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Message-ID: <1491827904.8850.178.camel@redhat.com>
Subject: Re: [PATCH] mm, numa: Fix bad pmd by atomically check for
 pmd_trans_huge when marking page tables prot_numa
From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@techsingularity.net>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
        Michal Hocko <mhocko@kernel.org>, Vlastimil Babka <vbabka@suse.cz>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Date: Mon, 10 Apr 2017 08:38:24 -0400
In-Reply-To: <20170410094825.2yfo5zehn7pchg6a@techsingularity.net>
References: <20170410094825.2yfo5zehn7pchg6a@techsingularity.net>
Organization: Red Hat, Inc
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On Mon, 2017-04-10 at 10:48 +0100, Mel Gorman wrote:
> 
> While this could be fixed with heavy locking, it's only necessary to
> make a copy of the PMD on the stack during change_pmd_range and avoid
> races. A new helper is created for this as the check if quite subtle
> and the
> existing similar helpful is not suitable. This passed 154 hours of
> testing
> (usually triggers between 20 minutes and 24 hours) without detecting
> bad
> PMDs or corruption. A basic test of an autonuma-intensive workload
> showed
> no significant change in behaviour.
> 
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
> Cc: stable@vger.kernel.org

Acked-by: Rik van Riel <riel@redhat.com>