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Date:   Wed, 14 Apr 2021 12:49:53 +0200
From:   Oscar Salvador <osalvador@suse.de>
To:     Michal Hocko <mhocko@suse.com>
Cc:     Mike Kravetz <mike.kravetz@oracle.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        David Hildenbrand <david@redhat.com>,
        Muchun Song <songmuchun@bytedance.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 3/7] mm,hugetlb: Clear HPageFreed outside of the lock
Message-ID: <20210414104953.GF20886@linux>
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On Wed, Apr 14, 2021 at 12:32:58PM +0200, Michal Hocko wrote:
> Well, to be precise it does the very same thing with memamp struct pages
> but that is before the initialization code you have pointed out above.
> In this context it just poisons the allocated content which is the GB
> page storage.

Right.

> > I checked, and when we get there in __alloc_bootmem_huge_page, page->private is
> > still zeroed, so I guess it should be safe to assume that we do not really need
> > to clear the flag in __prep_new_huge_page() routine?
> 
> It would be quite nasty if the struct pages content would be undefined.
> Maybe that is possible but then I would rather stick the initialization
> into __alloc_bootmem_huge_page.

Yes, but I do not think that is really possible unless I missed something.
Let us see what Mike thinks of it, if there are no objections, we can
get rid of the clearing flag right there.
 

-- 
Oscar Salvador
SUSE L3