On 04/16/2019 01:37 PM, Peter Zijlstra wrote: > On Tue, Apr 16, 2019 at 01:03:10PM -0400, Waiman Long wrote: >> On 04/16/2019 10:17 AM, Peter Zijlstra wrote: >>> On Tue, Apr 16, 2019 at 09:18:50AM -0400, Waiman Long wrote: >>>> On 04/16/2019 09:10 AM, Peter Zijlstra wrote: >>>>> On Mon, Apr 15, 2019 at 04:58:27PM -0400, Waiman Long wrote: >>>>>> This series contain 2 follow-up patches to alleviate the performance >>>>>> regression found in the page_fault1 test of the will-it-scale benchmark. >>>>>> This does not recover all the lost performance, but reclaim a sizeable >>>>>> portion of it. >>>>>> >>>>>> The regression was found on an Intel system. I have run the test on >>>>>> an AMD system. The regression wasn't seen there. There are only minor >>>>>> variations in performance. Perhaps the page fault path is quite different >>>>>> between Intel and AMD systems. >>>>> Can you please just fold this back into the appropriate patches? Trying >>>>> to review all the back and forth is painful. >>>> I will send out an update part 2 patch with patch 1 of this series >>>> merged into the writer spinning on reader patch. Patch 2 of this series >>>> will be a standalone one. >>> Hmm, in that case I can fold it back too. So hold off on sending it. >>> >>> I thought #2 was a fixup for an earlier patch as well. >> #2 is a performance fix. > Of this patch? > > 206038 N T Apr 13 Waiman Long (7.5K) ├─>[PATCH v4 11/16] locking/rwsem: > Enable readers spinning on writer > > Fixes should have a Fixes: tag. And if the patch it fixes isn't a commit > yet, the patch should be refreshed to not need a fix.
The original patch isn't wrong. This patch just introduce another idea to make it better. That is why I would still like to separate it as a distinct patch. Cheers, Longman