Commit f158ed61 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: convert deferred_split_huge_page() to deferred_split_folio() 

Now that both callers use a folio, pass the folio in and save a call to
compound_head().

Link: https://lkml.kernel.org/r/20230111142915.1001531-28-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent f8baa6be

Documentation/mm/transhuge.rst

+3 −3
Original line number Diff line number Diff line
@@ -153,8 +153,8 @@ clear where references should go after split: it will stay on the head page. 
Note that split_huge_pmd() doesn't have any limitations on refcounting:

pmd can be split at any point and never fails.



Partial unmap and deferred_split_huge_page()

============================================

Partial unmap and deferred_split_folio()

========================================



Unmapping part of THP (with munmap() or other way) is not going to free

memory immediately. Instead, we detect that a subpage of THP is not in use
@@ -166,6 +166,6 @@ the place where we can detect partial unmap. It also might be 
counterproductive since in many cases partial unmap happens during exit(2) if

a THP crosses a VMA boundary.



The function deferred_split_huge_page() is used to queue a page for splitting.

The function deferred_split_folio() is used to queue a folio for splitting.

The splitting itself will happen when we get memory pressure via shrinker

interface.

include/linux/huge_mm.h

+2 −2
Original line number Diff line number Diff line
@@ -187,7 +187,7 @@ static inline int split_huge_page(struct page *page) 
{

	return split_huge_page_to_list(page, NULL);

}

void deferred_split_huge_page(struct page *page);

void deferred_split_folio(struct folio *folio);



void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,

		unsigned long address, bool freeze, struct folio *folio);
@@ -340,7 +340,7 @@ static inline int split_huge_page(struct page *page) 
{

	return 0;

}

static inline void deferred_split_huge_page(struct page *page) {}

static inline void deferred_split_folio(struct folio *folio) {}

#define split_huge_pmd(__vma, __pmd, __address)	\

	do { } while (0)

mm/huge_memory.c

+1 −2
Original line number Diff line number Diff line
@@ -2815,9 +2815,8 @@ void free_transhuge_page(struct page *page) 
	free_compound_page(page);

}



void deferred_split_huge_page(struct page *page)

void deferred_split_folio(struct folio *folio)

{

	struct folio *folio = page_folio(page);

	struct deferred_split *ds_queue = get_deferred_split_queue(folio);

#ifdef CONFIG_MEMCG

	struct mem_cgroup *memcg = folio_memcg(folio);

mm/rmap.c

+1 −1
Original line number Diff line number Diff line
@@ -1427,7 +1427,7 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma, 
		 */

		if (folio_test_pmd_mappable(folio) && folio_test_anon(folio))

			if (!compound || nr < nr_pmdmapped)

				deferred_split_huge_page(&folio->page);

				deferred_split_folio(folio);

	}



	/*