Messages in this thread |  | | | Date | Tue, 5 Jan 2010 08:05:02 -0800 | | From | "Paul E. McKenney" <> | | Subject | Re: [RFC][PATCH 4/8] mm: RCU free vmas |
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On Tue, Jan 05, 2010 at 09:28:36AM +0100, Peter Zijlstra wrote: > On Mon, 2010-01-04 at 18:43 -0800, Paul E. McKenney wrote: > > On Mon, Jan 04, 2010 at 07:24:33PM +0100, Peter Zijlstra wrote: > > > TODO: > > > - should be SRCU, lack of call_srcu() > > > > > > In order to allow speculative vma lookups, RCU free the struct > > > vm_area_struct. > > > > > > We use two means of detecting a vma is still valid: > > > - firstly, we set RB_CLEAR_NODE once we remove a vma from the tree. > > > - secondly, we check the vma sequence number. > > > > > > These two things combined will guarantee that 1) the vma is still > > > present and two, it still covers the same range from when we looked it > > > up. > > > > OK, I think I see what you are up to here. I could get you a very crude > > throw-away call_srcu() fairly quickly. I don't yet have a good estimate > > of how long it will take me to merge SRCU into the treercu infrastructure, > > but am getting there. > > > > So, which release are you thinking in terms of? > > I'm not thinking any release yet, its very early and as Linus has > pointed out, I seem to have forgotten a rather big piece of the > picture :/ > > So I need to try and fix this glaring hole before we can continue.
OK, then I will think in terms of merging SRCU into treercu before providing any sort of call_srcu().
Thanx, Paul
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