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	madvise: convert madvise_free_pte_range() to use a folio
Saves a lot of calls to compound_head(). Link: https://lkml.kernel.org/r/20220902194653.1739778-44-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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					 1 changed files with 25 additions and 24 deletions
				
			
		
							
								
								
									
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								mm/madvise.c
									
									
									
									
									
								
							
							
						
						
									
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								mm/madvise.c
									
									
									
									
									
								
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			@ -601,6 +601,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
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	struct vm_area_struct *vma = walk->vma;
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	spinlock_t *ptl;
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	pte_t *orig_pte, *pte, ptent;
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	struct folio *folio;
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	struct page *page;
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	int nr_swap = 0;
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	unsigned long next;
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			@ -645,56 +646,56 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
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		page = vm_normal_page(vma, addr, ptent);
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		if (!page || is_zone_device_page(page))
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			continue;
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		folio = page_folio(page);
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		/*
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		 * If pmd isn't transhuge but the page is THP and
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		 * If pmd isn't transhuge but the folio is large and
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		 * is owned by only this process, split it and
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		 * deactivate all pages.
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		 */
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		if (PageTransCompound(page)) {
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			if (page_mapcount(page) != 1)
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		if (folio_test_large(folio)) {
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			if (folio_mapcount(folio) != 1)
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				goto out;
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			get_page(page);
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			if (!trylock_page(page)) {
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				put_page(page);
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			folio_get(folio);
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			if (!folio_trylock(folio)) {
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				folio_put(folio);
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				goto out;
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			}
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			pte_unmap_unlock(orig_pte, ptl);
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			if (split_huge_page(page)) {
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				unlock_page(page);
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				put_page(page);
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			if (split_folio(folio)) {
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				folio_unlock(folio);
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				folio_put(folio);
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				orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
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				goto out;
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			}
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			unlock_page(page);
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			put_page(page);
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			folio_unlock(folio);
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			folio_put(folio);
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			orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
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			pte--;
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			addr -= PAGE_SIZE;
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			continue;
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		}
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		VM_BUG_ON_PAGE(PageTransCompound(page), page);
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		if (PageSwapCache(page) || PageDirty(page)) {
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			if (!trylock_page(page))
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		if (folio_test_swapcache(folio) || folio_test_dirty(folio)) {
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			if (!folio_trylock(folio))
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				continue;
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			/*
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			 * If page is shared with others, we couldn't clear
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			 * PG_dirty of the page.
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			 * If folio is shared with others, we mustn't clear
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			 * the folio's dirty flag.
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			 */
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			if (page_mapcount(page) != 1) {
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				unlock_page(page);
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			if (folio_mapcount(folio) != 1) {
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				folio_unlock(folio);
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				continue;
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			}
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			if (PageSwapCache(page) && !try_to_free_swap(page)) {
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				unlock_page(page);
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			if (folio_test_swapcache(folio) &&
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			    !folio_free_swap(folio)) {
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				folio_unlock(folio);
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				continue;
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			}
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			ClearPageDirty(page);
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			unlock_page(page);
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			folio_clear_dirty(folio);
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			folio_unlock(folio);
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		}
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		if (pte_young(ptent) || pte_dirty(ptent)) {
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			@ -712,7 +713,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
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			set_pte_at(mm, addr, pte, ptent);
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			tlb_remove_tlb_entry(tlb, pte, addr);
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		}
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		mark_page_lazyfree(page);
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		mark_page_lazyfree(&folio->page);
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	}
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out:
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	if (nr_swap) {
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