* Re: [PATCH 01/33] rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)
From: Tamir Duberstein @ 2026-04-01 22:59 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, linux-arm-kernel, Alexandre Ghiti,
linux-riscv, nouveau, dri-devel, Rae Moar, linux-kselftest,
kunit-dev, Nick Desaulniers, Bill Wendling, Justin Stitt, llvm,
linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-2-ojeda@kernel.org>
On Wed, 01 Apr 2026 13:45:08 +0200, Miguel Ojeda <ojeda@kernel.org> wrote:
> As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
> we are going to follow Debian Stable's Rust versions as our minimum
> supported version.
>
> Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
> still uses to this day [3] (i.e. no update to Rust 1.85.1).
>
> [...]
Acked-by: Tamir Duberstein <tamird@kernel.org>
--
Tamir Duberstein <tamird@kernel.org>
^ permalink raw reply
* [PATCH v10 13/13] docs: add io_queue flag to isolcpus
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
The io_queue flag informs multiqueue device drivers where to place
hardware queues. Document this new flag in the isolcpus
command-line argument description.
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
.../admin-guide/kernel-parameters.txt | 22 ++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 03a550630644..9ed7c3ecd158 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2816,7 +2816,6 @@ Kernel parameters
"number of CPUs in system - 1".
managed_irq
-
Isolate from being targeted by managed interrupts
which have an interrupt mask containing isolated
CPUs. The affinity of managed interrupts is
@@ -2839,6 +2838,27 @@ Kernel parameters
housekeeping CPUs has no influence on those
queues.
+ io_queue
+ Isolate from I/O queue work caused by multiqueue
+ device drivers. Restrict the placement of
+ queues to housekeeping CPUs only, ensuring that
+ all I/O work is processed by a housekeeping CPU.
+
+ The io_queue configuration takes precedence
+ over managed_irq. When io_queue is used,
+ managed_irq placement constrains have no
+ effect.
+
+ Note: Offlining housekeeping CPUS which serve
+ isolated CPUs will be rejected. Isolated CPUs
+ need to be offlined before offlining the
+ housekeeping CPUs.
+
+ Note: When an isolated CPU issues an I/O request,
+ it is forwarded to a housekeeping CPU. This will
+ trigger a software interrupt on the completion
+ path.
+
The format of <cpu-list> is described above.
iucv= [HW,NET]
--
2.51.0
^ permalink raw reply related
* [PATCH v10 12/13] genirq/affinity: Restrict managed IRQ affinity to housekeeping CPUs
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
At present, the managed interrupt spreading algorithm distributes vectors
across all available CPUs within a given node or system. On systems
employing CPU isolation (e.g., "isolcpus=io_queue"), this behaviour
defeats the primary purpose of isolation by routing hardware interrupts
(such as NVMe completion queues) directly to isolated cores.
Update irq_create_affinity_masks() to respect the housekeeping CPU mask.
Introduce irq_spread_hk_filter() to intersect the natively calculated
affinity mask with the HK_TYPE_IO_QUEUE mask, thereby keeping managed
interrupts off isolated CPUs.
To ensure strict isolation whilst guaranteeing a valid routing destination:
1. Fallback mechanism: Should the initial spreading logic assign a
vector exclusively to isolated CPUs (resulting in an empty
intersection), the filter safely falls back to the system's
online housekeeping CPUs.
2. Hotplug safety: The fallback utilises data_race(cpu_online_mask)
instead of allocating a local cpumask snapshot. This circumvents
CONFIG_CPUMASK_OFFSTACK stack bloat hazards on high-core-count
systems. Furthermore, it prevents deadlocks with concurrent CPU
hotplug operations (e.g., during storage driver error recovery)
by eliminating the need to hold the CPU hotplug read lock.
3. Fast-path optimisation: The filtering logic is conditionally
executed only if housekeeping is enabled, thereby ensuring zero
overhead for standard configurations.
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
kernel/irq/affinity.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 076a5ef1e306..dd9e7f5fbdec 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -8,6 +8,24 @@
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/group_cpus.h>
+#include <linux/sched/isolation.h>
+
+/**
+ * irq_spread_hk_filter - Restrict an interrupt affinity mask to housekeeping CPUs
+ * @mask: The interrupt affinity mask to filter (in/out)
+ * @hk_mask: The system's housekeeping CPU mask
+ *
+ * Intersects @mask with @hk_mask to keep interrupts off isolated CPUs.
+ * If this intersection is empty (meaning all targeted CPUs were isolated),
+ * it falls back to the online housekeeping CPUs to guarantee a valid
+ * routing destination.
+ */
+static void irq_spread_hk_filter(struct cpumask *mask,
+ const struct cpumask *hk_mask)
+{
+ if (!cpumask_and(mask, mask, hk_mask))
+ cpumask_and(mask, hk_mask, data_race(cpu_online_mask));
+}
static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)
{
@@ -27,6 +45,8 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
{
unsigned int affvecs, curvec, usedvecs, i;
struct irq_affinity_desc *masks = NULL;
+ const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_IO_QUEUE);
+ bool hk_enabled = housekeeping_enabled(HK_TYPE_IO_QUEUE);
/*
* Determine the number of vectors which need interrupt affinities
@@ -83,8 +103,12 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
return NULL;
}
- for (int j = 0; j < nr_masks; j++)
+ for (int j = 0; j < nr_masks; j++) {
cpumask_copy(&masks[curvec + j].mask, &result[j]);
+ if (hk_enabled)
+ irq_spread_hk_filter(&masks[curvec + j].mask,
+ hk_mask);
+ }
kfree(result);
curvec += nr_masks;
--
2.51.0
^ permalink raw reply related
* [PATCH v10 08/13] virtio: blk/scsi: use block layer helpers to constrain queue affinity
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
Ensure that IRQ affinity setup also respects the queue-to-CPU mapping
constraints provided by the block layer. This allows the virtio drivers
to avoid assigning interrupts to CPUs that the block layer has excluded
(e.g., isolated CPUs).
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
drivers/block/virtio_blk.c | 4 +++-
drivers/scsi/virtio_scsi.c | 5 ++++-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index b1c9a27fe00f..9d737510454b 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -964,7 +964,9 @@ static int init_vq(struct virtio_blk *vblk)
unsigned short num_vqs;
unsigned short num_poll_vqs;
struct virtio_device *vdev = vblk->vdev;
- struct irq_affinity desc = { 0, };
+ struct irq_affinity desc = {
+ .mask = blk_mq_possible_queue_affinity(),
+ };
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
struct virtio_blk_config, num_queues,
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 0ed8558dad72..520a7da5386e 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -849,7 +849,10 @@ static int virtscsi_init(struct virtio_device *vdev,
u32 num_vqs, num_poll_vqs, num_req_vqs;
struct virtqueue_info *vqs_info;
struct virtqueue **vqs;
- struct irq_affinity desc = { .pre_vectors = 2 };
+ struct irq_affinity desc = {
+ .pre_vectors = 2,
+ .mask = blk_mq_possible_queue_affinity(),
+ };
num_req_vqs = vscsi->num_queues;
num_vqs = num_req_vqs + VIRTIO_SCSI_VQ_BASE;
--
2.51.0
^ permalink raw reply related
* [PATCH v10 11/13] blk-mq: prevent offlining hk CPUs with associated online isolated CPUs
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
When isolcpus=io_queue is enabled, and the last housekeeping CPU for a
given hctx goes offline, there would be no CPU left to handle I/O. To
prevent I/O stalls, prevent offlining housekeeping CPUs that are still
serving isolated CPUs.
When isolcpus=io_queue is enabled and the last housekeeping CPU
for a given hctx goes offline, no CPU would be left to handle I/O.
To prevent I/O stalls, disallow offlining housekeeping CPUs that are
still serving isolated CPUs.
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
block/blk-mq.c | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3da2215b2912..8671f2170880 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3699,6 +3699,43 @@ static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
return data.has_rq;
}
+static bool blk_mq_hctx_can_offline_hk_cpu(struct blk_mq_hw_ctx *hctx,
+ unsigned int this_cpu)
+{
+ const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_IO_QUEUE);
+
+ for (int i = 0; i < hctx->nr_ctx; i++) {
+ struct blk_mq_ctx *ctx = hctx->ctxs[i];
+
+ if (ctx->cpu == this_cpu)
+ continue;
+
+ /*
+ * Check if this context has at least one online
+ * housekeeping CPU; in this case the hardware context is
+ * usable.
+ */
+ if (cpumask_test_cpu(ctx->cpu, hk_mask) &&
+ cpu_online(ctx->cpu))
+ break;
+
+ /*
+ * The context doesn't have any online housekeeping CPUs,
+ * but there might be an online isolated CPU mapped to
+ * it.
