On Wed, 17 Feb 2010, Minchan Kim wrote: > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 3618be3..d5e3d70 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -32,6 +32,8 @@ int sysctl_panic_on_oom; > int sysctl_oom_kill_allocating_task; > int sysctl_oom_dump_tasks; > static DEFINE_SPINLOCK(zone_scan_lock); > + > +unsigned int nr_memdie; /* count of TIF_MEMDIE processes */ > /* #define DEBUG */ > > /* > @@ -295,6 +297,8 @@ static struct task_struct > *select_bad_process(unsigned long *ppoints, > > chosen = p; > *ppoints = ULONG_MAX; > + if (nr_memdie == 0) > + break; > } > > if (p->signal->oom_adj == OOM_DISABLE) Nack, finding a candidate task with TIF_MEMDIE set is not the only time we return ERR_PTR(-1UL) from select_bad_process(): we also do it if any other task other than current is PF_EXITING. Thus, we _must_ continue the tasklist scan to avoid needlessly killing current simply because it was the first PF_EXITING task in the tasklist. > @@ -403,8 +407,6 @@ static void __oom_kill_task(struct task_struct *p, > int verbose) > 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 > @@ -412,7 +414,11 @@ static void __oom_kill_task(struct task_struct > *p, int verbose) > */ > p->rt.time_slice = HZ; > set_tsk_thread_flag(p, TIF_MEMDIE); > - > + /* > + * nr_memdie is protected by task_lock. > + */ > + nr_memdie++; > + task_unlock(p); > force_sig(SIGKILL, p); > } > task_lock() is a per-task entity, i.e. each task_struct has an alloc_lock spinlock. This cannot protect a global variable. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>