Messages in this thread |  | | | Date | Mon, 12 Dec 2005 22:33:22 +0300 | | From | Oleg Nesterov <> | | Subject | Re: Semantics of smp_mb() [was : Re: [PATCH] Fix RCU race in access of nohz_cpu_mask ] |
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Srivatsa Vaddagiri wrote: > > Oleg, with all these inputs, I consider the patch I had sent to be correct.
Yes, I think so. My suspects were due to my misunderstanding. I was wrong when I said that we can ignore rmb() part of mb() in case when start_hz_timer() runs after rcu_start_batch().
rcp->cur++; // ->cur will be visible to other cpus // _before_ we will *READ* nohz_cpu_mask. // we don't have any 'timing' problems. // In other words: if another cpu does not // see the new value - we did not read this // mask yet. smp_mb(); Thanks for your patience.
> P.S :- Thanks to everybody who reponded clarifying this subject.
Yes! it was really helpful, thanks to all. I think it would be great to have Paul's very clear (and short!) explanation somewhere in Documentation/.
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