+ */
+ if (cpu_is_offline(ctx->cpu))
+ continue;
+
+ pr_warn("%s: trying to offline hctx%d but there is still an online isolcpu CPU %d mapped to it\n",
+ hctx->queue->disk->disk_name,
+ hctx->queue_num, ctx->cpu);
+ return false;
+ }
+
+ return true;
+}
+
static bool blk_mq_hctx_has_online_cpu(struct blk_mq_hw_ctx *hctx,
unsigned int this_cpu)
{
@@ -3731,6 +3768,11 @@ static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
struct blk_mq_hw_ctx, cpuhp_online);
int ret = 0;
+ if (housekeeping_enabled(HK_TYPE_IO_QUEUE)) {
+ if (!blk_mq_hctx_can_offline_hk_cpu(hctx, cpu))
+ return -EINVAL;
+ }
+
if (!hctx->nr_ctx || blk_mq_hctx_has_online_cpu(hctx, cpu))
return 0;
--
2.51.0
^ permalink raw reply related
* [PATCH v10 07/13] scsi: Use block layer helpers to constrain queue affinity
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
Ensure that IRQ affinity setup also respects the queue-to-CPU mapping
constraints provided by the block layer. This allows the SCSI drivers
to avoid assigning interrupts to CPUs that the block layer has excluded
(e.g., isolated CPUs).
Only convert drivers which are already using the
pci_alloc_irq_vectors_affinity with the PCI_IRQ_AFFINITY flag set.
Because these drivers are enabled to let the IRQ core code to
set the affinity. Also don't update qla2xxx because the nvme-fabrics
code is not ready yet.
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 1 +
drivers/scsi/megaraid/megaraid_sas_base.c | 5 ++++-
drivers/scsi/mpi3mr/mpi3mr_fw.c | 6 +++++-
drivers/scsi/mpt3sas/mpt3sas_base.c | 5 ++++-
drivers/scsi/pm8001/pm8001_init.c | 1 +
5 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index f69efc6494b8..d1f689224e7b 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -2605,6 +2605,7 @@ static int interrupt_preinit_v3_hw(struct hisi_hba *hisi_hba)
struct pci_dev *pdev = hisi_hba->pci_dev;
struct irq_affinity desc = {
.pre_vectors = BASE_VECTORS_V3_HW,
+ .mask = blk_mq_online_queue_affinity(),
};
min_msi = MIN_AFFINE_VECTORS_V3_HW;
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index ac71ea4898b2..7e2a3c187ee0 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -5925,7 +5925,10 @@ static int
__megasas_alloc_irq_vectors(struct megasas_instance *instance)
{
int i, irq_flags;
- struct irq_affinity desc = { .pre_vectors = instance->low_latency_index_start };
+ struct irq_affinity desc = {
+ .pre_vectors = instance->low_latency_index_start,
+ .mask = blk_mq_online_queue_affinity(),
+ };
struct irq_affinity *descp = &desc;
irq_flags = PCI_IRQ_MSIX;
diff --git a/drivers/scsi/mpi3mr/mpi3mr_fw.c b/drivers/scsi/mpi3mr/mpi3mr_fw.c
index c744210cc901..f9b8b3639c64 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_fw.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_fw.c
@@ -830,7 +830,11 @@ static int mpi3mr_setup_isr(struct mpi3mr_ioc *mrioc, u8 setup_one)
int max_vectors, min_vec;
int retval;
int i;
- struct irq_affinity desc = { .pre_vectors = 1, .post_vectors = 1 };
+ struct irq_affinity desc = {
+ .pre_vectors = 1,
+ .post_vectors = 1,
+ .mask = blk_mq_online_queue_affinity(),
+ };
if (mrioc->is_intr_info_set)
return 0;
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 79052f2accbd..91e1622b5b77 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -3370,7 +3370,10 @@ static int
_base_alloc_irq_vectors(struct MPT3SAS_ADAPTER *ioc)
{
int i, irq_flags = PCI_IRQ_MSIX;
- struct irq_affinity desc = { .pre_vectors = ioc->high_iops_queues };
+ struct irq_affinity desc = {
+ .pre_vectors = ioc->high_iops_queues,
+ .mask = blk_mq_online_queue_affinity(),
+ };
struct irq_affinity *descp = &desc;
/*
* Don't allocate msix vectors for poll_queues.
diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index e93ea76b565e..6360fa95bcf4 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -978,6 +978,7 @@ static u32 pm8001_setup_msix(struct pm8001_hba_info *pm8001_ha)
*/
struct irq_affinity desc = {
.pre_vectors = 1,
+ .mask = blk_mq_online_queue_affinity(),
};
rc = pci_alloc_irq_vectors_affinity(
pm8001_ha->pdev, 2, PM8001_MAX_MSIX_VEC,
--
2.51.0
^ permalink raw reply related
* [PATCH v10 10/13] blk-mq: use hk cpus only when isolcpus=io_queue is enabled
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
Extend the capabilities of the generic CPU to hardware queue (hctx)
mapping code, so it maps houskeeping CPUs and isolated CPUs to the
hardware queues evenly.
A hctx is only operational when there is at least one online
housekeeping CPU assigned (aka active_hctx). Thus, check the final
mapping that there is no hctx which has only offline housekeeing CPU and
online isolated CPUs.
Example mapping result:
16 online CPUs
isolcpus=io_queue,2-3,6-7,12-13
Queue mapping:
hctx0: default 0 2
hctx1: default 1 3
hctx2: default 4 6
hctx3: default 5 7
hctx4: default 8 12
hctx5: default 9 13
hctx6: default 10
hctx7: default 11
hctx8: default 14
hctx9: default 15
IRQ mapping:
irq 42 affinity 0 effective 0 nvme0q0
irq 43 affinity 0 effective 0 nvme0q1
irq 44 affinity 1 effective 1 nvme0q2
irq 45 affinity 4 effective 4 nvme0q3
irq 46 affinity 5 effective 5 nvme0q4
irq 47 affinity 8 effective 8 nvme0q5
irq 48 affinity 9 effective 9 nvme0q6
irq 49 affinity 10 effective 10 nvme0q7
irq 50 affinity 11 effective 11 nvme0q8
irq 51 affinity 14 effective 14 nvme0q9
irq 52 affinity 15 effective 15 nvme0q10
A corner case is when the number of online CPUs and present CPUs
differ and the driver asks for less queues than online CPUs, e.g.
8 online CPUs, 16 possible CPUs
isolcpus=io_queue,2-3,6-7,12-13
virtio_blk.num_request_queues=2
Queue mapping:
hctx0: default 0 1 2 3 4 5 6 7 8 12 13
hctx1: default 9 10 11 14 15
IRQ mapping
irq 27 affinity 0 effective 0 virtio0-config
irq 28 affinity 0-1,4-5,8 effective 5 virtio0-req.0
irq 29 affinity 9-11,14-15 effective 0 virtio0-req.1
Noteworthy is that for the normal/default configuration (!isoclpus) the
mapping will change for systems which have non hyperthreading CPUs. The
main assignment loop will completely rely that group_mask_cpus_evenly to
do the right thing. The old code would distribute the CPUs linearly over
the hardware context:
queue mapping for /dev/nvme0n1
hctx0: default 0 8
hctx1: default 1 9
hctx2: default 2 10
hctx3: default 3 11
hctx4: default 4 12
hctx5: default 5 13
hctx6: default 6 14
hctx7: default 7 15
The assign each hardware context the map generated by the
group_mask_cpus_evenly function:
queue mapping for /dev/nvme0n1
hctx0: default 0 1
hctx1: default 2 3
hctx2: default 4 5
hctx3: default 6 7
hctx4: default 8 9
hctx5: default 10 11
hctx6: default 12 13
hctx7: default 14 15
In case of hyperthreading CPUs, the resulting map stays the same.
Signed-off-by: Daniel Wagner <wagi@kernel.org>
[atomlin: Fixed absolute vs. relative hardware queue index mix-up in
blk_mq_map_queues and validation checks; fixed typographical errors.]
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
block/blk-mq-cpumap.c | 175 +++++++++++++++++++++++++++++++++++++-----
1 file changed, 157 insertions(+), 18 deletions(-)
diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
index 8244ecf87835..8d09af49a142 100644
--- a/block/blk-mq-cpumap.c
+++ b/block/blk-mq-cpumap.c
@@ -22,7 +22,18 @@ static unsigned int blk_mq_num_queues(const struct cpumask *mask,
{
unsigned int num;
- num = cpumask_weight(mask);
+ if (housekeeping_enabled(HK_TYPE_IO_QUEUE)) {
+ const struct cpumask *hk_mask;
+ struct cpumask avail_mask;
+
+ hk_mask = housekeeping_cpumask(HK_TYPE_IO_QUEUE);
+ cpumask_and(&avail_mask, mask, hk_mask);
+
+ num = cpumask_weight(&avail_mask);
+ } else {
+ num = cpumask_weight(mask);
+ }
+
return min_not_zero(num, max_queues);
}
@@ -31,9 +42,13 @@ static unsigned int blk_mq_num_queues(const struct cpumask *mask,
*
* Returns an affinity mask that represents the queue-to-CPU mapping
* requested by the block layer based on possible CPUs.
+ * This helper takes isolcpus settings into account.
