From e62986f87d05e415cfb0379a17a6cf85a2e59b48 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 19 Aug 2009 09:56:42 +0200
Subject: [PATCH 093/290] mm: Replace cgroup_page bit spinlock

Bit spinlocks are not working on RT. Replace them.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/page_cgroup.h |   28 ++++++++++++++++++++++++++++
 mm/page_cgroup.c            |    1 +
 2 files changed, 29 insertions(+)

diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index 961ecc7..2927c08 100644
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -30,6 +30,10 @@ enum {
  */
 struct page_cgroup {
 	unsigned long flags;
+#ifdef CONFIG_PREEMPT_RT_BASE
+	spinlock_t pcg_lock;
+	spinlock_t pcm_lock;
+#endif
 	struct mem_cgroup *mem_cgroup;
 	struct list_head lru;		/* per cgroup LRU list */
 };
@@ -96,30 +100,54 @@ static inline void lock_page_cgroup(struct page_cgroup *pc)
 	 * Don't take this lock in IRQ context.
 	 * This lock is for pc->mem_cgroup, USED, CACHE, MIGRATION
 	 */
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_lock(PCG_LOCK, &pc->flags);
+#else
+	spin_lock(&pc->pcg_lock);
+#endif
 }
 
 static inline void unlock_page_cgroup(struct page_cgroup *pc)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_unlock(PCG_LOCK, &pc->flags);
+#else
+	spin_unlock(&pc->pcg_lock);
+#endif
 }
 
 static inline void move_lock_page_cgroup(struct page_cgroup *pc,
 	unsigned long *flags)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	/*
 	 * We know updates to pc->flags of page cache's stats are from both of
 	 * usual context or IRQ context. Disable IRQ to avoid deadlock.
 	 */
 	local_irq_save(*flags);
 	bit_spin_lock(PCG_MOVE_LOCK, &pc->flags);
+#else
+	spin_lock_irqsave(&pc->pcm_lock, *flags);
+#endif
 }
 
 static inline void move_unlock_page_cgroup(struct page_cgroup *pc,
 	unsigned long *flags)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_unlock(PCG_MOVE_LOCK, &pc->flags);
 	local_irq_restore(*flags);
+#else
+	spin_unlock_irqrestore(&pc->pcm_lock, *flags);
+#endif
+}
+
+static inline void page_cgroup_lock_init(struct page_cgroup *pc)
+{
+#ifdef CONFIG_PREEMPT_RT_BASE
+	spin_lock_init(&pc->pcg_lock);
+	spin_lock_init(&pc->pcm_lock);
+#endif
 }
 
 #ifdef CONFIG_SPARSEMEM
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 2d123f9..2e0d18d 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -17,6 +17,7 @@ static void __meminit init_page_cgroup(struct page_cgroup *pc, unsigned long id)
 	set_page_cgroup_array_id(pc, id);
 	pc->mem_cgroup = NULL;
 	INIT_LIST_HEAD(&pc->lru);
+	page_cgroup_lock_init(pc);
 }
 static unsigned long total_usage;