All of lore.kernel.org
 help / color / mirror / Atom feed
From: akpm@linux-foundation.org
To: hannes@cmpxchg.org, mhocko@suse.cz, vdavydov@virtuozzo.com,
	mm-commits@vger.kernel.org
Subject: [merged] mm-remove-unnecessary-uses-of-lock_page_memcg.patch removed from -mm tree
Date: Wed, 16 Mar 2016 12:56:58 -0700	[thread overview]
Message-ID: <56e9ba8a.0sgCUoWqZTDeY26H%akpm@linux-foundation.org> (raw)


The patch titled
     Subject: mm: remove unnecessary uses of lock_page_memcg()
has been removed from the -mm tree.  Its filename was
     mm-remove-unnecessary-uses-of-lock_page_memcg.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Johannes Weiner <hannes@cmpxchg.org>
Subject: mm: remove unnecessary uses of lock_page_memcg()

There are several users that nest lock_page_memcg() inside lock_page() to
prevent page->mem_cgroup from changing.  But the page lock prevents pages
from moving between cgroups, so that is unnecessary overhead.

Remove lock_page_memcg() in contexts with locked contexts and fix the
debug code in the page stat functions to be okay with the page lock.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/memcontrol.h |   12 +++++++-----
 mm/filemap.c               |    7 +------
 mm/page-writeback.c        |    2 --
 mm/truncate.c              |    3 ---
 mm/vmscan.c                |    4 ----
 5 files changed, 8 insertions(+), 20 deletions(-)

diff -puN include/linux/memcontrol.h~mm-remove-unnecessary-uses-of-lock_page_memcg include/linux/memcontrol.h
--- a/include/linux/memcontrol.h~mm-remove-unnecessary-uses-of-lock_page_memcg
+++ a/include/linux/memcontrol.h
@@ -28,6 +28,7 @@
 #include <linux/eventfd.h>
 #include <linux/mmzone.h>
 #include <linux/writeback.h>
+#include <linux/page-flags.h>
 
 struct mem_cgroup;
 struct page;
@@ -464,18 +465,19 @@ void unlock_page_memcg(struct page *page
  * @idx: page state item to account
  * @val: number of pages (positive or negative)
  *
- * Callers must use lock_page_memcg() to prevent double accounting
- * when the page is concurrently being moved to another memcg:
+ * The @page must be locked or the caller must use lock_page_memcg()
+ * to prevent double accounting when the page is concurrently being
+ * moved to another memcg:
  *
- *   lock_page_memcg(page);
+ *   lock_page(page) or lock_page_memcg(page)
  *   if (TestClearPageState(page))
  *     mem_cgroup_update_page_stat(page, state, -1);
- *   unlock_page_memcg(page);
+ *   unlock_page(page) or unlock_page_memcg(page)
  */
 static inline void mem_cgroup_update_page_stat(struct page *page,
 				 enum mem_cgroup_stat_index idx, int val)
 {
-	VM_BUG_ON(!rcu_read_lock_held());
+	VM_BUG_ON(!(rcu_read_lock_held() || PageLocked(page)));
 
 	if (page->mem_cgroup)
 		this_cpu_add(page->mem_cgroup->stat->count[idx], val);
diff -puN mm/filemap.c~mm-remove-unnecessary-uses-of-lock_page_memcg mm/filemap.c
--- a/mm/filemap.c~mm-remove-unnecessary-uses-of-lock_page_memcg
+++ a/mm/filemap.c
@@ -176,8 +176,7 @@ static void page_cache_tree_delete(struc
 /*
  * Delete a page from the page cache and free it. Caller has to make
  * sure the page is locked and that nobody else uses it - or that usage
- * is safe.  The caller must hold the mapping's tree_lock and
- * lock_page_memcg().
+ * is safe.  The caller must hold the mapping's tree_lock.
  */
 void __delete_from_page_cache(struct page *page, void *shadow)
 {
@@ -260,11 +259,9 @@ void delete_from_page_cache(struct page
 
 	freepage = mapping->a_ops->freepage;
 
-	lock_page_memcg(page);
 	spin_lock_irqsave(&mapping->tree_lock, flags);
 	__delete_from_page_cache(page, NULL);
 	spin_unlock_irqrestore(&mapping->tree_lock, flags);
-	unlock_page_memcg(page);
 
 	if (freepage)
 		freepage(page);
@@ -557,7 +554,6 @@ int replace_page_cache_page(struct page
 		new->mapping = mapping;
 		new->index = offset;
 
