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Date:   Tue, 12 Apr 2022 09:10:26 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Yu Zhao <yuzhao@google.com>, Stephen Rothwell <sfr@rothwell.id.au>,
        linux-mm@kvack.org, Andi Kleen <ak@linux.intel.com>,
        Aneesh Kumar <aneesh.kumar@linux.ibm.com>,
        Barry Song <21cnbao@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Hillf Danton <hdanton@sina.com>, Jens Axboe <axboe@kernel.dk>,
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        Johannes Weiner <hannes@cmpxchg.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>,
        Mel Gorman <mgorman@suse.de>,
        Michael Larabel <Michael@michaellarabel.com>,
        Michal Hocko <mhocko@kernel.org>,
        Mike Rapoport <rppt@kernel.org>,
        Rik van Riel <riel@surriel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Will Deacon <will@kernel.org>,
        Ying Huang <ying.huang@intel.com>,
        linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, page-reclaim@google.com,
        x86@kernel.org, Brian Geffon <bgeffon@google.com>,
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        Oleksandr Natalenko <oleksandr@natalenko.name>,
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        Donald Carr <d@chaos-reins.com>,
        Holger =?iso-8859-1?Q?Hoffst=E4tte?= 
        <holger@applied-asynchrony.com>,
        Konstantin Kharlamov <Hi-Angel@yandex.ru>,
        Shuang Zhai <szhai2@cs.rochester.edu>,
        Sofia Trinh <sofia.trinh@edi.works>,
        Vaibhav Jain <vaibhav@linux.ibm.com>
Subject: Re: [PATCH v10 08/14] mm: multi-gen LRU: support page table walks
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 <20220407031525.2368067-9-yuzhao@google.com>
 <20220411191621.0378467ad99ebc822d5ad005@linux-foundation.org>
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On Mon, Apr 11, 2022 at 07:16:21PM -0700, Andrew Morton wrote:
> On Wed,  6 Apr 2022 21:15:20 -0600 Yu Zhao <yuzhao@google.com> wrote:

> > +#ifdef CONFIG_LRU_GEN
> > +static void mem_cgroup_attach(struct cgroup_taskset *tset)
> > +{
> > +	struct cgroup_subsys_state *css;
> > +	struct task_struct *task = NULL;
> > +
> > +	cgroup_taskset_for_each_leader(task, css, tset)
> > +		break;
> 
> Does this actually do anything?

Yeah, it finds the first leader if there is any, but this is indeed
quite terrible coding style.