linux-kernel - [PATCH v7 01/10] lib/group_cpus: Add group_masks_cpus

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250702-isolcpus-io-queues-v7-1-557aa7eacce4@kernel.org>
Date: Wed, 02 Jul 2025 18:33:51 +0200
From: Daniel Wagner <wagi@...nel.org>
To: Jens Axboe <axboe@...nel.dk>, Keith Busch <kbusch@...nel.org>, 
 Christoph Hellwig <hch@....de>, Sagi Grimberg <sagi@...mberg.me>, 
 "Michael S. Tsirkin" <mst@...hat.com>
Cc: Aaron Tomlin <atomlin@...mlin.com>, 
 "Martin K. Petersen" <martin.petersen@...cle.com>, 
 Thomas Gleixner <tglx@...utronix.de>, 
 Costa Shulyupin <costa.shul@...hat.com>, Juri Lelli <juri.lelli@...hat.com>, 
 Valentin Schneider <vschneid@...hat.com>, Waiman Long <llong@...hat.com>, 
 Ming Lei <ming.lei@...hat.com>, Frederic Weisbecker <frederic@...nel.org>, 
 Mel Gorman <mgorman@...e.de>, Hannes Reinecke <hare@...e.de>, 
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>, 
 linux-kernel@...r.kernel.org, linux-block@...r.kernel.org, 
 linux-nvme@...ts.infradead.org, megaraidlinux.pdl@...adcom.com, 
 linux-scsi@...r.kernel.org, storagedev@...rochip.com, 
 virtualization@...ts.linux.dev, GR-QLogic-Storage-Upstream@...vell.com, 
 Daniel Wagner <wagi@...nel.org>
Subject: [PATCH v7 01/10] lib/group_cpus: Add group_masks_cpus_evenly()

group_mask_cpus_evenly() allows the caller to pass in a CPU mask that
should be evenly distributed. This new function is a more generic
version of the existing group_cpus_evenly(), which always distributes
all present CPUs into groups.

Signed-off-by: Daniel Wagner <wagi@...nel.org>
---
 include/linux/group_cpus.h |  3 +++
 lib/group_cpus.c           | 64 +++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/include/linux/group_cpus.h b/include/linux/group_cpus.h
index 9d4e5ab6c314b31c09fda82c3f6ac18f77e9de36..d4604dce1316a08400e982039006331f34c18ee8 100644
--- a/include/linux/group_cpus.h
+++ b/include/linux/group_cpus.h
@@ -10,5 +10,8 @@
 #include <linux/cpu.h>

 struct cpumask *group_cpus_evenly(unsigned int numgrps, unsigned int *nummasks);
+struct cpumask *group_mask_cpus_evenly(unsigned int numgrps,
+				       const struct cpumask *cpu_mask,
+				       unsigned int *nummasks);

 #endif
diff --git a/lib/group_cpus.c b/lib/group_cpus.c
index 6d08ac05f371bf880571507d935d9eb501616a84..00c9b7a10c8acd29239fe20d2a30fdae22ef74a5 100644
--- a/lib/group_cpus.c
+++ b/lib/group_cpus.c
@@ -8,6 +8,7 @@
 #include <linux/cpu.h>
 #include <linux/sort.h>
 #include <linux/group_cpus.h>
+#include <linux/sched/isolation.h>

 #ifdef CONFIG_SMP

@@ -425,6 +426,59 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps, unsigned int *nummasks)
 	*nummasks = min(nr_present + nr_others, numgrps);
 	return masks;
 }
+EXPORT_SYMBOL_GPL(group_cpus_evenly);
+
+/**
+ * group_mask_cpus_evenly - Group all CPUs evenly per NUMA/CPU locality
+ * @numgrps: number of groups
+ * @cpu_mask: CPU to consider for the grouping
+ * @nummasks: number of initialized cpusmasks
+ *
+ * Return: cpumask array if successful, NULL otherwise. And each element
+ * includes CPUs assigned to this group.
+ *
+ * Try to put close CPUs from viewpoint of CPU and NUMA locality into
+ * same group. Allocate present CPUs on these groups evenly.
+ */
+struct cpumask *group_mask_cpus_evenly(unsigned int numgrps,
+				       const struct cpumask *cpu_mask,
+				       unsigned int *nummasks)
+{
+	cpumask_var_t *node_to_cpumask;
+	cpumask_var_t nmsk;
+	int ret = -ENOMEM;
+	struct cpumask *masks = NULL;
+
+	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
+		return NULL;
+
+	node_to_cpumask = alloc_node_to_cpumask();
+	if (!node_to_cpumask)
+		goto fail_nmsk;
+
+	masks = kcalloc(numgrps, sizeof(*masks), GFP_KERNEL);
+	if (!masks)
+		goto fail_node_to_cpumask;
+
+	build_node_to_cpumask(node_to_cpumask);
+
+	ret = __group_cpus_evenly(0, numgrps, node_to_cpumask, cpu_mask, nmsk,
+				  masks);
+
+fail_node_to_cpumask:
+	free_node_to_cpumask(node_to_cpumask);
+
+fail_nmsk:
+	free_cpumask_var(nmsk);
+	if (ret < 0) {
+		kfree(masks);
+		return NULL;
+	}
+	*nummasks = ret;
+	return masks;
+}
+EXPORT_SYMBOL_GPL(group_mask_cpus_evenly);
+
 #else /* CONFIG_SMP */
 struct cpumask *group_cpus_evenly(unsigned int numgrps, unsigned int *nummasks)
 {
@@ -442,5 +496,13 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps, unsigned int *nummasks)
 	*nummasks = 1;
 	return masks;
 }
-#endif /* CONFIG_SMP */
 EXPORT_SYMBOL_GPL(group_cpus_evenly);
+
+struct cpumask *group_mask_cpus_evenly(unsigned int numgrps,
+				       const struct cpumask *cpu_mask,
+				       unsigned int *nummasks)
+{
+	return group_cpus_evenly(numgrps, nummasks);
+}
+EXPORT_SYMBOL_GPL(group_mask_cpus_evenly);
+#endif /* CONFIG_SMP */

-- 
2.50.0