After rebase to VZ8 the code which sets memcg->overdraft was moved to
mem_cgroup_scan_tasks() which is completely wrong (for instance in VZ7
we had this code in oom_unlock(), so everywhere in oom we always had
->overdraft information properly set). Now we don't have proper refresh
of ->overdraft information in two cases: in global oom and in berserker.
Let's fix this by spliting the refresh code to separate function
refresh_mem_cgroup_overdraft() and call it where it is really needed
(where later in stack oom_badness uses the refreshed ->overdraft).
Fixes: c31dabeaf42d ("memcg: add oom_guarantee")
Signed-off-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
Feature: mm/oom: OOM guarantee feature
---
include/linux/memcontrol.h | 6 ++++++
mm/memcontrol.c | 30 +++++++++++++++++++-----------
mm/oom_kill.c | 4 ++++
3 files changed, 29 insertions(+), 11 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 4719eb84894f..9c2b8774639e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -22,6 +22,7 @@
#include <linux/writeback.h>
#include <linux/page-flags.h>
#include <linux/virtinfo.h>
+#include <linux/oom.h>
struct mem_cgroup;
struct obj_cgroup;
@@ -1004,6 +1005,7 @@ void mem_cgroup_print_oom_context(struct mem_cgroup
*memcg,
void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg);
unsigned long mem_cgroup_overdraft(struct mem_cgroup *memcg);
+void refresh_mem_cgroup_overdraft(struct oom_control *oc);
static inline void mem_cgroup_enter_user_fault(void)
{
@@ -1529,6 +1531,10 @@ static inline unsigned long mem_cgroup_overdraft(struct
mem_cgroup *memcg)
return 0;
}
+static inline void refresh_mem_cgroup_overdraft(struct oom_control *oc)
+{
+}
+
static inline void
mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
{
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a0a7c3b4ed35..8ca27af8d902 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1308,17 +1308,6 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
for_each_mem_cgroup_tree(iter, memcg) {
struct css_task_iter it;
struct task_struct *task;
- struct mem_cgroup *parent;
-
- /*
- * Update overdraft of each cgroup under us. This
- * information will be used in oom_badness.
- */
- iter->overdraft = mem_cgroup_overdraft(iter);
- parent = parent_mem_cgroup(iter);
- if (parent && iter != memcg)
- iter->overdraft = max(iter->overdraft,
- parent->overdraft);
css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
while (!ret && (task = css_task_iter_next(&it)))
@@ -1518,6 +1507,25 @@ unsigned long mem_cgroup_overdraft(struct mem_cgroup
*memcg)
return usage > guarantee ? (usage - guarantee) : 0;
}
+void refresh_mem_cgroup_overdraft(struct oom_control *oc)
+{
+ struct mem_cgroup *iter;
+
+ for_each_mem_cgroup_tree(iter, oc->memcg) {
+ struct mem_cgroup *parent;
+
+ /*
+ * Update overdraft of each cgroup under us. This
+ * information will be used in oom_badness.
+ */
+ iter->overdraft = mem_cgroup_overdraft(iter);
+ parent = parent_mem_cgroup(iter);
+ if (parent && iter != oc->memcg)
+ iter->overdraft = max(iter->overdraft,
+ parent->overdraft);
+ }
+}
+
bool mem_cgroup_dcache_is_low(struct mem_cgroup *memcg, int
vfs_cache_min_ratio)
{
unsigned long anon, file, dcache;
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 1d44024d6c6f..d27e04295e7f 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -378,6 +378,8 @@ static void select_bad_process(struct oom_control *oc)
{
oc->chosen_points = LONG_MIN;
+ refresh_mem_cgroup_overdraft(oc);
+
if (is_memcg_oom(oc))
mem_cgroup_scan_tasks(oc->memcg, oom_evaluate_task, oc);
else {
@@ -1073,6 +1075,8 @@ static void oom_berserker(struct oom_control *oc)
if (rage < 0)
return;
+ refresh_mem_cgroup_overdraft(oc);
+
/*
* So, we are in rage. Kill (1 << rage) youngest tasks that are
* as bad as the victim.
--
2.43.0
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