sched/topology: Set correct NUMA topology type

srikard · Ingo Molnar · commit e5e96fafd902 · 2018-09-10T10:13:45.000+02:00
With the following commit: 051f3ca ("sched/topology: Introduce NUMA identity node sched domain") the scheduler introduced a new NUMA level. However this leads to the NUMA topology on 2 node systems to not be marked as NUMA_DIRECT anymore. After this commit, it gets reported as NUMA_BACKPLANE, because sched_domains_numa_level is now 2 on 2 node systems. Fix this by allowing setting systems that have up to 2 NUMA levels as NUMA_DIRECT. While here remove code that assumes that level can be 0. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andre Wild <wild@linux.vnet.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org> Fixes: 051f3ca "Introduce NUMA identity node sched domain" Link: http://lkml.kernel.org/r/1533920419-17410-1-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
@@ -1295,7 +1295,7 @@ static void init_numa_topology_type(void)
 
 	n = sched_max_numa_distance;
 
-	if (sched_domains_numa_levels <= 1) {
+	if (sched_domains_numa_levels <= 2) {
 		sched_numa_topology_type = NUMA_DIRECT;
 		return;
 	}
@@ -1380,9 +1380,6 @@ void sched_init_numa(void)
 			break;
 	}
 
-	if (!level)
-		return;
-
 	/*
 	 * 'level' contains the number of unique distances
 	 *

Original file line number	Diff line number	Diff line change
`@@ -1295,7 +1295,7 @@ static void init_numa_topology_type(void)`
`1295`	`1295`
`1296`	`1296`	`n = sched_max_numa_distance;`
`1297`	`1297`
`1298`		`- if (sched_domains_numa_levels <= 1) {`
	`1298`	`+ if (sched_domains_numa_levels <= 2) {`
`1299`	`1299`	`sched_numa_topology_type = NUMA_DIRECT;`
`1300`	`1300`	`return;`
`1301`	`1301`	`}`
`@@ -1380,9 +1380,6 @@ void sched_init_numa(void)`
`1380`	`1380`	`break;`
`1381`	`1381`	`}`
`1382`	`1382`
`1383`		`- if (!level)`
`1384`		`- return;`
`1385`		`-`
`1386`	`1383`	`/*`
`1387`	`1384`	`* 'level' contains the number of unique distances`
`1388`	`1385`	`*`