*/
const struct cpumask *blk_mq_possible_queue_affinity(void)
{
+ if (housekeeping_enabled(HK_TYPE_IO_QUEUE))
+ return housekeeping_cpumask(HK_TYPE_IO_QUEUE);
+
return cpu_possible_mask;
}
EXPORT_SYMBOL_GPL(blk_mq_possible_queue_affinity);
@@ -46,6 +61,14 @@ EXPORT_SYMBOL_GPL(blk_mq_possible_queue_affinity);
*/
const struct cpumask *blk_mq_online_queue_affinity(void)
{
+ /*
+ * Return the stable housekeeping mask if enabled. Callers (e.g.,
+ * the IRQ affinity core) are responsible for safely intersecting
+ * this with a local snapshot of the online mask.
+ */
+ if (housekeeping_enabled(HK_TYPE_IO_QUEUE))
+ return housekeeping_cpumask(HK_TYPE_IO_QUEUE);
+
return cpu_online_mask;
}
EXPORT_SYMBOL_GPL(blk_mq_online_queue_affinity);
@@ -57,7 +80,8 @@ EXPORT_SYMBOL_GPL(blk_mq_online_queue_affinity);
* ignored.
*
* Calculates the number of queues to be used for a multiqueue
- * device based on the number of possible CPUs.
+ * device based on the number of possible CPUs. This helper
+ * takes isolcpus settings into account.
*/
unsigned int blk_mq_num_possible_queues(unsigned int max_queues)
{
@@ -72,7 +96,8 @@ EXPORT_SYMBOL_GPL(blk_mq_num_possible_queues);
* ignored.
*
* Calculates the number of queues to be used for a multiqueue
- * device based on the number of online CPUs.
+ * device based on the number of online CPUs. This helper
+ * takes isolcpus settings into account.
*/
unsigned int blk_mq_num_online_queues(unsigned int max_queues)
{
@@ -80,23 +105,104 @@ unsigned int blk_mq_num_online_queues(unsigned int max_queues)
}
EXPORT_SYMBOL_GPL(blk_mq_num_online_queues);
+static bool blk_mq_validate(struct blk_mq_queue_map *qmap,
+ const struct cpumask *active_hctx)
+{
+ /*
+ * Verify if the mapping is usable when housekeeping
+ * configuration is enabled
+ */
+
+ for (int queue = 0; queue < qmap->nr_queues; queue++) {
+ int cpu;
+
+ if (cpumask_test_cpu(queue, active_hctx)) {
+ /*
+ * This hctx has at least one online CPU thus it
+ * is able to serve any assigned isolated CPU.
+ */
+ continue;
+ }
+
+ /*
+ * There is no housekeeping online CPU for this hctx, all
+ * good as long as all non-housekeeping CPUs are also
+ * offline.
+ */
+ for_each_online_cpu(cpu) {
+ if (qmap->mq_map[cpu] != qmap->queue_offset + queue)
+ continue;
+
+ pr_warn("Unable to create a usable CPU-to-queue mapping with the given constraints\n");
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static void blk_mq_map_fallback(struct blk_mq_queue_map *qmap)
+{
+ unsigned int cpu;
+
+ /*
+ * Map all CPUs to the first hctx to ensure at least one online
+ * CPU is serving it.
+ */
+ for_each_possible_cpu(cpu)
+ qmap->mq_map[cpu] = 0;
+}
+
void blk_mq_map_queues(struct blk_mq_queue_map *qmap)
{
- const struct cpumask *masks;
+ struct cpumask *masks __free(kfree) = NULL;
+ const struct cpumask *constraint;
unsigned int queue, cpu, nr_masks;
+ cpumask_var_t active_hctx;
- masks = group_cpus_evenly(qmap->nr_queues, &nr_masks);
- if (!masks) {
- for_each_possible_cpu(cpu)
- qmap->mq_map[cpu] = qmap->queue_offset;
- return;
- }
+ if (!zalloc_cpumask_var(&active_hctx, GFP_KERNEL))
+ goto fallback;
+
+ if (housekeeping_enabled(HK_TYPE_IO_QUEUE))
+ constraint = housekeeping_cpumask(HK_TYPE_IO_QUEUE);
+ else
+ constraint = cpu_possible_mask;
+
+ /* Map CPUs to the hardware contexts (hctx) */
+ masks = group_mask_cpus_evenly(qmap->nr_queues, constraint, &nr_masks);
+ if (!masks)
+ goto free_fallback;
for (queue = 0; queue < qmap->nr_queues; queue++) {
- for_each_cpu(cpu, &masks[queue % nr_masks])
+ unsigned int idx = (qmap->queue_offset + queue) % nr_masks;
+
+ for_each_cpu(cpu, &masks[idx]) {
qmap->mq_map[cpu] = qmap->queue_offset + queue;
+
+ if (cpu_online(cpu))
+ cpumask_set_cpu(queue, active_hctx);
+ }
+ }
+
+ /* Map any unassigned CPU evenly to the hardware contexts (hctx) */
+ queue = cpumask_first(active_hctx);
+ for_each_cpu_andnot(cpu, cpu_possible_mask, constraint) {
+ qmap->mq_map[cpu] = qmap->queue_offset + queue;
+ queue = cpumask_next_wrap(queue, active_hctx);
}
- kfree(masks);
+
+ if (!blk_mq_validate(qmap, active_hctx))
+ goto free_fallback;
+
+ free_cpumask_var(active_hctx);
+
+ return;
+
+free_fallback:
+ free_cpumask_var(active_hctx);
+
+fallback:
+ blk_mq_map_fallback(qmap);
}
EXPORT_SYMBOL_GPL(blk_mq_map_queues);
@@ -133,24 +239,57 @@ void blk_mq_map_hw_queues(struct blk_mq_queue_map *qmap,
struct device *dev, unsigned int offset)
{
- const struct cpumask *mask;
+ cpumask_var_t active_hctx, mask;
unsigned int queue, cpu;
if (!dev->bus->irq_get_affinity)
goto fallback;
+ if (!zalloc_cpumask_var(&active_hctx, GFP_KERNEL))
+ goto fallback;
+
+ if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
+ free_cpumask_var(active_hctx);
+ goto fallback;
+ }
+
+ /* Map CPUs to the hardware contexts (hctx) */
for (queue = 0; queue < qmap->nr_queues; queue++) {
- mask = dev->bus->irq_get_affinity(dev, queue + offset);
- if (!mask)
- goto fallback;
+ const struct cpumask *affinity_mask;
+
+ affinity_mask = dev->bus->irq_get_affinity(dev, offset + queue);
+ if (!affinity_mask)
+ goto free_fallback;
- for_each_cpu(cpu, mask)
+ for_each_cpu(cpu, affinity_mask) {
qmap->mq_map[cpu] = qmap->queue_offset + queue;
+
+ cpumask_set_cpu(cpu, mask);
+ if (cpu_online(cpu))
+ cpumask_set_cpu(queue, active_hctx);
+ }
}
+ /* Map any unassigned CPU evenly to the hardware contexts (hctx) */
+ queue = cpumask_first(active_hctx);
+ for_each_cpu_andnot(cpu, cpu_possible_mask, mask) {
+ qmap->mq_map[cpu] = qmap->queue_offset + queue;
+ queue = cpumask_next_wrap(queue, active_hctx);
+ }
+
+ if (!blk_mq_validate(qmap, active_hctx))
+ goto free_fallback;
+
+ free_cpumask_var(active_hctx);
+ free_cpumask_var(mask);
+
return;
+free_fallback:
+ free_cpumask_var(active_hctx);
+ free_cpumask_var(mask);
+
fallback:
- blk_mq_map_queues(qmap);
+ blk_mq_map_fallback(qmap);
}
EXPORT_SYMBOL_GPL(blk_mq_map_hw_queues);
--
2.51.0
^ permalink raw reply related
* [PATCH v10 06/13] nvme-pci: use block layer helpers to constrain queue affinity
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
Ensure that IRQ affinity setup also respects the queue-to-CPU mapping
constraints provided by the block layer. This allows the NVMe driver
to avoid assigning interrupts to CPUs that the block layer has excluded
(e.g., isolated CPUs).
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
drivers/nvme/host/pci.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index b78ba239c8ea..8e05ad06283e 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2862,6 +2862,7 @@ static int nvme_setup_irqs(struct nvme_dev *dev, unsigned int nr_io_queues)
.pre_vectors = 1,
.calc_sets = nvme_calc_irq_sets,
.priv = dev,
+ .mask = blk_mq_possible_queue_affinity(),
};
unsigned int irq_queues, poll_queues;
unsigned int flags = PCI_IRQ_ALL_TYPES | PCI_IRQ_AFFINITY;
--
2.51.0
^ permalink raw reply related
* [PATCH v10 09/13] isolation: Introduce io_queue isolcpus type
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
Multiqueue drivers spread I/O queues across all CPUs for optimal
performance. However, these drivers are not aware of CPU isolation
requirements and will distribute queues without considering the isolcpus
configuration.
