Date: Fri, 15 Dec 2017 12:51:25 +0300
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org, Zi Yan <zi.yan@cs.rutgers.edu>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrea Reale <ar@linux.vnet.ibm.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 1/3] mm, numa: rework do_pages_move
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On Fri, Dec 15, 2017 at 10:28:59AM +0100, Michal Hocko wrote:
> On Thu 14-12-17 18:35:58, Kirill A. Shutemov wrote:
> > On Wed, Dec 13, 2017 at 03:39:48PM +0100, Michal Hocko wrote:
> [...]
> > > +	err = 0;
> > > +	if (page_to_nid(page) == node)
> > > +		goto out_putpage;
> > > +
> > > +	err = -EACCES;
> > > +	if (page_mapcount(page) > 1 &&
> > > +			!migrate_all)
> > 
> > Non-sensible line break.
> 
> fixed
> 
> > > +		goto out_putpage;
> > > +
> > > +	if (PageHuge(page)) {
> > > +		if (PageHead(page)) {
> > > +			isolate_huge_page(page, pagelist);
> > > +			err = 0;
> > > +		}
> > > +	} else {
> > 
> > Hm. I think if the page is PageTail() we have to split the huge page.
> > If an user asks to migrate part of THP, we shouldn't migrate the whole page,
> > otherwise it's not transparent anymore.
> 
> Well, as I've said in the cover letter. There are more things which are
> worth considering but I've tried to keep the original semantic so
> further changes should be done in separete patches. I will work on those
> but I would prefer this to stay smaller if you do not mind.

Sure.

Fill free to use my ack.

-- 
 Kirill A. Shutemov