[PATCH v1 10/12] mm: memcontrol: rename {un}lock_page_memcg() to... | linux-mm

[PATCH v1 10/12] mm: memcontrol: rename {un}lock_page_memcg() to {un}lock_page_objcg()

From: Muchun Song <hidden>
Date: 2021-08-14 05:26:36
Also in: lkml
Subsystem: control group (cgroup), control group - memory resource controller (memcg), documentation, filesystems (vfs and infrastructure), memory management, memory management - rmap (reverse mapping), memory management - thp (transparent huge page), page cache, the rest · Maintainers: Tejun Heo, Johannes Weiner, Michal Koutný, Michal Hocko, Roman Gushchin, Shakeel Butt, Jonathan Corbet, Alexander Viro, Christian Brauner, Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Matthew Wilcox, Linus Torvalds

Now the lock_page_memcg() does not lock a page and memcg binding, it
actually lock a page and objcg binding. So rename lock_page_memcg()
to lock_page_objcg().

This is just code cleanup without any functionality changes.

Signed-off-by: Muchun Song <redacted>
---
 Documentation/admin-guide/cgroup-v1/memory.rst |  2 +-
 fs/buffer.c                                    |  8 ++++----
 include/linux/memcontrol.h                     | 14 +++++++-------
 mm/filemap.c                                   |  2 +-
 mm/huge_memory.c                               |  4 ++--
 mm/memcontrol.c                                | 24 ++++++++++++------------
 mm/page-writeback.c                            |  6 +++---
 mm/rmap.c                                      | 14 +++++++-------
 8 files changed, 37 insertions(+), 37 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst
index 41191b5fb69d..dd582312b91a 100644
--- a/Documentation/admin-guide/cgroup-v1/memory.rst
+++ b/Documentation/admin-guide/cgroup-v1/memory.rst

@@ -291,7 +291,7 @@ Lock order is as follows:
 
   Page lock (PG_locked bit of page->flags)
     mm->page_table_lock or split pte_lock
-      lock_page_memcg (memcg->move_lock)
+      lock_page_objcg (memcg->move_lock)
         mapping->i_pages lock
           lruvec->lru_lock.

diff --git a/fs/buffer.c b/fs/buffer.c
index 88123f84885a..c3d20ebb1d0b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c

@@ -635,14 +635,14 @@ int __set_page_dirty_buffers(struct page *page)
 	 * Lock out page's memcg migration to keep PageDirty
 	 * synchronized with per-memcg dirty page counters.
 	 */
-	lock_page_memcg(page);
+	lock_page_objcg(page);
 	newly_dirty = !TestSetPageDirty(page);
 	spin_unlock(&mapping->private_lock);
 
 	if (newly_dirty)
 		__set_page_dirty(page, mapping, 1);
 
-	unlock_page_memcg(page);
+	unlock_page_objcg(page);
 
 	if (newly_dirty)
 		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);

@@ -1139,13 +1139,13 @@ void mark_buffer_dirty(struct buffer_head *bh)
 		struct page *page = bh->b_page;
 		struct address_space *mapping = NULL;
 
-		lock_page_memcg(page);
+		lock_page_objcg(page);
 		if (!TestSetPageDirty(page)) {
 			mapping = page_mapping(page);
 			if (mapping)
 				__set_page_dirty(page, mapping, 0);
 		}
-		unlock_page_memcg(page);
+		unlock_page_objcg(page);
 		if (mapping)
 			__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
 	}

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 92c98a952bab..611e6a6d7b00 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h

@@ -417,12 +417,12 @@ static inline struct obj_cgroup *folio_objcg(struct folio *folio)
  * proper memory cgroup pointer. It's not safe to call this function
  * against some type of folios, e.g. slab folios or ex-slab folios.
  *
- * For a folio any of the following ensures folio and memcg binding
- * stability:
+ * For a page any of the following ensures page and objcg binding
+ * stability (But the folio can be reparented to its parent memcg):
  *
  * - the folio lock
  * - LRU isolation
- * - lock_page_memcg()
+ * - lock_page_objcg()
  * - exclusive reference
  *
  * Based on the stable binding of folio and objcg, for a folio any of the

@@ -970,8 +970,8 @@ extern bool cgroup_memory_noswap;
 
 void folio_memcg_lock(struct folio *folio);
 void folio_memcg_unlock(struct folio *folio);
-void lock_page_memcg(struct page *page);
-void unlock_page_memcg(struct page *page);
+void lock_page_objcg(struct page *page);
+void unlock_page_objcg(struct page *page);
 
 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);

@@ -1388,11 +1388,11 @@ mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
 {
 }
 
-static inline void lock_page_memcg(struct page *page)
+static inline void lock_page_objcg(struct page *page)
 {
 }
 
-static inline void unlock_page_memcg(struct page *page)
+static inline void unlock_page_objcg(struct page *page)
 {
 }

diff --git a/mm/filemap.c b/mm/filemap.c
index 53913fced7ae..b5298fd17d14 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c

