Messages in this thread | | | Date | Tue, 16 Jun 2015 19:11:53 +0200 | From | Daniel Wagner <> | Subject | Re: call_rcu from trace_preempt |
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On 06/16/2015 05:41 PM, Steven Rostedt wrote: > On Tue, 16 Jun 2015 14:38:53 +0200 > Daniel Wagner <wagi@monom.org> wrote: >> *map, void *key) >> if (l) { >> hlist_del_rcu(&l->hash_node); >> htab->count--; >> - kfree_rcu(l, rcu); >> + /* kfree_rcu(l, rcu); */ > > So this kfree_rcu() is only being used to defer a free, and has nothing > to do with having to free 'l' from rcu?
Not 100% sure but I got the impression kfree_rcu only defers the free.
>> +static int free_thread(void *arg) >> +{ >> + unsigned long flags; >> + struct htab_elem *l; >> + >> + while (!kthread_should_stop()) { >> + spin_lock_irqsave(&elem_freelist_lock, flags); >> + while (!list_empty(&elem_freelist)) { >> + l = list_entry(elem_freelist.next, >> + struct htab_elem, list); >> + list_del(&l->list); >> + kfree(l); >> + } >> + spin_unlock_irqrestore(&elem_freelist_lock, flags); > > Wow! This is burning up CPU isn't it?
Sure, this is a very busy thread :) I was just experimenting if defering it to a thread would paper of the problem.
> If you just need to delay the kfree, why not use irq_work for that job?
Good point. I tried that tomorrow.
cheers, daniel
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