oom: dump_tasks use find_lock_task_mm too

dump_task() should use find_lock_task_mm() too. It is necessary for
protecting task-exiting race.

dump_tasks() currently filters any task that does not have an attached
->mm since it incorrectly assumes that it must either be in the process of
exiting and has detached its memory or that it's a kernel thread;
multithreaded tasks may actually have subthreads that have a valid ->mm
pointer and thus those threads should actually be displayed.  This change
finds those threads, if they exist, and emit their information along with
the rest of the candidate tasks for kill.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KOSAKI Motohiro 2010-08-09 17:18:46 -07:00 committed by Linus Torvalds
parent dd8e8f405c
commit c55db95788
1 changed files with 21 additions and 18 deletions

View File

@ -336,35 +336,38 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
*/
static void dump_tasks(const struct mem_cgroup *mem)
{
struct task_struct *g, *p;
struct task_struct *p;
struct task_struct *task;
printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj "
"name\n");
do_each_thread(g, p) {
struct mm_struct *mm;
for_each_process(p) {
/*
* We don't have is_global_init() check here, because the old
* code do that. printing init process is not big matter. But
* we don't hope to make unnecessary compatibility breaking.
*/
if (p->flags & PF_KTHREAD)
continue;
if (mem && !task_in_mem_cgroup(p, mem))
continue;
if (!thread_group_leader(p))
continue;
task_lock(p);
mm = p->mm;
if (!mm) {
task = find_lock_task_mm(p);
if (!task) {
/*
* total_vm and rss sizes do not exist for tasks with no
* mm so there's no need to report them; they can't be
* oom killed anyway.
* Probably oom vs task-exiting race was happen and ->mm
* have been detached. thus there's no need to report
* them; they can't be oom killed anyway.
*/
task_unlock(p);
continue;
}
printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d %3d %s\n",
p->pid, __task_cred(p)->uid, p->tgid, mm->total_vm,
get_mm_rss(mm), (int)task_cpu(p), p->signal->oom_adj,
p->comm);
task_unlock(p);
} while_each_thread(g, p);
task->pid, __task_cred(task)->uid, task->tgid,
task->mm->total_vm, get_mm_rss(task->mm),
(int)task_cpu(task), task->signal->oom_adj, p->comm);
task_unlock(task);
}
}
static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,