linux-kernel - Re: [PATCHv3, RESEND 8/8] khugepaged: Introduce 'max_ptes

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Date:   Thu, 16 Apr 2020 11:25:56 -0700
From:   Yang Shi <yang.shi@...ux.alibaba.com>
To:     "Kirill A. Shutemov" <kirill@...temov.name>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        akpm@...ux-foundation.org, Andrea Arcangeli <aarcange@...hat.com>,
        Zi Yan <ziy@...dia.com>, Ralph Campbell <rcampbell@...dia.com>,
        John Hubbard <jhubbard@...dia.com>,
        William Kucharski <william.kucharski@...cle.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv3, RESEND 8/8] khugepaged: Introduce 'max_ptes_shared'
 tunable



On 4/16/20 8:52 AM, Kirill A. Shutemov wrote:
> On Wed, Apr 15, 2020 at 02:25:30PM -0700, Yang Shi wrote:
>>> @@ -595,6 +626,12 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
>>>    		VM_BUG_ON_PAGE(!PageAnon(page), page);
>>> +		if (page_mapcount(page) > 1 &&
>>> +				++shared > khugepaged_max_ptes_shared) {
>>> +			result = SCAN_EXCEED_SHARED_PTE;
>> It may be better to extract the check into a helper? For example, bool
>> exceed_max_ptes_shared(struct page)?
> It might be reasonable as part of wider cleanup: the same has to be done
> to khugepaged_max_ptes_none and khugepaged_max_ptes_swap.
>
> Volunteers? :P

Fine, I will take it. :-)

>