[PATCH 2/4] BIO tracking take2

[Hirokazu Takahashi]

Hi,

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


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


diff -dupr linux-2.6.26-rc2.cg1/mm/memcontrol.c linux-2.6.26-rc2/mm/memcontrol.c
--- linux-2.6.26-rc2.cg1/mm/memcontrol.c	2008-05-19 12:33:32.000000000 +0900
+++ linux-2.6.26-rc2/mm/memcontrol.c	2008-05-19 12:34:16.000000000 +0900
@@ -228,6 +228,47 @@ struct mem_cgroup *mem_cgroup_from_task(
 				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);
+}
+
+static inline struct mem_cgroup *get_mem_page_cgroup(struct page_cgroup *pc)
+{
+	struct mem_cgroup *mem = pc->mem_cgroup;
+	css_get(&mem->css);
+	return 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;
+
+	mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+	get_mem_cgroup(mem);
+	return mem;
+}
+
 static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
 			struct page_cgroup *pc)
 {
@@ -278,6 +319,26 @@ 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(mz, 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(mz, pc);
+	spin_unlock_irqrestore(&mz->lru_lock, flags);
+}
+
 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
 {
 	int ret;
@@ -317,6 +378,36 @@ 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;
+		}
+	}
+	return 0;
+}
+
 /*
  * Calculate mapped_ratio under memory controller. This will be used in
  * vmscan.c for deteremining we have to reclaim mapped pages.
@@ -517,7 +608,7 @@ 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.
@@ -538,7 +629,7 @@ static int mem_cgroup_force_empty(struct
 	}
 	ret = 0;
 out:
-	css_put(&mem->css);
+	put_mem_cgroup(mem);
 	return ret;
 }
 
@@ -825,10 +916,37 @@ struct cgroup_subsys mem_cgroup_subsys =
 
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
 
+struct mem_cgroup;
+
 static inline int mem_cgroup_disabled(void)
 {
 	return 1;
 }
+
+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 *get_mem_page_cgroup(struct page_cgroup *pc)
+{
+	return NULL;
+}
+
+static inline struct mem_cgroup *mm_get_mem_cgroup(struct mm_struct *mm)
+{
+	return NULL;
+}
+
+static inline int mem_cgroup_try_to_allocate(struct mem_cgroup *mem,
+					gfp_t gfp_mask)
+{
+	return 0;
+}
+  
 #endif /* CONFIG_CGROUP_MEM_RES_CTLR */
 
 static inline int page_cgroup_locked(struct page *page)
@@ -863,12 +981,7 @@ static int mem_cgroup_charge_common(stru
 				struct mem_cgroup *memcg)
 {
 	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 */
 
 	if (mem_cgroup_disabled())
 		return 0;
@@ -912,50 +1025,18 @@ retry:
 			mm = &init_mm;
 
 		rcu_read_lock();
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-		mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
-		/*
-		 * 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);
 		rcu_read_unlock();
 	} else {
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
 		mem = memcg;
-		css_get(&memcg->css);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+		get_mem_cgroup(mem);
 	}
 
-#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;
-		}
-	}
-#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);
 	pc->page = page;
 	/*
 	 * If a page is accounted as a page cache, insert to inactive list.
@@ -974,29 +1055,19 @@ 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);
 		kmem_cache_free(page_cgroup_cache, 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(mz, pc);
-	spin_unlock_irqrestore(&mz->lru_lock, flags);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+	mem_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);
 	kmem_cache_free(page_cgroup_cache, pc);
 err:
 	return -ENOMEM;
@@ -1039,11 +1110,6 @@ int mem_cgroup_getref(struct page *page)
 void mem_cgroup_uncharge_page(struct page *page)
 {
 	struct page_cgroup *pc;
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-	struct mem_cgroup *mem;
-	struct mem_cgroup_per_zone *mz;
-	unsigned long flags;
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
 
 	if (mem_cgroup_disabled())
 		return;
@@ -1060,21 +1126,12 @@ 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(mz, pc);
-		spin_unlock_irqrestore(&mz->lru_lock, flags);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+		mem_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);
 
 		kmem_cache_free(page_cgroup_cache, pc);
 		return;
@@ -1100,10 +1157,7 @@ int mem_cgroup_prepare_migration(struct 
 	lock_page_cgroup(page);
 	pc = page_get_page_cgroup(page);
 	if (pc) {
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-		mem = pc->mem_cgroup;
-		css_get(&mem->css);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+		mem = get_mem_page_cgroup(pc);
 		if (pc->flags & PAGE_CGROUP_FLAG_CACHE)
 			ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
 	}
@@ -1111,9 +1165,7 @@ int mem_cgroup_prepare_migration(struct 
 	if (mem) {
 		ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
 			ctype, mem);
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-		css_put(&mem->css);
-#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
+		put_mem_cgroup(mem);
 	}
 	return ret;
 }
--
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