[PATCH 3/4] Block I/O tracking

[Hirokazu Takahashi]

Hi,

This patch is for cleaning up the code of the cgroup memory subsystem
to remove some "#ifdef"s.


Signed-off-by: Hirokazu Takahashi <taka@xxxxxxxxxxxxx>


--- linux-2.6.25-rc5.pagecgroup3/mm/memcontrol.c	2008-03-18 13:01:57.000000000 +0900
+++ linux-2.6.25-rc5-mm1/mm/memcontrol.c	2008-03-18 14:00:23.000000000 +0900
@@ -216,6 +216,51 @@ static struct mem_cgroup *mem_cgroup_fro
 				struct mem_cgroup, css);
 }
 
+static inline void get_mem_cgroup(struct mem_cgroup *mem)
+{
+	css_get(&mem->css);
+}
+
+static inline void put_mem_cgroup(struct mem_cgroup *mem)
+{
+	css_put(&mem->css);
+}
+
+static inline void set_mem_cgroup(struct page_cgroup *pc,
+                                        struct mem_cgroup *mem)
+{
+	pc->mem_cgroup = mem;
+}
+
+static inline void clear_mem_cgroup(struct page_cgroup *pc)
+{
+	struct mem_cgroup *mem = pc->mem_cgroup;
+	res_counter_uncharge(&mem->res, PAGE_SIZE);
+	pc->mem_cgroup = NULL;
+	put_mem_cgroup(mem);
+}
+
+/* This sould be called in an RCU-protected section. */
+static inline struct mem_cgroup *mm_get_mem_cgroup(struct mm_struct *mm)
+{
+	struct mem_cgroup *mem = rcu_dereference(mm->mem_cgroup);
+	get_mem_cgroup(mem);
+	return mem;
+}
+
+static inline void mm_init_mem_cgroup(struct mm_struct *mm,
+					struct task_struct *p)
+{
+	struct mem_cgroup *mem = mem_cgroup_from_task(p);
+	get_mem_cgroup(mem);
+	mm->mem_cgroup = mem;
+}
+
+static inline void mm_free_mem_cgroup(struct mm_struct *mm)
+{
+	put_mem_cgroup(mm->mem_cgroup);
+}
+
 static void __mem_cgroup_remove_list(struct page_cgroup *pc)
 {
 	int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
@@ -266,6 +311,26 @@ static void __mem_cgroup_move_lists(stru
 	}
 }
 
+static inline void mem_cgroup_add_page(struct page_cgroup *pc)
+{
+	struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&mz->lru_lock, flags);
+	__mem_cgroup_add_list(pc);
+	spin_unlock_irqrestore(&mz->lru_lock, flags);
+}
+
+static inline void mem_cgroup_remove_page(struct page_cgroup *pc)
+{
+	struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&mz->lru_lock, flags);
+	__mem_cgroup_remove_list(pc);
+	spin_unlock_irqrestore(&mz->lru_lock, flags);
+}
+
 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
 {
 	int ret;
@@ -305,6 +370,37 @@ void mem_cgroup_move_lists(struct page *
 	unlock_page_cgroup(page);
 }
 
+static inline int mem_cgroup_try_to_allocate(struct mem_cgroup *mem,
+						gfp_t gfp_mask)
+{
+	unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+
+	while (res_counter_charge(&mem->res, PAGE_SIZE)) {
+		if (!(gfp_mask & __GFP_WAIT))
+			return -1;
+
+		if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
+			continue;
+
+		/*
+		 * try_to_free_mem_cgroup_pages() might not give us a full
+		 * picture of reclaim. Some pages are reclaimed and might be
+		 * moved to swap cache or just unmapped from the cgroup.
+		 * Check the limit again to see if the reclaim reduced the
+		 * current usage of the cgroup before giving up
+		 */
+		if (res_counter_check_under_limit(&mem->res))
+			continue;
+
+		if (!nr_retries--) {
+			mem_cgroup_out_of_memory(mem, gfp_mask);
+			return -1;
+		}
+		congestion_wait(WRITE, HZ/10);
+	}
+	return 0;
+}
+
 /*
  * Calculate mapped_ratio under memory controller. This will be used in
  * vmscan.c for deteremining we have to reclaim mapped pages.
@@ -497,7 +593,7 @@ static int mem_cgroup_force_empty(struct
 	if (mem_cgroup_disabled())
 		return 0;
 
