From: Aaron Tomlin <atomlin@atomlin•com>
To: axboe@kernel•dk, kbusch@kernel•org, hch@lst•de, sagi@grimberg•me,
mst@redhat•com
Cc: atomlin@atomlin•com, aacraid@microsemi•com,
James.Bottomley@HansenPartnership•com,
martin.petersen@oracle•com, liyihang9@h-partners•com,
kashyap.desai@broadcom•com, sumit.saxena@broadcom•com,
shivasharan.srikanteshwara@broadcom•com,
chandrakanth.patil@broadcom•com, sathya.prakash@broadcom•com,
sreekanth.reddy@broadcom•com,
suganath-prabu.subramani@broadcom•com, ranjan.kumar@broadcom•com,
jinpu.wang@cloud•ionos.com, tglx@kernel•org, mingo@redhat•com,
peterz@infradead•org, juri.lelli@redhat•com,
vincent.guittot@linaro•org, akpm@linux-foundation•org,
maz@kernel•org, ruanjinjie@huawei•com, bigeasy@linutronix•de,
yphbchou0911@gmail•com, wagi@kernel•org, frederic@kernel•org,
longman@redhat•com, chenridong@huawei•com, hare@suse•de,
kch@nvidia•com, ming.lei@redhat•com, tom.leiming@gmail•com,
steve@abita•co, sean@ashe•io, chjohnst@gmail•com, neelx@suse•com,
mproche@gmail•com, nick.lange@gmail•com,
marco.crivellari@suse•com, linux-block@vger•kernel.org,
linux-kernel@vger•kernel.org, virtualization@lists•linux.dev,
linux-nvme@lists•infradead.org, linux-scsi@vger•kernel.org,
megaraidlinux.pdl@broadcom•com, mpi3mr-linuxdrv.pdl@broadcom•com,
MPT-FusionLinux.pdl@broadcom•com
Subject: [PATCH v12 03/13] lib/group_cpus: Add group_mask_cpus_evenly()
Date: Wed, 22 Apr 2026 14:52:05 -0400 [thread overview]
Message-ID: <20260422185215.100929-4-atomlin@atomlin.com> (raw)
In-Reply-To: <20260422185215.100929-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel•org>
group_mask_cpu_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@kernel•org>
Reviewed-by: Hannes Reinecke <hare@suse•de>
[atomlin: Test numgrps == 0 in group_mask_cpus_evenly()]
Signed-off-by: Aaron Tomlin <atomlin@atomlin•com>
---
include/linux/group_cpus.h | 3 ++
lib/group_cpus.c | 62 ++++++++++++++++++++++++++++++++++++++
2 files changed, 65 insertions(+)
diff --git a/include/linux/group_cpus.h b/include/linux/group_cpus.h
index 9d4e5ab6c314..defab4123a82 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 *mask,
+ unsigned int *nummasks);
#endif
diff --git a/lib/group_cpus.c b/lib/group_cpus.c
index b8d54398f88a..c55a8970db2a 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>
static void grp_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
unsigned int cpus_per_grp)
@@ -563,3 +564,64 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps, unsigned int *nummasks)
return masks;
}
EXPORT_SYMBOL_GPL(group_cpus_evenly);
+
+/**
+ * group_mask_cpus_evenly - Group all CPUs evenly per NUMA/CPU locality
+ * @numgrps: number of cpumasks to create
+ * @mask: CPUs to consider for the grouping
+ * @nummasks: number of initialized cpusmasks
+ *
+ * Return: cpumask array if successful, NULL otherwise. Only the CPUs
+ * marked in the mask will be considered for the grouping. And each
+ * element includes CPUs assigned to this group. nummasks contains the
+ * number of initialized masks which can be less than numgrps. cpu_mask
+ *
+ * Try to put close CPUs from viewpoint of CPU and NUMA locality into
+ * same group, and run two-stage grouping:
+ * 1) allocate present CPUs on these groups evenly first
+ * 2) allocate other possible CPUs on these groups evenly
+ *
+ * We guarantee in the resulted grouping that all CPUs are covered, and
+ * no same CPU is assigned to multiple groups
+ */
+struct cpumask *group_mask_cpus_evenly(unsigned int numgrps,
+ const struct cpumask *mask,
+ unsigned int *nummasks)
+{
+ cpumask_var_t *node_to_cpumask;
+ cpumask_var_t nmsk;
+ int ret = -ENOMEM;
+ struct cpumask *masks = NULL;
+
+ if (numgrps == 0)
+ return 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, 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);
--
2.51.0
next prev parent reply other threads:[~2026-04-22 18:52 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-22 18:52 [PATCH v12 00/13] blk: honor isolcpus configuration Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 01/13] scsi: aacraid: use block layer helpers to calculate num of queues Aaron Tomlin
