This patchset adds support of Write-Through (WT) mapping on x86. The study below shows that using WT mapping may be useful for non-volatile memory. http://www.hpl.hp.com/techreports/2012/HPL-2012-236.pdf This patchset applies on top of the Juergen's patchset below, which provides the basis of the PAT management. https://lkml.org/lkml/2014/10/27/71 All new/modified interfaces have been tested. v4: - Added set_memory_wt() by adding WT support of regular memory. v3: - Dropped the set_memory_wt() patch. (Andy Lutomirski) - Refactored the !pat_enabled handling. (H. Peter Anvin, Andy Lutomirski) - Added the picture of PTE encoding. (Konrad Rzeszutek Wilk) v2: - Changed WT to use slot 7 of the PAT MSR. (H. Peter Anvin, Andy Lutomirski) - Changed to have conservative checks to exclude all Pentium 2, 3, M, and 4 families. (Ingo Molnar, Henrique de Moraes Holschuh, Andy Lutomirski) - Updated documentation to cover WT interfaces and usages. (Andy Lutomirski, Yigal Korman) --- Toshi Kani (7): 1/7 x86, mm, pat: Set WT to PA7 slot of PAT MSR 2/7 x86, mm, pat: Change reserve_memtype() to handle WT 3/7 x86, mm, asm-gen: Add ioremap_wt() for WT 4/7 x86, mm, pat: Add pgprot_writethrough() for WT 5/7 x86, mm, pat: Refactor !pat_enable handling 6/7 x86, mm, asm: Add WT support to set_page_memtype() 7/7 x86, mm: Add set_memory_wt() for WT --- Documentation/x86/pat.txt | 13 ++- arch/x86/include/asm/cacheflush.h | 34 ++++--- arch/x86/include/asm/io.h | 2 + arch/x86/include/asm/pgtable_types.h | 3 + arch/x86/mm/init.c | 6 +- arch/x86/mm/iomap_32.c | 18 ++-- arch/x86/mm/ioremap.c | 26 +++++- arch/x86/mm/pageattr.c | 61 ++++++++++-- arch/x86/mm/pat.c | 174 +++++++++++++++++++++-------------- include/asm-generic/io.h | 4 + include/asm-generic/iomap.h | 4 + include/asm-generic/pgtable.h | 4 + 12 files changed, 233 insertions(+), 116 deletions(-) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>