@@ -112,7 +112,7 @@
  *    ->i_pages lock		(page_remove_rmap->set_page_dirty)
  *    bdi.wb->list_lock		(page_remove_rmap->set_page_dirty)
  *    ->inode->i_lock		(page_remove_rmap->set_page_dirty)
- *    ->memcg->move_lock	(page_remove_rmap->lock_page_memcg)
+ *    ->memcg->move_lock	(page_remove_rmap->lock_page_objcg)
  *    bdi.wb->list_lock		(zap_pte_range->set_page_dirty)
  *    ->inode->i_lock		(zap_pte_range->set_page_dirty)
  *    ->private_lock		(zap_pte_range->__set_page_dirty_buffers)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 731e1b894407..eb3c07c00d2c 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c

@@ -2227,7 +2227,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 				atomic_inc(&page[i]._mapcount);
 		}
 
-		lock_page_memcg(page);
+		lock_page_objcg(page);
 		if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
 			/* Last compound_mapcount is gone. */
 			__mod_lruvec_page_state(page, NR_ANON_THPS,

@@ -2238,7 +2238,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 					atomic_dec(&page[i]._mapcount);
 			}
 		}
-		unlock_page_memcg(page);
+		unlock_page_objcg(page);
 	}
 
 	smp_wmb(); /* make pte visible before pmd */

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 52a878081452..9464e6d2d735 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c

@@ -2135,18 +2135,18 @@ void folio_memcg_lock(struct folio *folio)
 	 * When charge migration first begins, we can have multiple
 	 * critical sections holding the fast-path RCU lock and one
 	 * holding the slowpath move_lock. Track the task who has the
-	 * move_lock for unlock_page_memcg().
+	 * move_lock for unlock_page_objcg().
 	 */
 	memcg->move_lock_task = current;
 	memcg->move_lock_flags = flags;
 }
 EXPORT_SYMBOL(folio_memcg_lock);
 
-void lock_page_memcg(struct page *page)
+void lock_page_objcg(struct page *page)
 {
 	folio_memcg_lock(page_folio(page));
 }
-EXPORT_SYMBOL(lock_page_memcg);
+EXPORT_SYMBOL(lock_page_objcg);
 
 static void __folio_memcg_unlock(struct mem_cgroup *memcg)
 {

@@ -2176,11 +2176,11 @@ void folio_memcg_unlock(struct folio *folio)
 }
 EXPORT_SYMBOL(folio_memcg_unlock);
 
-void unlock_page_memcg(struct page *page)
+void unlock_page_objcg(struct page *page)
 {
 	folio_memcg_unlock(page_folio(page));
 }
-EXPORT_SYMBOL(unlock_page_memcg);
+EXPORT_SYMBOL(unlock_page_objcg);
 
 struct obj_stock {
 #ifdef CONFIG_MEMCG_KMEM

@@ -2887,7 +2887,7 @@ static void commit_charge(struct folio *folio, struct obj_cgroup *objcg)
 	 *
 	 * - the page lock
 	 * - LRU isolation
-	 * - lock_page_memcg()
+	 * - lock_page_objcg()
 	 * - exclusive reference
 	 */
 	folio->memcg_data = (unsigned long)objcg;

@@ -5826,7 +5826,7 @@ static int mem_cgroup_move_account(struct page *page,
 	 * with (un)charging, migration, LRU putback, or anything else
 	 * that would rely on a stable page's memory cgroup.
 	 *
-	 * Note that lock_page_memcg is a memcg lock, not a page lock,
+	 * Note that lock_page_objcg is a memcg lock, not a page lock,
 	 * to save space. As soon as we switch page's memory cgroup to a
 	 * new memcg that isn't locked, the above state can change
 	 * concurrently again. Make sure we're truly done with it.

@@ -6281,7 +6281,7 @@ static void mem_cgroup_move_charge(void)
 {
 	lru_add_drain_all();
 	/*
-	 * Signal lock_page_memcg() to take the memcg's move_lock
+	 * Signal lock_page_objcg() to take the memcg's move_lock
 	 * while we're moving its pages to another memcg. Then wait
 	 * for already started RCU-only updates to finish.
 	 */

@@ -6313,14 +6313,14 @@ static void mem_cgroup_move_charge(void)
 	/*
 	 * Moving its pages to another memcg is finished. Wait for already
 	 * started RCU-only updates to finish to make sure that the caller
-	 * of lock_page_memcg() can unlock the correct move_lock. The
+	 * of lock_page_objcg() can unlock the correct move_lock. The
 	 * possible bad scenario would like:
 	 *
 	 * CPU0:				CPU1:
 	 * mem_cgroup_move_charge()
 	 *     walk_page_range()
 	 *
-	 *					lock_page_memcg(page)
+	 *					unlock_page_objcg(page)
 	 *					    memcg = folio_memcg()
 	 *					    spin_lock_irqsave(&memcg->move_lock)
 	 *					    memcg->move_lock_task = current

