Commit 8dd1e896 authored by Vishal Moola (Oracle)'s avatar Vishal Moola (Oracle) Committed by Andrew Morton
Browse files

mm/khugepaged: convert __collapse_huge_page_isolate() to use folios 

Patch series "Some khugepaged folio conversions", v3.

This patchset converts a number of functions to use folios.  This cleans
up some khugepaged code and removes a large number of hidden
compound_head() calls.


This patch (of 5):

Replaces 11 calls to compound_head() with 1, and removes 1348 bytes of
kernel text.

Link: https://lkml.kernel.org/r/20231020183331.10770-1-vishal.moola@gmail.com
Link: https://lkml.kernel.org/r/20231020183331.10770-2-vishal.moola@gmail.com


Signed-off-by: default avatarVishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarYang Shi <shy828301@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b7812c86

mm/khugepaged.c

+23 −22
Original line number Diff line number Diff line
@@ -542,6 +542,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
					struct list_head *compound_pagelist)

{

	struct page *page = NULL;

	struct folio *folio = NULL;

	pte_t *_pte;

	int none_or_zero = 0, shared = 0, result = SCAN_FAIL, referenced = 0;

	bool writable = false;
@@ -576,7 +577,8 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
			goto out;

		}



		VM_BUG_ON_PAGE(!PageAnon(page), page);

		folio = page_folio(page);

		VM_BUG_ON_FOLIO(!folio_test_anon(folio), folio);



		if (page_mapcount(page) > 1) {

			++shared;
@@ -588,16 +590,15 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
			}

		}



		if (PageCompound(page)) {

			struct page *p;

			page = compound_head(page);

		if (folio_test_large(folio)) {

			struct folio *f;



			/*

			 * Check if we have dealt with the compound page

			 * already

			 */

			list_for_each_entry(p, compound_pagelist, lru) {

				if (page == p)

			list_for_each_entry(f, compound_pagelist, lru) {

				if (folio == f)

					goto next;

			}

		}
@@ -608,7 +609,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
		 * is needed to serialize against split_huge_page

		 * when invoked from the VM.

		 */

		if (!trylock_page(page)) {

		if (!folio_trylock(folio)) {

			result = SCAN_PAGE_LOCK;

			goto out;

		}
@@ -624,8 +625,8 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
		 * but not from this process. The other process cannot write to

		 * the page, only trigger CoW.

		 */

		if (!is_refcount_suitable(page)) {

			unlock_page(page);

		if (!is_refcount_suitable(&folio->page)) {

			folio_unlock(folio);

			result = SCAN_PAGE_COUNT;

			goto out;

		}
@@ -634,27 +635,27 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
		 * Isolate the page to avoid collapsing an hugepage

		 * currently in use by the VM.

		 */

		if (!isolate_lru_page(page)) {

			unlock_page(page);

		if (!folio_isolate_lru(folio)) {

			folio_unlock(folio);

			result = SCAN_DEL_PAGE_LRU;

			goto out;

		}

		mod_node_page_state(page_pgdat(page),

				NR_ISOLATED_ANON + page_is_file_lru(page),

				compound_nr(page));

		VM_BUG_ON_PAGE(!PageLocked(page), page);

		VM_BUG_ON_PAGE(PageLRU(page), page);

		node_stat_mod_folio(folio,

				NR_ISOLATED_ANON + folio_is_file_lru(folio),

				folio_nr_pages(folio));

		VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);

		VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);



		if (PageCompound(page))

			list_add_tail(&page->lru, compound_pagelist);

		if (folio_test_large(folio))

			list_add_tail(&folio->lru, compound_pagelist);

next:

		/*

		 * If collapse was initiated by khugepaged, check that there is

		 * enough young pte to justify collapsing the page

		 */

		if (cc->is_khugepaged &&

		    (pte_young(pteval) || page_is_young(page) ||

		     PageReferenced(page) || mmu_notifier_test_young(vma->vm_mm,

		    (pte_young(pteval) || folio_test_young(folio) ||

		     folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,

								     address)))

			referenced++;
@@ -668,13 +669,13 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
		result = SCAN_LACK_REFERENCED_PAGE;

	} else {

		result = SCAN_SUCCEED;

		trace_mm_collapse_huge_page_isolate(page, none_or_zero,

		trace_mm_collapse_huge_page_isolate(&folio->page, none_or_zero,

						    referenced, writable, result);

		return result;

	}

out:

	release_pte_pages(pte, _pte, compound_pagelist);

	trace_mm_collapse_huge_page_isolate(page, none_or_zero,

	trace_mm_collapse_huge_page_isolate(&folio->page, none_or_zero,

					    referenced, writable, result);

	return result;

}