mm, x86: add support for PUD-sized transparent hugepages

The current transparent hugepage code only supports PMDs.  This patch
adds support for transparent use of PUDs with DAX.  It does not include
support for anonymous pages.  x86 support code also added.

Most of this patch simply parallels the work that was done for huge
PMDs.  The only major difference is how the new ->pud_entry method in
mm_walk works.  The ->pmd_entry method replaces the ->pte_entry method,
whereas the ->pud_entry method works along with either ->pmd_entry or
->pte_entry.  The pagewalk code takes care of locking the PUD before
calling ->pud_walk, so handlers do not need to worry whether the PUD is
stable.

[dave.jiang@intel.com: fix SMP x86 32bit build for native_pud_clear()]
  Link: http://lkml.kernel.org/r/148719066814.31111.3239231168815337012.stgit@djiang5-desk3.ch.intel.com
[dave.jiang@intel.com: native_pud_clear missing on i386 build]
  Link: http://lkml.kernel.org/r/148640375195.69754.3315433724330910314.stgit@djiang5-desk3.ch.intel.com
Link: http://lkml.kernel.org/r/148545059381.17912.8602162635537598445.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Alexander Kapshuk <alexander.kapshuk@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
index 033fc7bbcefa..a49b3259cad7 100644
--- a/include/linux/pfn_t.h
+++ b/include/linux/pfn_t.h
@@ -90,6 +90,13 @@ static inline pmd_t pfn_t_pmd(pfn_t pfn, pgprot_t pgprot)
 {
 	return pfn_pmd(pfn_t_to_pfn(pfn), pgprot);
 }
+
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+static inline pud_t pfn_t_pud(pfn_t pfn, pgprot_t pgprot)
+{
+	return pfn_pud(pfn_t_to_pfn(pfn), pgprot);
+}
+#endif
 #endif
 
 #ifdef __HAVE_ARCH_PTE_DEVMAP
@@ -106,5 +113,10 @@ static inline bool pfn_t_devmap(pfn_t pfn)
 }
 pte_t pte_mkdevmap(pte_t pte);
 pmd_t pmd_mkdevmap(pmd_t pmd);
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
+	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
+pud_t pud_mkdevmap(pud_t pud);
 #endif
+#endif /* __HAVE_ARCH_PTE_DEVMAP */
+
 #endif /* _LINUX_PFN_T_H_ */