Merge tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache

Pull folio updates from Matthew Wilcox:

 - Rewrite how munlock works to massively reduce the contention on
   i_mmap_rwsem (Hugh Dickins):

     https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/

 - Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
   Hellwig):

     https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/

 - Convert GUP to use folios and make pincount available for order-1
   pages. (Matthew Wilcox)

 - Convert a few more truncation functions to use folios (Matthew
   Wilcox)

 - Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
   Wilcox)

 - Convert rmap_walk to use folios (Matthew Wilcox)

 - Convert most of shrink_page_list() to use a folio (Matthew Wilcox)

 - Add support for creating large folios in readahead (Matthew Wilcox)

* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
  mm/damon: minor cleanup for damon_pa_young
  selftests/vm/transhuge-stress: Support file-backed PMD folios
  mm/filemap: Support VM_HUGEPAGE for file mappings
  mm/readahead: Switch to page_cache_ra_order
  mm/readahead: Align file mappings for non-DAX
  mm/readahead: Add large folio readahead
  mm: Support arbitrary THP sizes
  mm: Make large folios depend on THP
  mm: Fix READ_ONLY_THP warning
  mm/filemap: Allow large folios to be added to the page cache
  mm: Turn can_split_huge_page() into can_split_folio()
  mm/vmscan: Convert pageout() to take a folio
  mm/vmscan: Turn page_check_references() into folio_check_references()
  mm/vmscan: Account large folios correctly
  mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
  mm/vmscan: Free non-shmem folios without splitting them
  mm/rmap: Constify the rmap_walk_control argument
  mm/rmap: Convert rmap_walk() to take a folio
  mm: Turn page_anon_vma() into folio_anon_vma()
  mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
  ...

1 files changed, 2 insertions, 30 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index bd3416eb5fbc..3aa839f81e63 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2672,6 +2672,8 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
 	vma->vm_prev = NULL;
 	do {
 		vma_rb_erase(vma, &mm->mm_rb);
+		if (vma->vm_flags & VM_LOCKED)
+			mm->locked_vm -= vma_pages(vma);
 		mm->map_count--;
 		tail_vma = vma;
 		vma = vma->vm_next;
@@ -2776,22 +2778,6 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 	return __split_vma(mm, vma, addr, new_below);
 }
 
-static inline void
-unlock_range(struct vm_area_struct *start, unsigned long limit)
-{
-	struct mm_struct *mm = start->vm_mm;
-	struct vm_area_struct *tmp = start;
-
-	while (tmp && tmp->vm_start < limit) {
-		if (tmp->vm_flags & VM_LOCKED) {
-			mm->locked_vm -= vma_pages(tmp);
-			munlock_vma_pages_all(tmp);
-		}
-
-		tmp = tmp->vm_next;
-	}
-}
-
 /* Munmap is split into 2 main parts -- this part which finds
  * what needs doing, and the areas themselves, which do the
  * work.  This now handles partial unmappings.
@@ -2872,12 +2858,6 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
 			return error;
 	}
 
-	/*
-	 * unlock any mlock()ed ranges before detaching vmas
-	 */
-	if (mm->locked_vm)
-		unlock_range(vma, end);
-
 	/* Detach vmas from rbtree */
 	if (!detach_vmas_to_be_unmapped(mm, vma, prev, end))
 		downgrade = false;
@@ -3145,20 +3125,12 @@ void exit_mmap(struct mm_struct *mm)
 		 * Nothing can be holding mm->mmap_lock here and the above call
 		 * to mmu_notifier_release(mm) ensures mmu notifier callbacks in
 		 * __oom_reap_task_mm() will not block.
-		 *
-		 * This needs to be done before calling unlock_range(),
-		 * which clears VM_LOCKED, otherwise the oom reaper cannot
-		 * reliably test it.
 		 */
 		(void)__oom_reap_task_mm(mm);
-
 		set_bit(MMF_OOM_SKIP, &mm->flags);
 	}
 
 	mmap_write_lock(mm);
-	if (mm->locked_vm)
-		unlock_range(mm->mmap, ULONG_MAX);
-
 	arch_exit_mmap(mm);
 
 	vma = mm->mmap;