-	css_get(&mem->css);
+	get_mem_cgroup(mem);
 	/*
 	 * page reclaim code (kswapd etc..) will move pages between
 	 * active_list <-> inactive_list while we don't take a lock.
@@ -518,7 +614,7 @@ static int mem_cgroup_force_empty(struct
 	}
 	ret = 0;
 out:
-	css_put(&mem->css);
+	put_mem_cgroup(mem);
 	return ret;
 }
 
@@ -750,9 +846,9 @@ static void mem_cgroup_move_task(struct 
 	if (p->tgid != p->pid)
 		goto out;
 
-	css_get(&mem->css);
+	get_mem_cgroup(mem);
 	rcu_assign_pointer(mm->mem_cgroup, mem);
-	css_put(&old_mem->css);
+	put_mem_cgroup(old_mem);
 
 out:
 	mmput(mm);
@@ -770,29 +866,47 @@ struct cgroup_subsys mem_cgroup_subsys =
 };
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
 
+struct mem_cgroup;
+
 static inline int mem_cgroup_disabled(void)
 {
 	return 1;
 }
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
 
-void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p)
+static inline void mem_cgroup_add_page(struct page_cgroup *pc) {}
+static inline void mem_cgroup_remove_page(struct page_cgroup *pc) {}
+static inline void get_mem_cgroup(struct mem_cgroup *mem) {}
+static inline void put_mem_cgroup(struct mem_cgroup *mem) {}
+static inline void set_mem_cgroup(struct page_cgroup *pc,
+					struct mem_cgroup *mem) {}
+static inline void clear_mem_cgroup(struct page_cgroup *pc) {}
+
+static inline struct mem_cgroup *mm_get_mem_cgroup(struct mm_struct *mm)
 {
-	struct mem_cgroup *mem;
+	return NULL;
+}
 
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	mem = mem_cgroup_from_task(p);
-	css_get(&mem->css);
-	mm->mem_cgroup = mem;
+static inline void mm_init_mem_cgroup(struct mm_struct *mm,
+					struct task_struct *p) {}
+static inline void mm_free_mem_cgroup(struct mm_struct *mm) {}
+
+static inline int mem_cgroup_try_to_allocate(struct mem_cgroup *mem,
+					gfp_t gfp_mask)
+{
+	return 0;
+}
+  
 #endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+
+void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p)
+{
+	mm_init_mem_cgroup(mm, p);
 	mm_init_bio_cgroup(mm, p);
 }
 
 void mm_free_cgroup(struct mm_struct *mm)
 {
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	css_put(&mm->mem_cgroup->css);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	mm_free_mem_cgroup(mm);
 	mm_free_bio_cgroup(mm);
 }
 
@@ -827,12 +941,7 @@ static int mem_cgroup_charge_common(stru
 				gfp_t gfp_mask, enum charge_type ctype)
 {
 	struct page_cgroup *pc;
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
 	struct mem_cgroup *mem;
-	unsigned long flags;
-	unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
-	struct mem_cgroup_per_zone *mz;
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
 	struct bio_cgroup *biog;
   
 	if (mem_cgroup_disabled() && bio_cgroup_disabled())
@@ -876,46 +985,18 @@ retry:
 		mm = &init_mm;
 
 	rcu_read_lock();
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	mem = rcu_dereference(mm->mem_cgroup);
 	/*
 	 * For every charge from the cgroup, increment reference count
 	 */
-	css_get(&mem->css);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	mem = mm_get_mem_cgroup(mm);
 	biog = mm_get_bio_cgroup(mm);
 	rcu_read_unlock();
 
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	while (res_counter_charge(&mem->res, PAGE_SIZE)) {
-		if (!(gfp_mask & __GFP_WAIT))
-			goto out;
-
-		if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
-			continue;
-
-		/*
-		 * try_to_free_mem_cgroup_pages() might not give us a full
-		 * picture of reclaim. Some pages are reclaimed and might be
-		 * moved to swap cache or just unmapped from the cgroup.
-		 * Check the limit again to see if the reclaim reduced the
-		 * current usage of the cgroup before giving up
-		 */
-		if (res_counter_check_under_limit(&mem->res))
-			continue;
-
-		if (!nr_retries--) {
-			mem_cgroup_out_of_memory(mem, gfp_mask);
-			goto out;
-		}
-		congestion_wait(WRITE, HZ/10);
-	}
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	if (mem_cgroup_try_to_allocate(mem, gfp_mask) < 0)
+		goto out;
 
