Fixed one here.
==
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Now, at calculating dirty limit, vm_dirty_param() is called.
This function returns dirty-limit related parameters considering
memory cgroup settings.
Now, assume that vm_dirty_bytes=100M (global dirty limit) and
memory cgroup has 1G of pages and 40 dirty_ratio, dirtyable memory is
500MB.
In this case, global_dirty_limits will consider dirty_limt as
500 *0.4 = 200MB. This is bad...memory cgroup is not back door.
This patch limits the return value of vm_dirty_param() considring
global settings.
Changelog:
- fixed an argument "mem" int to u64
- fixed to use global available memory to cap memcg's value.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 5 +++--
mm/memcontrol.c | 30 +++++++++++++++++++++++++++++-
mm/page-writeback.c | 3 ++-
3 files changed, 34 insertions(+), 4 deletions(-)
Index: dirty_limit_new/mm/memcontrol.c
===================================================================
--- dirty_limit_new.orig/mm/memcontrol.c
+++ dirty_limit_new/mm/memcontrol.c
@@ -1171,9 +1171,11 @@ static void __mem_cgroup_dirty_param(str
* can be moved after our access and writeback tends to take long time. At
* least, "memcg" will not be freed while holding rcu_read_lock().
*/
-void vm_dirty_param(struct vm_dirty_param *param)
+void vm_dirty_param(struct vm_dirty_param *param,
+ u64 mem, u64 global)
{
struct mem_cgroup *memcg;
+ u64 limit, bglimit;
if (mem_cgroup_disabled()) {
global_vm_dirty_param(param);
@@ -1183,6 +1185,32 @@ void vm_dirty_param(struct vm_dirty_para
rcu_read_lock();
memcg = mem_cgroup_from_task(current);
__mem_cgroup_dirty_param(param, memcg);
+ /*
+ * A limitation under memory cgroup is under global vm, too.
+ */
+ if (vm_dirty_ratio)
+ limit = global * vm_dirty_ratio / 100;
+ else
+ limit = vm_dirty_bytes;
+ if (param->dirty_ratio) {
+ param->dirty_bytes = mem * param->dirty_ratio / 100;
+ param->dirty_ratio = 0;
+ }
+ if (param->dirty_bytes > limit)
+ param->dirty_bytes = limit;
+
+ if (dirty_background_ratio)
+ bglimit = global * dirty_background_ratio / 100;
+ else
+ bglimit = dirty_background_bytes;
+
+ if (param->dirty_background_ratio) {
+ param->dirty_background_bytes =
+ mem * param->dirty_background_ratio / 100;
+ param->dirty_background_ratio = 0;
+ }
+ if (param->dirty_background_bytes > bglimit)
+ param->dirty_background_bytes = bglimit;
rcu_read_unlock();
}
Index: dirty_limit_new/include/linux/memcontrol.h
===================================================================
--- dirty_limit_new.orig/include/linux/memcontrol.h
+++ dirty_limit_new/include/linux/memcontrol.h
@@ -171,7 +171,7 @@ static inline void mem_cgroup_dec_page_s
}
bool mem_cgroup_has_dirty_limit(void);
-void vm_dirty_param(struct vm_dirty_param *param);
+void vm_dirty_param(struct vm_dirty_param *param, u64 mem, u64 global);
s64 mem_cgroup_page_stat(enum mem_cgroup_nr_pages_item item);
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
@@ -360,7 +360,8 @@ static inline bool mem_cgroup_has_dirty_
return false;
}
-static inline void vm_dirty_param(struct vm_dirty_param *param)
+static inline void vm_dirty_param(struct vm_dirty_param *param,
+ u64 mem, u64 global)
{
global_vm_dirty_param(param);
}
Index: dirty_limit_new/mm/page-writeback.c
===================================================================
--- dirty_limit_new.orig/mm/page-writeback.c
+++ dirty_limit_new/mm/page-writeback.c
@@ -466,7 +466,8 @@ void global_dirty_limits(unsigned long *
struct task_struct *tsk;
struct vm_dirty_param dirty_param;
- vm_dirty_param(&dirty_param);
+ vm_dirty_param(&dirty_param,
+ available_memory, global_dirtyable_memory());
if (dirty_param.dirty_bytes)
dirty = DIV_ROUND_UP(dirty_param.dirty_bytes, PAGE_SIZE);
--
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