linux-kernel - Re: [RFC PATCH 2/8] hugetlb: recompute min_count when dropping hugetlb

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Message-ID: <YFr6A927XhhiciFj@dhcp22.suse.cz>
Date:   Wed, 24 Mar 2021 09:36:19 +0100
From:   Michal Hocko <mhocko@...e.com>
To:     Mike Kravetz <mike.kravetz@...cle.com>
Cc:     Peter Zijlstra <peterz@...radead.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Shakeel Butt <shakeelb@...gle.com>,
        Oscar Salvador <osalvador@...e.de>,
        David Hildenbrand <david@...hat.com>,
        Muchun Song <songmuchun@...edance.com>,
        David Rientjes <rientjes@...gle.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Matthew Wilcox <willy@...radead.org>,
        HORIGUCHI NAOYA <naoya.horiguchi@....com>,
        "Aneesh Kumar K . V" <aneesh.kumar@...ux.ibm.com>,
        Waiman Long <longman@...hat.com>, Peter Xu <peterx@...hat.com>,
        Mina Almasry <almasrymina@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [RFC PATCH 2/8] hugetlb: recompute min_count when dropping
 hugetlb_lock

On Tue 23-03-21 16:18:08, Mike Kravetz wrote:
[...]
> Here is another thought.
> In patch 5 you suggest removing all pages from hugetlb with the lock
> held, and adding them to a list.  Then, drop the lock and free all
> pages on the list.  If we do this, then the value computed here (min_count)
> can not change while we are looping.  So, this patch would be unnecessary.
> That is another argument in favor of batching the frees.
> 
> Unless there is something wrong in my thinking, I am going to take that
> approach and drop this patch.

Makes sense
-- 
Michal Hocko
SUSE Labs