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From:   Joonsoo Kim <js1304@gmail.com>
Date:   Mon, 1 Jun 2020 15:40:00 +0900
Message-ID: <CAAmzW4Ne3V6p2a9R4KiHCRX47nVp4+2A-GATmf2DxbxpzkjHBA@mail.gmail.com>
Subject: Re: [PATCH v2 00/12] clean-up the migration target allocation functions
To:     Vlastimil Babka <vbabka@suse.cz>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>, kernel-team@lge.com,
        Christoph Hellwig <hch@infradead.org>,
        Roman Gushchin <guro@fb.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Michal Hocko <mhocko@suse.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>
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2020=EB=85=84 5=EC=9B=94 29=EC=9D=BC (=EA=B8=88) =EC=98=A4=ED=9B=84 3:50, J=
oonsoo Kim <js1304@gmail.com>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> 2020=EB=85=84 5=EC=9B=94 29=EC=9D=BC (=EA=B8=88) =EC=98=A4=EC=A0=84 4:25,=
 Vlastimil Babka <vbabka@suse.cz>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
> >
> > On 5/27/20 8:44 AM, js1304@gmail.com wrote:
> > > From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > >
> > > This patchset clean-up the migration target allocation functions.
> > >
> > > * Changes on v2
> > > - add acked-by tags
> > > - fix missing compound_head() call for the patch #3
> > > - remove thisnode field on alloc_control and use __GFP_THISNODE direc=
tly
> > > - fix missing __gfp_mask setup for the patch
> > > "mm/hugetlb: do not modify user provided gfp_mask"
> > >
> > > * Cover-letter
> > >
> > > Contributions of this patchset are:
> > > 1. unify two hugetlb alloc functions. As a result, one is remained.
> > > 2. make one external hugetlb alloc function to internal one.
> > > 3. unify three functions for migration target allocation.
> > >
> > > The patchset is based on next-20200526.
> > > The patchset is available on:
> >
> > I went through the series and I'd like to make some high-level suggesti=
ons
> > first, that should hopefully simplify the code a bit more and reduce ch=
urn:
>
> Thanks for review!
> I have not enough time today to check your suggestions.
> I will check on next week and then reply again.
>
> Thanks.
>
> > - in the series, alloc_huge_page_nodemask() becomes the only caller of
> > alloc_migrate_huge_page(). So you can inline the code there, and it's o=
ne less
> > function out of many with similar name :)
> >
> > - after that, alloc_huge_page_nodemask(ac) uses ac mostly just to extra=
ct
> > individual fields, and only pass it as a whole to dequeue_huge_page_nod=
emask().
> > The only other caller of dequeue...() is dequeue_huge_page_vma() who ha=
s to
> > construct ac from scratch. It might be probably simpler not to introduc=
e struct
> > alloc_control into hugetlb code at all, and only keep it for
> > alloc_migrate_target(), at which point it can have a more specific name=
 as
> > discussed and there's less churn
> >
> > - I'd suggest not change signature of migrate_pages(), free_page_t and
> > new_page_t, keeping the opaque private field is fine as not all callbac=
ks use
> > struct alloc_context pointer, and then e.g. compaction_alloc has to use=
 the
> > private field etc. alloc_migration_target() can simply cast the private=
 to
> > struct alloc_control *ac as the first thing

Looks like all your suggestions are reasonable. I will try them and make v3=
.

Thanks.