[PATCH] Swapless page migration: rip out swap based logic (d75a0fcd) · Commits · 戴 / test

include/linux/rmap.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -91,7 +91,6 @@ static inline void page_dup_rmap(struct page *page)
		*/
		int page_referenced(struct page *, int is_locked);
		int try_to_unmap(struct page *, int ignore_refs);
		void remove_from_swap(struct page *page);

		/*
		* Called from mm/filemap_xip.c to unmap empty zero page

mm/migrate.c

+3 −72

Original line number	Diff line number	Diff line
		@@ -70,10 +70,6 @@ int isolate_lru_page(struct page page, struct list_head pagelist)
		*/
		int migrate_prep(void)
		{
		/* Must have swap device for migration */
		if (nr_swap_pages <= 0)
		return -ENODEV;

		/*
		* Clear the LRU lists so pages can be isolated.
		* Note that pages may be moved off the LRU after we have
		@@ -245,52 +241,6 @@ out:
		pte_unmap_unlock(ptep, ptl);
		}

		/*
		* swapout a single page
		* page is locked upon entry, unlocked on exit
		*/
		static int swap_page(struct page *page)
		{
		struct address_space *mapping = page_mapping(page);

		if (page_mapped(page) && mapping)
		if (try_to_unmap(page, 1) != SWAP_SUCCESS)
		goto unlock_retry;

		if (PageDirty(page)) {
		/* Page is dirty, try to write it out here */
		switch(pageout(page, mapping)) {
		case PAGE_KEEP:
		case PAGE_ACTIVATE:
		goto unlock_retry;

		case PAGE_SUCCESS:
		goto retry;

		case PAGE_CLEAN:
		; /* try to free the page below */
		}
		}

		if (PagePrivate(page)) {
		if (!try_to_release_page(page, GFP_KERNEL) \|\|
		(!mapping && page_count(page) == 1))
		goto unlock_retry;
		}

		if (remove_mapping(mapping, page)) {
		/* Success */
		unlock_page(page);
		return 0;
		}

		unlock_retry:
		unlock_page(page);

		retry:
		return -EAGAIN;
		}

		/*
		* Replace the page in the mapping.
		*
		@@ -517,8 +467,7 @@ static int fallback_migrate_page(struct address_space *mapping,
		* Two lists are passed to this function. The first list
		* contains the pages isolated from the LRU to be migrated.
		* The second list contains new pages that the pages isolated
		* can be moved to. If the second list is NULL then all
		* pages are swapped out.
		* can be moved to.
		*
		* The function returns after 10 attempts or if no pages
		* are movable anymore because to has become empty
		@@ -574,29 +523,11 @@ redo:
		* Only wait on writeback if we have already done a pass where
		* we we may have triggered writeouts for lots of pages.
		*/
		if (pass > 0) {
		if (pass > 0)
		wait_on_page_writeback(page);
		} else {
		else
		if (PageWriteback(page))
		goto unlock_page;
		}

		/*
		* Anonymous pages must have swap cache references otherwise
		* the information contained in the page maps cannot be
		* preserved.
		*/
		if (PageAnon(page) && !PageSwapCache(page)) {
		if (!add_to_swap(page, GFP_KERNEL)) {
		rc = -ENOMEM;
		goto unlock_page;
		}
		}

		if (!to) {
		rc = swap_page(page);
		goto next;
		}

		/*
		* Establish swap ptes for anonymous pages or destroy pte

mm/rmap.c

+0 −38

Original line number	Diff line number	Diff line
		@@ -205,44 +205,6 @@ out:
		return anon_vma;
		}

		#ifdef CONFIG_MIGRATION
		/*
		* Remove an anonymous page from swap replacing the swap pte's
		* through real pte's pointing to valid pages and then releasing
		* the page from the swap cache.
		*
		* Must hold page lock on page and mmap_sem of one vma that contains
		* the page.
		*/
		void remove_from_swap(struct page *page)
		{
		struct anon_vma *anon_vma;
		struct vm_area_struct *vma;
		unsigned long mapping;

		if (!PageSwapCache(page))
		return;

		mapping = (unsigned long)page->mapping;

		if (!mapping \|\| (mapping & PAGE_MAPPING_ANON) == 0)
		return;

		/*
		* We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
		*/
		anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON);
		spin_lock(&anon_vma->lock);

		list_for_each_entry(vma, &anon_vma->head, anon_vma_node)
		remove_vma_swap(vma, page);

		spin_unlock(&anon_vma->lock);
		delete_from_swap_cache(page);
		}
		EXPORT_SYMBOL(remove_from_swap);
		#endif

		/*
		* At what user virtual address is page expected in vma?
		*/

mm/swapfile.c

+0 −9

Original line number	Diff line number	Diff line
		@@ -618,15 +618,6 @@ static int unuse_mm(struct mm_struct *mm,
		return 0;
		}

		#ifdef CONFIG_MIGRATION
		int remove_vma_swap(struct vm_area_struct vma, struct page page)
		{
		swp_entry_t entry = { .val = page_private(page) };

		return unuse_vma(vma, entry, page);
		}
		#endif

		/*
		* Scan swap_map from current position to next entry still in use.
		* Recycle to start on reaching the end, returning 0 when empty.

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