From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org,Dave Hansen
<dave.hansen@linux.intel.com>,yang.shi@linux.alibaba.com,rientjes@google.com,ying.huang@intel.com,dan.j.williams@intel.com,david@redhat.com,osalvador@suse.de
Subject: [PATCH 01/10] mm/numa: node demotion data structure and lookup
Date: Thu, 04 Mar 2021 15:59:51 -0800 [thread overview]
Message-ID: <20210304235951.271553C2@viggo.jf.intel.com> (raw)
In-Reply-To: <20210304235949.7922C1C3@viggo.jf.intel.com>
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.
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:[~2021-03-05 0:00 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 ` Dave Hansen [this message]
2021-03-08 23:58 ` [PATCH 01/10] mm/numa: node demotion data structure and lookup Yang Shi
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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