Re: [RFC PATCH] asynchronous page fault.

From: Balbir Singh
Date: Sun Dec 27 2009 - 19:58:12 EST


* Peter Zijlstra <peterz@xxxxxxxxxxxxx> [2009-12-27 12:19:56]:

> Your changelog states as much.
>
> "Even if RB-tree rotation occurs while we walk tree for look-up, we just
> miss vma without oops."
>
> However, since this is the case, do we still need the
> rcu_assign_pointer() conversion your patch does? All I can see it do is
> slow down all RB-tree users, without any gain.

Don't we need the rcu_assign_pointer() on the read side primarily to
make sure the pointer is still valid and assignments (writes) are not
re-ordered? Are you suggesting that the pointer assignment paths be
completely atomic?

--
Balbir
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