1. 24 Mar, 2020 3 commits
    • Thomas Hellstrom (VMware)'s avatar
      mm: Split huge pages on write-notify or COW · 327e9fd4
      Thomas Hellstrom (VMware) authored
      The functions wp_huge_pmd() and wp_huge_pud() currently relies on the
      huge_fault() callback to split huge page table entries if needed.
      However for module users that requires export of the split_huge_xxx()
      functionality which may be undesired. Instead split pre-existing huge
      page-table entries on VM_FAULT_FALLBACK return.
      
      We currently only do COW and write-notify on the PTE level, so if the
      huge_fault() handler returns VM_FAULT_FALLBACK on wp faults,
      split the huge pages and page-table entries. Also do this for huge PUDs
      if there is no huge_fault() handler and the vma is not anonymous, similar
      to how it's done for PMDs.
      
      Note that fs/dax.c still does the splitting in the huge_fault() handler,
      but as huge_fault() A follow-up patch can remove the dax.c split_huge_pmd()
      if needed.
      
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Ralph Campbell <rcampbell@nvidia.com>
      Cc: "Jérôme Glisse" <jglisse@redhat.com>
      Cc: "Christian König" <christian.koenig@amd.com>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Signed-off-by: default avatarThomas Hellstrom (VMware) <thomas_os@shipmail.org>
      Acked-by: default avatarChristian König <christian.koenig@amd.com>
      Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      327e9fd4
    • Thomas Hellstrom (VMware)'s avatar
      mm: Introduce vma_is_special_huge · 2484ca9b
      Thomas Hellstrom (VMware) authored
      For VM_PFNMAP and VM_MIXEDMAP vmas that want to support transhuge pages
      and -page table entries, introduce vma_is_special_huge() that takes the
      same codepaths as vma_is_dax().
      
      The use of "special" follows the definition in memory.c, vm_normal_page():
      "Special" mappings do not wish to be associated with a "struct page"
      (either it doesn't exist, or it exists but they don't want to touch it)
      
      For PAGE_SIZE pages, "special" is determined per page table entry to be
      able to deal with COW pages. But since we don't have huge COW pages,
      we can classify a vma as either "special huge" or "normal huge".
      
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Ralph Campbell <rcampbell@nvidia.com>
      Cc: "Jérôme Glisse" <jglisse@redhat.com>
      Cc: "Christian König" <christian.koenig@amd.com>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Signed-off-by: default avatarThomas Hellstrom (VMware) <thomas_os@shipmail.org>
      Acked-by: default avatarChristian König <christian.koenig@amd.com>
      Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      2484ca9b
    • Thomas Hellstrom (VMware)'s avatar
      fs: Constify vma argument to vma_is_dax · f05a3849
      Thomas Hellstrom (VMware) authored
      The function is used by upcoming vma_is_special_huge() with which we want
      to use a const vma argument. Since for vma_is_dax() the vma argument is
      only dereferenced for reading, constify it.
      
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Ralph Campbell <rcampbell@nvidia.com>
      Cc: "Jérôme Glisse" <jglisse@redhat.com>
      Cc: "Christian König" <christian.koenig@amd.com>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Signed-off-by: default avatarThomas Hellstrom (VMware) <thomas_os@shipmail.org>
      Reviewed-by: default avatarRoland Scheidegger <sroland@vmware.com>
      Acked-by: default avatarChristian König <christian.koenig@amd.com>
      f05a3849
  2. 20 Mar, 2020 2 commits
  3. 19 Mar, 2020 33 commits
  4. 18 Mar, 2020 2 commits