Re: [linux-next:master] [mm/hugetlb_vmemmap] 875fa64577: vm-scalability.throughput -34.3% regression

[Muchun Song]

> On Jul 14, 2024, at 20:26, Oliver Sang <oliver.sang@xxxxxxxxx> wrote:
> 
> hi, Yu Zhao,
> 
> On Wed, Jul 10, 2024 at 12:22:40AM -0600, Yu Zhao wrote:
>> On Mon, Jul 8, 2024 at 11:11 PM kernel test robot <oliver.sang@xxxxxxxxx> wrote:
>>> 
>>> Hello,
>>> 
>>> kernel test robot noticed a -34.3% regression of vm-scalability.throughput on:
>>> 
>>> 
>>> commit: 875fa64577da9bc8e9963ee14fef8433f20653e7 ("mm/hugetlb_vmemmap: fix race with speculative PFN walkers")
>> 
>> This is likely caused by synchronize_rcu() wandering into the
>> allocation path. I'll patch that up soon.
>> 
> 
> we noticed this commit has already been merged into mainline
> 
> [bd225530a4c717714722c3731442b78954c765b3] mm/hugetlb_vmemmap: fix race with speculative PFN walkers
> branch: linus/master

Did you test with HVO enabled (there are two ways to enable HVO: 1) adding cmdline with "hugetlb_free_vmemmap=on"
or 2) write 1 to /proc/sys/vm/hugetlb_optimize_vmemmap)? I want to confirm if the regression is related
to HVO routine.

Thanks.

> 
> and the regression still exists in our tests. do you want us to test your
> patch? Thanks!