 	pc->ref_cnt = 1;
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	pc->mem_cgroup = mem;
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	set_mem_cgroup(pc, mem);
 	set_bio_cgroup(pc, biog);
 	pc->page = page;
 	pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
@@ -930,31 +1011,21 @@ retry:
 		 * We take lock_page_cgroup(page) again and read
 		 * page->cgroup, increment refcnt.... just retry is OK.
 		 */
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-		res_counter_uncharge(&mem->res, PAGE_SIZE);
-		css_put(&mem->css);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+		clear_mem_cgroup(pc);
 		clear_bio_cgroup(pc);
 		kfree(pc);
 		goto retry;
 	}
 	page_assign_page_cgroup(page, pc);
 
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	mz = page_cgroup_zoneinfo(pc);
-	spin_lock_irqsave(&mz->lru_lock, flags);
-	__mem_cgroup_add_list(pc);
-	spin_unlock_irqrestore(&mz->lru_lock, flags);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	mem_cgroup_add_page(pc);
 	bio_cgroup_add_page(pc);
 
 	unlock_page_cgroup(page);
 done:
 	return 0;
 out:
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	css_put(&mem->css);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	put_mem_cgroup(mem);
 	put_bio_cgroup(biog);
 	kfree(pc);
 err:
@@ -983,9 +1054,6 @@ int mem_cgroup_cache_charge(struct page 
 void mem_cgroup_uncharge_page(struct page *page)
 {
 	struct page_cgroup *pc;
-	struct mem_cgroup *mem;
-	struct mem_cgroup_per_zone *mz;
-	unsigned long flags;
 
 	if (mem_cgroup_disabled() && bio_cgroup_disabled())
 		return;
@@ -1002,22 +1070,13 @@ void mem_cgroup_uncharge_page(struct pag
 	VM_BUG_ON(pc->ref_cnt <= 0);
 
 	if (--(pc->ref_cnt) == 0) {
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-		mz = page_cgroup_zoneinfo(pc);
-		spin_lock_irqsave(&mz->lru_lock, flags);
-		__mem_cgroup_remove_list(pc);
-		spin_unlock_irqrestore(&mz->lru_lock, flags);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+		mem_cgroup_remove_page(pc);
 		bio_cgroup_remove_page(pc);
 
 		page_assign_page_cgroup(page, NULL);
 		unlock_page_cgroup(page);
 
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-		mem = pc->mem_cgroup;
-		res_counter_uncharge(&mem->res, PAGE_SIZE);
-		css_put(&mem->css);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+		clear_mem_cgroup(pc);
 		clear_bio_cgroup(pc);
 
 		kfree(pc);
@@ -1060,8 +1119,6 @@ void mem_cgroup_end_migration(struct pag
 void mem_cgroup_page_migration(struct page *page, struct page *newpage)
 {
 	struct page_cgroup *pc;
-	struct mem_cgroup_per_zone *mz;
-	unsigned long flags;
 
 	lock_page_cgroup(page);
 	pc = page_get_page_cgroup(page);
@@ -1070,12 +1127,7 @@ void mem_cgroup_page_migration(struct pa
 		return;
 	}
 
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	mz = page_cgroup_zoneinfo(pc);
-	spin_lock_irqsave(&mz->lru_lock, flags);
-	__mem_cgroup_remove_list(pc);
-	spin_unlock_irqrestore(&mz->lru_lock, flags);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	mem_cgroup_remove_page(pc);
 	bio_cgroup_remove_page(pc);
 
 	page_assign_page_cgroup(page, NULL);
@@ -1085,12 +1137,7 @@ void mem_cgroup_page_migration(struct pa
 	lock_page_cgroup(newpage);
 	page_assign_page_cgroup(newpage, pc);
 
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	mz = page_cgroup_zoneinfo(pc);
-	spin_lock_irqsave(&mz->lru_lock, flags);
-	__mem_cgroup_add_list(pc);
-	spin_unlock_irqrestore(&mz->lru_lock, flags);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	mem_cgroup_add_page(pc);
 	bio_cgroup_add_page(pc);
 
 	unlock_page_cgroup(newpage);
--
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