| Date | Tue, 21 Oct 2014 10:07:40 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH 4/6] SRCU free VMAs |
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On Mon, Oct 20, 2014 at 04:41:45PM -0700, Linus Torvalds wrote: > On Mon, Oct 20, 2014 at 2:56 PM, Peter Zijlstra <peterz@infradead.org> wrote: > > Manage the VMAs with SRCU such that we can do a lockless VMA lookup. > > Can you explain why srcu, and not plain regular rcu? > > Especially as you then *note* some of the problems srcu can have. > Making it regular rcu would also seem to make it possible to make the > seqlock be just a seqcount, no?
Because we need to hold onto the RCU read side lock across the entire fault, which can involve IO and all kinds of other blocking ops.
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