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Commit 52629506 authored by Joonsoo Kim's avatar Joonsoo Kim Committed by Linus Torvalds
Browse files

mm/rmap: use rmap_walk() in try_to_unmap() 



Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.

So, just use it in try_to_unmap().

In this patch, I change following things.

1. enable rmap_walk() if !CONFIG_MIGRATION.
2. mechanical change to use rmap_walk() in try_to_unmap().

Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0dd1c7bb

include/linux/rmap.h

+1 −4
Original line number Diff line number Diff line
@@ -190,7 +190,7 @@ int page_referenced_one(struct page *, struct vm_area_struct *, 


int try_to_unmap(struct page *, enum ttu_flags flags);

int try_to_unmap_one(struct page *, struct vm_area_struct *,

			unsigned long address, enum ttu_flags flags);

			unsigned long address, void *arg);



/*

 * Called from mm/filemap_xip.c to unmap empty zero page
@@ -256,9 +256,6 @@ struct rmap_walk_control { 
	bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);

};



/*

 * Called by migrate.c to remove migration ptes, but might be used more later.

 */

int rmap_walk(struct page *page, struct rmap_walk_control *rwc);



#else	/* !CONFIG_MMU */

mm/ksm.c

+2 −2
Original line number Diff line number Diff line
@@ -1982,7 +1982,7 @@ again: 
				continue;



			ret = try_to_unmap_one(page, vma,

					rmap_item->address, flags);

					rmap_item->address, (void *)flags);

			if (ret != SWAP_AGAIN || !page_mapped(page)) {

				anon_vma_unlock_read(anon_vma);

				goto out;
@@ -1996,7 +1996,6 @@ out: 
	return ret;

}



#ifdef CONFIG_MIGRATION

int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)

{

	struct stable_node *stable_node;
@@ -2054,6 +2053,7 @@ out: 
	return ret;

}



#ifdef CONFIG_MIGRATION

void ksm_migrate_page(struct page *newpage, struct page *oldpage)

{

	struct stable_node *stable_node;

mm/rmap.c

+36 −12
Original line number Diff line number Diff line
@@ -1179,15 +1179,18 @@ out: 
/*

 * Subfunctions of try_to_unmap: try_to_unmap_one called

 * repeatedly from try_to_unmap_ksm, try_to_unmap_anon or try_to_unmap_file.

 *

 * @arg: enum ttu_flags will be passed to this argument

 */

int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,

		     unsigned long address, enum ttu_flags flags)

		     unsigned long address, void *arg)

{

	struct mm_struct *mm = vma->vm_mm;

	pte_t *pte;

	pte_t pteval;

	spinlock_t *ptl;

	int ret = SWAP_AGAIN;

	enum ttu_flags flags = (enum ttu_flags)arg;



	pte = page_check_address(page, mm, address, &ptl, 0);

	if (!pte)
@@ -1513,6 +1516,11 @@ bool is_vma_temporary_stack(struct vm_area_struct *vma) 
	return false;

}



static bool invalid_migration_vma(struct vm_area_struct *vma, void *arg)

{

	return is_vma_temporary_stack(vma);

}



/**

 * try_to_unmap_anon - unmap or unlock anonymous page using the object-based

 * rmap method
@@ -1558,7 +1566,7 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags) 
			continue;



		address = vma_address(page, vma);

		ret = try_to_unmap_one(page, vma, address, flags);

		ret = try_to_unmap_one(page, vma, address, (void *)flags);

		if (ret != SWAP_AGAIN || !page_mapped(page))

			break;

	}
@@ -1592,7 +1600,7 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags) 
	mutex_lock(&mapping->i_mmap_mutex);

	vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {

		unsigned long address = vma_address(page, vma);

		ret = try_to_unmap_one(page, vma, address, flags);

		ret = try_to_unmap_one(page, vma, address, (void *)flags);

		if (ret != SWAP_AGAIN || !page_mapped(page))

			goto out;

	}
@@ -1614,6 +1622,11 @@ out: 
	return ret;

}



static int page_not_mapped(struct page *page)

{

	return !page_mapped(page);

};



/**

 * try_to_unmap - try to remove all page table mappings to a page

 * @page: the page to get unmapped
@@ -1631,16 +1644,29 @@ out: 
int try_to_unmap(struct page *page, enum ttu_flags flags)

{

	int ret;

	struct rmap_walk_control rwc = {

		.rmap_one = try_to_unmap_one,

		.arg = (void *)flags,

		.done = page_not_mapped,

		.file_nonlinear = try_to_unmap_nonlinear,

		.anon_lock = page_lock_anon_vma_read,

	};



	BUG_ON(!PageLocked(page));

	VM_BUG_ON(!PageHuge(page) && PageTransHuge(page));



	if (unlikely(PageKsm(page)))

		ret = try_to_unmap_ksm(page, flags);

	else if (PageAnon(page))

		ret = try_to_unmap_anon(page, flags);

	else

		ret = try_to_unmap_file(page, flags);

	/*

	 * During exec, a temporary VMA is setup and later moved.

	 * The VMA is moved under the anon_vma lock but not the

	 * page tables leading to a race where migration cannot

	 * find the migration ptes. Rather than increasing the

	 * locking requirements of exec(), migration skips

	 * temporary VMAs until after exec() completes.

	 */

	if (flags & TTU_MIGRATION && !PageKsm(page) && PageAnon(page))

		rwc.invalid_vma = invalid_migration_vma;



	ret = rmap_walk(page, &rwc);



	if (ret != SWAP_MLOCK && !page_mapped(page))

		ret = SWAP_SUCCESS;

	return ret;
@@ -1683,7 +1709,6 @@ void __put_anon_vma(struct anon_vma *anon_vma) 
	anon_vma_free(anon_vma);

}



#ifdef CONFIG_MIGRATION

static struct anon_vma *rmap_walk_anon_lock(struct page *page,

					struct rmap_walk_control *rwc)

{
@@ -1785,7 +1810,6 @@ int rmap_walk(struct page *page, struct rmap_walk_control *rwc) 
	else

		return rmap_walk_file(page, rwc);

}

#endif /* CONFIG_MIGRATION */



#ifdef CONFIG_HUGETLB_PAGE

/*