From: Joel Fernandes <joel@joelfernandes.org>
To: "Li, Aubrey" <aubrey.li@linux.intel.com>
Cc: Nishanth Aravamudan <naravamudan@digitalocean.com>,
Julien Desfossez <jdesfossez@digitalocean.com>,
Peter Zijlstra <peterz@infradead.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
Vineeth Pillai <viremana@linux.microsoft.com>,
Aaron Lu <aaron.lwe@gmail.com>,
Aubrey Li <aubrey.intel@gmail.com>,
tglx@linutronix.de, linux-kernel@vger.kernel.org,
mingo@kernel.org, torvalds@linux-foundation.org,
fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com,
Phil Auld <pauld@redhat.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Mel Gorman <mgorman@techsingularity.net>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
vineeth@bitbyteword.org, Chen Yu <yu.c.chen@intel.com>,
Christian Brauner <christian.brauner@ubuntu.com>,
Agata Gruza <agata.gruza@intel.com>,
Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com>,
graf@amazon.com, konrad.wilk@oracle.com, dfaggioli@suse.com,
pjt@google.com, rostedt@goodmis.org, derkling@google.com,
benbjiang@tencent.com,
Alexandre Chartre <alexandre.chartre@oracle.com>,
James.Bottomley@hansenpartnership.com, OWeisse@umich.edu,
Dhaval Giani <dhaval.giani@oracle.com>,
Junaid Shahid <junaids@google.com>,
jsbarnes@google.com, chris.hyser@oracle.com,
"Paul E. McKenney" <paulmck@kernel.org>,
Tim Chen <tim.c.chen@intel.com>
Subject: Re: [PATCH v8 -tip 19/26] sched: Add a second-level tag for nested CGroup usecase
Date: Thu, 5 Nov 2020 10:52:05 -0500 [thread overview]
Message-ID: <20201105155205.GC2656962@google.com> (raw)
In-Reply-To: <6c07e70d-52f2-69ff-e1fa-690cd2c97f3d@linux.intel.com>
On Wed, Oct 28, 2020 at 02:23:02PM +0800, Li, Aubrey wrote:
> On 2020/10/20 9:43, Joel Fernandes (Google) wrote:
> > Google has a usecase where the first level tag to tag a CGroup is not
> > sufficient. So, a patch is carried for years where a second tag is added which
> > is writeable by unprivileged users.
> >
> > Google uses DAC controls to make the 'tag' possible to set only by root while
> > the second-level 'color' can be changed by anyone. The actual names that
> > Google uses is different, but the concept is the same.
> >
> > The hierarchy looks like:
> >
> > Root group
> > / \
> > A B (These are created by the root daemon - borglet).
> > / \ \
> > C D E (These are created by AppEngine within the container).
> >
> > The reason why Google has two parts is that AppEngine wants to allow a subset of
> > subcgroups within a parent tagged cgroup sharing execution. Think of these
> > subcgroups belong to the same customer or project. Because these subcgroups are
> > created by AppEngine, they are not tracked by borglet (the root daemon),
> > therefore borglet won't have a chance to set a color for them. That's where
> > 'color' file comes from. Color could be set by AppEngine, and once set, the
> > normal tasks within the subcgroup would not be able to overwrite it. This is
> > enforced by promoting the permission of the color file in cgroupfs.
> >
> > The 'color' is a 8-bit value allowing for upto 256 unique colors. IMHO, having
> > more than these many CGroups sounds like a scalability issue so this suffices.
> > We steal the lower 8-bits of the cookie to set the color.
> >
>
> So when color = 0, tasks in group A C D can run together on the HTs in same core,
> And if I set the color of taskC in group C = 1, then taskC has a different cookie
> from taskA and taskD, so in terms of taskA, what's the difference between taskC
> and [taskB or taskE]? The color breaks the relationship that C belongs to A.
C does belong to A in the sense, A cannot share with B, this implies C can
never share with B. Setting C's color does not change that fact. So coloring
is irrelevant in your question.
Sure, A cannot share with C either after coloring, but that's irrelevant and
not the point of doing the coloring.
