linux-kernel - Re: [Patch v4 0/4] mm/mremap: cleanup move_page

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Message-ID: <20200710081436.3f75omeq5xpjeoc6@box>
Date:   Fri, 10 Jul 2020 11:14:36 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Wei Yang <richard.weiyang@...ux.alibaba.com>
Cc:     Dmitry Osipenko <digetx@...il.com>, akpm@...ux-foundation.org,
        kirill.shutemov@...ux.intel.com, vbabka@...e.cz,
        yang.shi@...ux.alibaba.com, thomas_os@...pmail.org,
        anshuman.khandual@....com, sean.j.christopherson@...el.com,
        peterx@...hat.com, aneesh.kumar@...ux.ibm.com, willy@...radead.org,
        thellstrom@...are.com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [Patch v4 0/4] mm/mremap: cleanup move_page_tables() a little

On Fri, Jul 10, 2020 at 09:14:10AM +0800, Wei Yang wrote:
> On Thu, Jul 09, 2020 at 10:38:58PM +0300, Dmitry Osipenko wrote:
> >08.07.2020 12:50, Wei Yang пишет:
> >> move_page_tables() tries to move page table by PMD or PTE.
> >> 
> >> The root reason is if it tries to move PMD, both old and new range should be
> >> PMD aligned. But current code calculate old range and new range separately.
> >> This leads to some redundant check and calculation.
> >> 
> >> This cleanup tries to consolidate the range check in one place to reduce some
> >> extra range handling.
> >> 
> >> v4:
> >>   * remove a redundant parentheses pointed by Kirill
> >> 
> >> v3:
> >>   * merge patch 1 with 2 as suggested by Kirill
> >
> >>   * add patch 4 to simplify the logic to calculate next and extent
> >
> >Hello, Wei!
> >
> >Unfortunately you re-introduced the offending change that was fixed in
> >v2 and today's next-20200709 on ARM32 is broken once again:
> >
> >BUG: Bad rss-counter state mm:db85ec46 type:MM_ANONPAGES val:190
> >
> 
> Ah, my bad, I forget the error we met last time. It is the different format of
> pmd_addr_end.
> 
> Sorry for that.
> 
> @ Kirill
> 
> If you agree, I would leave the extent/next calculation as it is in patch 3.

Okay.

-- 
 Kirill A. Shutemov