Re: [PATCH 1/2] memcg, oom: provide more precise dump info whilememcg oom happening
From: Sha Zhengju
Date: Thu Nov 08 2012 - 07:37:32 EST
On 11/08/2012 02:02 AM, David Rientjes wrote:
On Wed, 7 Nov 2012, Sha Zhengju wrote:
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0eab7d5..2df5e72 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -118,6 +118,14 @@ static const char * const mem_cgroup_events_names[] = {
"pgmajfault",
};
+static const char * const mem_cgroup_lru_names[] = {
+ "inactive_anon",
+ "active_anon",
+ "inactive_file",
+ "active_file",
+ "unevictable",
+};
+
/*
* Per memcg event counter is incremented at every pagein/pageout. With THP,
* it will be incremated by the number of pages. This counter is used for
@@ -1501,8 +1509,59 @@ static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
spin_unlock_irqrestore(&memcg->move_lock, *flags);
}
+#define K(x) ((x)<< (PAGE_SHIFT-10))
+static void mem_cgroup_print_oom_stat(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *mi;
+ unsigned int i;
+
+ if (!memcg->use_hierarchy&& memcg != root_mem_cgroup) {
+ for (i = 0; i< MEM_CGROUP_STAT_NSTATS; i++) {
+ if (i == MEM_CGROUP_STAT_SWAP&& !do_swap_account)
+ continue;
+ printk(KERN_CONT "%s:%ldKB ", mem_cgroup_stat_names[i],
This printk isn't continuing any previous printk, so using KERN_CONT here
will require a short header to be printed first ("Memcg: "?) with
KERN_INFO before the iterations.
Yep...I think I lost it while rebasing... sorry for the stupid mistake.
+ K(mem_cgroup_read_stat(memcg, i)));
+ }
+
+ for (i = 0; i< MEM_CGROUP_EVENTS_NSTATS; i++)
+ printk(KERN_CONT "%s:%lu ", mem_cgroup_events_names[i],
+ mem_cgroup_read_events(memcg, i));
+
+ for (i = 0; i< NR_LRU_LISTS; i++)
+ printk(KERN_CONT "%s:%luKB ", mem_cgroup_lru_names[i],
+ K(mem_cgroup_nr_lru_pages(memcg, BIT(i))));
+ } else {
+
Spurious newline.
Eek, is there really no way to avoid this if-conditional and just use
for_each_mem_cgroup_tree() for everything and use
mem_cgroup_iter_break(memcg, iter);
break;
for !memcg->use_hierarchy?
Now I'm shamed at my bad brain of yesterday by sending this chunk out...
Yes, the if-part code above is obviously unwanted, and the
for_each_mem_cgroup_tree
can handle hierarchy already.
+ for (i = 0; i< MEM_CGROUP_STAT_NSTATS; i++) {
+ long long val = 0;
+
+ if (i == MEM_CGROUP_STAT_SWAP&& !do_swap_account)
+ continue;
+ for_each_mem_cgroup_tree(mi, memcg)
+ val += mem_cgroup_read_stat(mi, i);
+ printk(KERN_CONT "%s:%lldKB ", mem_cgroup_stat_names[i], K(val));
+ }
+
+ for (i = 0; i< MEM_CGROUP_EVENTS_NSTATS; i++) {
+ unsigned long long val = 0;
+
+ for_each_mem_cgroup_tree(mi, memcg)
+ val += mem_cgroup_read_events(mi, i);
+ printk(KERN_CONT "%s:%llu ",
+ mem_cgroup_events_names[i], val);
+ }
+
+ for (i = 0; i< NR_LRU_LISTS; i++) {
+ unsigned long long val = 0;
+
+ for_each_mem_cgroup_tree(mi, memcg)
+ val += mem_cgroup_nr_lru_pages(mi, BIT(i));
+ printk(KERN_CONT "%s:%lluKB ", mem_cgroup_lru_names[i], K(val));
+ }
+ }
+ printk(KERN_CONT "\n");
+}
/**
- * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
* @memcg: The memory cgroup that went over limit
* @p: Task that is going to be killed
*
@@ -1569,6 +1628,8 @@ done:
res_counter_read_u64(&memcg->kmem, RES_USAGE)>> 10,
res_counter_read_u64(&memcg->kmem, RES_LIMIT)>> 10,
res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
+
+ mem_cgroup_print_oom_stat(memcg);
I think this should be folded into mem_cgroup_print_oom_info(), I don't
see a need for a new function.
}
/*
@@ -5195,14 +5256,6 @@ static int memcg_numa_stat_show(struct cgroup *cont, struct cftype *cft,
}
#endif /* CONFIG_NUMA */
-static const char * const mem_cgroup_lru_names[] = {
- "inactive_anon",
- "active_anon",
- "inactive_file",
- "active_file",
- "unevictable",
-};
-
static inline void mem_cgroup_lru_names_not_uptodate(void)
{
BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 7e9e911..4b8a6dd 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -421,8 +421,10 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
cpuset_print_task_mems_allowed(current);
task_unlock(current);
dump_stack();
- mem_cgroup_print_oom_info(memcg, p);
- show_mem(SHOW_MEM_FILTER_NODES);
+ if (memcg)
+ mem_cgroup_print_oom_info(memcg, p);
mem_cgroup_print_oom_info() already returns immediately for !memcg, so I'm
not sure why this change is made.
Here the if-else checking is aiming at printing distinct messages for
memcg & non-memcg.
IMHO, global state has little actual use for memcg-oom and why not we
wipe off itï
Though mem_cgroup_print_oom_info already checking for !memcg, the
if-statement
can avoid one function call and save the deep-enough oom call stack a
little.
+ else
+ show_mem(SHOW_MEM_FILTER_NODES);
Well that's disappointing if memcg == root_mem_cgroup, we'd probably like
to know the global memory state to determine what the problem is.
I really wondering if there is any case that can pass root_mem_cgroup
down here.
It's called by global or memcg oom killer and the global oom will set
memcg=NULL
directly instead of root_mem_cgroup. Besides, root memcg will not go
through charging
and there is no chance to call mem_cgroup_out_of_memory for root cgroup
tasks.
Thanks,
Sha
if (sysctl_oom_dump_tasks)
dump_tasks(memcg, nodemask);
}
.
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