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To:     Michal Hocko <mhocko@suse.com>, Oscar Salvador <osalvador@suse.de>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Muchun Song <songmuchun@bytedance.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
References: <20210415103544.6791-1-osalvador@suse.de>
 <20210415103544.6791-4-osalvador@suse.de> <YHgmgtJRadMB2c5k@dhcp22.suse.cz>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
Subject: Re: [PATCH v8 3/7] mm,hugetlb: Drop clearing of flag from
 prep_new_huge_page
Message-ID: <cf4a3e6d-f69a-cf0b-dc66-b55ad06a1d1c@redhat.com>
Date:   Thu, 15 Apr 2021 14:41:41 +0200
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On 15.04.21 13:41, Michal Hocko wrote:
> On Thu 15-04-21 12:35:40, Oscar Salvador wrote:
>> Pages allocated after boot get its private field cleared by means
>> of post_alloc_hook().
> 
> You surely meant to say s@boot@page/cma allocator@ here

I think this also includes allocating gigantic pages via 
alloc_contig_pages() directly. post_alloc_hook() covers both.

> 
>> Pages allocated during boot, that is directly from the memblock allocator,
>> get cleared by paging_init()->..->memmap_init_zone->..->__init_single_page()
>> before any memblock allocation.
>>
>> Based on this ground, let us remove the clearing of the flag from
>> prep_new_huge_page() as it is not needed.
> 
> I would also mention that this is a leftover from 6c0371490140
> ("hugetlb: convert PageHugeFreed to HPageFreed flag"). Previously the
> explicit clearing was necessary because compound allocations do not get
> this initialization (see prep_compound_page).
> 
>> Signed-off-by: Oscar Salvador <osalvador@suse.de>
> 
> with that
> Acked-by: Michal Hocko <mhocko@suse.com>
> 

Reviewed-by: David Hildenbrand <david@redhat.com>


-- 
Thanks,

David / dhildenb