Messages in this thread | | | Date | Wed, 23 Sep 2015 13:44:53 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 02/11] x86/mm/hotplug: Remove pgd_list use from the memory hotplug code |
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On 09/22, Linus Torvalds wrote: > > However, this now becomes a pattern for the series, and that just makes me think > > "Why is this not a 'for_each_mm()' pattern helper?"
And we already have other users. And note that oom_kill_process() does _not_ follow this pattern and that is why it is buggy.
So this is funny, but I was thinking about almost the same, something like
struct task_struct *next_task_with_mm(struct task_struct *p) { struct task_struct *t;
p = p->group_leader; while ((p = next_task(p)) != &init_task) { if (p->flags & PF_KTHREAD) continue;
t = find_lock_task_mm(p); if (t) return t; }
return NULL; }
#define for_each_task_lock_mm(p) for (p = &init_task; (p = next_task_with_mm(p)); task_unlock(p))
So that you can do
for_each_task_lock_mm(p) { do_something_with(p->mm);
if (some_condition()) { // UNFORTUNATELY you can't just do "break" task_unlock(p); break; } }
do you think it makes sense?
In fact it can't be simpler, we can move task_unlock() into next_task_with_mm(), it can check ->mm != NULL or p != init_task.
Oleg.
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