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Wed, 13 Jan 2021 03:04:00 -0800 (PST) MIME-Version: 1.0 References: <20210113052209.75531-1-songmuchun@bytedance.com> <20210113052209.75531-2-songmuchun@bytedance.com> <20210113105657.GA26599@linux> In-Reply-To: <20210113105657.GA26599@linux> From: Muchun Song Date: Wed, 13 Jan 2021 19:03:21 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v4 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one To: Oscar Salvador Cc: Mike Kravetz , Andrew Morton , Naoya Horiguchi , Andi Kleen , mhocko@suse.cz, Linux Memory Management List , LKML , Yang Shi , Michal Hocko Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jan 13, 2021 at 6:57 PM Oscar Salvador wrote: > > On Wed, Jan 13, 2021 at 01:22:04PM +0800, Muchun Song wrote: > > diff --git a/mm/migrate.c b/mm/migrate.c > > index 4385f2fb5d18..a6631c4eb6a6 100644 > > --- a/mm/migrate.c > > +++ b/mm/migrate.c > > @@ -1279,6 +1279,12 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, > > return -ENOSYS; > > } > > > > + if (page_count(hpage) == 1) { > > + /* page was freed from under us. So we are done. */ > > + putback_active_hugepage(hpage); > > + return MIGRATEPAGE_SUCCESS; > > + } > > + > > I was a bit puzzled as why we did not go to the "goto" block that already does > this, but then I saw the put_new_page/new_hpage handlind further down. > It could be re-arranged but out of scope, so: Agree. I also thought about this. :) > > Reviewed-by: Oscar Salvador > Thanks. > > -- > Oscar Salvador > SUSE L3