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Message-Id: <20221208183101.1162006-5-yury.norov@gmail.com>
Date: Thu, 8 Dec 2022 10:31:00 -0800
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Barry Song <baohua@...nel.org>,
Ben Segall <bsegall@...gle.com>,
haniel Bristot de Oliveira <bristot@...hat.com>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Gal Pressman <gal@...dia.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Heiko Carstens <hca@...ux.ibm.com>,
Ingo Molnar <mingo@...hat.com>,
Jakub Kicinski <kuba@...nel.org>,
Jason Gunthorpe <jgg@...dia.com>,
Jesse Brandeburg <jesse.brandeburg@...el.com>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
Juri Lelli <juri.lelli@...hat.com>,
Leon Romanovsky <leonro@...dia.com>,
Mel Gorman <mgorman@...e.de>,
Peter Zijlstra <peterz@...radead.org>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Saeed Mahameed <saeedm@...dia.com>,
Steven Rostedt <rostedt@...dmis.org>,
Tariq Toukan <tariqt@...dia.com>,
Tariq Toukan <ttoukan.linux@...il.com>,
Tony Luck <tony.luck@...el.com>,
Valentin Schneider <vschneid@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>
Cc: Yury Norov <yury.norov@...il.com>, linux-crypto@...r.kernel.org,
netdev@...r.kernel.org, linux-rdma@...r.kernel.org
Subject: [PATCH v3 4/5] cpumask: improve on cpumask_local_spread() locality
Switch cpumask_local_spread() to use newly added sched_numa_find_nth_cpu(),
which takes into account distances to each node in the system.
For the following NUMA configuration:
root@...ian:~# numactl -H
available: 4 nodes (0-3)
node 0 cpus: 0 1 2 3
node 0 size: 3869 MB
node 0 free: 3740 MB
node 1 cpus: 4 5
node 1 size: 1969 MB
node 1 free: 1937 MB
node 2 cpus: 6 7
node 2 size: 1967 MB
node 2 free: 1873 MB
node 3 cpus: 8 9 10 11 12 13 14 15
node 3 size: 7842 MB
node 3 free: 7723 MB
node distances:
node 0 1 2 3
0: 10 50 30 70
1: 50 10 70 30
2: 30 70 10 50
3: 70 30 50 10
The new cpumask_local_spread() traverses cpus for each node like this:
node 0: 0 1 2 3 6 7 4 5 8 9 10 11 12 13 14 15
node 1: 4 5 8 9 10 11 12 13 14 15 0 1 2 3 6 7
node 2: 6 7 0 1 2 3 8 9 10 11 12 13 14 15 4 5
node 3: 8 9 10 11 12 13 14 15 4 5 6 7 0 1 2 3
Signed-off-by: Yury Norov <yury.norov@...il.com>
---
lib/cpumask.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/lib/cpumask.c b/lib/cpumask.c
index c7c392514fd3..255974cd6734 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -110,7 +110,7 @@ void __init free_bootmem_cpumask_var(cpumask_var_t mask)
#endif
/**
- * cpumask_local_spread - select the i'th cpu with local numa cpu's first
+ * cpumask_local_spread - select the i'th cpu based on NUMA distances
* @i: index number
* @node: local numa_node
*
@@ -132,15 +132,7 @@ unsigned int cpumask_local_spread(unsigned int i, int node)
if (cpu < nr_cpu_ids)
return cpu;
} else {
- /* NUMA first. */
- cpu = cpumask_nth_and(i, cpu_online_mask, cpumask_of_node(node));
- if (cpu < nr_cpu_ids)
- return cpu;
-
- i -= cpumask_weight_and(cpu_online_mask, cpumask_of_node(node));
-
- /* Skip NUMA nodes, done above. */
- cpu = cpumask_nth_andnot(i, cpu_online_mask, cpumask_of_node(node));
+ cpu = sched_numa_find_nth_cpu(cpu_online_mask, i, node);
if (cpu < nr_cpu_ids)
return cpu;
}
--
2.34.1
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