[PATCH 28/29] memory controller add switch to control what type of pages to limit v7

[menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org]

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From: Balbir Singh <balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>

Choose if we want cached pages to be accounted or not.  By default both are
accounted for.  A new set of tunables are added.

echo -n 1 > mem_control_type

switches the accounting to account for only mapped pages

echo -n 3 > mem_control_type

switches the behaviour back

Signed-off-by: Balbir Singh <balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Cc: Pavel Emelianov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>
Cc: Paul Menage <menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>
Cc: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
Cc: Nick Piggin <nickpiggin-/E1597aS9LT0CCvOHzKKcA@public.gmane.org>
Cc: Kirill Korotaev <dev-3ImXcnM4P+0@public.gmane.org>
Cc: Herbert Poetzl <herbert-dBHVzrDq9nF4Lj/PQRBjDg@public.gmane.org>
Cc: David Rientjes <rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Vaidyanathan Srinivasan <svaidy-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Signed-off-by: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
---

 include/linux/memcontrol.h |    9 +++
 mm/filemap.c               |    2 
 mm/memcontrol.c            |   92 +++++++++++++++++++++++++++++++++++
 mm/swap_state.c            |    2 
 4 files changed, 103 insertions(+), 2 deletions(-)

diff -puN include/linux/memcontrol.h~memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7 include/linux/memcontrol.h
--- a/include/linux/memcontrol.h~memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7
+++ a/include/linux/memcontrol.h
@@ -20,6 +20,8 @@
 #ifndef _LINUX_MEMCONTROL_H
 #define _LINUX_MEMCONTROL_H
 
+#include <linux/mm.h>
+
 struct mem_cgroup;
 struct page_cgroup;
 
@@ -40,6 +42,7 @@ extern unsigned long mem_cgroup_isola
 					struct mem_cgroup *mem_cont,
 					int active);
 extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem);
+extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm);
 
 static inline void mem_cgroup_uncharge_page(struct page *page)
 {
@@ -84,6 +87,12 @@ static inline void mem_cgroup_move_li
 {
 }
 
+static inline int mem_cgroup_cache_charge(struct page *page,
+						struct mm_struct *mm)
+{
+	return 0;
+}
+
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff -puN mm/filemap.c~memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7 mm/filemap.c
--- a/mm/filemap.c~memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7
+++ a/mm/filemap.c
@@ -444,7 +444,7 @@ int add_to_page_cache(struct page *page,
 
 	if (error == 0) {
 
-		error = mem_cgroup_charge(page, current->mm);
+		error = mem_cgroup_cache_charge(page, current->mm);
 		if (error)
 			goto out;
 
diff -puN mm/memcontrol.c~memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7 mm/memcontrol.c
--- a/mm/memcontrol.c~memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7
+++ a/mm/memcontrol.c
@@ -28,6 +28,8 @@
 #include <linux/spinlock.h>
 #include <linux/fs.h>
 
+#include <asm/uaccess.h>
+
 struct cgroup_subsys mem_cgroup_subsys;
 static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
 
@@ -59,6 +61,7 @@ struct mem_cgroup {
 	 * spin_lock to protect the per cgroup LRU
 	 */
 	spinlock_t lru_lock;
+	unsigned long control_type;	/* control RSS or RSS+Pagecache */
 };
 
 /*
@@ -81,6 +84,15 @@ struct page_cgroup {
 					/* mapped and cached states     */
 };
 
+enum {
+	MEM_CGROUP_TYPE_UNSPEC = 0,
+	MEM_CGROUP_TYPE_MAPPED,
+	MEM_CGROUP_TYPE_CACHED,
+	MEM_CGROUP_TYPE_ALL,
+	MEM_CGROUP_TYPE_MAX,
+} mem_control_type;
+
+static struct mem_cgroup init_mem_cgroup;
 
 static inline
 struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
@@ -361,6 +373,22 @@ err:
 }
 
