Messages in this thread | | | Date | Wed, 6 Aug 2008 20:19:20 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [RFC][PATCH 2/2] rcu classic: new algorithm for callbacks-processing(v2) |
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On Wed, Aug 06, 2008 at 03:08:10PM +0800, Lai Jiangshan wrote: > Paul E. McKenney wrote: > [...] > > > > Tell me more about percpu_ptr(). > > Sorry about this. percpu_ptr is used for dynamic allocation percpu pointer.
Yep, that I knew.
> It seems that we cannot get a pointer from a static declare percpu data > which can be used as a dynamic allocation percpu data's pointer.
Sad but true... Ran into this with SRCU a couple of years back. :-/
> > > [...] > > > > I have a somewhat different goal here. I want to simplify the memory > > ordering design without giving up too much performance -- the current > > state in mainline is much too fragile, in my opinion, especially given > > that the grace-period code paths are not fastpaths. > > > > Next step -- hierarchical grace-period detection to handle the 4096-CPU > > machines that I was being buttonholed about at OLS... > > > > Would you be interested in applying your multi-tailed list change to > > preemptable RCU? > > > It's not necessary. Actually I like one tail per list which is good for > readability. > > But in my patch, the most work is combining lists, not > moving a list to next list, so i use multi-tailed simplify this works > and others(etc: "if (rdp->nxtlist)" will be changed to be a more > complex and less readability statement if i use one-tail-per-list) > > These not means multi-tailed is good thing.
It does indeed depend on the details of the implementation.
Thanx, Paul
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