From: Michal Hocko <mhocko@suse.com>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Shakeel Butt <shakeelb@google.com>,
Yang Shi <shy828301@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave.hansen@intel.com>,
Ying Huang <ying.huang@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
David Rientjes <rientjes@google.com>,
Linux MM <linux-mm@kvack.org>, Cgroups <cgroups@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v1 00/11] Manage the top tier memory in a tiered memory
Date: Fri, 16 Apr 2021 08:38:40 +0200 [thread overview]
Message-ID: <YHkw8Ou2VAgHYTjl@dhcp22.suse.cz> (raw)
In-Reply-To: <4a864946-a316-3d9c-8780-64c6281276d1@linux.intel.com>
On Thu 15-04-21 15:31:46, Tim Chen wrote:
>
>
> On 4/9/21 12:24 AM, Michal Hocko wrote:
> > On Thu 08-04-21 13:29:08, Shakeel Butt wrote:
> >> On Thu, Apr 8, 2021 at 11:01 AM Yang Shi <shy828301@gmail.com> wrote:
> > [...]
> >>> The low priority jobs should be able to be restricted by cpuset, for
> >>> example, just keep them on second tier memory nodes. Then all the
> >>> above problems are gone.
> >
> > Yes, if the aim is to isolate some users from certain numa node then
> > cpuset is a good fit but as Shakeel says this is very likely not what
> > this work is aiming for.
> >
> >> Yes that's an extreme way to overcome the issue but we can do less
> >> extreme by just (hard) limiting the top tier usage of low priority
> >> jobs.
> >
> > Per numa node high/hard limit would help with a more fine grained control.
> > The configuration would be tricky though. All low priority memcgs would
> > have to be carefully configured to leave enough for your important
> > processes. That includes also memory which is not accounted to any
> > memcg.
> > The behavior of those limits would be quite tricky for OOM situations
> > as well due to a lack of NUMA aware oom killer.
> >
>
> Another downside of putting limits on individual NUMA
> node is it would limit flexibility.
Let me just clarify one thing. I haven't been proposing per NUMA limits.
As I've said above it would be quite tricky to use and the behavior
would be tricky as well. All I am saying is that we do not want to have
an interface that is tightly bound to any specific HW setup (fast RAM as
a top tier and PMEM as a fallback) that you have proposed here. We want
to have a generic NUMA based abstraction. How that abstraction is going
to look like is an open question and it really depends on usecase that
we expect to see.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-04-16 6:38 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-05 17:08 [RFC PATCH v1 00/11] Manage the top tier memory in a tiered memory Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 01/11] mm: Define top tier memory node mask Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 02/11] mm: Add soft memory limit for mem cgroup Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 03/11] mm: Account the top tier memory usage per cgroup Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 04/11] mm: Report top tier memory usage in sysfs Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 05/11] mm: Add soft_limit_top_tier tree for mem cgroup Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 06/11] mm: Handle top tier memory in cgroup soft limit memory tree utilities Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 07/11] mm: Account the total top tier memory in use Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 08/11] mm: Add toptier option for mem_cgroup_soft_limit_reclaim() Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 09/11] mm: Use kswapd to demote pages when toptier memory is tight Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 10/11] mm: Set toptier_scale_factor via sysctl Tim Chen
2021-04-05 17:08 ` [RFC PATCH v1 11/11] mm: Wakeup kswapd if toptier memory need soft reclaim Tim Chen
2021-04-06 9:08 ` [RFC PATCH v1 00/11] Manage the top tier memory in a tiered memory Michal Hocko
2021-04-07 22:33 ` Tim Chen
2021-04-08 11:52 ` Michal Hocko
2021-04-09 23:26 ` Tim Chen
2021-04-12 19:20 ` Shakeel Butt
2021-04-14 8:59 ` Jonathan Cameron
2021-04-15 0:42 ` Tim Chen
2021-04-13 2:15 ` Huang, Ying
2021-04-13 8:33 ` Michal Hocko
2021-04-12 14:03 ` Shakeel Butt
2021-04-08 17:18 ` Shakeel Butt
2021-04-08 18:00 ` Yang Shi
2021-04-08 20:29 ` Shakeel Butt
2021-04-08 20:50 ` Yang Shi
2021-04-12 14:03 ` Shakeel Butt
2021-04-09 7:24 ` Michal Hocko
2021-04-15 22:31 ` Tim Chen
2021-04-16 6:38 ` Michal Hocko [this message]
2021-04-14 23:22 ` Tim Chen
2021-04-09 2:58 ` Huang, Ying
2021-04-09 20:50 ` Yang Shi
2021-04-15 22:25 ` Tim Chen
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