@@ -6331,14 +6331,14 @@ static void mem_cgroup_move_charge(void)
 	 *     memcg_offline_kmem()
 	 *         memcg_reparent_objcgs() <== reparented
 	 *
-	 *					unlock_page_memcg(page)
+	 *					unlock_page_objcg(page)
 	 *					    memcg = folio_memcg() <== memcg has been changed
 	 *					    if (memcg->move_lock_task == current) <== false
 	 *					        spin_unlock_irqrestore(&memcg->move_lock)
 	 *
 	 * Once mem_cgroup_move_charge() returns (it means that the cgroup_mutex
 	 * would be released soon), the page can be reparented to its parent
-	 * memcg. When the unlock_page_memcg() is called for the page, we will
+	 * memcg. When the unlock_page_objcg() is called for the page, we will
 	 * miss unlock the move_lock. So using synchronize_rcu to wait for
 	 * already started RCU-only updates to finish before this function
 	 * returns (mem_cgroup_move_charge() and mem_cgroup_css_offline() are

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 5b171aa067c1..d8fd7308dd39 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c

@@ -2434,7 +2434,7 @@ EXPORT_SYMBOL(__set_page_dirty_no_writeback);
 /*
  * Helper function for set_page_dirty family.
  *
- * Caller must hold lock_page_memcg().
+ * Caller must hold lock_page_objcg().
  *
  * NOTE: This relies on being atomic wrt interrupts.
  */

@@ -2468,7 +2468,7 @@ static void folio_account_dirtied(struct folio *folio,
 /*
  * Helper function for deaccounting dirty page without writeback.
  *
- * Caller must hold lock_page_memcg().
+ * Caller must hold lock_page_objcg().
  */
 void folio_account_cleaned(struct folio *folio, struct address_space *mapping,
 			  struct bdi_writeback *wb)

@@ -2489,7 +2489,7 @@ void folio_account_cleaned(struct folio *folio, struct address_space *mapping,
  * If warn is true, then emit a warning if the folio is not uptodate and has
  * not been truncated.
  *
- * The caller must hold lock_page_memcg().
+ * The caller must hold lock_page_objcg().
  */
 void __folio_mark_dirty(struct folio *folio, struct address_space *mapping,
 			     int warn)

diff --git a/mm/rmap.c b/mm/rmap.c
index 09c41e1f44d8..232494888628 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c

@@ -32,7 +32,7 @@
  *                 swap_lock (in swap_duplicate, swap_info_get)
  *                   mmlist_lock (in mmput, drain_mmlist and others)
  *                   mapping->private_lock (in __set_page_dirty_buffers)
- *                     lock_page_memcg move_lock (in __set_page_dirty_buffers)
+ *                     lock_page_objcg move_lock (in __set_page_dirty_buffers)
  *                       i_pages lock (widely used)
  *                         lruvec->lru_lock (in folio_lruvec_lock_irq)
  *                   inode->i_lock (in set_page_dirty's __mark_inode_dirty)

@@ -1125,7 +1125,7 @@ void do_page_add_anon_rmap(struct page *page,
 	bool first;
 
 	if (unlikely(PageKsm(page)))
-		lock_page_memcg(page);
+		lock_page_objcg(page);
 	else
 		VM_BUG_ON_PAGE(!PageLocked(page), page);

@@ -1153,7 +1153,7 @@ void do_page_add_anon_rmap(struct page *page,
 	}
 
 	if (unlikely(PageKsm(page))) {
-		unlock_page_memcg(page);
+		unlock_page_objcg(page);
 		return;
 	}

@@ -1213,7 +1213,7 @@ void page_add_file_rmap(struct page *page, bool compound)
 	int i, nr = 1;
 
 	VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
-	lock_page_memcg(page);
+	lock_page_objcg(page);
 	if (compound && PageTransHuge(page)) {
 		int nr_pages = thp_nr_pages(page);

@@ -1242,7 +1242,7 @@ void page_add_file_rmap(struct page *page, bool compound)
 	}
 	__mod_lruvec_page_state(page, NR_FILE_MAPPED, nr);
 out:
-	unlock_page_memcg(page);
+	unlock_page_objcg(page);
 }
 
 static void page_remove_file_rmap(struct page *page, bool compound)

@@ -1343,7 +1343,7 @@ static void page_remove_anon_compound_rmap(struct page *page)
  */
 void page_remove_rmap(struct page *page, bool compound)
 {
-	lock_page_memcg(page);
+	lock_page_objcg(page);
 
 	if (!PageAnon(page)) {
 		page_remove_file_rmap(page, compound);

@@ -1382,7 +1382,7 @@ void page_remove_rmap(struct page *page, bool compound)
 	 * faster for those pages still in swapcache.
 	 */
 out:
-	unlock_page_memcg(page);
+	unlock_page_objcg(page);
 }
 
 /*

-- 
2.11.0

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