Introduce a new isolcpus mask that allows users to define which CPUs
should have I/O queues assigned. This is similar to managed_irq, but
intended for drivers that do not use the managed IRQ infrastructure
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
include/linux/sched/isolation.h | 1 +
kernel/sched/isolation.c | 7 +++++++
2 files changed, 8 insertions(+)
diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index dc3975ff1b2e..7b266fc2a405 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -18,6 +18,7 @@ enum hk_type {
HK_TYPE_MANAGED_IRQ,
/* Inverse of boot-time nohz_full= or isolcpus=nohz arguments */
HK_TYPE_KERNEL_NOISE,
+ HK_TYPE_IO_QUEUE,
HK_TYPE_MAX,
/*
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index ef152d401fe2..3406e3024fd4 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -16,6 +16,7 @@ enum hk_flags {
HK_FLAG_DOMAIN = BIT(HK_TYPE_DOMAIN),
HK_FLAG_MANAGED_IRQ = BIT(HK_TYPE_MANAGED_IRQ),
HK_FLAG_KERNEL_NOISE = BIT(HK_TYPE_KERNEL_NOISE),
+ HK_FLAG_IO_QUEUE = BIT(HK_TYPE_IO_QUEUE),
};
DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
@@ -340,6 +341,12 @@ static int __init housekeeping_isolcpus_setup(char *str)
continue;
}
+ if (!strncmp(str, "io_queue,", 9)) {
+ str += 9;
+ flags |= HK_FLAG_IO_QUEUE;
+ continue;
+ }
+
/*
* Skip unknown sub-parameter and validate that it is not
* containing an invalid character.
--
2.51.0
^ permalink raw reply related
* [PATCH v10 05/13] blk-mq: add blk_mq_{online|possible}_queue_affinity
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
Introduce blk_mq_{online|possible}_queue_affinity, which returns the
queue-to-CPU mapping constraints defined by the block layer. This allows
other subsystems (e.g., IRQ affinity setup) to respect block layer
requirements.
It is necessary to provide versions for both the online and possible CPU
masks because some drivers want to spread their I/O queues only across
online CPUs, while others prefer to use all possible CPUs. And the mask
used needs to match with the number of queues requested
(see blk_num_{online|possible}_queues).
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
block/blk-mq-cpumap.c | 24 ++++++++++++++++++++++++
include/linux/blk-mq.h | 2 ++
2 files changed, 26 insertions(+)
diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
index 705da074ad6c..8244ecf87835 100644
--- a/block/blk-mq-cpumap.c
+++ b/block/blk-mq-cpumap.c
@@ -26,6 +26,30 @@ static unsigned int blk_mq_num_queues(const struct cpumask *mask,
return min_not_zero(num, max_queues);
}
+/**
+ * blk_mq_possible_queue_affinity - Return block layer queue affinity
+ *
+ * Returns an affinity mask that represents the queue-to-CPU mapping
+ * requested by the block layer based on possible CPUs.
+ */
+const struct cpumask *blk_mq_possible_queue_affinity(void)
+{
+ return cpu_possible_mask;
+}
+EXPORT_SYMBOL_GPL(blk_mq_possible_queue_affinity);
+
+/**
+ * blk_mq_online_queue_affinity - Return block layer queue affinity
+ *
+ * Returns an affinity mask that represents the queue-to-CPU mapping
+ * requested by the block layer based on online CPUs.
+ */
+const struct cpumask *blk_mq_online_queue_affinity(void)
+{
+ return cpu_online_mask;
+}
+EXPORT_SYMBOL_GPL(blk_mq_online_queue_affinity);
+
/**
* blk_mq_num_possible_queues - Calc nr of queues for multiqueue devices
* @max_queues: The maximum number of queues the hardware/driver
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 18a2388ba581..ebc45557aee8 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -969,6 +969,8 @@ int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
void blk_mq_unfreeze_queue_non_owner(struct request_queue *q);
void blk_freeze_queue_start_non_owner(struct request_queue *q);
+const struct cpumask *blk_mq_possible_queue_affinity(void);
+const struct cpumask *blk_mq_online_queue_affinity(void);
unsigned int blk_mq_num_possible_queues(unsigned int max_queues);
unsigned int blk_mq_num_online_queues(unsigned int max_queues);
void blk_mq_map_queues(struct blk_mq_queue_map *qmap);
--
2.51.0
^ permalink raw reply related
* [PATCH v10 04/13] genirq/affinity: Add cpumask to struct irq_affinity
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
Pass a cpumask to irq_create_affinity_masks as an additional constraint
to consider when creating the affinity masks. This allows the caller to
exclude specific CPUs, e.g., isolated CPUs (see the 'isolcpus' kernel
command-line parameter).
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
include/linux/interrupt.h | 16 ++++++++++------
kernel/irq/affinity.c | 12 ++++++++++--
2 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 6cd26ffb0505..afd5a2c75b43 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -287,18 +287,22 @@ struct irq_affinity_notify {
* @nr_sets: The number of interrupt sets for which affinity
* spreading is required
* @set_size: Array holding the size of each interrupt set
+ * @mask: cpumask that constrains which CPUs to consider when
+ * calculating the number and size of the interrupt sets
* @calc_sets: Callback for calculating the number and size
* of interrupt sets
* @priv: Private data for usage by @calc_sets, usually a
* pointer to driver/device specific data.
*/
struct irq_affinity {
- unsigned int pre_vectors;
- unsigned int post_vectors;
- unsigned int nr_sets;
- unsigned int set_size[IRQ_AFFINITY_MAX_SETS];
- void (*calc_sets)(struct irq_affinity *, unsigned int nvecs);
- void *priv;
+ unsigned int pre_vectors;
+ unsigned int post_vectors;
+ unsigned int nr_sets;
+ unsigned int set_size[IRQ_AFFINITY_MAX_SETS];
+ const struct cpumask *mask;
+ void (*calc_sets)(struct irq_affinity *,
+ unsigned int nvecs);
+ void *priv;
};
/**
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 85c45cfe7223..076a5ef1e306 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -70,7 +70,13 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
*/
for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {
unsigned int nr_masks, this_vecs = affd->set_size[i];
- struct cpumask *result = group_cpus_evenly(this_vecs, &nr_masks);
+ struct cpumask *result;
+
+ if (affd->mask)
+ result = group_mask_cpus_evenly(this_vecs, affd->mask,
+ &nr_masks);
+ else
+ result = group_cpus_evenly(this_vecs, &nr_masks);
if (!result) {
kfree(masks);
@@ -115,7 +121,9 @@ unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
if (resv > minvec)
return 0;
- if (affd->calc_sets) {
+ if (affd->mask) {
+ set_vecs = cpumask_weight(affd->mask);
+ } else if (affd->calc_sets) {
set_vecs = maxvec - resv;
} else {
cpus_read_lock();
--
2.51.0
^ permalink raw reply related
* [PATCH v10 03/13] lib/group_cpus: Add group_mask_cpus_evenly()
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-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.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
include/linux/group_cpus.h | 3 ++
lib/group_cpus.c | 59 ++++++++++++++++++++++++++++++++++++++
2 files changed, 62 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..d3e9a20250ff 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 +564,61 @@ 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 (!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
^ permalink raw reply related
* [PATCH v10 02/13] lib/group_cpus: remove dead !SMP code
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
The support for the !SMP configuration has been removed from the core by
commit cac5cefbade9 ("sched/smp: Make SMP unconditional").
While one can technically still compile a uniprocessor kernel, the core
scheduler now mandates SMP unconditionally, rendering this particular
!SMP fallback handling redundant. Therefore, remove the #ifdef CONFIG_SMP
guards and the fallback logic.
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
[atomlin: Updated commit message to clarify !SMP removal context]
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
lib/group_cpus.c | 20 --------------------
1 file changed, 20 deletions(-)
diff --git a/lib/group_cpus.c b/lib/group_cpus.c
index e6e18d7a49bb..b8d54398f88a 100644
--- a/lib/group_cpus.c
+++ b/lib/group_cpus.c
@@ -9,8 +9,6 @@
#include <linux/sort.h>
#include <linux/group_cpus.h>
-#ifdef CONFIG_SMP
-
static void grp_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
unsigned int cpus_per_grp)
{
@@ -564,22 +562,4 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps, unsigned int *nummasks)
*nummasks = min(nr_present + nr_others, numgrps);
return masks;
}
-#else /* CONFIG_SMP */
-struct cpumask *group_cpus_evenly(unsigned int numgrps, unsigned int *nummasks)
-{
- struct cpumask *masks;
-
- if (numgrps == 0)
- return NULL;
-
- masks = kzalloc_objs(*masks, numgrps);
- if (!masks)
- return NULL;
-
- /* assign all CPUs(cpu 0) to the 1st group only */
- cpumask_copy(&masks[0], cpu_possible_mask);
- *nummasks = 1;
- return masks;
-}
-#endif /* CONFIG_SMP */
EXPORT_SYMBOL_GPL(group_cpus_evenly);
--
2.51.0
^ permalink raw reply related
* [PATCH v10 01/13] scsi: aacraid: use block layer helpers to calculate num of queues
From: Aaron Tomlin @ 2026-04-01 22:23 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401222312.772334-1-atomlin@atomlin.com>
From: Daniel Wagner <wagi@kernel.org>
The calculation of the upper limit for queues does not depend solely on
the number of online CPUs; for example, the isolcpus kernel
command-line option must also be considered.
