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Message-ID: <1efe101a-da55-3043-c964-f23e10bcfa79@intel.com>
Date:   Wed, 27 Apr 2022 13:03:58 +0800
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Subject: Re: [memcg] a8c49af3be: hackbench.throughput -13.7% regression
Content-Language: en-US
To:     Shakeel Butt <shakeelb@google.com>
CC:     kernel test robot <oliver.sang@intel.com>,
        Yosry Ahmed <yosryahmed@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Muchun Song <songmuchun@bytedance.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>, <lkp@lists.01.org>,
        kernel test robot <lkp@intel.com>,
        Huang Ying <ying.huang@intel.com>,
        Feng Tang <feng.tang@intel.com>,
        Xing Zhengjun <zhengjun.xing@linux.intel.com>
References: <20220420055807.GA16310@xsang-OptiPlex-9020>
 <43598597-72e1-6750-9bee-031fd463fc3b@intel.com>
 <CALvZod4_vNWYxzGR3BksZYgoti-9hOioMGwF2UVRnwcAGpFqXA@mail.gmail.com>
From:   Yin Fengwei <fengwei.yin@intel.com>
In-Reply-To: <CALvZod4_vNWYxzGR3BksZYgoti-9hOioMGwF2UVRnwcAGpFqXA@mail.gmail.com>
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On 4/27/2022 1:02 PM, Shakeel Butt wrote:
> Hi Yin,
> 
> On Tue, Apr 26, 2022 at 7:53 PM Yin Fengwei <fengwei.yin@intel.com> wrote:
>>
> [...]
>>
>> If I comment out one line added by the commit <a8c49af3be> :
>> static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages)
>> {
>>         /* mod_memcg_state(memcg, MEMCG_KMEM, nr_pages); */  <--- comment out this line.
> 
> Can you to comment out the following block instead of the above line
> and see if there is any impact?
> 
>>         if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
>>                 if (nr_pages > 0)
>>                         page_counter_charge(&memcg->kmem, nr_pages);
>>                 else
>>                         page_counter_uncharge(&memcg->kmem, -nr_pages);
>>         }
>> }
OK. I will give it a try and send the result out.


Regards
Yin, Fengwei

>>