arm64/mm: enable HugeTLB migration for contiguous bit HugeTLB pages

Let arm64 subscribe to the previously added framework in which
architecture can inform whether a given huge page size is supported for
migration.  This just overrides the default function
arch_hugetlb_migration_supported() and enables migration for all
possible HugeTLB page sizes on arm64.

With this, HugeTLB migration support on arm64 now covers all possible
HugeTLB options.

          CONT PTE    PMD    CONT PMD    PUD
          --------    ---    --------    ---
  4K:        64K      2M        32M      1G
  16K:        2M     32M         1G
  64K:        2M    512M        16G

Link: http://lkml.kernel.org/r/1545121450-1663-6-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index fb660987545598494ecf9724c6140d4c35c3ccfa..c6a07a3b433e3d09b9b0ff08ed53a881470b6508 100644 (file)
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -20,6 +20,11 @@
 
 #include <asm/page.h>
 
+#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
+#define arch_hugetlb_migration_supported arch_hugetlb_migration_supported
+extern bool arch_hugetlb_migration_supported(struct hstate *h);
+#endif
+
 #define __HAVE_ARCH_HUGE_PTEP_GET
 static inline pte_t huge_ptep_get(pte_t *ptep)
 {

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 28cbc22d7e3052a836b1993c6e96327eace00e6e..6b4a47b3adf4d8e186d96e0b53bd564a353797cb 100644 (file)
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -27,6 +27,26 @@
 #include <asm/tlbflush.h>
 #include <asm/pgalloc.h>
 
+#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
+bool arch_hugetlb_migration_supported(struct hstate *h)
+{
+       size_t pagesize = huge_page_size(h);
+
+       switch (pagesize) {
+#ifdef CONFIG_ARM64_4K_PAGES
+       case PUD_SIZE:
+#endif
+       case PMD_SIZE:
+       case CONT_PMD_SIZE:
+       case CONT_PTE_SIZE:
+               return true;
+       }
+       pr_warn("%s: unrecognized huge page size 0x%lx\n",
+                       __func__, pagesize);
+       return false;
+}
+#endif
+
 int pmd_huge(pmd_t pmd)
 {
        return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);