From 7de856ffd007f132fd4a0474b289a622a3f88cd7 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Tue, 20 Aug 2024 17:49:16 +0800 Subject: [PATCH] mm: khugepaged: support shmem mTHP collapse Shmem already supports the allocation of mTHP, but khugepaged does not yet support collapsing mTHP folios. Now khugepaged is ready to support mTHP, and this patch enables the collapse of shmem mTHP. Link: https://lkml.kernel.org/r/b9da76aab4276eb6e5d12c479af2b5eea5b4575d.1724140601.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Cc: Barry Song <21cnbao@gmail.com> Cc: David Hildenbrand Cc: Hugh Dickins Cc: Matthew Wilcox Cc: Ryan Roberts Cc: Yang Shi Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/khugepaged.c | 28 +++++++++++----------------- 1 file changed, 11 insertions(+), 17 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 4996f7487c134..4a83c40d90538 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1843,7 +1843,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, } } while (1); - for (index = start; index < end; index++) { + for (index = start; index < end;) { xas_set(&xas, index); folio = xas_load(&xas); @@ -1862,6 +1862,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, } } nr_none++; + index++; continue; } @@ -1943,12 +1944,10 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, * we locked the first folio, then a THP might be there already. * This will be discovered on the first iteration. */ - if (folio_test_large(folio)) { - result = folio_order(folio) == HPAGE_PMD_ORDER && - folio->index == start - /* Maybe PMD-mapped */ - ? SCAN_PTE_MAPPED_HUGEPAGE - : SCAN_PAGE_COMPOUND; + if (folio_order(folio) == HPAGE_PMD_ORDER && + folio->index == start) { + /* Maybe PMD-mapped */ + result = SCAN_PTE_MAPPED_HUGEPAGE; goto out_unlock; } @@ -2009,6 +2008,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, * Accumulate the folios that are being collapsed. */ list_add_tail(&folio->lru, &pagelist); + index += folio_nr_pages(folio); continue; out_unlock: folio_unlock(folio); @@ -2261,16 +2261,10 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, continue; } - /* - * TODO: khugepaged should compact smaller compound pages - * into a PMD sized page - */ - if (folio_test_large(folio)) { - result = folio_order(folio) == HPAGE_PMD_ORDER && - folio->index == start - /* Maybe PMD-mapped */ - ? SCAN_PTE_MAPPED_HUGEPAGE - : SCAN_PAGE_COMPOUND; + if (folio_order(folio) == HPAGE_PMD_ORDER && + folio->index == start) { + /* Maybe PMD-mapped */ + result = SCAN_PTE_MAPPED_HUGEPAGE; /* * For SCAN_PTE_MAPPED_HUGEPAGE, further processing * by the caller won't touch the page cache, and so -- 2.39.5