Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200516124857.75004-1-lecopzer@gmail.com> <CAFA6WYNwp+_ENiS8QDao5+RXyt5ofJZyq6c5CKG_d0CNEmBNYg@mail.gmail.com>
 <CANr2M19unLW8n0P2DiOYEZ=GZcaD-L2ygPht_5HNtNZ6e4h6xQ@mail.gmail.com>
 <20200518104524.GA1224@C02TD0UTHF1T.local> <a9002b5e-aec5-b6e0-7174-87b93351d60c@arm.com>
 <CAFA6WYPKD0Kkn5yQiKZQkM+tT0iW4oPnndegD-iau9EwB5DYog@mail.gmail.com> <20200518141946.GA3164@C02TD0UTHF1T.local>
In-Reply-To: <20200518141946.GA3164@C02TD0UTHF1T.local>
From:   Sumit Garg <sumit.garg@linaro.org>
Date:   Tue, 19 May 2020 12:18:04 +0530
Message-ID: <CAFA6WYP7QhcQZrWua7NOqaqOO8Zd8QeWpHr4_QbDZFgjQ+Qung@mail.gmail.com>
Subject: Re: [PATCH 0/3] arm64: perf: Add support for Perf NMI interrupts
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     Alexandru Elisei <alexandru.elisei@arm.com>,
        Lecopzer Chen <lecopzer@gmail.com>,
        julien.thierry.kdev@gmail.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Jian-Lin Chen <lecopzer.chen@mediatek.com>,
        alexander.shishkin@linux.intel.com,
        Catalin Marinas <catalin.marinas@arm.com>, jolsa@redhat.com,
        acme@kernel.org, Peter Zijlstra <peterz@infradead.org>,
        mingo@redhat.com, linux-mediatek@lists.infradead.org,
        matthias.bgg@gmail.com, namhyung@kernel.org,
        Will Deacon <will@kernel.org>, yj.chiang@mediatek.com,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, 18 May 2020 at 19:49, Mark Rutland <mark.rutland@arm.com> wrote:
>
> On Mon, May 18, 2020 at 07:39:23PM +0530, Sumit Garg wrote:
> > On Mon, 18 May 2020 at 16:47, Alexandru Elisei <alexandru.elisei@arm.com> wrote:
> > > On 5/18/20 11:45 AM, Mark Rutland wrote:
> > > > On Mon, May 18, 2020 at 02:26:00PM +0800, Lecopzer Chen wrote:
> > > >> HI Sumit,
> > > >>
> > > >> Thanks for your information.
> > > >>
> > > >> I've already implemented IPI (same as you did [1], little difference
> > > >> in detail), hardlockup detector and perf in last year(2019) for
> > > >> debuggability.
> > > >> And now we tend to upstream to reduce kernel maintaining effort.
> > > >> I'm glad if someone in ARM can do this work :)
> > > >>
> > > >> Hi Julien,
> > > >>
> > > >> Does any Arm maintainers can proceed this action?
> > > > Alexandru (Cc'd) has been rebasing and reworking Julien's patches, which
> > > > is my preferred approach.
> > > >
> > > > I understand that's not quite ready for posting since he's investigating
> > > > some of the nastier subtleties (e.g. mutual exclusion with the NMI), but
> > > > maybe we can put the work-in-progress patches somewhere in the mean
> > > > time.
> > > >
> > > > Alexandru, do you have an idea of what needs to be done, and/or when you
> > > > expect you could post that?
> > >
> > > I'm currently working on rebasing the patches on top of 5.7-rc5, when I have
> > > something usable I'll post a link (should be a couple of days). After that I will
> > > address the review comments, and I plan to do a thorough testing because I'm not
> > > 100% confident that some of the assumptions around the locks that were removed are
> > > correct. My guess is this will take a few weeks.
> > >
> >
> > Thanks Mark, Alex for the status updates on perf NMI feature.
> >
> > Alex,
> >
> > As the hard-lockup detection patch [1] has a dependency on perf NMI
> > patch-set, I will rebase and test hard-lockup detector when you have
> > got a working tree. But due to the dependency, I think patch [1]
> > should be accepted along with perf NMI patch-set. So would you be open
> > to include this patch as part of your series?
> >
> > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2020-May/732227.html
>
> While it depends on the perf NMI bits, I don't think it makes sense to
> tie that into the series given it's trying to achieve something very
> different.
>
> I think that should be reposted separately once the perf NMI bits are in
> shape.

Okay, fair enough. Will keep it as a separate patch then.

-Sumit

>
> Thanks,
> Mark.