[Devel] [PATCH rh7 2/4] mm/rmap: make rmap_walk to get the rmap_walk_control argument

Vladimir Davydov vdavydov at virtuozzo.com
Tue Dec 8 05:03:46 PST 2015


From: Joonsoo Kim <iamjoonsoo.kim at lge.com>

In each rmap traverse case, there is some difference so that we need
function pointers and arguments to them in order to handle these

For this purpose, struct rmap_walk_control is introduced in this patch,
and will be extended in following patch.  Introducing and extending are
separate, because it clarify changes.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim at lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi at ah.jp.nec.com>
Cc: Mel Gorman <mgorman at suse.de>
Cc: Hugh Dickins <hughd at google.com>
Cc: Rik van Riel <riel at redhat.com>
Cc: Ingo Molnar <mingo at kernel.org>
Cc: Hillf Danton <dhillf at gmail.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
(cherry picked from commit 051ac83adf69eea4f57a97356e4282e395a5fa6d)
Signed-off-by: Vladimir Davydov <vdavydov at virtuozzo.com>
---
 include/linux/ksm.h  |  7 +++----
 include/linux/rmap.h |  9 +++++++--
 mm/ksm.c             |  6 +++---
 mm/migrate.c         |  7 ++++++-
 mm/rmap.c            | 19 ++++++++-----------
 5 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 45c9b6a17bcb..0eef8cb0baf7 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -76,8 +76,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
 int page_referenced_ksm(struct page *page,
 			struct mem_cgroup *memcg, unsigned long *vm_flags);
 int try_to_unmap_ksm(struct page *page, enum ttu_flags flags);
-int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *,
-		  struct vm_area_struct *, unsigned long, void *), void *arg);
+int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc);
 void ksm_migrate_page(struct page *newpage, struct page *oldpage);
 
 #else  /* !CONFIG_KSM */
@@ -120,8 +119,8 @@ static inline int try_to_unmap_ksm(struct page *page, enum ttu_flags flags)
 	return 0;
 }
 
-static inline int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page*,
-		struct vm_area_struct *, unsigned long, void *), void *arg)
+static inline int rmap_walk_ksm(struct page *page,
+			struct rmap_walk_control *rwc)
 {
 	return 0;
 }
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 9775b7b2ece7..083b1dfcf3d2 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -237,11 +237,16 @@ extern struct anon_vma *page_lock_anon_vma_read(struct page *page);
 extern void page_unlock_anon_vma_read(struct anon_vma *anon_vma);
 int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
 
+struct rmap_walk_control {
+	void *arg;
+	int (*rmap_one)(struct page *page, struct vm_area_struct *vma,
+					unsigned long addr, void *arg);
+};
+
 /*
  * Called by migrate.c to remove migration ptes, but might be used more later.
  */
-int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
-		struct vm_area_struct *, unsigned long, void *), void *arg);
+int rmap_walk(struct page *page, struct rmap_walk_control *rwc);
 
 #else	/* !CONFIG_MMU */
 
diff --git a/mm/ksm.c b/mm/ksm.c
index 74e4c0899274..ff2d5a3d0410 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2003,8 +2003,7 @@ out:
 }
 
 #ifdef CONFIG_MIGRATION
-int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *,
-		  struct vm_area_struct *, unsigned long, void *), void *arg)
+int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
 {
 	struct stable_node *stable_node;
 	struct rmap_item *rmap_item;
@@ -2039,7 +2038,8 @@ again:
 			if ((rmap_item->mm == vma->vm_mm) == search_new_forks)
 				continue;
 
-			ret = rmap_one(page, vma, rmap_item->address, arg);
+			ret = rwc->rmap_one(page, vma,
+					rmap_item->address, rwc->arg);
 			if (ret != SWAP_AGAIN) {
 				anon_vma_unlock_read(anon_vma);
 				goto out;
diff --git a/mm/migrate.c b/mm/migrate.c
index c608326dbc3d..ce9a97cc170a 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -196,7 +196,12 @@ out:
  */
 static void remove_migration_ptes(struct page *old, struct page *new)
 {
-	rmap_walk(new, remove_migration_pte, old);
+	struct rmap_walk_control rwc = {
+		.rmap_one = remove_migration_pte,
+		.arg = old,
+	};
+
+	rmap_walk(new, &rwc);
 }
 
 /*
diff --git a/mm/rmap.c b/mm/rmap.c
index df4b9d1a58ec..362c5e83f072 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1771,8 +1771,7 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page)
  * rmap_walk() and its helpers rmap_walk_anon() and rmap_walk_file():
  * Called by migrate.c to remove migration ptes, but might be used more later.
  */
-static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
-		struct vm_area_struct *, unsigned long, void *), void *arg)
+static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
 {
 	struct anon_vma *anon_vma;
 	pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -1786,7 +1785,7 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
 	anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
 		struct vm_area_struct *vma = avc->vma;
 		unsigned long address = vma_address(page, vma);
-		ret = rmap_one(page, vma, address, arg);
+		ret = rwc->rmap_one(page, vma, address, rwc->arg);
 		if (ret != SWAP_AGAIN)
 			break;
 	}
@@ -1794,8 +1793,7 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
 	return ret;
 }
 
-static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
-		struct vm_area_struct *, unsigned long, void *), void *arg)
+static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
 {
 	struct address_space *mapping = page->mapping;
 	pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -1807,7 +1805,7 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
 	mutex_lock(&mapping->i_mmap_mutex);
 	vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
 		unsigned long address = vma_address(page, vma);
-		ret = rmap_one(page, vma, address, arg);
+		ret = rwc->rmap_one(page, vma, address, rwc->arg);
 		if (ret != SWAP_AGAIN)
 			break;
 	}
@@ -1820,17 +1818,16 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
 	return ret;
 }
 
-int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
-		struct vm_area_struct *, unsigned long, void *), void *arg)
+int rmap_walk(struct page *page, struct rmap_walk_control *rwc)
 {
 	VM_BUG_ON(!PageLocked(page));
 
 	if (unlikely(PageKsm(page)))
-		return rmap_walk_ksm(page, rmap_one, arg);
+		return rmap_walk_ksm(page, rwc);
 	else if (PageAnon(page))
-		return rmap_walk_anon(page, rmap_one, arg);
+		return rmap_walk_anon(page, rwc);
 	else
-		return rmap_walk_file(page, rmap_one, arg);
+		return rmap_walk_file(page, rwc);
 }
 #endif /* CONFIG_MIGRATION */
 
-- 
2.1.4



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