2026-05-05 18:42 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 02/13] lib/group_cpus: remove dead !SMP code Aaron Tomlin
2026-04-27 15:21 ` Sebastian Andrzej Siewior
2026-04-29 23:32 ` Aaron Tomlin
2026-04-22 18:52 ` Aaron Tomlin [this message]
2026-04-22 18:52 ` [PATCH v12 04/13] genirq/affinity: Add cpumask to struct irq_affinity Aaron Tomlin
2026-05-05 20:40 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 05/13] blk-mq: add blk_mq_{online|possible}_queue_affinity Aaron Tomlin
2026-04-27 15:34 ` Sebastian Andrzej Siewior
2026-04-28 12:53 ` Daniel Wagner
2026-04-29 7:15 ` Hannes Reinecke
2026-05-05 20:55 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 06/13] nvme-pci: use block layer helpers to constrain queue affinity Aaron Tomlin
2026-05-05 19:47 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 07/13] scsi: Use " Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 08/13] virtio: blk/scsi: use " Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 09/13] isolation: Introduce io_queue isolcpus type Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 10/13] blk-mq: use hk cpus only when isolcpus=io_queue is enabled Aaron Tomlin
2026-05-02 21:25 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 11/13] blk-mq: prevent offlining hk CPUs with associated online isolated CPUs Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 12/13] genirq/affinity: Restrict managed IRQ affinity to housekeeping CPUs Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 13/13] docs: add io_queue flag to isolcpus Aaron Tomlin
2026-04-27 10:55 ` [PATCH v12 00/13] blk: honor isolcpus configuration Florian Bezdeka
2026-04-28 13:08 ` Daniel Wagner
2026-04-29 21:01 ` Florian Bezdeka
2026-04-30 12:09 ` Daniel Wagner
2026-04-30 15:45 ` Jan Kiszka
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260422185215.100929-4-atomlin@atomlin.com \
--to=atomlin@atomlin$(echo .)com \
--cc=James.Bottomley@HansenPartnership$(echo .)com \
--cc=MPT-FusionLinux.pdl@broadcom$(echo .)com \
--cc=aacraid@microsemi$(echo .)com \
--cc=akpm@linux-foundation$(echo .)org \
--cc=axboe@kernel$(echo .)dk \
--cc=bigeasy@linutronix$(echo .)de \
--cc=chandrakanth.patil@broadcom$(echo .)com \
--cc=chenridong@huawei$(echo .)com \
--cc=chjohnst@gmail$(echo .)com \
--cc=frederic@kernel$(echo .)org \
--cc=hare@suse$(echo .)de \
--cc=hch@lst$(echo .)de \
--cc=jinpu.wang@cloud$(echo .)ionos.com \
--cc=juri.lelli@redhat$(echo .)com \
--cc=kashyap.desai@broadcom$(echo .)com \
--cc=kbusch@kernel$(echo .)org \
--cc=kch@nvidia$(echo .)com \
--cc=linux-block@vger$(echo .)kernel.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-nvme@lists$(echo .)infradead.org \
--cc=linux-scsi@vger$(echo .)kernel.org \
--cc=liyihang9@h-partners$(echo .)com \
--cc=longman@redhat$(echo .)com \
--cc=marco.crivellari@suse$(echo .)com \
--cc=martin.petersen@oracle$(echo .)com \
--cc=maz@kernel$(echo .)org \
--cc=megaraidlinux.pdl@broadcom$(echo .)com \
--cc=ming.lei@redhat$(echo .)com \
--cc=mingo@redhat$(echo .)com \
--cc=mpi3mr-linuxdrv.pdl@broadcom$(echo .)com \
--cc=mproche@gmail$(echo .)com \
--cc=mst@redhat$(echo .)com \
--cc=neelx@suse$(echo .)com \
--cc=nick.lange@gmail$(echo .)com \
--cc=peterz@infradead$(echo .)org \
--cc=ranjan.kumar@broadcom$(echo .)com \
--cc=ruanjinjie@huawei$(echo .)com \
--cc=sagi@grimberg$(echo .)me \
--cc=sathya.prakash@broadcom$(echo .)com \
--cc=sean@ashe$(echo .)io \
--cc=shivasharan.srikanteshwara@broadcom$(echo .)com \
--cc=sreekanth.reddy@broadcom$(echo .)com \
--cc=steve@abita$(echo .)co \
--cc=suganath-prabu.subramani@broadcom$(echo .)com \
--cc=sumit.saxena@broadcom$(echo .)com \
--cc=tglx@kernel$(echo .)org \
--cc=tom.leiming@gmail$(echo .)com \
--cc=vincent.guittot@linaro$(echo .)org \
--cc=virtualization@lists$(echo .)linux.dev \
--cc=wagi@kernel$(echo .)org \
--cc=yphbchou0911@gmail$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox