From: Tim Chen <tim.c.chen@linux.intel.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.cz>,
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: Thu, 15 Apr 2021 15:25:05 -0700 [thread overview]
Message-ID: <86a6f2e1-8aed-00fc-fbd7-9250277b201f@linux.intel.com> (raw)
In-Reply-To: <CALvZod7StYJCPnWRNLnYQV8S5CBLtE0w4r2rH-wZzNs9jGJSRg@mail.gmail.com>
On 4/8/21 10:18 AM, Shakeel Butt wrote:
>
> Using v1's soft limit like behavior can potentially cause high
> priority jobs to stall to make enough space on top tier memory on
> their allocation path and I think this patchset is aiming to reduce
> that impact by making kswapd do that work. However I think the more
> concerning issue is the low priority job hogging the top tier memory.
>
> The possible ways the low priority job can hog the top tier memory are
> by allocating non-movable memory or by mlocking the memory. (Oh there
> is also pinning the memory but I don't know if there is a user api to
> pin memory?) For the mlocked memory, you need to either modify the
> reclaim code or use a different mechanism for demoting cold memory.
>
> Basically I am saying we should put the upfront control (limit) on the
> usage of top tier memory by the jobs.
>
Circling back to your comment here.
I agree that soft limit is deficient in this scenario that you
have pointed out. Eventually I was shooting for a hard limit on a
memory tier for a cgroup that's similar to the v2 memory controller
interface (see mail in the other thread). That interface should
satisfy the hard constraint you want to place on the low priority
jobs.
Tim
prev parent reply other threads:[~2021-04-15 22:25 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
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 [this message]
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