Messages in this thread | | | Subject | Re: calling smp_call_function_many() with non-stable CPU mask | From | Mike Galbraith <> | Date | Tue, 01 Feb 2011 09:40:01 +0100 |
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On Tue, 2011-02-01 at 09:27 +0100, Jan Beulich wrote: > There are a couple of examples of smp_call_function_many() getting > called with mm_cpumask() as the first argument. Since that mask > generally can change while smp_call_function_many() is executing, > it seems there might be a problem with the case where that mask > becomes empty after the initial checks, but before the mask is made > permanent (by copying into data->cpumask). > > Shouldn't there be a check of data->refs being zero right after > setting it (to avoid having csd_lock_wait() wait for a remote CPU > to clear the lock flag, and to avoid adding the entry to > call_function.queue)? > > If that isn't considered necessary, is it then incorrect to pass > in-flight CPU masks to smp_call_function_many() (and should > this requirement then be documented somewhere, and the > existing calls all be inspected for correctness)?
Freshly baked.
http://www.google.de/url?sa=t&source=web&cd=1&ved=0CBUQFjAA&url=http%3A% 2F%2Flkml.org%2Flkml%2F2011%2F2%2F1%2F18&rct=j&q=PATCH%202%2F3%20v2%5D% 20smp_call_function_many%3A%20handle%20concurrent%20clearing%20of% 20mask&ei=M8ZHTda-LILCswaE6uyVAw&usg=AFQjCNE4M55BFGih2jXsHoAkNd5oTzpQvQ&cad=rja
-Mike
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