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Date: Wed, 8 Mar 2017 14:05:36 +0100
From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Xishi Qiu <qiuxishi@huawei.com>, Vlastimil Babka <vbabka@suse.cz>,
        Mel Gorman <mgorman@techsingularity.net>,
        Minchan Kim <minchan@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Yisheng Xie <xieyisheng1@huawei.com>, Linux MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] mm: use is_migrate_highatomic() to simplify the code
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On Mon 06-03-17 12:43:18, Andrew Morton wrote:
> On Mon, 6 Mar 2017 14:38:33 +0100 Michal Hocko <mhocko@kernel.org> wrote:
> 
> > On Fri 03-03-17 15:06:19, Andrew Morton wrote:
> > > On Fri, 3 Mar 2017 14:18:08 +0100 Michal Hocko <mhocko@kernel.org> wrote:
> > > 
> > > > On Fri 03-03-17 19:10:13, Xishi Qiu wrote:
> > > > > Introduce two helpers, is_migrate_highatomic() and is_migrate_highatomic_page().
> > > > > Simplify the code, no functional changes.
> > > > 
> > > > static inline helpers would be nicer than macros
> > > 
> > > Always.
> > > 
> > > We made a big dependency mess in mmzone.h.  internal.h works.
> > 
> > Just too bad we have three different header files for
> > is_migrate_isolate{_page} - include/linux/page-isolation.h
> > is_migrate_cma{_page} - include/linux/mmzone.h
> > is_migrate_highatomic{_page} - mm/internal.h
> > 
> > I guess we want all of them in internal.h?
> 
> I suppose so.  arch/powerpc/mm/mmu_context_iommu.c is using
> is_migrate_cma_page which would need some attention.  

Ble. I am really wondering whether these helpers actually make the end
result really worth all the troubles and the mess.

-- 
Michal Hocko
SUSE Labs