linux-kernel - Re: [RFC PATCH 2/3] hugetlb: do not update address in huge_pmd

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Date:   Mon, 30 May 2022 18:14:45 +0800
From:   Baolin Wang <baolin.wang@...ux.alibaba.com>
To:     Mike Kravetz <mike.kravetz@...cle.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     Muchun Song <songmuchun@...edance.com>,
        Michal Hocko <mhocko@...e.com>, Peter Xu <peterx@...hat.com>,
        Naoya Horiguchi <naoya.horiguchi@...ux.dev>,
        James Houghton <jthoughton@...gle.com>,
        Mina Almasry <almasrymina@...gle.com>,
        "Aneesh Kumar K . V" <aneesh.kumar@...ux.vnet.ibm.com>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [RFC PATCH 2/3] hugetlb: do not update address in
 huge_pmd_unshare



On 5/28/2022 6:58 AM, Mike Kravetz wrote:
> As an optimization for loops sequentially processing hugetlb address
> ranges, huge_pmd_unshare would update a passed address if it unshared a
> pmd.  Updating a loop control variable outside the loop like this is
> generally a bad idea.  These loops are now using hugetlb_mask_last_hp
> to optimize scanning when non-present ptes are discovered.  The same
> can be done when huge_pmd_unshare returns 1 indicating a pmd was
> unshared.
> 
> Remove address update from huge_pmd_unshare.  Change the passed argument
> type and update all callers.  In loops sequentially processing addresses
> use hugetlb_mask_last_hp to update address if pmd is unshared.
> 
> Signed-off-by: Mike Kravetz <mike.kravetz@...cle.com>

LGTM. Please feel free to add:
Reviewed-by: Baolin Wang <baolin.wang@...ux.alibaba.com>