From: Yang Shi <shy828301@gmail.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>,
Yang Shi <yang.shi@linux.alibaba.com>,
David Rientjes <rientjes@google.com>,
Huang Ying <ying.huang@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
David Hildenbrand <david@redhat.com>,
Oscar Salvador <osalvador@suse.de>
Subject: Re: [PATCH 01/10] mm/numa: node demotion data structure and lookup
Date: Mon, 8 Mar 2021 15:58:56 -0800 [thread overview]
Message-ID: <CAHbLzkqee9w6m4NQ4+=Dmp+E10=DVYGYP4FzA8hMJNvBAMMQ0w@mail.gmail.com> (raw)
In-Reply-To: <20210304235951.271553C2@viggo.jf.intel.com>
On Thu, Mar 4, 2021 at 4:00 PM Dave Hansen <dave.hansen@linux.intel.com> wrote:
>
>
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> Prepare for the kernel to auto-migrate pages to other memory nodes
> with a user defined node migration table. This allows creating single
> migration target for each NUMA node to enable the kernel to do NUMA
> page migrations instead of simply reclaiming colder pages. A node
> with no target is a "terminal node", so reclaim acts normally there.
> The migration target does not fundamentally _need_ to be a single node,
> but this implementation starts there to limit complexity.
>
> If you consider the migration path as a graph, cycles (loops) in the
> graph are disallowed. This avoids wasting resources by constantly
> migrating (A->B, B->A, A->B ...). The expectation is that cycles will
> never be allowed.
Reviewed-by: Yang Shi <shy828301@gmail.com>
>
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Yang Shi <yang.shi@linux.alibaba.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: osalvador <osalvador@suse.de>
>
> --
>
> changes since 20200122:
> * Make node_demotion[] __read_mostly
>
> changes in July 2020:
> - Remove loop from next_demotion_node() and get_online_mems().
> This means that the node returned by next_demotion_node()
> might now be offline, but the worst case is that the
> allocation fails. That's fine since it is transient.
> ---
>
> b/mm/migrate.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff -puN mm/migrate.c~0006-node-Define-and-export-memory-migration-path mm/migrate.c
> --- a/mm/migrate.c~0006-node-Define-and-export-memory-migration-path 2021-03-04 15:35:51.353806441 -0800
> +++ b/mm/migrate.c 2021-03-04 15:35:51.359806441 -0800
> @@ -1157,6 +1157,23 @@ out:
> return rc;
> }
>
> +static int node_demotion[MAX_NUMNODES] __read_mostly =
> + {[0 ... MAX_NUMNODES - 1] = NUMA_NO_NODE};
> +
> +/**
> + * next_demotion_node() - Get the next node in the demotion path
> + * @node: The starting node to lookup the next node
> + *
> + * @returns: node id for next memory node in the demotion path hierarchy
> + * from @node; NUMA_NO_NODE if @node is terminal. This does not keep
> + * @node online or guarantee that it *continues* to be the next demotion
> + * target.
> + */
> +int next_demotion_node(int node)
> +{
> + return node_demotion[node];
> +}
> +
> /*
> * Obtain the lock on page, remove all ptes and migrate the page
> * to the newly allocated page in newpage.
> _
>
next prev parent reply other threads:[~2021-03-08 23:59 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 23:59 [PATCH 00/10] [v6] Migrate Pages in lieu of discard Dave Hansen
2021-03-04 23:59 ` [PATCH 01/10] mm/numa: node demotion data structure and lookup Dave Hansen
2021-03-08 23:58 ` Yang Shi [this message]
2021-03-04 23:59 ` [PATCH 02/10] mm/numa: automatically generate node migration order Dave Hansen
2021-03-08 23:59 ` Yang Shi
2021-03-04 23:59 ` [PATCH 03/10] mm/migrate: update node demotion order during on hotplug events Dave Hansen
2021-03-09 0:03 ` Yang Shi
2021-03-09 22:07 ` Dave Hansen
2021-03-04 23:59 ` [PATCH 04/10] mm/migrate: make migrate_pages() return nr_succeeded Dave Hansen
2021-03-09 0:05 ` Yang Shi
2021-03-04 23:59 ` [PATCH 05/10] mm/migrate: demote pages during reclaim Dave Hansen
2021-03-09 0:10 ` Yang Shi
2021-03-09 23:05 ` Dave Hansen
2021-03-05 0:00 ` [PATCH 06/10] mm/vmscan: add page demotion counter Dave Hansen
2021-03-09 0:11 ` Yang Shi
2021-03-05 0:00 ` [PATCH 07/10] mm/vmscan: add helper for querying ability to age anonymous pages Dave Hansen
2021-03-09 0:14 ` Yang Shi
2021-03-20 4:05 ` Greg Thelen
2021-03-05 0:00 ` [PATCH 08/10] mm/vmscan: Consider anonymous pages without swap Dave Hansen
2021-03-09 0:17 ` Yang Shi
2021-03-09 23:08 ` Dave Hansen
2021-03-05 0:00 ` [PATCH 09/10] mm/vmscan: never demote for memcg reclaim Dave Hansen
2021-03-09 0:17 ` Yang Shi
2021-03-05 0:00 ` [PATCH 10/10] mm/migrate: new zone_reclaim_mode to enable reclaim migration Dave Hansen
2021-03-09 0:24 ` Yang Shi
2021-03-09 21:53 ` Dave Hansen
2021-03-09 0:34 ` [PATCH 00/10] [v6] Migrate Pages in lieu of discard Yang Shi
2021-03-09 21:52 ` Dave Hansen
2021-04-01 18:32 [PATCH 00/10] [v7][RESEND] " Dave Hansen
2021-04-01 18:32 ` [PATCH 01/10] mm/numa: node demotion data structure and lookup Dave Hansen
2021-04-08 8:03 ` Oscar Salvador
2021-04-08 21:29 ` Dave Hansen
2021-04-09 5:32 ` Wei Xu
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