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From:   Qian Cai <cai@lca.pw>
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Subject: Re: [PATCH] mm/page_alloc: Add a reason for reserved pages in has_unmovable_pages()
Date:   Thu, 3 Oct 2019 07:19:15 -0400
Message-Id: <285C0297-BF27-4095-87B6-AFC88C1F3C0F@lca.pw>
References: <37b43978-5652-576c-8990-451e751b7c67@arm.com>
Cc:     linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Oscar Salvador <osalvador@suse.de>,
        Mel Gorman <mgorman@techsingularity.net>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Pavel Tatashin <pavel.tatashin@microsoft.com>,
        linux-kernel@vger.kernel.org
In-Reply-To: <37b43978-5652-576c-8990-451e751b7c67@arm.com>
To:     Anshuman Khandual <Anshuman.Khandual@arm.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


> On Oct 3, 2019, at 5:32 AM, Anshuman Khandual <Anshuman.Khandual@arm.com> w=
rote:
>=20
> Even though page flags does contain reserved bit information, the problem
> is that we are explicitly printing the reason for this page dump. In this
> case it is caused by the fact that it is a reserved page.
>=20
> page dumped because: <reason>
>=20
> The proposed change makes it explicit that the dump is caused because a
> non movable page with reserved bit set. It also helps in differentiating=20=

> between reserved bit condition and the last one "if (found > count)".

Then, someone later would like to add a reason for every different page flag=
s just because they *think* they are special.=