Messages in this thread | | | Date | Fri, 12 Aug 2016 17:32:51 -0400 | From | Waiman Long <> | Subject | Re: [RESEND PATCH v4] x86/hpet: Reduce HPET counter read contention |
| |
On 08/12/2016 05:20 PM, Dave Hansen wrote: > On 08/12/2016 02:10 PM, Waiman Long wrote: >>> I don't think this is right. If the HPET ever returns the same value >>> twice in a row (unlikely because it's generally too slow to read, but >>> it's plausible that someone will make a fast HPET some day), then this >>> could deadlock. >> What is the deadlock scenario you are talking about? > A reader loops waiting for the HPET update by looking for the value to > change. If the HPET updater does an update, but the HPET itself hasn't > advanced, it will write the same value as was there before. The reader > will keep looping thinking there was no update.
I should have addressed this problem in my new v5 patch.
Cheers, Longman
| |