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Date:   Thu, 26 May 2022 11:14:50 +0100
From:   Mel Gorman <mgorman@techsingularity.net>
To:     Muchun Song <songmuchun@bytedance.com>
Cc:     Nicolas Saenz Julienne <nsaenzju@redhat.com>,
        Marcelo Tosatti <mtosatti@redhat.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Michal Hocko <mhocko@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 1/6] mm/page_alloc: Add page->buddy_list and
 page->pcp_list
Message-ID: <20220526101450.GE3441@techsingularity.net>
References: <20220509130805.20335-1-mgorman@techsingularity.net>
 <20220509130805.20335-2-mgorman@techsingularity.net>
 <Yn4ZsKEmtnquHhWJ@FVFYT0MHHV2J.usts.net>
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On Fri, May 13, 2022 at 04:41:20PM +0800, Muchun Song wrote:
> > @@ -94,6 +95,10 @@ struct page {
> >  					/* Count page's or folio's mlocks */
> >  					unsigned int mlock_count;
> >  				};
> > +
> > +				/* Or, free page */
> > +				struct list_head buddy_list;
> > +				struct list_head pcp_list;
> >  			};
> 
> Since you have clarified "lru" member, should we go further?
> Like union "index" to "pcp_migratetype" and "private" to "order"
> since buddy allocator reuses "index" and "private" as well.
> My initial idea is as follows, it is more clear for me, what
> do you think?
> 

I think it would be more appropriate to split it out as a separate type as
suggested by Matthew Wilcox. While I would not be opposed to your approach
as such, it's outside the context of the series which is modifying how
PCP works.

-- 
Mel Gorman
SUSE Labs