| Date | Mon, 16 Jan 2017 16:13:19 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4 07/15] lockdep: Implement crossrelease feature |
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On Fri, Dec 09, 2016 at 02:12:03PM +0900, Byungchul Park wrote: > + /* > + * We assign class_idx here redundantly even though following > + * memcpy will cover it, in order to ensure a rcu reader can > + * access the class_idx atomically without lock. > + * > + * Here we assume setting a word-sized variable is atomic.
which one, where?
> + */ > + xlock->hlock.class_idx = hlock->class_idx; > + gen_id = (unsigned int)atomic_inc_return(&cross_gen_id); > + WRITE_ONCE(xlock->gen_id, gen_id); > + memcpy(&xlock->hlock, hlock, sizeof(struct held_lock)); > + INIT_LIST_HEAD(&xlock->xlock_entry); > + list_add_tail_rcu(&xlock->xlock_entry, &xlocks_head);
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