From: "Christian König" <christian.koenig@amd.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
"David (ChunMing) Zhou" <David1.Zhou@amd.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Alex Deucher" <alexander.deucher@amd.com>,
"David Airlie" <airlied@linux.ie>,
"Jani Nikula" <jani.nikula@linux.intel.com>,
"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
"Doug Ledford" <dledford@redhat.com>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Mike Marciniszyn" <mike.marciniszyn@intel.com>,
"Dennis Dalessandro" <dennis.dalessandro@intel.com>,
"Sudeep Dutt" <sudeep.dutt@intel.com>,
"Ashutosh Dixit" <ashutosh.dixit@intel.com>,
"Dimitri Sivanich" <sivanich@sgi.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Juergen Gross" <jgross@suse.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Andrea Arcangeli" <aarcange@redhat.com>,
kvm@vger.kernel.org, amd-gfx@lists.freedesktop.org,
dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
linux-rdma@vger.kernel.org, xen-devel@lists.xenproject.org,
linux-mm@kvack.org, "David Rientjes" <rientjes@google.com>,
"Felix Kuehling" <felix.kuehling@amd.com>
Subject: Re: [RFC PATCH] mm, oom: distinguish blockable mode for mmu notifiers
Date: Mon, 2 Jul 2018 14:24:29 +0200 [thread overview]
Message-ID: <02d1d52c-f534-f899-a18c-a3169123ac7c@amd.com> (raw)
In-Reply-To: <20180702122003.GN19043@dhcp22.suse.cz>
Am 02.07.2018 um 14:20 schrieb Michal Hocko:
> On Mon 02-07-18 14:13:42, Christian König wrote:
>> Am 02.07.2018 um 13:54 schrieb Michal Hocko:
>>> On Mon 02-07-18 11:14:58, Christian König wrote:
>>>> Am 27.06.2018 um 09:44 schrieb Michal Hocko:
>>>>> This is the v2 of RFC based on the feedback I've received so far. The
>>>>> code even compiles as a bonus ;) I haven't runtime tested it yet, mostly
>>>>> because I have no idea how.
>>>>>
>>>>> Any further feedback is highly appreciated of course.
>>>> That sounds like it should work and at least the amdgpu changes now look
>>>> good to me on first glance.
>>>>
>>>> Can you split that up further in the usual way? E.g. adding the blockable
>>>> flag in one patch and fixing all implementations of the MMU notifier in
>>>> follow up patches.
>>> But such a code would be broken, no? Ignoring the blockable state will
>>> simply lead to lockups until the fixup parts get applied.
>> Well to still be bisect-able you only need to get the interface change in
>> first with fixing the function signature of the implementations.
> That would only work if those functions return -AGAIN unconditionally.
> Otherwise they would pretend to not block while that would be obviously
> incorrect. This doesn't sound correct to me.
>
>> Then add all the new code to the implementations and last start to actually
>> use the new interface.
>>
>> That is a pattern we use regularly and I think it's good practice to do
>> this.
> But we do rely on the proper blockable handling.
Yeah, but you could add the handling only after you have all the
implementations in place. Don't you?
>>> Is the split up really worth it? I was thinking about that but had hard
>>> times to end up with something that would be bisectable. Well, except
>>> for returning -EBUSY until all notifiers are implemented. Which I found
>>> confusing.
>> It at least makes reviewing changes much easier, cause as driver maintainer
>> I can concentrate on the stuff only related to me.
>>
>> Additional to that when you cause some unrelated side effect in a driver we
>> can much easier pinpoint the actual change later on when the patch is
>> smaller.
>>
>>>> This way I'm pretty sure Felix and I can give an rb on the amdgpu/amdkfd
>>>> changes.
>>> If you are worried to give r-b only for those then this can be done even
>>> for larger patches. Just make your Reviewd-by more specific
>>> R-b: name # For BLA BLA
>> Yeah, possible alternative but more work for me when I review it :)
> I definitely do not want to add more work to reviewers and I completely
> see how massive "flag days" like these are not popular but I really
> didn't find a reasonable way around that would be both correct and
> wouldn't add much more churn on the way. So if you really insist then I
> would really appreciate a hint on the way to achive the same without any
> above downsides.
Well, I don't insist on this. It's just from my point of view that this
patch doesn't needs to be one patch, but could be split up.
Could be that I just don't know the code or the consequences of adding
that well enough to really judge.
Christian.
next prev parent reply other threads:[~2018-07-02 12:25 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-22 15:02 [RFC PATCH] mm, oom: distinguish blockable mode for mmu notifiers Michal Hocko
2018-06-22 15:13 ` Christian König
2018-06-22 15:24 ` Michal Hocko
2018-06-22 20:09 ` Felix Kuehling
2018-06-25 8:01 ` Michal Hocko
2018-06-25 13:31 ` Michal Hocko
[not found] ` <152968180950.11773.3374981930722769733@mail.alporthouse.com>
2018-06-22 15:57 ` [Intel-gfx] " Michal Hocko
2018-06-22 16:18 ` Jerome Glisse
2018-06-22 16:25 ` Jerome Glisse
2018-06-24 8:11 ` Paolo Bonzini
2018-06-25 7:57 ` Michal Hocko
2018-06-25 8:10 ` Paolo Bonzini
2018-06-25 8:45 ` Michal Hocko
2018-06-25 10:34 ` Paolo Bonzini
2018-06-25 11:08 ` Michal Hocko
2018-06-27 7:44 ` Michal Hocko
2018-07-02 9:14 ` Christian König
2018-07-02 11:54 ` Michal Hocko
2018-07-02 12:13 ` Christian König
2018-07-02 12:20 ` Michal Hocko
2018-07-02 12:24 ` Christian König [this message]
2018-07-02 12:35 ` Michal Hocko
2018-07-02 12:39 ` Christian König
2018-07-02 12:56 ` Michal Hocko
2018-07-09 12:29 ` Michal Hocko
2018-07-10 13:40 ` Leon Romanovsky
2018-07-10 14:14 ` Michal Hocko
2018-07-10 16:20 ` Leon Romanovsky
2018-07-11 9:03 ` Michal Hocko
2018-07-11 10:14 ` Leon Romanovsky
2018-07-11 11:13 ` Michal Hocko
2018-07-11 12:08 ` Leon Romanovsky
2018-07-16 7:59 ` Leon Romanovsky
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=02d1d52c-f534-f899-a18c-a3169123ac7c@amd.com \
--to=christian.koenig@amd.com \
--cc=David1.Zhou@amd.com \
--cc=aarcange@redhat.com \
--cc=airlied@linux.ie \
--cc=alexander.deucher@amd.com \
--cc=amd-gfx@lists.freedesktop.org \
--cc=ashutosh.dixit@intel.com \
--cc=boris.ostrovsky@oracle.com \
--cc=dennis.dalessandro@intel.com \
--cc=dledford@redhat.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=felix.kuehling@amd.com \
--cc=intel-gfx@lists.freedesktop.org \
--cc=jani.nikula@linux.intel.com \
--cc=jgg@ziepe.ca \
--cc=jglisse@redhat.com \
--cc=jgross@suse.com \
--cc=joonas.lahtinen@linux.intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-rdma@vger.kernel.org \
--cc=mhocko@kernel.org \
--cc=mike.marciniszyn@intel.com \
--cc=pbonzini@redhat.com \
--cc=rientjes@google.com \
--cc=rkrcmar@redhat.com \
--cc=rodrigo.vivi@intel.com \
--cc=sivanich@sgi.com \
--cc=sudeep.dutt@intel.com \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).