Messages in this thread | | | Date | Wed, 11 Mar 2009 18:03:30 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [patch -mm] cpusets: add memory_slab_hardwall flag |
| |
On Mon, Mar 09, 2009 at 02:50:06PM -0400, Christoph Lameter wrote: > Again these are fastpath modifications. > > Scanning the partial list for matching nodes is an expensive operation. > > Adding RCU into the fast paths is also another big worry.
Hello, Christoph,
Adding synchronize_rcu() into a fast path would certainly be a problem, but call_rcu() should be OK. If the data structure is updated often (old elements removed and new elements added), then the cache misses from elements that were removed, went cache-cold, and then were added again could potentially cause trouble, but read-mostly data structures should be OK.
Or were you worried about some other aspect of RCU overhead?
Thanx, Paul
| |