mm: fix khugepaged with shmem_enabled=advise

Pass vm_flags as a parameter to shmem_is_huge, rather than reading the
flags from the vm_area_struct in question.  This allows the updated flags
from hugepage_madvise to be passed to the check, which is necessary
because madvise does not update the vm_area_struct's flags until after
hugepage_madvise returns.

This fixes an issue when shmem_enabled=madvise, where MADV_HUGEPAGE on
shmem was not able to register the mm_struct with khugepaged.  Prior to
cd89fb065099, the mm_struct was registered by MADV_HUGEPAGE regardless of
the value of shmem_enabled (which was only checked when scanning vmas).

Link: https://lkml.kernel.org/r/20230113023011.1784015-1-stevensd@google.com
Fixes: cd89fb065099 ("mm,thp,shmem: make khugepaged obey tmpfs mount flags")
Signed-off-by: David Stevens <stevensd@chromium.org>
Cc: David Stevens <stevensd@chromium.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index d500ea9..d09d54b 100644 (file)
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -92,14 +92,8 @@ extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
 int shmem_unuse(unsigned int type);
 
-extern bool shmem_is_huge(struct vm_area_struct *vma, struct inode *inode,
-                         pgoff_t index, bool shmem_huge_force);
-static inline bool shmem_huge_enabled(struct vm_area_struct *vma,
-                                     bool shmem_huge_force)
-{
-       return shmem_is_huge(vma, file_inode(vma->vm_file), vma->vm_pgoff,
-                            shmem_huge_force);
-}
+extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
+                         struct mm_struct *mm, unsigned long vm_flags);
 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
                                                pgoff_t start, pgoff_t end);

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 868fccc..1d6977d 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -119,7 +119,8 @@ bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags,
         * own flags.
         */
        if (!in_pf && shmem_file(vma->vm_file))
-               return shmem_huge_enabled(vma, !enforce_sysfs);
+               return shmem_is_huge(file_inode(vma->vm_file), vma->vm_pgoff,
+                                    !enforce_sysfs, vma->vm_mm, vm_flags);
 
        /* Enforce sysfs THP requirements as necessary */
        if (enforce_sysfs &&

diff --git a/mm/shmem.c b/mm/shmem.c
index c5048c6..9e1015c 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -468,15 +468,14 @@ static bool shmem_confirm_swap(struct address_space *mapping,
 
 static int shmem_huge __read_mostly = SHMEM_HUGE_NEVER;
 
-bool shmem_is_huge(struct vm_area_struct *vma, struct inode *inode,
-                  pgoff_t index, bool shmem_huge_force)
+bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
+                  struct mm_struct *mm, unsigned long vm_flags)
 {
        loff_t i_size;
 
        if (!S_ISREG(inode->i_mode))
                return false;
-       if (vma && ((vma->vm_flags & VM_NOHUGEPAGE) ||
-           test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)))
+       if (mm && ((vm_flags & VM_NOHUGEPAGE) || test_bit(MMF_DISABLE_THP, &mm->flags)))
                return false;
        if (shmem_huge == SHMEM_HUGE_DENY)
                return false;
@@ -493,7 +492,7 @@ bool shmem_is_huge(struct vm_area_struct *vma, struct inode *inode,
                        return true;
                fallthrough;
        case SHMEM_HUGE_ADVISE:
-               if (vma && (vma->vm_flags & VM_HUGEPAGE))
+               if (mm && (vm_flags & VM_HUGEPAGE))
                        return true;
                fallthrough;
        default:
@@ -676,8 +675,8 @@ static long shmem_unused_huge_count(struct super_block *sb,
 
 #define shmem_huge SHMEM_HUGE_DENY
 
-bool shmem_is_huge(struct vm_area_struct *vma, struct inode *inode,
-                  pgoff_t index, bool shmem_huge_force)
+bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
+                  struct mm_struct *mm, unsigned long vm_flags)
 {
        return false;
 }
@@ -1068,7 +1067,7 @@ static int shmem_getattr(struct user_namespace *mnt_userns,
                        STATX_ATTR_NODUMP);
        generic_fillattr(&init_user_ns, inode, stat);
 
-       if (shmem_is_huge(NULL, inode, 0, false))
+       if (shmem_is_huge(inode, 0, false, NULL, 0))
                stat->blksize = HPAGE_PMD_SIZE;
 
        if (request_mask & STATX_BTIME) {
@@ -1926,7 +1925,8 @@ repeat:
                return 0;
        }
 
-       if (!shmem_is_huge(vma, inode, index, false))
+       if (!shmem_is_huge(inode, index, false,
+                          vma ? vma->vm_mm : NULL, vma ? vma->vm_flags : 0))
                goto alloc_nohuge;
 
        huge_gfp = vma_thp_gfp_mask(vma);