oom: remove unnecessary code and cleanup

Remove the redundancy in __oom_kill_task() since:

 - init can never be passed to this function: it will never be PF_EXITING
   or selectable from select_bad_process(), and

 - it will never be passed a task from oom_kill_task() without an ->mm
   and we're unconcerned about detachment from exiting tasks, there's no
   reason to protect them against SIGKILL or access to memory reserves.

Also moves the kernel log message to a higher level since the verbosity is
not always emitted here; we need not print an error message if an exiting
task is given a longer timeslice.

__oom_kill_task() only has a single caller, so it can be merged into that
function at the same time.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Rientjes 2010-08-09 17:18:57 -07:00 committed by Linus Torvalds
parent 8e4228e1ed
commit b940fd7035

View file

@ -410,61 +410,25 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
}
#define K(x) ((x) << (PAGE_SHIFT-10))
/*
* Send SIGKILL to the selected process irrespective of CAP_SYS_RAW_IO
* flag though it's unlikely that we select a process with CAP_SYS_RAW_IO
* set.
*/
static void __oom_kill_task(struct task_struct *p, int verbose)
{
if (is_global_init(p)) {
WARN_ON(1);
printk(KERN_WARNING "tried to kill init!\n");
return;
}
p = find_lock_task_mm(p);
if (!p)
return;
if (verbose)
printk(KERN_ERR "Killed process %d (%s) "
"vsz:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
task_pid_nr(p), p->comm,
K(p->mm->total_vm),
K(get_mm_counter(p->mm, MM_ANONPAGES)),
K(get_mm_counter(p->mm, MM_FILEPAGES)));
task_unlock(p);
/*
* We give our sacrificial lamb high priority and access to
* all the memory it needs. That way it should be able to
* exit() and clear out its resources quickly...
*/
p->rt.time_slice = HZ;
set_tsk_thread_flag(p, TIF_MEMDIE);
force_sig(SIGKILL, p);
}
static int oom_kill_task(struct task_struct *p)
{
/* WARNING: mm may not be dereferenced since we did not obtain its
* value from get_task_mm(p). This is OK since all we need to do is
* compare mm to q->mm below.
*
* Furthermore, even if mm contains a non-NULL value, p->mm may
* change to NULL at any time since we do not hold task_lock(p).
* However, this is of no concern to us.
*/
if (!p->mm || p->signal->oom_adj == OOM_DISABLE)
p = find_lock_task_mm(p);
if (!p || p->signal->oom_adj == OOM_DISABLE) {
task_unlock(p);
return 1;
}
pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
task_pid_nr(p), p->comm, K(p->mm->total_vm),
K(get_mm_counter(p->mm, MM_ANONPAGES)),
K(get_mm_counter(p->mm, MM_FILEPAGES)));
task_unlock(p);
__oom_kill_task(p, 1);
p->rt.time_slice = HZ;
set_tsk_thread_flag(p, TIF_MEMDIE);
force_sig(SIGKILL, p);
return 0;
}
#undef K
static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
unsigned long points, struct mem_cgroup *mem,