To account for this, the block layer provides a helper function to
retrieve the maximum number of queues. Use it to set an appropriate
upper queue number limit.
Fixes: 94970cfb5f10 ("scsi: use block layer helpers to calculate num of queues")
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
drivers/scsi/aacraid/comminit.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/scsi/aacraid/comminit.c b/drivers/scsi/aacraid/comminit.c
index 9bd3f5b868bc..ec165b57182d 100644
--- a/drivers/scsi/aacraid/comminit.c
+++ b/drivers/scsi/aacraid/comminit.c
@@ -469,8 +469,7 @@ void aac_define_int_mode(struct aac_dev *dev)
}
/* Don't bother allocating more MSI-X vectors than cpus */
- msi_count = min(dev->max_msix,
- (unsigned int)num_online_cpus());
+ msi_count = blk_mq_num_online_queues(dev->max_msix);
dev->max_msix = msi_count;
--
2.51.0
^ permalink raw reply related
* [PATCH v10 00/13] blk: honor isolcpus configuration
From: Aaron Tomlin @ 2026-04-01 22:22 UTC (permalink / raw)
To: axboe, kbusch, hch, sagi, mst
Cc: atomlin, aacraid, James.Bottomley, martin.petersen, liyihang9,
kashyap.desai, sumit.saxena, shivasharan.srikanteshwara,
chandrakanth.patil, sathya.prakash, sreekanth.reddy,
suganath-prabu.subramani, ranjan.kumar, jinpu.wang, tglx, mingo,
peterz, juri.lelli, vincent.guittot, akpm, maz, ruanjinjie,
bigeasy, yphbchou0911, wagi, frederic, longman, chenridong, hare,
kch, ming.lei, steve, sean, chjohnst, neelx, mproche, linux-block,
linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
Hi Jens, Keith, Christoph, Sagi, Michael,
I have decided to drive this series forward on behalf of Daniel Wagner, the
original author. This iteration addresses the outstanding architectural and
concurrency concerns raised during the previous review cycle, and the series
has been rebased on v7.0-rc5-509-g545475aebc2a.
Building upon prior iterations, this series introduces critical
architectural refinements to the mapping and affinity spreading algorithms
to guarantee thread safety and resilience against concurrent CPU-hotplug
operations. Previously, the block layer relied on a shared global static
mask (i.e., blk_hk_online_mask), which proved vulnerable to race conditions
during rapid hotplug events. This vulnerability was recently highlighted by
the kernel test robot, which encountered a NULL pointer dereference during
rcutorture (cpuhotplug) stress testing due to concurrent mask modification.
To resolve this, the architecture has been fundamentally hardened. The
global static state has been eradicated. Instead, the IRQ affinity core now
employs a newly introduced irq_spread_hk_filter(), which safely intersects
the natively calculated affinity mask with the HK_TYPE_IO_QUEUE mask.
Crucially, this is achieved using a local, hotplug-safe snapshot via
data_race(cpu_online_mask). This approach circumvents the hotplug lock
deadlocks previously identified by Thomas Gleixner, whilst explicitly
avoiding CONFIG_CPUMASK_OFFSTACK stack bloat hazards on high-core-count
systems. A robust fallback mechanism guarantees that should an interrupt
vector be assigned exclusively to isolated cores, it is safely re-routed to
the system's online housekeeping CPUs.
Furthermore, following rigorous testing of multiple queue maps (such as
NVMe poll queues) alongside isolated CPUs, this tenth iteration resolves a
critical page fault regression. The multi-queue mapping logic has been
corrected to strictly maintain absolute hardware queue indices, ensuring
faultless queue initialization and preventing out-of-bounds memory access.
Please let me know your thoughts.
Changes in v10:
- Fixed a page fault regression encountered when initialising secondary
queue maps (e.g., NVMe poll queues). Restored the qmap->queue_offset to
the mq_map assignment to ensure CPUs are strictly mapped to absolute
hardware indices (Keith Busch)
- Corrected the active_hctx tracker to utilise relative queue indices,
preventing out-of-bounds mask assignments
- Fixed the blk_mq_validate() sanity check to properly evaluate absolute
queue indices against the offset-adjusted loop index
- Corrected typographical errors within block/blk-mq-cpumap.c
(Keith Busch)
- Clarified the commit message regarding the removal of the !SMP fallback
code, explicitly noting that the core scheduler now mandates SMP
unconditionally (Sebastian Andrzej Siewior)
- Added missing "Signed-off-by:" tags to properly record the patch series
chain of custody
- Linked to v9: https://lore.kernel.org/lkml/20260330221047.630206-1-atomlin@atomlin.com/
Changes in v9:
- Added "Reviewed-by:" tags
- Introduced irq_spread_hk_filter() to safely restrict managed IRQ
affinity to housekeeping CPUs (Thomas Gleixner)
- Removed the unsafe global static variable blk_hk_online_mask from
blk-mq-cpumap.c and blk-mq.c. blk_mq_online_queue_affinity() now returns
a stable pointer, delegating safe intersection to the callers to prevent
concurrent modification races (Thomas Gleixner, Hannes Reinecke)
- Resolved BUG: kernel NULL pointer dereference in __blk_mq_all_tag_iter
reported by the kernel test robot during cpuhotplug rcutorture stress
testing
- Linked to v8: https://lore.kernel.org/lkml/20250905-isolcpus-io-queues-v8-0-885984c5daca@kernel.org/
Changes in v8:
- Added commit 524f5eea4bbe ("lib/group_cpus: remove !SMP code")
- Merged the new mapping logic directly into the existing function to
avoid special casing
- Refined the group_mask_cpus_evenly() implementation with the following
updates:
- Corrected the function name typo (changed group_masks_cpus_evenly to
group_mask_cpus_evenly)
- Updated the documentation comment to accurately reflect the function's
behavior
- Renamed the cpu_mask argument to mask for consistency
- Added a new patch for aacraid to include the missing number of queues
calculation
- Restricted updates to only affect SCSI drivers that support
PCI_IRQ_AFFINITY and do not utilize nvme-fabrics
- Removed the __free cleanup attribute usage for cpumask_var_t allocations
due to compatibility issues
- Updated the documentation to explicitly highlight the limitations
surrounding CPU offlining
- Collected accumulated Reviewed-by and Acked-by tags
- Linked to v7: https://patch.msgid.link/20250702-isolcpus-io-queues-v7-0-557aa7eacce4@kernel.org
Changes in v7:
- Sent out the first part of the series independently:
https://lore.kernel.org/all/20250617-isolcpus-queue-counters-v1-0-13923686b54b@kernel.org/
- Added comprehensive kernel command-line documentation
- Added validation logic to ensure the resulting CPU-to-queue mapping is
fully operational
- Rewrote the isolcpus mapping code to properly account for active
hardware contexts (hctx)
- Introduced blk_mq_map_hk_irq_queues, which utilizes the mask retrieved
from irq_get_affinity()
- Refactored blk_mq_map_hk_queues to require the caller to explicitly test
for HK_TYPE_MANAGED_IRQ
- Linked to v6: https://patch.msgid.link/20250424-isolcpus-io-queues-v6-0-9a53a870ca1f@kernel.org
Changes in v6:
- Reintroduced the io_queue type for the isolcpus kernel parameter
- Prevented the offlining of a housekeeping CPU if an isolated CPU is
still present, upgrading this behavior from a simple warning to a hard
restriction
- Linked to v5: https://lore.kernel.org/r/20250110-isolcpus-io-queues-v5-0-0e4f118680b0@kernel.org
Changes in v5:
- Rebased the series onto the latest for-6.14/block branch.
