From: Mike Kravetz <mike.kravetz@oracle.com>
To: Miaohe Lin <linmiaohe@huawei.com>, akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/hugetlb: Remove redundant VM_BUG_ON_PAGE on putback_active_hugepage()
Date: Mon, 8 Feb 2021 19:39:28 -0800 [thread overview]
Message-ID: <90572a26-a55c-10d1-3c7e-bcdea1f32fe2@oracle.com> (raw)
In-Reply-To: <a5a09912-72ab-f494-0f29-5e3b7fb7c5a4@huawei.com>
On 2/8/21 6:10 PM, Miaohe Lin wrote:
> Hi:
> On 2021/2/9 9:26, Mike Kravetz wrote:
>> On 2/8/21 12:37 AM, Miaohe Lin wrote:
>>> PageHead(page) is implicitly checked in set_page_huge_active() via the
>>> PageHeadHuge(page) check. So remove this explicit one.
>>
>> I do not disagree with the code change. However, this commit message
>> is not accurate. set_page_huge_active() no longer exists in the tree
>> you are changing. It was replaced with SetHPageMigratable. Also, the
>> VM_BUG_ON_PAGE(!PageHeadHuge(page), page) was removed in the process.
>> So, there is no redundant check.
>>
>> However, a quick audit of calling code reveals that all callers know they
>> are operating on a hugetlb head page.
>>
>
> So I should change the commit log like:
>
> All callers know they are operating on a hugetlb head page. So this VM_BUG_ON_PAGE
> can't catch anything useful.
>
> and send a v2. Right?
Correct,
--
Mike Kravetz
next prev parent reply other threads:[~2021-02-09 3:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-08 8:37 Miaohe Lin
2021-02-09 1:26 ` Mike Kravetz
2021-02-09 2:10 ` Miaohe Lin
2021-02-09 3:39 ` Mike Kravetz [this message]
2021-02-09 6:19 ` Miaohe Lin
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