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From: Shakeel Butt <shakeel.butt@linux.dev>
To: Oliver Sang <oliver.sang@intel.com>
Cc: Qi Zheng <qi.zheng@linux.dev>, oe-lkp@lists.linux.dev, lkp@intel.com, 
	linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, 
	David Carlier <devnexen@gmail.com>, Allen Pais <apais@linux.microsoft.com>, 
	Axel Rasmussen <axelrasmussen@google.com>, Baoquan He <bhe@redhat.com>, 
	Chengming Zhou <chengming.zhou@linux.dev>, Chen Ridong <chenridong@huawei.com>, 
	David Hildenbrand <david@kernel.org>, Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>, 
	Harry Yoo <harry.yoo@oracle.com>, Hugh Dickins <hughd@google.com>, 
	Imran Khan <imran.f.khan@oracle.com>, Johannes Weiner <hannes@cmpxchg.org>, 
	Kamalesh Babulal <kamalesh.babulal@oracle.com>, Lance Yang <lance.yang@linux.dev>, 
	Liam Howlett <Liam.Howlett@oracle.com>, Lorenzo Stoakes <ljs@kernel.org>, Michal Hocko <mhocko@suse.com>, 
	Michal =?utf-8?Q?Koutn=C3=BD?= <mkoutny@suse.com>, Mike Rapoport <rppt@kernel.org>, 
	Muchun Song <muchun.song@linux.dev>, Muchun Song <songmuchun@bytedance.com>, 
	Nhat Pham <nphamcs@gmail.com>, Roman Gushchin <roman.gushchin@linux.dev>, 
	Suren Baghdasaryan <surenb@google.com>, Usama Arif <usamaarif642@gmail.com>, 
	Vlastimil Babka <vbabka@kernel.org>, Wei Xu <weixugc@google.com>, Yosry Ahmed <yosry@kernel.org>, 
	Yuanchu Xie <yuanchu@google.com>, Zi Yan <ziy@nvidia.com>, Usama Arif <usama.arif@linux.dev>, 
	cgroups@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [linus:master] [mm] 01b9da291c: stress-ng.switch.ops_per_sec
 67.7% regression
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On Sun, May 17, 2026 at 12:38:48PM -0700, Shakeel Butt wrote:
> On Sun, May 17, 2026 at 08:55:50PM +0800, Oliver Sang wrote:
> > hi, Shakeel, hi, Qi,
> > 
> > #2: when we test above patch, we found the server easy to crash while running
> > tests. we try to run up to 20 times, only 2 of them run successfully (above
> > 37739220 is just the average data from these 2 runs, since the data is stable,
> > we think maybe it's ok to report to you with this data).
> > we also noticed for [1] there is a [syzbot ci] report in [2]. since we don't
> > have serial output for our test server in this report which is for performance
> > tests, we cannot say if other 18 runs failed due to similar reason. just FYI.
> > 
> 
> The syzbot report is simply a rcu warning which will be fixed in v2. Do you
> have more details on the crash you are seeing? Is it page counter underflow
> warning?
> 
> Thanks again for the help.

Hi Oliver, it seems like sashiko found another issue with v2, so, if you have
not yet started the test, you can skip it.

Also I am rethinking the approach, so I will send a prototype in response on
this email for which I will need your help in testing.