From: Andrew Morton <akpm@linux-foundation.org>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Hocko" <mhocko@kernel.org>,
"Vladimir Davydov" <vdavydov.dev@gmail.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Balbir Singh" <bsingharora@gmail.com>,
"Ira Weiny" <ira.weiny@intel.com>,
stable@vger.kernel.org
Subject: Re: [PATCH] mm/memcg: fix device private memcg accounting
Date: Fri, 9 Oct 2020 15:50:55 -0700 [thread overview]
Message-ID: <20201009155055.f87de51ea04d4ea879e3981a@linux-foundation.org> (raw)
In-Reply-To: <20201009215952.2726-1-rcampbell@nvidia.com>
On Fri, 9 Oct 2020 14:59:52 -0700 Ralph Campbell <rcampbell@nvidia.com> wrote:
> The code in mc_handle_swap_pte() checks for non_swap_entry() and returns
> NULL before checking is_device_private_entry() so device private pages
> are never handled.
> Fix this by checking for non_swap_entry() after handling device private
> swap PTEs.
>
> Cc: stable@vger.kernel.org
I was going to ask "what are the end-user visible effects of the bug".
This is important information with a cc:stable.
>
> I'm not sure exactly how to test this. I ran the HMM self tests but
> that is a minimal sanity check. I think moving the self test from one
> memory cgroup to another while it is running would exercise this patch.
> I'm looking at how the test could move itself to another group after
> migrating some anonymous memory to the test driver.
>
But this makes me suspect the answer is "there aren't any that we know
of". Are you sure a cc:stable is warranted?
next prev parent reply other threads:[~2020-10-09 22:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 21:59 Ralph Campbell
2020-10-09 22:50 ` Andrew Morton [this message]
2020-10-10 0:00 ` Ralph Campbell
2020-10-12 13:28 ` Johannes Weiner
2020-10-12 17:11 ` Ralph Campbell
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