- Updated the documentation regarding the managed_irq parameters
- Reworded the commit message for "blk-mq: issue warning when offlining
hctx with online isolcpus" for better clarity
- Split the input and output parameters in the patch "lib/group_cpus: let
group_cpu_evenly return number of groups"
- Dropped the patch "sched/isolation: document HK_TYPE housekeeping
option"
- Linked to v4: https://lore.kernel.org/r/20241217-isolcpus-io-queues-v4-0-5d355fbb1e14@kernel.org
Changes in v4:
- Added the patch "blk-mq: issue warning when offlining hctx with online
isolcpus"
- Fixed the check in group_cpus_evenly(); the condition now properly uses
housekeeping_enabled() instead of cpumask_weight(), as the latter always
returns a valid mask
- Dropped the Fixes: tag from "lib/group_cpus.c: honor housekeeping config
when grouping CPUs"
- Fixed an overlong line warning in the patch "scsi: use block layer
helpers to calculate num of queues"
- Dropped the patch "sched/isolation: Add io_queue housekeeping option" in
favor of simply documenting the housekeeping hk_type enum
- Added the patch "lib/group_cpus: let group_cpu_evenly return number of
groups"
- Collected accumulated Reviewed-by and Acked-by tags
- Split the patchset by moving foundational changes into a separate
preparation series:
https://lore.kernel.org/linux-nvme/20241202-refactor-blk-affinity-helpers-v6-0-27211e9c2cd5@kernel.org/
- Linked to v3: https://lore.kernel.org/r/20240806-isolcpus-io-queues-v3-0-da0eecfeaf8b@suse.de
Changes in v3:
- Integrated patches from Ming Lei
(https://lore.kernel.org/all/20210709081005.421340-1-ming.lei@redhat.com/):
"virtio: add APIs for retrieving vq affinity" and "blk-mq: introduce
blk_mq_dev_map_queues"
- Replaced all instances of blk_mq_pci_map_queues and
blk_mq_virtio_map_queues with the new unified blk_mq_dev_map_queues
- Updated and expanded the helper functions used for calculating the
number of queues
- Added the CPU-to-hctx mapping function specifically to support the
isolcpus=io_queue parameter
- Documented the hk_type enum and the newly introduced isolcpus=io_queue
parameter
- Added the patch "scsi: pm8001: do not overwrite PCI queue mapping"
- Linked to v2: https://lore.kernel.org/r/20240627-isolcpus-io-queues-v2-0-26a32e3c4f75@suse.de
Changes in v2:
- Updated the feature documentation for clarity and completeness
- Split the blk/nvme-pci patch into smaller, logical commits
- Dropped the HK_TYPE_IO_QUEUE macro in favor of reusing
HK_TYPE_MANAGED_IRQ
- Linked to v1: https://lore.kernel.org/r/20240621-isolcpus-io-queues-v1-0-8b169bf41083@suse.de
Aaron Tomlin (1):
genirq/affinity: Restrict managed IRQ affinity to housekeeping CPUs
Daniel Wagner (12):
scsi: aacraid: use block layer helpers to calculate num of queues
lib/group_cpus: remove dead !SMP code
lib/group_cpus: Add group_mask_cpus_evenly()
genirq/affinity: Add cpumask to struct irq_affinity
blk-mq: add blk_mq_{online|possible}_queue_affinity
nvme-pci: use block layer helpers to constrain queue affinity
scsi: Use block layer helpers to constrain queue affinity
virtio: blk/scsi: use block layer helpers to constrain queue affinity
isolation: Introduce io_queue isolcpus type
blk-mq: use hk cpus only when isolcpus=io_queue is enabled
blk-mq: prevent offlining hk CPUs with associated online isolated CPUs
docs: add io_queue flag to isolcpus
.../admin-guide/kernel-parameters.txt | 22 +-
block/blk-mq-cpumap.c | 199 ++++++++++++++++--
block/blk-mq.c | 42 ++++
drivers/block/virtio_blk.c | 4 +-
drivers/nvme/host/pci.c | 1 +
drivers/scsi/aacraid/comminit.c | 3 +-
drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 1 +
drivers/scsi/megaraid/megaraid_sas_base.c | 5 +-
drivers/scsi/mpi3mr/mpi3mr_fw.c | 6 +-
drivers/scsi/mpt3sas/mpt3sas_base.c | 5 +-
drivers/scsi/pm8001/pm8001_init.c | 1 +
drivers/scsi/virtio_scsi.c | 5 +-
include/linux/blk-mq.h | 2 +
include/linux/group_cpus.h | 3 +
include/linux/interrupt.h | 16 +-
include/linux/sched/isolation.h | 1 +
kernel/irq/affinity.c | 38 +++-
kernel/sched/isolation.c | 7 +
lib/group_cpus.c | 65 ++++--
19 files changed, 378 insertions(+), 48 deletions(-)
base-commit: 545475aebc2a2e8df14fadc911a7a2d03ddd6a1f
--
2.51.0
^ permalink raw reply
* Re: [PATCH v9 09/13] isolation: Introduce io_queue isolcpus type
From: Aaron Tomlin @ 2026-04-01 20:58 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: axboe, kbusch, hch, sagi, mst, aacraid, James.Bottomley,
martin.petersen, liyihang9, kashyap.desai, sumit.saxena,
shivasharan.srikanteshwara, chandrakanth.patil, sathya.prakash,
sreekanth.reddy, suganath-prabu.subramani, ranjan.kumar,
jinpu.wang, tglx, mingo, peterz, juri.lelli, vincent.guittot,
akpm, maz, ruanjinjie, yphbchou0911, wagi, frederic, longman,
chenridong, hare, kch, ming.lei, steve, sean, chjohnst, neelx,
mproche, linux-block, linux-kernel, virtualization, linux-nvme,
linux-scsi, megaraidlinux.pdl, mpi3mr-linuxdrv.pdl,
MPT-FusionLinux.pdl
In-Reply-To: <20260401124947.-d4D5Cr-@linutronix.de>
[-- Attachment #1: Type: text/plain, Size: 3646 bytes --]
On Wed, Apr 01, 2026 at 02:49:47PM +0200, Sebastian Andrzej Siewior wrote:
> On 2026-03-30 18:10:43 [-0400], Aaron Tomlin wrote:
> > From: Daniel Wagner <wagi@kernel.org>
> >
> > Multiqueue drivers spread I/O queues across all CPUs for optimal
> > performance. However, these drivers are not aware of CPU isolation
> > requirements and will distribute queues without considering the isolcpus
> > configuration.
> >
> > Introduce a new isolcpus mask that allows users to define which CPUs
> > should have I/O queues assigned. This is similar to managed_irq, but
> > intended for drivers that do not use the managed IRQ infrastructure
>
> I set down and documented the behaviour of managed_irq at
> https://lore.kernel.org/all/20260401110232.ET5RxZfl@linutronix.de/
>
> Could we please clarify whether we want to keep it and this
> additionally or if managed_irq could be used instead. This adds another
> bit. If networking folks jump in on managed_irqs, would they need to
> duplicate this with their net sub flag?
Hi Sebastian,
Thank you for taking the time to document the "managed_irq" behaviour; it
is immensely helpful. You raise a highly pertinent point regarding the
potential proliferation of "isolcpus=" flags. It is certainly a situation
that must be managed carefully to prevent every subsystem from demanding
its own bit.
To clarify the reasoning behind introducing "io_queue" rather than strictly
relying on managed_irq:
The managed_irq flag belongs firmly to the interrupt subsystem. It dictates
whether a CPU is eligible to receive hardware interrupts whose affinity is
managed by the kernel. Whilst many modern block drivers use managed IRQs,
the block layer multi-queue mapping encompasses far more than just
interrupt routing. It maps logical queues to CPUs to handle I/O submission,
software queues, and crucially, poll queues, which do not utilise
interrupts at all. Furthermore, there are specific drivers that do not use
the managed IRQ infrastructure but still rely on the block layer for queue
distribution.
If managed_irq were solely relied upon, the IRQ subsystem would
successfully keep hardware interrupts off the isolated CPUs, but the block
layer would still blindly map polling queues or non-managed queues to those
same isolated CPUs. This would force isolated CPUs to process I/O
submissions or handle polling tasks, thereby breaking the strict isolation.
Regarding the point about the networking subsystem, it is a very valid
comparison. If the networking layer wishes to respect isolcpus in the
future, adding a net flag would indeed exacerbate the bit proliferation.
For the present time, retaining io_queue seems the most prudent approach to
ensure that block queue mapping remains semantically distinct from
interrupt delivery. This provides an immediate and clean architectural
boundary. However, if the consensus amongst the maintainers suggests that
this is too granular, alternative approaches could certainly be considered
for the future. For instance, a broader, more generic flag could be
introduced to encompass both block and future networking queue mappings.
Alternatively, if semantic conflation is deemed acceptable, the existing
managed_irq housekeeping mask could simply be overloaded within the block
layer to restrict all queue mappings.
Keeping the current separation appears to be the cleanest solution for this
series, but your thoughts, and those of the wider community, on potentially
migrating to a consolidated generic flag in the future would be very much
welcomed.
