mm/huge_memory.c: add missing read-only THP checking in transparent_hugepage_enabled()

Since commit 99cb0dbd47a1 ("mm,thp: add read-only THP support for
(non-shmem) FS"), read-only THP file mapping is supported.  But it forgot
to add checking for it in transparent_hugepage_enabled().  To fix it, we
add checking for read-only THP file mapping and also introduce helper
transhuge_vma_enabled() to check whether thp is enabled for specified vma
to reduce duplicated code.  We rename transparent_hugepage_enabled to
transparent_hugepage_active to make the code easier to follow as suggested
by David Hildenbrand.

Link: https://lkml.kernel.org/r/20210511134857.1581273-4-linmiaohe@huawei.com
Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 0e101e70d2ced9eab4af0559030f65be4c4fbfd8..90b4f8cadb9ff1b428b0f52cb62e5070eccc328f 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -828,7 +828,7 @@ static int show_smap(struct seq_file *m, void *v)
        __show_smap(m, &mss, false);
 
        seq_printf(m, "THPeligible:    %d\n",
-                  transparent_hugepage_enabled(vma));
+                  transparent_hugepage_active(vma));
 
        if (arch_pkeys_enabled())
                seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 0a526f211fec2fdce6cea85220acdcb0f5c38ec9..a35c13d1f48738dd6815ecc4fcc46cf2db99b619 100644 (file)
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -115,9 +115,19 @@ extern struct kobj_attribute shmem_enabled_attr;
 
 extern unsigned long transparent_hugepage_flags;
 
+static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
+                                         unsigned long vm_flags)
+{
+       /* Explicitly disabled through madvise. */
+       if ((vm_flags & VM_NOHUGEPAGE) ||
+           test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
+               return false;
+       return true;
+}
+
 /*
  * to be used on vmas which are known to support THP.
- * Use transparent_hugepage_enabled otherwise
+ * Use transparent_hugepage_active otherwise
  */
 static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
 {
@@ -128,15 +138,12 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
        if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX))
                return false;
 
-       if (vma->vm_flags & VM_NOHUGEPAGE)
+       if (!transhuge_vma_enabled(vma, vma->vm_flags))
                return false;
 
        if (vma_is_temporary_stack(vma))
                return false;
 
-       if (test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
-               return false;
-
        if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_FLAG))
                return true;
 
@@ -150,7 +157,7 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
        return false;
 }
 
-bool transparent_hugepage_enabled(struct vm_area_struct *vma);
+bool transparent_hugepage_active(struct vm_area_struct *vma);
 
 static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
                unsigned long haddr)
@@ -351,7 +358,7 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
        return false;
 }
 
-static inline bool transparent_hugepage_enabled(struct vm_area_struct *vma)
+static inline bool transparent_hugepage_active(struct vm_area_struct *vma)
 {
        return false;
 }
@@ -362,6 +369,12 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
        return false;
 }
 
+static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
+                                         unsigned long vm_flags)
+{
+       return false;
+}
+
 static inline void prep_transhuge_page(struct page *page) {}
 
 static inline bool is_transparent_hugepage(struct page *page)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 109bbce80a83723cbddcb2667a7fc88d2cde4a92..64d43d9204f468a3e2c89c5028f0c38291409d8d 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -63,7 +63,14 @@ static struct shrinker deferred_split_shrinker;
 static atomic_t huge_zero_refcount;
 struct page *huge_zero_page __read_mostly;
 
-bool transparent_hugepage_enabled(struct vm_area_struct *vma)
+static inline bool file_thp_enabled(struct vm_area_struct *vma)
+{
+       return transhuge_vma_enabled(vma, vma->vm_flags) && vma->vm_file &&
+              !inode_is_open_for_write(vma->vm_file->f_inode) &&
+              (vma->vm_flags & VM_EXEC);
+}
+
+bool transparent_hugepage_active(struct vm_area_struct *vma)
 {
        /* The addr is used to check if the vma size fits */
        unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE;
@@ -74,6 +81,8 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma)
                return __transparent_hugepage_enabled(vma);
        if (vma_is_shmem(vma))
                return shmem_huge_enabled(vma);
+       if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS))
+               return file_thp_enabled(vma);
 
        return false;
 }

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 6c0185fdd81581dc51bb0c2fbd2f5ab7e5e0582f..d97b20fad6e8e61c6fd36f101e9e326632c3c388 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -442,9 +442,7 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
 static bool hugepage_vma_check(struct vm_area_struct *vma,
                               unsigned long vm_flags)
 {
-       /* Explicitly disabled through madvise. */
-       if ((vm_flags & VM_NOHUGEPAGE) ||
-           test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
+       if (!transhuge_vma_enabled(vma, vm_flags))
                return false;
 
        /* Enabled via shmem mount options or sysfs settings. */

diff --git a/mm/shmem.c b/mm/shmem.c
index 53f21016608e3c63f102fcab98ed6f422c1bdd67..5fa21d66af203b7a251167d25f5c4106dddf04cf 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4040,8 +4040,7 @@ bool shmem_huge_enabled(struct vm_area_struct *vma)
        loff_t i_size;
        pgoff_t off;
 
-       if ((vma->vm_flags & VM_NOHUGEPAGE) ||
-           test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
+       if (!transhuge_vma_enabled(vma, vma->vm_flags))
                return false;
        if (shmem_huge == SHMEM_HUGE_FORCE)
                return true;