_MINUS, we can get the actual
behavior the caller wanted (WC if you can manage it, UC otherwise).
This recovers the 40% performance improvement of using WC in the DRM
to upload vertex data.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel/cpu')
0 files changed, 0 insertions, 0 deletions