linux-kernel - Re: [PATCH v4 1/3] mm/hwpoison: mf_mutex for soft offline and unpoison

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Message-ID: <993a94b8-b845-5f28-691e-5fd14f2597ee@oracle.com>
Date:   Fri, 21 Jan 2022 10:59:14 -0800
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     Naoya Horiguchi <naoya.horiguchi@...ux.dev>, linux-mm@...ck.org
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Oscar Salvador <osalvador@...e.de>,
        Michal Hocko <mhocko@...e.com>,
        Ding Hui <dinghui@...gfor.com.cn>,
        Tony Luck <tony.luck@...el.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Yang Shi <shy828301@...il.com>, Peter Xu <peterx@...hat.com>,
        Naoya Horiguchi <naoya.horiguchi@....com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/3] mm/hwpoison: mf_mutex for soft offline and
 unpoison

On 1/20/22 16:09, Mike Kravetz wrote:
> On 11/15/21 00:40, Naoya Horiguchi wrote:
>> From: Naoya Horiguchi <naoya.horiguchi@....com>
>>
>> Originally mf_mutex is introduced to serialize multiple MCE events, but
>> it is not that useful to allow unpoison to run in parallel with memory_failure()
>> and soft offline.  So apply mf_mutex to soft offline and unpoison.
>> The memory failure handler and soft offline handler get simpler with this.
>>

Sorry for the late question.

It is not directly part of this change, but can we also remove the check in
__soft_offline_page after this comment?

        /*
         * Check PageHWPoison again inside page lock because PageHWPoison
         * is set by memory_failure() outside page lock. Note that
         * memory_failure() also double-checks PageHWPoison inside page lock,
         * so there's no race between soft_offline_page() and memory_failure().
         */

-- 
Mike Kravetz