Kind regards,
--
Aaron Tomlin
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^ permalink raw reply
* Re: [PATCH v2] block: Increase BLK_DEF_MAX_SECTORS_CAP
From: Keith Busch @ 2026-04-01 20:55 UTC (permalink / raw)
To: Damien Le Moal
Cc: Mira Limbeck, axboe, hch, linux-block, martin.petersen,
Friedrich Weber
In-Reply-To: <7a0cfc66-3131-4b94-87f2-cbb96595ebb6@kernel.org>
On Thu, Apr 02, 2026 at 05:02:22AM +0900, Damien Le Moal wrote:
> On 4/1/26 19:32, Mira Limbeck wrote:
> >
> > Apr 01 11:41:19 pve-test-hba kernel: sd 9:2:2:0: [sdc] tag#3962 page boundary curr_buff: 0x00000000f4d7cfce
> > Apr 01 11:41:19 pve-test-hba kernel: BUG: unable to handle page fault for address: ff3a241243d70000
> > Apr 01 11:41:19 pve-test-hba kernel: #PF: supervisor write access in kernel mode
> > Apr 01 11:41:19 pve-test-hba kernel: #PF: error_code(0x0002) - not-present page
> > Apr 01 11:41:19 pve-test-hba kernel: PGD 100010067 P4D 10066d067 PUD 10066e067 PMD 11f0fa067 PTE 0
> > Apr 01 11:41:19 pve-test-hba kernel: Oops: Oops: 0002 [#3] SMP NOPTI
> > Apr 01 11:41:19 pve-test-hba kernel: CPU: 15 UID: 0 PID: 6695 Comm: vgs Tainted: G D W E 7.0.0-rc6 #19 PREEMPT(full)
> > Apr 01 11:41:19 pve-test-hba kernel: Tainted: [D]=DIE, [W]=WARN, [E]=UNSIGNED_MODULE
> > Apr 01 11:41:19 pve-test-hba kernel: Hardware name: <snip>
> > Apr 01 11:41:19 pve-test-hba kernel: RIP: 0010:_base_build_sg_scmd_ieee+0x478/0x590 [mpt3sas]
>
> There may be an issue with the mpt3sas driver with large commands.
>
> However, I am using that driver all day long and doing lots of testing with
> gigantic read/write commands all the time. I have never seen any issues.
> The difference is that I am using the SAS-SATA FW for the Broadcom HBA, so no
> NVMe support, and my target devices are SAS or SATA HDDs, not SSDs.
It's only the NVMe attached ones that use base_make_prp_nvme, and it
looks like the ioc->pcie_sgl_dma_pool that provides the buffer for the
entries is too small for a transfer larger than 2MB. So it's overrunning
the allocated buffer.
^ permalink raw reply
* Re: [PATCH 6.1.y 5/8] nvme-apple: remove an extra queue reference
From: Fedor Pchelkin @ 2026-04-01 20:45 UTC (permalink / raw)
To: Heyne, Maximilian, Christoph Hellwig
Cc: Sagi Grimberg, stable@vger.kernel.org, Sven Peter,
Chaitanya Kulkarni, Keith Busch, Jens Axboe, Hector Martin,
Alyssa Rosenzweig, James E.J. Bottomley, Martin K. Petersen,
Alim Akhtar, Avri Altman, Bart Van Assche, Sasha Levin,
Peter Wang, Greg Kroah-Hartman, Seunghui Lee, Sanjeev Yadav,
Wonkon Kim, Brian Kao, Hannes Reinecke, Ming Lei,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org
In-Reply-To: <20260401-pliny-ashley-ff03a0b6@mheyne-amazon>
Hello,
"Heyne, Maximilian" <mheyne@amazon.de> wrote:
> From: Christoph Hellwig <hch@lst.de>
>
> [ Upstream commit 941f7298c70c7668416e7845fa76eb72c07d966b ]
>
> Now that blk_mq_destroy_queue does not release the queue reference, there
> is no need for a second admin queue reference to be held by the
> apple_nvme structure.
This patch is probably buggy in upstream. It removes extra reference
->get, but doesn't remove the corresponding ->put which is located
inside apple_nvme_free_ctrl().
I'm reporting here currently just for the heads up - was looking at the
same nvme regression problem at 6.1.y, found this thread, and the
nvme-apple changes appeared suspicious.
nvme-apple patch is not required to fix the regression (this also holds
true for [PATCH 6.1.y 3/8] scsi: remove an extra queue reference). Maybe
they shouldn't go to stable.
That said, the other part of the backport series FWIW looks good to me,
and I've also verified it resolves the 6.1.y regression.
Thanks.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
> Reviewed-by: Sven Peter <sven@svenpeter.dev>
> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
> Reviewed-by: Keith Busch <kbusch@kernel.org>
> Link: https://lore.kernel.org/r/20221018135720.670094-5-hch@lst.de
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Maximilian Heyne <mheyne@amazon.de>
> ---
> drivers/nvme/host/apple.c | 9 ---------
> 1 file changed, 9 deletions(-)
>
> diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
> index c5fc293c22123..c84ebfcfdeb88 100644
> --- a/drivers/nvme/host/apple.c
> +++ b/drivers/nvme/host/apple.c
> @@ -1507,15 +1507,6 @@ static int apple_nvme_probe(struct platform_device *pdev)
> goto put_dev;
> }
>
> - if (!blk_get_queue(anv->ctrl.admin_q)) {
> - nvme_start_admin_queue(&anv->ctrl);
> - blk_mq_destroy_queue(anv->ctrl.admin_q);
> - blk_put_queue(anv->ctrl.admin_q);
> - anv->ctrl.admin_q = NULL;
> - ret = -ENODEV;
> - goto put_dev;
> - }
> -
> nvme_reset_ctrl(&anv->ctrl);
> async_schedule(apple_nvme_async_probe, anv);
>
> --
> 2.50.1
^ permalink raw reply
* Re: [PATCH] blk-crypto: fix name of the bio completion callback
From: Eric Biggers @ 2026-04-01 20:19 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: axboe, linux-block
In-Reply-To: <20260401135854.125109-1-hch@lst.de>
On Wed, Apr 01, 2026 at 03:58:51PM +0200, Christoph Hellwig wrote:
> Fix a simple naming issue in the documentation: the completion
> routine is called bi_end_io and not bi_complete.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> Documentation/block/inline-encryption.rst | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
- Eric
^ permalink raw reply
* Re: [PATCH v2] block: Increase BLK_DEF_MAX_SECTORS_CAP
From: Damien Le Moal @ 2026-04-01 20:02 UTC (permalink / raw)
To: Mira Limbeck; +Cc: axboe, hch, linux-block, martin.petersen, Friedrich Weber
In-Reply-To: <ac2256a0-25ce-4453-8c47-04cb7716d46a@proxmox.com>
On 4/1/26 19:32, Mira Limbeck wrote:
> Sorry if I wasn't clear enough, we did test the following mainline
> kernels without any downstream patches (git tags):
> v6.16 (unaffected)
> v6.17 (affected)
> v7.0-rc5 (affected)
>
> Afterwards we started to bisect between mainline 6.16
> (038d61fd642278bab63ee8ef722c50d10ab01e8f) and mainline 6.17
> (e5f0a698b34ed76002dc5cff3804a61c80233a7a) without any downstream
> patches, which led us to this commit as the first bad one:
> 9b8b84879d4adc506b0d3944e20b28d9f3f6994b
Note: the proper way to reference a patch is to use 12-digits commit ID and
patch title:
9b8b84879d4a ("block: Increase BLK_DEF_MAX_SECTORS_CAP")
as that make it easier to know what one is talking about without having to go
look what patch that ID references.
> Building our downstream kernel 6.17 with this commit reverted, fixed it.
Nope, this is likely not fixing anything but rather hiding the issue. With this
patch reverted, the default max_sectors_kb will be 1280, so all requests will be
chunked to that size at most, and your devices will not see large commands.
However, simply doing something like:
echo 4096 > /sys/block/<dev>/queue/max_sectors_kb
will put your system in a state that is equivalent to the patch being applied
and you will likely see the issue again. Try.
> To make sure that's also the case for the current mainline kernel, we've
> tried 7.0-rc6 today (v7.0-rc6, 7aaa8047eafd0bd628065b15757d9b48c5f9c07d,
> affected), and again with this commit reverted (unaffected).
Same comment as above.
> Here the logs from 7.0-rc6:
>
> Apr 01 11:41:19 pve-test-hba kernel: sd 9:2:2:0: [sdc] tag#3962 page boundary curr_buff: 0x00000000f4d7cfce
> Apr 01 11:41:19 pve-test-hba kernel: BUG: unable to handle page fault for address: ff3a241243d70000
> Apr 01 11:41:19 pve-test-hba kernel: #PF: supervisor write access in kernel mode
> Apr 01 11:41:19 pve-test-hba kernel: #PF: error_code(0x0002) - not-present page
> Apr 01 11:41:19 pve-test-hba kernel: PGD 100010067 P4D 10066d067 PUD 10066e067 PMD 11f0fa067 PTE 0
> Apr 01 11:41:19 pve-test-hba kernel: Oops: Oops: 0002 [#3] SMP NOPTI
> Apr 01 11:41:19 pve-test-hba kernel: CPU: 15 UID: 0 PID: 6695 Comm: vgs Tainted: G D W E 7.0.0-rc6 #19 PREEMPT(full)
> Apr 01 11:41:19 pve-test-hba kernel: Tainted: [D]=DIE, [W]=WARN, [E]=UNSIGNED_MODULE
> Apr 01 11:41:19 pve-test-hba kernel: Hardware name: <snip>
> Apr 01 11:41:19 pve-test-hba kernel: RIP: 0010:_base_build_sg_scmd_ieee+0x478/0x590 [mpt3sas]
There may be an issue with the mpt3sas driver with large commands.
However, I am using that driver all day long and doing lots of testing with
gigantic read/write commands all the time. I have never seen any issues.
