linux-kernel - Re: [PATCH] mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()

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Message-ID: <23247c25-a637-d1b0-574f-84d1cd0ded1d@oracle.com>
Date:   Wed, 11 Mar 2020 11:20:15 -0700
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     Vlastimil Babka <vbabka@...e.cz>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        "Kirill A.Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCH] mm/hugetlb: remove unnecessary memory fetch in
 PageHeadHuge()

On 3/11/20 10:24 AM, Vlastimil Babka wrote:
> Commit f1e61557f023 ("mm: pack compound_dtor and compound_order into one word
> in struct page") changed compound_dtor from a pointer to an array index in
> order to pack it. To check if page has the hugeltbfs compound_dtor, we can
> just compare the index directly without fetching the function pointer.
> Said commit did that with PageHuge() and we can do the same with PageHeadHuge()
> to make the code a bit smaller and faster.
> 
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
> Cc: Mike Kravetz <mike.kravetz@...cle.com>
> Cc: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>

Thanks!

Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
-- 
Mike Kravetz