From: Suren Baghdasaryan <surenb@google.com>
To: Michal Hocko <mhocko@suse.com>
Cc: akpm@linux-foundation.org,
Alexey Alexandrov <aalexand@google.com>,
ccross@google.com, sumit.semwal@linaro.org,
dave.hansen@intel.com, keescook@chromium.org,
willy@infradead.org, kirill.shutemov@linux.intel.com,
vbabka@suse.cz, hannes@cmpxchg.org, corbet@lwn.net,
viro@zeniv.linux.org.uk, rdunlap@infradead.org,
kaleshsingh@google.com, peterx@redhat.com, rppt@kernel.org,
peterz@infradead.org, catalin.marinas@arm.com,
vincenzo.frascino@arm.com, chinwen.chang@mediatek.com,
axelrasmussen@google.com, aarcange@redhat.com, jannh@google.com,
apopple@nvidia.com, jhubbard@nvidia.com, yuzhao@google.com,
will@kernel.org, fenghua.yu@intel.com,
thunder.leizhen@huawei.com, hughd@google.com,
feng.tang@intel.com, jgg@ziepe.ca, guro@fb.com,
tglx@linutronix.de, krisman@collabora.com,
chris.hyser@oracle.com, pcc@google.com, ebiederm@xmission.com,
axboe@kernel.dk, legion@kernel.org, eb@emlix.com,
gorcunov@gmail.com, pavel@ucw.cz, songmuchun@bytedance.com,
viresh.kumar@linaro.org, thomascedeno@google.com,
sashal@kernel.org, cxfcosmos@gmail.com,
linux@rasmusvillemoes.dk, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, kernel-team@android.com
Subject: Re: [PATCH v11 2/3] mm: add a field to store names for private anonymous memory
Date: Tue, 16 Nov 2021 08:29:10 -0800 [thread overview]
Message-ID: <CAJuCfpH6Cg=CDut_9vd3BcX6U_X0WR2tFkqKePLU7aPxFO0UDw@mail.gmail.com> (raw)
In-Reply-To: <YZN/BMImQqrK4MWm@dhcp22.suse.cz>
On Tue, Nov 16, 2021 at 1:51 AM Michal Hocko <mhocko@suse.com> wrote:
>
> On Mon 15-11-21 10:59:20, Suren Baghdasaryan wrote:
> [...]
> > Hi Andrew,
> > I haven't seen any feedback on my patchset for some time now. I think
> > I addressed all the questions and comments (please correct me if I
> > missed anything).
>
> I believe the strings vs. ids have been mostly hand waved away. The
> biggest argument for the former was convenience for developers to have
> something human readable. There was no actual proposal about the naming
> convention so we are relying on some unwritten rules or knowledge of the
> code to be debugged to make human readable string human understandable
> ones. I believe this has never been properly resolved except for - this
> has been used in Android and working just fine. I am not convinced TBH.
>
> So in the end we are adding a user interface that brings a runtime and
> resource overhead that will be hard to change in the future. Reference
> counting handles a part of that and that is nice but ids simply do not
> have any of that.
I explained the way this interface is used and why ids would not work
for us in https://lore.kernel.org/all/CAJuCfpESeM_Xd8dhCj_okNggtDUXx3Nn9FpL_f9qsKXKZzCKpA@mail.gmail.com.
I explored all the proposed alternatives, all of which would be
prohibitive for our needs due to performance costs compared to this
solution. I wish I could come up with something simpler but a simpler
solution simply does not meet our needs.
It's true that this approach does not formalize how VMAs are named but
I don't see why kernel should impose a naming convention. I can see
some systems defining more formal conventions but I believe it should
be up to the userspace to do that.
>
> > Can it be accepted as is or is there something I should address
> > further?
>
> Is the above reason to nack it? No, I do not think so. I just do not
> feel like I want to ack it either. Concerns have been expressed and I
> have to say that I would like a minimalistic approach much more. Also
> extending ids into string is always possible. The other way around is
> not possible.
Unfortunately, extending ids into strings comes with the cost we can't
afford in Android. Therefore I don't see a point for me to upstream
such a solution which I can't use.
Thanks,
Suren.
>
> --
> Michal Hocko
> SUSE Labs
next prev parent reply other threads:[~2021-11-16 17:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 21:55 [PATCH v11 1/3] mm: rearrange madvise code to allow for reuse Suren Baghdasaryan
2021-10-19 21:55 ` [PATCH v11 2/3] mm: add a field to store names for private anonymous memory Suren Baghdasaryan
2021-10-19 21:58 ` Suren Baghdasaryan
2021-11-16 5:19 ` Andrew Morton
2021-11-16 6:10 ` Suren Baghdasaryan
2021-10-27 18:35 ` Alexey Alexandrov
2021-10-27 20:01 ` Suren Baghdasaryan
2021-10-28 22:08 ` Suren Baghdasaryan
2021-11-15 18:59 ` Suren Baghdasaryan
2021-11-16 9:51 ` Michal Hocko
2021-11-16 16:29 ` Suren Baghdasaryan [this message]
2021-10-19 21:55 ` [PATCH v11 3/3] mm: add anonymous vma name refcounting Suren Baghdasaryan
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