Messages in this thread |  | | From | Rusty Russell <> | Subject | Re: [Lse-tech] Re: RFC: patch to allow lock-free traversal of lists with insertion | Date | Sat, 13 Oct 2001 17:25:27 +1000 |
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In message <Pine.LNX.4.33.0110120948540.31692-100000@penguin.transmeta.com> you write: > Yes. With maybe > > non_preempt() > .. > preempt() > > around it for the pre-emption patches.
Sure, if they want pre-emption on SMP. Of course, then they'll want priority inheritence.
> However, you also need to make your free _free_ be aware of the count. > Which means that the current RCU patch is really unusable for this. You > need to have the "count" always in a generic place (put it with the hash), > and your schedule-time free needs to do > > if (atomic_read(&count)) > skip_this_do_it_next_time
WTF? I'll spell it out for you again:
static inline void foo_put(struct foo *foo) { if (atomic_dec_and_test(foo->use)) kfree(foo); }
Write side normal:
lock unhash(foo) unlock foo_put(foo)
Write side RCU:
lock unhash(foo) unlock rcu_call(foo_put, foo); /* ie. call foo_put(foo) "later". */
That's all. Really.
> Do that, and the RCU patches may start looking usable for the real world.
I know you're under strain, but think harder please.
Rusty. -- Premature optmztion is rt of all evl. --DK - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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