-		lock_page_memcg(old);
 		spin_lock_irqsave(&mapping->tree_lock, flags);
 		__delete_from_page_cache(old, NULL);
 		error = radix_tree_insert(&mapping->page_tree, offset, new);
@@ -572,7 +568,6 @@ int replace_page_cache_page(struct page
 		if (PageSwapBacked(new))
 			__inc_zone_page_state(new, NR_SHMEM);
 		spin_unlock_irqrestore(&mapping->tree_lock, flags);
-		unlock_page_memcg(old);
 		mem_cgroup_migrate(old, new);
 		radix_tree_preload_end();
 		if (freepage)
diff -puN mm/page-writeback.c~mm-remove-unnecessary-uses-of-lock_page_memcg mm/page-writeback.c
--- a/mm/page-writeback.c~mm-remove-unnecessary-uses-of-lock_page_memcg
+++ a/mm/page-writeback.c
@@ -2700,7 +2700,6 @@ int clear_page_dirty_for_io(struct page
 		 * always locked coming in here, so we get the desired
 		 * exclusion.
 		 */
-		lock_page_memcg(page);
 		wb = unlocked_inode_to_wb_begin(inode, &locked);
 		if (TestClearPageDirty(page)) {
 			mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
@@ -2709,7 +2708,6 @@ int clear_page_dirty_for_io(struct page
 			ret = 1;
 		}
 		unlocked_inode_to_wb_end(inode, locked);
-		unlock_page_memcg(page);
 		return ret;
 	}
 	return TestClearPageDirty(page);
diff -puN mm/truncate.c~mm-remove-unnecessary-uses-of-lock_page_memcg mm/truncate.c
--- a/mm/truncate.c~mm-remove-unnecessary-uses-of-lock_page_memcg
+++ a/mm/truncate.c
@@ -527,7 +527,6 @@ invalidate_complete_page2(struct address
 	if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
 		return 0;
 
-	lock_page_memcg(page);
 	spin_lock_irqsave(&mapping->tree_lock, flags);
 	if (PageDirty(page))
 		goto failed;
@@ -535,7 +534,6 @@ invalidate_complete_page2(struct address
 	BUG_ON(page_has_private(page));
 	__delete_from_page_cache(page, NULL);
 	spin_unlock_irqrestore(&mapping->tree_lock, flags);
-	unlock_page_memcg(page);
 
 	if (mapping->a_ops->freepage)
 		mapping->a_ops->freepage(page);
@@ -544,7 +542,6 @@ invalidate_complete_page2(struct address
 	return 1;
 failed:
 	spin_unlock_irqrestore(&mapping->tree_lock, flags);
-	unlock_page_memcg(page);
 	return 0;
 }
 
diff -puN mm/vmscan.c~mm-remove-unnecessary-uses-of-lock_page_memcg mm/vmscan.c
--- a/mm/vmscan.c~mm-remove-unnecessary-uses-of-lock_page_memcg
+++ a/mm/vmscan.c
@@ -607,7 +607,6 @@ static int __remove_mapping(struct addre
 	BUG_ON(!PageLocked(page));
 	BUG_ON(mapping != page_mapping(page));
 
-	lock_page_memcg(page);
 	spin_lock_irqsave(&mapping->tree_lock, flags);
 	/*
 	 * The non racy check for a busy page.
@@ -647,7 +646,6 @@ static int __remove_mapping(struct addre
 		mem_cgroup_swapout(page, swap);
 		__delete_from_swap_cache(page);
 		spin_unlock_irqrestore(&mapping->tree_lock, flags);
-		unlock_page_memcg(page);
 		swapcache_free(swap);
 	} else {
 		void (*freepage)(struct page *);
@@ -675,7 +673,6 @@ static int __remove_mapping(struct addre
 			shadow = workingset_eviction(mapping, page);
 		__delete_from_page_cache(page, shadow);
 		spin_unlock_irqrestore(&mapping->tree_lock, flags);
-		unlock_page_memcg(page);
 
 		if (freepage != NULL)
 			freepage(page);
@@ -685,7 +682,6 @@ static int __remove_mapping(struct addre
 
 cannot_free:
 	spin_unlock_irqrestore(&mapping->tree_lock, flags);
-	unlock_page_memcg(page);
 	return 0;
 }
 
_

Patches currently in -mm which might be from hannes@cmpxchg.org are

mm-oom_kill-dont-ignore-oom-score-on-exiting-tasks.patch
mm-scale-kswapd-watermarks-in-proportion-to-memory.patch
mm-scale-kswapd-watermarks-in-proportion-to-memory-v3.patch
mm-memcontrol-reclaim-when-shrinking-memoryhigh-below-usage.patch
mm-memcontrol-reclaim-and-oom-kill-when-shrinking-memorymax-below-usage.patch
mm-memcontrol-clarify-the-uncharge_list-loop.patch


                 reply	other threads:[~2016-03-16 19:56 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=56e9ba8a.0sgCUoWqZTDeY26H%akpm@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=hannes@cmpxchg.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mhocko@suse.cz \
    --cc=mm-commits@vger.kernel.org \
    --cc=vdavydov@virtuozzo.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.