Messages in this thread Patch in this message | | | Date | Tue, 3 Feb 2009 12:50:13 +0530 | From | Balbir Singh <> | Subject | [-mm patch] Show memcg information during OOM (v2) |
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Description: Add RSS and swap to OOM output from memcg
From: Balbir Singh <balbir@linux.vnet.ibm.com>
Changelog v2..v1:
1. Add more information about task's memcg and the memcg over it's limit 2. Print data in KB 3. Move the print routine outside task_lock() 4. Use rcu_read_lock() around cgroup_path, strictly speaking it is not required, but relying on the current memcg implementation is not a good idea.
This patch displays memcg values like failcnt, usage and limit when an OOM occurs due to memcg.
NOTE: In case the path exceeds 128 bytes, we omit printing the name of the cgroups. It is possible to circumvent this problem by using static arrays of PAGE_SIZE and we know that OOM is serialized when invoked from the memory controller. This did not seem like a good idea, but can be implemented if 128 bytes seems like a severe limitation.
Thanks go out to Johannes Weiner, Li Zefan, David Rientjes, Kamezawa Hiroyuki, Daisuke Nishimura and KOSAKI Motohiro for review.
Sample output -------------
Task in /a/x killed as a result of limit of /a memory: usage 1048576kB, limit 1048576kB, failcnt 4183 memory+swap: usage 1400964kB, limit 9007199254740991kB, failcnt 0
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> ---
include/linux/memcontrol.h | 6 ++++ mm/memcontrol.c | 61 ++++++++++++++++++++++++++++++++++++++++++++ mm/oom_kill.c | 1 + 3 files changed, 68 insertions(+), 0 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 326f45c..56f1af2 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -104,6 +104,8 @@ struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, struct zone *zone); struct zone_reclaim_stat* mem_cgroup_get_reclaim_stat_from_page(struct page *page); +extern void mem_cgroup_print_mem_info(struct mem_cgroup *memcg, + struct task_struct *p); #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP extern int do_swap_account; @@ -270,6 +272,10 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page) return NULL; } +void mem_cgroup_print_mem_info(struct mem_cgroup *memcg, struct task_struct *p) +{ +} + #endif /* CONFIG_CGROUP_MEM_CONT */ #endif /* _LINUX_MEMCONTROL_H */ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 8e4be9c..e7f82b6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -42,6 +42,7 @@ struct cgroup_subsys mem_cgroup_subsys __read_mostly; #define MEM_CGROUP_RECLAIM_RETRIES 5 +#define MEM_CGROUP_OOM_BUF_SIZE 128 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP /* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */ @@ -813,6 +814,66 @@ bool mem_cgroup_oom_called(struct task_struct *task) rcu_read_unlock(); return ret; } + +/** + * mem_cgroup_print_mem_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 + * + * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is + * enabled + */ +void mem_cgroup_print_mem_info(struct mem_cgroup *memcg, struct task_struct *p) +{ + struct cgroup *task_cgrp; + struct cgroup *mem_cgrp; + /* + * Need a buffer on stack, can't rely on allocations. + */ + char task_memcg_name[MEM_CGROUP_OOM_BUF_SIZE]; + char memcg_name[MEM_CGROUP_OOM_BUF_SIZE]; + int ret; + + if (!memcg) + return; + + mem_cgrp = memcg->css.cgroup; + task_cgrp = mem_cgroup_from_task(p)->css.cgroup; + + rcu_read_lock(); + ret = cgroup_path(task_cgrp, task_memcg_name, MEM_CGROUP_OOM_BUF_SIZE); + if (ret < 0) { + /* + * Unfortunately, we are unable to convert to a useful name + * But we'll still print out the usage information + */ + rcu_read_unlock(); + goto done; + } + ret = cgroup_path(mem_cgrp, memcg_name, MEM_CGROUP_OOM_BUF_SIZE); + if (ret < 0) { + rcu_read_unlock(); + goto done; + } + + rcu_read_unlock(); + + printk(KERN_INFO "Task in %s killed as a result of limit of %s\n", + task_memcg_name, memcg_name); +done: + + printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", + res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, + res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, + res_counter_read_u64(&memcg->res, RES_FAILCNT)); + printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " + "failcnt %llu\n", + res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, + res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, + res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); +} + /* * Unlike exported interface, "oom" parameter is added. if oom==true, * oom-killer can be invoked. diff --git a/mm/oom_kill.c b/mm/oom_kill.c index d3b9bac..951356f 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -394,6 +394,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, cpuset_print_task_mems_allowed(current); task_unlock(current); dump_stack(); + mem_cgroup_print_mem_info(mem, current); show_mem(); if (sysctl_oom_dump_tasks) dump_tasks(mem); -- Balbir
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