Commit 2cf13384 authored by David Stevens's avatar David Stevens Committed by Andrew Morton
Browse files

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
cd89fb06, 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: cd89fb06 ("mm,thp,shmem: make khugepaged obey tmpfs mount flags")
Signed-off-by: default avatarDavid 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 2973d822

include/linux/shmem_fs.h

+2 −8
Original line number Diff line number Diff line
@@ -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);

mm/huge_memory.c

+2 −1
Original line number Diff line number Diff line
@@ -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 &&

mm/shmem.c

+9 −9
Original line number Diff line number Diff line
@@ -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 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, 
		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);