From: Michal Hocko <mhocko@kernel.org>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Qian Cai <cai@lca.pw>, Alexey Dobriyan <adobriyan@gmail.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Andrew Morton <akpm@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Toshiki Fukasawa <t-fukasawa@vx.jp.nec.com>,
Konstantin Khlebnikov <koct9i@gmail.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Anthony Yznaga <anthony.yznaga@oracle.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Dan Williams <dan.j.williams@intel.com>,
Logan Gunthorpe <logang@deltatee.com>,
Ira Weiny <ira.weiny@intel.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v1] mm: Fix access of uninitialized memmaps in fs/proc/page.c
Date: Wed, 9 Oct 2019 13:24:24 +0200 [thread overview]
Message-ID: <20191009112424.GY6681@dhcp22.suse.cz> (raw)
In-Reply-To: <67aeaacc-d850-5c81-bd17-e95c7f7f75df@redhat.com>
On Wed 09-10-19 12:19:59, David Hildenbrand wrote:
[...]
> > pfn_to_online_page makes sense because offline pages are not really in a
> > defined state. This would be worth a patch of its own. I remember there
>
> The issue is, once I check for pfn_to_online_page(), these functions
> can't handle ZONE_DEVICE at all anymore. Especially in regards to
> memory_failure() I don't think this is acceptable.
Could you be more specific please? I am not sure I am following.
> So while I
> (personally) only care about adding pfn_to_online_page() checks, the
> in-this-sense-fragile-subsection ZONE_DEVICE implementation requires me
> to introduce a temporary check for initialized memmaps.
>
> > was a discussion about the uninitialized zone device memmaps. It would
> > be really good to summarize this discussion in the changelog and
> > conclude why the explicit check is really good and what were other
> > alternatives considered.
>
> Yeah, I also expressed my feelings and the issues to be solved by
> ZONE_DEVICE people in https://lkml.org/lkml/2019/9/6/114. However, the
> discussion stalled and nobody really proposed a solution or followed up.
I will try to get back to that discussion but is there any technical
reason that prevents any conclusion or it is just stuck on a lack of
time of the participants?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-10-09 11:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 9:12 [PATCH v1] mm: Fix access of uninitialized memmaps in fs/proc/page.c David Hildenbrand
2019-10-09 9:37 ` Michal Hocko
2019-10-09 10:19 ` David Hildenbrand
2019-10-09 11:24 ` Michal Hocko [this message]
2019-10-09 12:58 ` David Hildenbrand
2019-10-09 13:22 ` Michal Hocko
2019-10-09 13:24 ` David Hildenbrand
2019-10-09 13:29 ` Michal Hocko
2019-10-09 13:32 ` David Hildenbrand
2019-10-09 9:57 ` Naoya Horiguchi
2019-10-10 7:30 ` David Hildenbrand
2019-10-11 0:11 ` Naoya Horiguchi
2019-10-11 0:50 ` Naoya Horiguchi
2019-10-11 9:53 ` David Hildenbrand
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