The difference is that I am using the SAS-SATA FW for the Broadcom HBA, so no
NVMe support, and my target devices are SAS or SATA HDDs, not SSDs.
Something may be wrong with the NVMe support in that HBA, or, your SSDs do not
like large commands and cause issues. That is easy to test: try connecting your
SSDs directly to PCI and test them by issuing large read/write commands with fio
(you will need to use iomem=mmaphuge option to use hugepages for the IO buffers
to ensure that you do not get the IOs chunked into small commands due to memory
fragmentation).
At least from my point of view and my tests, that commit is perfectly fine. As
mentioned above, it is only changing the default value, and that's something
that can be done manually even without this patch. So this is definitely not the
root cause and it is simply exposing a problem that already existed.
We have seen that for several devices in the ata subsystem and had to quirk many
drives that are choking on large commands.
We just need to figure out where the problem is (HBA and/or SSD) and can then
look into how to avoid that problem.
--
Damien Le Moal
Western Digital Research
^ permalink raw reply
* Re: [PATCH v9 02/13] lib/group_cpus: remove dead !SMP code
From: Aaron Tomlin @ 2026-04-01 19:31 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: axboe, kbusch, hch, sagi, mst, aacraid, James.Bottomley,
martin.petersen, liyihang9, kashyap.desai, sumit.saxena,
shivasharan.srikanteshwara, chandrakanth.patil, sathya.prakash,
sreekanth.reddy, suganath-prabu.subramani, ranjan.kumar,
jinpu.wang, tglx, mingo, peterz, juri.lelli, vincent.guittot,
akpm, maz, ruanjinjie, yphbchou0911, wagi, frederic, longman,
chenridong, hare, kch, ming.lei, steve, sean, chjohnst, neelx,
mproche, linux-block, linux-kernel, virtualization, linux-nvme,
linux-scsi, megaraidlinux.pdl, mpi3mr-linuxdrv.pdl,
MPT-FusionLinux.pdl
In-Reply-To: <20260401122908.hxUnR63u@linutronix.de>
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On Wed, Apr 01, 2026 at 02:29:08PM +0200, Sebastian Andrzej Siewior wrote:
> On 2026-03-30 18:10:36 [-0400], Aaron Tomlin wrote:
> > From: Daniel Wagner <wagi@kernel.org>
> >
> > The support for the !SMP configuration has been removed from the core by
> > commit cac5cefbade9 ("sched/smp: Make SMP unconditional").
>
> !SMP is not dead code here. You can very much compile a !SMP kernel at
> which point the code below will be used. It is more that the sched
> department decided that scheduler's maintenance will be easier since we
> don't have to deal with !SMP case anymore.
>
> If you wish to remove the !SMP case here you need to argue as such.
>
> > Signed-off-by: Daniel Wagner <wagi@kernel.org>
> > Reviewed-by: Hannes Reinecke <hare@suse.de>
>
> The previous patch, this one and probably the following lack a
> Signed-off-by line with your name.
>
Hi Sebastian,
Thank you for your review and for clarifying the precise nature of the !SMP
configuration.
Fair point. Describing it broadly as "dead code" is indeed inaccurate,
given that one can certainly still compile a uniprocessor kernel. I shall
amend the commit message in the next series to properly articulate the
reasoning: we are removing this specific !SMP fallback logic because the
core scheduler now mandates SMP unconditionally (as per commit
cac5cefbade9), rendering this particular handling redundant for our
purposes, rather than it being globally obsolete.
Furthermore, my apologies for the oversight regarding the missing
Signed-off-by tags.
Kind regards,
--
Aaron Tomlin
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^ permalink raw reply
* Re: [PATCH v9 09/13] isolation: Introduce io_queue isolcpus type
From: Waiman Long @ 2026-04-01 19:05 UTC (permalink / raw)
To: Sebastian Andrzej Siewior, Aaron Tomlin
Cc: axboe, kbusch, hch, sagi, mst, aacraid, James.Bottomley,
martin.petersen, liyihang9, kashyap.desai, sumit.saxena,
shivasharan.srikanteshwara, chandrakanth.patil, sathya.prakash,
sreekanth.reddy, suganath-prabu.subramani, ranjan.kumar,
jinpu.wang, tglx, mingo, peterz, juri.lelli, vincent.guittot,
akpm, maz, ruanjinjie, yphbchou0911, wagi, frederic, chenridong,
hare, kch, ming.lei, steve, sean, chjohnst, neelx, mproche,
linux-block, linux-kernel, virtualization, linux-nvme, linux-scsi,
megaraidlinux.pdl, mpi3mr-linuxdrv.pdl, MPT-FusionLinux.pdl
In-Reply-To: <20260401124947.-d4D5Cr-@linutronix.de>
On 4/1/26 8:49 AM, Sebastian Andrzej Siewior wrote:
> On 2026-03-30 18:10:43 [-0400], Aaron Tomlin wrote:
>> From: Daniel Wagner <wagi@kernel.org>
>>
>> Multiqueue drivers spread I/O queues across all CPUs for optimal
>> performance. However, these drivers are not aware of CPU isolation
>> requirements and will distribute queues without considering the isolcpus
>> configuration.
>>
>> Introduce a new isolcpus mask that allows users to define which CPUs
>> should have I/O queues assigned. This is similar to managed_irq, but
>> intended for drivers that do not use the managed IRQ infrastructure
> I set down and documented the behaviour of managed_irq at
> https://lore.kernel.org/all/20260401110232.ET5RxZfl@linutronix.de/
>
> Could we please clarify whether we want to keep it and this
> additionally or if managed_irq could be used instead. This adds another
> bit. If networking folks jump in on managed_irqs, would they need to
> duplicate this with their net sub flag?
Yes, I will very much prefer to reuse an existing HK cpumask like
managed_irqs for this purpose, if possible, rather than adding another
cpumask that we need to manage. Note that we are in the process of
making these housekeeping cpumasks modifiable at run time in the near
future.
Cheers,
Longman
^ permalink raw reply
* Re: [PATCH 12/33] rust: macros: update `extract_if` MSRV TODO comment
From: Miguel Ojeda @ 2026-04-01 17:45 UTC (permalink / raw)
To: Gary Guo
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <DHHVSX66206Y.3E7I9QUNTCJ8I@garyguo.net>
On Wed, Apr 1, 2026 at 4:18 PM Gary Guo <gary@garyguo.net> wrote:
>
> When I write the comment the intention is to enable the unstable feature and
> switch.
Yeah, that is what I meant as the alternative in the commit message.
I am OK with either.
(By the way, I wondered why you mentioned 1.85 in the comment, I guess
it was supposed to be 1.86 instead originally, i.e. "above" as in >
1.86)
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH 09/33] rust: kbuild: make `--remap-path-prefix` workaround conditional
From: Miguel Ojeda @ 2026-04-01 17:39 UTC (permalink / raw)
To: Gary Guo
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <DHHVLQAOMLWB.3FHHSYKNM5TNP@garyguo.net>
On Wed, Apr 1, 2026 at 4:08 PM Gary Guo <gary@garyguo.net> wrote:
>
> Okay, I see what the comments mean now. Perhaps squash this to the previous
> commit?
This one was mostly to ensure the workaround was not needed anymore,
i.e. it is more "optional" than the other.
In fact, we may want to just not have neither of the patches, i.e. we
could just remove the workaround given the timelines of the branches
-- please see my reply on the previous one on this.
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH 08/33] rust: kbuild: simplify `--remap-path-prefix` workaround
From: Miguel Ojeda @ 2026-04-01 17:36 UTC (permalink / raw)
To: Gary Guo
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <DHHVEPJHLGDW.1E6KDP9BUFG5U@garyguo.net>
On Wed, Apr 1, 2026 at 3:59 PM Gary Guo <gary@garyguo.net> wrote:
>
> I'm not sure that I parse this. You do remove the filter-out completely below?
(I see you saw the other commit)
> Looks like this is going to conflict with rust-fixes (which adds the
> --remap-path-scope). Perhaps worth doing a back merge?
It would be only a couple lines conflicting, so it should be fine.
Having said that, when I was doing this, I wondered if we should even
consider keeping the workaround. In other words, locally for
`rust-next`, the "normal" commit would be to remove the workaround
entirely because there the flag doesn't exist to begin with (i.e. the
workaround should have been removed back when the revert landed).
Then, when conflict happens in linux-next, we can just keep the
addition of the flag from your commit -- the rest can say as-is, i.e.
no workaround needed, because you only enable both flags in a version
(1.95.0) where there is no need for the workaround (which was for <
1.87.0).
It is also why I added the second commit here, i.e. the "make it
conditional", because I was testing that indeed we didn't need the
workaround anymore.
So it may just simpler to do that. What I thought was that perhaps the
workaround is good even if we ourselves don't pass the flag, e.g.
someone else may be passing it. But the chances are very low,
restricted to a couple versions, and the error is obvious and at build
time anyway.
Cheers,
Miguel
^ permalink raw reply
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