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Date:   Fri, 21 Apr 2023 11:08:08 -0400
From:   Johannes Weiner <hannes@cmpxchg.org>
To:     Mel Gorman <mgorman@techsingularity.net>
Cc:     linux-mm@kvack.org, Kaiyang Zhao <kaiyang2@cs.cmu.edu>,
        Vlastimil Babka <vbabka@suse.cz>,
        David Rientjes <rientjes@google.com>,
        linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [RFC PATCH 06/26] mm: page_alloc: consolidate free page
 accounting
Message-ID: <20230421150808.GC320347@cmpxchg.org>
References: <20230418191313.268131-1-hannes@cmpxchg.org>
 <20230418191313.268131-7-hannes@cmpxchg.org>
 <20230421125453.np6b5hirktkj6ji5@techsingularity.net>
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On Fri, Apr 21, 2023 at 01:54:53PM +0100, Mel Gorman wrote:
> On Tue, Apr 18, 2023 at 03:12:53PM -0400, Johannes Weiner wrote:
> > Free page accounting currently happens a bit too high up the call
> > stack, where it has to deal with guard pages, compaction capturing,
> > block stealing and even page isolation. This is subtle and fragile,
> > and makes it difficult to hack on the code.
> > 
> > Push the accounting down to where pages enter and leave the physical
> > freelists, where all these higher-level exceptions are of no concern.
> > 
> > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> 
> I didn't look too closely at this one as I'm scanning through to see how
> the overall series works and this is mostly a mechanical patch.
> However, it definitely breaks build
> 
> > @@ -843,7 +843,7 @@ static int __init debug_guardpage_minorder_setup(char *buf)
> >  early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
> >  
> >  static inline bool set_page_guard(struct zone *zone, struct page *page,
> > -				unsigned int order, int migratetype)
> > +				  unsigned int order
> >  {
> >  	if (!debug_guardpage_enabled())
> >  		return false;

Oops, this is under a config I didn't test. Will fix. Thanks.