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Date: Tue, 21 Oct 2014 16:21:33 -0400
From: Johannes Weiner <hannes@...xchg.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Michal Hocko <mhocko@...e.cz>,
Vladimir Davydov <vdavydov@...allels.com>, linux-mm@...ck.org,
cgroups@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [patch 1/4] mm: memcontrol: inline memcg->move_lock locking
The wrappers around taking and dropping the memcg->move_lock spinlock
add nothing of value. Inline the spinlock calls into the callsites.
Signed-off-by: Johannes Weiner <hannes@...xchg.org>
---
mm/memcontrol.c | 34 +++++++++-------------------------
1 file changed, 9 insertions(+), 25 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 293db8234179..1ff125d2a427 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1507,23 +1507,6 @@ static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
return false;
}
-/*
- * Take this lock when
- * - a code tries to modify page's memcg while it's USED.
- * - a code tries to modify page state accounting in a memcg.
- */
-static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
- unsigned long *flags)
-{
- spin_lock_irqsave(&memcg->move_lock, *flags);
-}
-
-static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
- unsigned long *flags)
-{
- spin_unlock_irqrestore(&memcg->move_lock, *flags);
-}
-
#define K(x) ((x) << (PAGE_SHIFT-10))
/**
* mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
@@ -2013,7 +1996,7 @@ again:
return;
/*
* If this memory cgroup is not under account moving, we don't
- * need to take move_lock_mem_cgroup(). Because we already hold
+ * need to take &memcg->move_lock. Because we already hold
* rcu_read_lock(), any calls to move_account will be delayed until
* rcu_read_unlock().
*/
@@ -2021,9 +2004,9 @@ again:
if (atomic_read(&memcg->moving_account) <= 0)
return;
- move_lock_mem_cgroup(memcg, flags);
+ spin_lock_irqsave(&memcg->move_lock, *flags);
if (memcg != pc->mem_cgroup) {
- move_unlock_mem_cgroup(memcg, flags);
+ spin_unlock_irqrestore(&memcg->move_lock, *flags);
goto again;
}
*locked = true;
@@ -2038,7 +2021,7 @@ void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
* lock is held because a routine modifies pc->mem_cgroup
* should take move_lock_mem_cgroup().
*/
- move_unlock_mem_cgroup(pc->mem_cgroup, flags);
+ spin_unlock_irqrestore(&pc->mem_cgroup->move_lock, *flags);
}
void mem_cgroup_update_page_stat(struct page *page,
@@ -3083,7 +3066,7 @@ static int mem_cgroup_move_account(struct page *page,
if (pc->mem_cgroup != from)
goto out_unlock;
- move_lock_mem_cgroup(from, &flags);
+ spin_lock_irqsave(&from->move_lock, flags);
if (!PageAnon(page) && page_mapped(page)) {
__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
@@ -3107,7 +3090,8 @@ static int mem_cgroup_move_account(struct page *page,
/* caller should have done css_get */
pc->mem_cgroup = to;
- move_unlock_mem_cgroup(from, &flags);
+ spin_unlock_irqrestore(&from->move_lock, flags);
+
ret = 0;
local_irq_disable();
@@ -6033,9 +6017,9 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
* but there might still be references, e.g. from finishing
* writeback. Follow the charge moving protocol here.
*/
- move_lock_mem_cgroup(memcg, &flags);
+ spin_lock_irqsave(&memcg->move_lock, flags);
pc->mem_cgroup = NULL;
- move_unlock_mem_cgroup(memcg, &flags);
+ spin_unlock_irqrestore(&memcg->move_lock, flags);
if (lrucare)
unlock_page_lru(oldpage, isolated);
--
2.1.2
--
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