Messages in this thread | | | From | Thomas Gleixner <> | Subject | RE: [patch 14/30] drm/i915/pmu: Replace open coded kstat_irqs() copy | Date | Fri, 11 Dec 2020 22:10:36 +0100 |
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On Fri, Dec 11 2020 at 14:19, David Laight wrote: > From: Thomas Gleixner >> You can't catch that. If this really becomes an issue you need a >> sequence counter around it. > > Or just two copies of the high word. > Provided the accesses are sequenced: > writer: > load high:low > add small_value,high:low > store high > store low > store high_copy > reader: > load high_copy > load low > load high > if (high != high_copy) > low = 0;
And low = 0 is solving what? You need to loop back and retry until it's consistent and then it's nothing else than an open coded sequence count.
Thanks,
tglx
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