Commit 906f9cdf authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

mm/huge_memory: rename freeze_page() to unmap_page() 

The term "freeze" is used in several ways in the kernel, and in mm it
has the particular meaning of forcing page refcount temporarily to 0.
freeze_page() is just too confusing a name for a function that unmaps a
page: rename it unmap_page(), and rename unfreeze_page() remap_page().

Went to change the mention of freeze_page() added later in mm/rmap.c,
but found it to be incorrect: ordinary page reclaim reaches there too;
but the substance of the comment still seems correct, so edit it down.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261514080.2275@eggly.anvils


Fixes: e9b61f19 ("thp: reintroduce split_huge_page()")
Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>	[4.8+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7c0950d4

mm/huge_memory.c

+6 −6
Original line number Diff line number Diff line
@@ -2350,7 +2350,7 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma, 
	}

}



static void freeze_page(struct page *page)

static void unmap_page(struct page *page)

{

	enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS |

		TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD;
@@ -2365,7 +2365,7 @@ static void freeze_page(struct page *page) 
	VM_BUG_ON_PAGE(!unmap_success, page);

}



static void unfreeze_page(struct page *page)

static void remap_page(struct page *page)

{

	int i;

	if (PageTransHuge(page)) {
@@ -2483,7 +2483,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, 


	spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);



	unfreeze_page(head);

	remap_page(head);



	for (i = 0; i < HPAGE_PMD_NR; i++) {

		struct page *subpage = head + i;
@@ -2664,7 +2664,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) 
	}



	/*

	 * Racy check if we can split the page, before freeze_page() will

	 * Racy check if we can split the page, before unmap_page() will

	 * split PMDs

	 */

	if (!can_split_huge_page(head, &extra_pins)) {
@@ -2673,7 +2673,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) 
	}



	mlocked = PageMlocked(page);

	freeze_page(head);

	unmap_page(head);

	VM_BUG_ON_PAGE(compound_mapcount(head), head);



	/* Make sure the page is not on per-CPU pagevec as it takes pin */
@@ -2727,7 +2727,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) 
fail:		if (mapping)

			xa_unlock(&mapping->i_pages);

		spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);

		unfreeze_page(head);

		remap_page(head);

		ret = -EBUSY;

	}

mm/rmap.c

+3 −10
Original line number Diff line number Diff line
@@ -1627,16 +1627,9 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, 
						      address + PAGE_SIZE);

		} else {

			/*

			 * We should not need to notify here as we reach this

			 * case only from freeze_page() itself only call from

			 * split_huge_page_to_list() so everything below must

			 * be true:

			 *   - page is not anonymous

			 *   - page is locked

			 *

			 * So as it is a locked file back page thus it can not

			 * be remove from the page cache and replace by a new

			 * page before mmu_notifier_invalidate_range_end so no

			 * This is a locked file-backed page, thus it cannot

			 * be removed from the page cache and replaced by a new

			 * page before mmu_notifier_invalidate_range_end, so no

			 * concurrent thread might update its page table to

			 * point at new page while a device still is using this

			 * page.

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