 /*
+ * See if the cached pages should be charged at all?
+ */
+int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm)
+{
+	struct mem_cgroup *mem;
+	if (!mm)
+		mm = &init_mm;
+
+	mem = rcu_dereference(mm->mem_cgroup);
+	if (mem->control_type == MEM_CGROUP_TYPE_ALL)
+		return mem_cgroup_charge(page, mm);
+	else
+		return 0;
+}
+
+/*
  * Uncharging is always a welcome operation, we never complain, simply
  * uncharge.
  */
@@ -370,6 +398,10 @@ void mem_cgroup_uncharge(struct page_
 	struct page *page;
 	unsigned long flags;
 
+	/*
+	 * This can handle cases when a page is not charged at all and we
+	 * are switching between handling the control_type.
+	 */
 	if (!pc)
 		return;
 
@@ -405,6 +437,60 @@ static ssize_t mem_cgroup_write(struc
 				cft->private, userbuf, nbytes, ppos);
 }
 
+static ssize_t mem_control_type_write(struct cgroup *cont,
+			struct cftype *cft, struct file *file,
+			const char __user *userbuf,
+			size_t nbytes, loff_t *pos)
+{
+	int ret;
+	char *buf, *end;
+	unsigned long tmp;
+	struct mem_cgroup *mem;
+
+	mem = mem_cgroup_from_cont(cont);
+	buf = kmalloc(nbytes + 1, GFP_KERNEL);
+	ret = -ENOMEM;
+	if (buf == NULL)
+		goto out;
+
+	buf[nbytes] = 0;
+	ret = -EFAULT;
+	if (copy_from_user(buf, userbuf, nbytes))
+		goto out_free;
+
+	ret = -EINVAL;
+	tmp = simple_strtoul(buf, &end, 10);
+	if (*end != '\0')
+		goto out_free;
+
+	if (tmp <= MEM_CGROUP_TYPE_UNSPEC || tmp >= MEM_CGROUP_TYPE_MAX)
+		goto out_free;
+
+	mem->control_type = tmp;
+	ret = nbytes;
+out_free:
+	kfree(buf);
+out:
+	return ret;
+}
+
+static ssize_t mem_control_type_read(struct cgroup *cont,
+				struct cftype *cft,
+				struct file *file, char __user *userbuf,
+				size_t nbytes, loff_t *ppos)
+{
+	unsigned long val;
+	char buf[64], *s;
+	struct mem_cgroup *mem;
+
+	mem = mem_cgroup_from_cont(cont);
+	s = buf;
+	val = mem->control_type;
+	s += sprintf(s, "%lu\n", val);
+	return simple_read_from_buffer((void __user *)userbuf, nbytes,
+			ppos, buf, s - buf);
+}
+
 static struct cftype mem_cgroup_files[] = {
 	{
 		.name = "usage",
@@ -422,6 +508,11 @@ static struct cftype mem_cgroup_files
 		.private = RES_FAILCNT,
 		.read = mem_cgroup_read,
 	},
+	{
+		.name = "control_type",
+		.write = mem_control_type_write,
+		.read = mem_control_type_read,
+	},
 };
 
 static struct mem_cgroup init_mem_cgroup;
@@ -444,6 +535,7 @@ mem_cgroup_create(struct cgroup_su
 	INIT_LIST_HEAD(&mem->active_list);
 	INIT_LIST_HEAD(&mem->inactive_list);
 	spin_lock_init(&mem->lru_lock);
+	mem->control_type = MEM_CGROUP_TYPE_ALL;
 	return &mem->css;
 }
 
diff -puN mm/swap_state.c~memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7 mm/swap_state.c
--- a/mm/swap_state.c~memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7
+++ a/mm/swap_state.c
@@ -81,7 +81,7 @@ static int __add_to_swap_cache(struct pa
 	error = radix_tree_preload(gfp_mask);
 	if (!error) {
 
-		error = mem_cgroup_charge(page, current->mm);
+		error = mem_cgroup_cache_charge(page, current->mm);
 		if (error)
 			goto out;
 
_

--