thanks,
- Joel
next prev parent reply other threads:[~2020-11-05 15:52 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-20 1:43 [PATCH v8 -tip 00/26] Core scheduling Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 01/26] sched: Wrap rq::lock access Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 02/26] sched: Introduce sched_class::pick_task() Joel Fernandes (Google)
2020-10-22 7:59 ` Li, Aubrey
2020-10-22 15:25 ` Joel Fernandes
2020-10-23 5:25 ` Li, Aubrey
2020-10-23 21:47 ` Joel Fernandes
2020-10-24 2:48 ` Li, Aubrey
2020-10-24 11:10 ` Vineeth Pillai
2020-10-24 12:27 ` Vineeth Pillai
2020-10-24 23:48 ` Li, Aubrey
2020-10-26 9:01 ` Peter Zijlstra
2020-10-27 3:17 ` Li, Aubrey
2020-10-27 14:19 ` Joel Fernandes
2020-10-27 15:23 ` Joel Fernandes
2020-10-27 14:14 ` Joel Fernandes
2020-10-20 1:43 ` [PATCH v8 -tip 03/26] sched: Core-wide rq->lock Joel Fernandes (Google)
2020-10-26 11:59 ` Peter Zijlstra
2020-10-27 16:27 ` Joel Fernandes
2020-10-20 1:43 ` [PATCH v8 -tip 04/26] sched/fair: Add a few assertions Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 05/26] sched: Basic tracking of matching tasks Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 06/26] sched: Add core wide task selection and scheduling Joel Fernandes (Google)
2020-10-23 13:51 ` Peter Zijlstra
2020-10-23 13:54 ` Peter Zijlstra
2020-10-23 17:57 ` Joel Fernandes
2020-10-23 19:26 ` Peter Zijlstra
2020-10-23 21:31 ` Joel Fernandes
2020-10-26 8:28 ` Peter Zijlstra
2020-10-27 16:58 ` Joel Fernandes
2020-10-26 9:31 ` Peter Zijlstra
2020-11-05 18:50 ` Joel Fernandes
2020-11-05 22:07 ` Joel Fernandes
2020-10-23 15:05 ` Peter Zijlstra
2020-10-23 17:59 ` Joel Fernandes
2020-10-20 1:43 ` [PATCH v8 -tip 07/26] sched/fair: Fix forced idle sibling starvation corner case Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 08/26] sched/fair: Snapshot the min_vruntime of CPUs on force idle Joel Fernandes (Google)
2020-10-26 12:47 ` Peter Zijlstra
2020-10-28 15:29 ` Joel Fernandes
2020-10-28 18:39 ` Joel Fernandes
2020-10-29 16:59 ` Joel Fernandes
2020-10-29 18:24 ` Joel Fernandes
2020-10-29 18:59 ` Peter Zijlstra
2020-10-30 2:36 ` Joel Fernandes
2020-10-30 2:42 ` Joel Fernandes
2020-10-30 8:41 ` Peter Zijlstra
2020-10-31 21:41 ` Joel Fernandes
2020-10-20 1:43 ` [PATCH v8 -tip 09/26] sched: Trivial forced-newidle balancer Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 10/26] sched: migration changes for core scheduling Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 11/26] irq_work: Cleanup Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 12/26] arch/x86: Add a new TIF flag for untrusted tasks Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 13/26] kernel/entry: Add support for core-wide protection of kernel-mode Joel Fernandes (Google)
2020-10-20 3:41 ` Randy Dunlap
2020-11-03 0:20 ` Joel Fernandes
2020-10-22 5:48 ` Li, Aubrey
2020-11-03 0:50 ` Joel Fernandes
2020-10-30 10:29 ` Alexandre Chartre
2020-11-03 1:20 ` Joel Fernandes
2020-11-06 16:57 ` Alexandre Chartre
2020-11-06 17:43 ` Joel Fernandes
2020-11-06 18:07 ` Alexandre Chartre
2020-11-10 9:35 ` Alexandre Chartre
2020-11-10 22:42 ` Joel Fernandes
2020-11-16 10:08 ` Alexandre Chartre
2020-11-16 14:50 ` Joel Fernandes
2020-11-16 15:43 ` Joel Fernandes
2020-10-20 1:43 ` [PATCH v8 -tip 14/26] entry/idle: Enter and exit kernel protection during idle entry and exit Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 15/26] entry/kvm: Protect the kernel when entering from guest Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 16/26] sched: cgroup tagging interface for core scheduling Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 17/26] sched: Split the cookie and setup per-task cookie on fork Joel Fernandes (Google)
2020-11-04 22:30 ` chris hyser
2020-11-05 14:49 ` Joel Fernandes
2020-11-09 23:30 ` chris hyser
2020-10-20 1:43 ` [PATCH v8 -tip 18/26] sched: Add a per-thread core scheduling interface Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 19/26] sched: Add a second-level tag for nested CGroup usecase Joel Fernandes (Google)
2020-10-31 0:42 ` Josh Don
2020-11-03 2:54 ` Joel Fernandes
[not found] ` <6c07e70d-52f2-69ff-e1fa-690cd2c97f3d@linux.intel.com>
2020-11-05 15:52 ` Joel Fernandes [this message]
2020-10-20 1:43 ` [PATCH v8 -tip 20/26] sched: Release references to the per-task cookie on exit Joel Fernandes (Google)
2020-11-04 21:50 ` chris hyser
2020-11-05 15:46 ` Joel Fernandes
2020-10-20 1:43 ` [PATCH v8 -tip 21/26] sched: Handle task addition to CGroup Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 22/26] sched/debug: Add CGroup node for printing group cookie if SCHED_DEBUG Joel Fernandes (Google)
2020-10-20 1:43 ` [PATCH v8 -tip 23/26] kselftest: Add tests for core-sched interface Joel Fernandes (Google)
2020-10-30 22:20 ` [PATCH] sched: Change all 4 space tabs to actual tabs John B. Wyatt IV
2020-10-20 1:43 ` [PATCH v8 -tip 24/26] sched: Move core-scheduler interfacing code to a new file Joel Fernandes (Google)
2020-10-26 1:05 ` Li, Aubrey
2020-11-03 2:58 ` Joel Fernandes
2020-10-20 1:43 ` [PATCH v8 -tip 25/26] Documentation: Add core scheduling documentation Joel Fernandes (Google)
2020-10-20 3:36 ` Randy Dunlap
2020-11-12 16:11 ` Joel Fernandes
2020-10-20 1:43 ` [PATCH v8 -tip 26/26] sched: Debug bits Joel Fernandes (Google)
2020-10-30 13:26 ` [PATCH v8 -tip 00/26] Core scheduling Ning, Hongyu
2020-11-06 2:58 ` Li, Aubrey
2020-11-06 17:54 ` Joel Fernandes
2020-11-09 6:04 ` Li, Aubrey
2020-11-06 20:55 ` [RFT for v9] (Was Re: [PATCH v8 -tip 00/26] Core scheduling) Joel Fernandes
2020-11-13 9:22 ` Ning, Hongyu
2020-11-13 10:01 ` Ning, Hongyu
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