| Date | Fri, 6 Aug 2021 13:00:51 +0200 | From | Peter Zijlstra <> | Subject | Re: [patch V3 50/64] locking/rtmutex: Extend the rtmutex core to support ww_mutex |
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On Thu, Aug 05, 2021 at 05:13:50PM +0200, Thomas Gleixner wrote: > static __always_inline bool __waiter_less(struct rb_node *a, const struct rb_node *b) > { > - return rt_mutex_waiter_less(__node_2_waiter(a), __node_2_waiter(b));
Given ^
> + struct rt_mutex_waiter *aw = __node_2_waiter(a); > + struct rt_mutex_waiter *bw = __node_2_waiter(b); > + > + if (rt_mutex_waiter_less(aw, bw)) > + return 1;
We can, with this new build_ww_mutex(), do:
if (!build_ww_mutex()) return 0;
here, to preserve the old behaviour.
> + if (rt_mutex_waiter_less(bw, aw)) > + return 0; > + > + /* NOTE: relies on waiter->ww_ctx being set before insertion */ > + if (build_ww_mutex() && aw->ww_ctx) {
Then it can go away here.
> + if (!bw->ww_ctx) > + return 1; > + > + return (signed long)(aw->ww_ctx->stamp - > + bw->ww_ctx->stamp) < 0; > + } > + > + return 0; > }
Also, I found a note that said I had to check what this code does for !RT tasks, lemme go do that now.
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