[PATCH 11/13] blk-mq: allow the driver to pass in an affinity mask
Christoph Hellwig
hch at lst.de
Mon Jul 4 01:39:32 PDT 2016
Allow drivers to pass in the affinity mask from the generic interrupt
layer, and spread queues based on that. If the driver doesn't pass in
a mask we will create it using the genirq helper. As this helper was
modelled after the blk-mq algorithm there should be no change in
behavior.
Signed-off-by: Christoph Hellwig <hch at lst.de>
---
block/Makefile | 2 +-
block/blk-mq-cpumap.c | 120 -------------------------------------------------
block/blk-mq.c | 68 +++++++++++++++++++++++++---
block/blk-mq.h | 8 ----
include/linux/blk-mq.h | 1 +
5 files changed, 65 insertions(+), 134 deletions(-)
delete mode 100644 block/blk-mq-cpumap.c
diff --git a/block/Makefile b/block/Makefile
index 9eda232..aeb318d 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -6,7 +6,7 @@ obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-tag.o blk-sysfs.o \
blk-flush.o blk-settings.o blk-ioc.o blk-map.o \
blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \
blk-lib.o blk-mq.o blk-mq-tag.o \
- blk-mq-sysfs.o blk-mq-cpu.o blk-mq-cpumap.o ioctl.o \
+ blk-mq-sysfs.o blk-mq-cpu.o ioctl.o \
genhd.o scsi_ioctl.o partition-generic.o ioprio.o \
badblocks.o partitions/
diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
deleted file mode 100644
index d0634bc..0000000
--- a/block/blk-mq-cpumap.c
+++ /dev/null
@@ -1,120 +0,0 @@
-/*
- * CPU <-> hardware queue mapping helpers
- *
- * Copyright (C) 2013-2014 Jens Axboe
- */
-#include <linux/kernel.h>
-#include <linux/threads.h>
-#include <linux/module.h>
-#include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/cpu.h>
-
-#include <linux/blk-mq.h>
-#include "blk.h"
-#include "blk-mq.h"
-
-static int cpu_to_queue_index(unsigned int nr_cpus, unsigned int nr_queues,
- const int cpu)
-{
- return cpu * nr_queues / nr_cpus;
-}
-
-static int get_first_sibling(unsigned int cpu)
-{
- unsigned int ret;
-
- ret = cpumask_first(topology_sibling_cpumask(cpu));
- if (ret < nr_cpu_ids)
- return ret;
-
- return cpu;
-}
-
-int blk_mq_update_queue_map(unsigned int *map, unsigned int nr_queues,
- const struct cpumask *online_mask)
-{
- unsigned int i, nr_cpus, nr_uniq_cpus, queue, first_sibling;
- cpumask_var_t cpus;
-
- if (!alloc_cpumask_var(&cpus, GFP_ATOMIC))
- return 1;
-
- cpumask_clear(cpus);
- nr_cpus = nr_uniq_cpus = 0;
- for_each_cpu(i, online_mask) {
- nr_cpus++;
- first_sibling = get_first_sibling(i);
- if (!cpumask_test_cpu(first_sibling, cpus))
- nr_uniq_cpus++;
- cpumask_set_cpu(i, cpus);
- }
-
- queue = 0;
- for_each_possible_cpu(i) {
- if (!cpumask_test_cpu(i, online_mask)) {
- map[i] = 0;
- continue;
- }
-
- /*
- * Easy case - we have equal or more hardware queues. Or
- * there are no thread siblings to take into account. Do
- * 1:1 if enough, or sequential mapping if less.
- */
- if (nr_queues >= nr_cpus || nr_cpus == nr_uniq_cpus) {
- map[i] = cpu_to_queue_index(nr_cpus, nr_queues, queue);
- queue++;
- continue;
- }
-
- /*
- * Less then nr_cpus queues, and we have some number of
- * threads per cores. Map sibling threads to the same
- * queue.
- */
- first_sibling = get_first_sibling(i);
- if (first_sibling == i) {
- map[i] = cpu_to_queue_index(nr_uniq_cpus, nr_queues,
- queue);
- queue++;
- } else
- map[i] = map[first_sibling];
- }
-
- free_cpumask_var(cpus);
- return 0;
-}
-
-unsigned int *blk_mq_make_queue_map(struct blk_mq_tag_set *set)
-{
- unsigned int *map;
-
- /* If cpus are offline, map them to first hctx */
- map = kzalloc_node(sizeof(*map) * nr_cpu_ids, GFP_KERNEL,
- set->numa_node);
- if (!map)
- return NULL;
-
- if (!blk_mq_update_queue_map(map, set->nr_hw_queues, cpu_online_mask))
- return map;
-
- kfree(map);
- return NULL;
-}
-
-/*
- * We have no quick way of doing reverse lookups. This is only used at
- * queue init time, so runtime isn't important.
- */
-int blk_mq_hw_queue_to_node(unsigned int *mq_map, unsigned int index)
-{
- int i;
-
- for_each_possible_cpu(i) {
- if (index == mq_map[i])
- return local_memory_node(cpu_to_node(i));
- }
-
- return NUMA_NO_NODE;
-}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 622cb22..fdd8d3a 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -22,6 +22,7 @@
#include <linux/sched/sysctl.h>
#include <linux/delay.h>
#include <linux/crash_dump.h>
+#include <linux/interrupt.h>
#include <trace/events/block.h>
@@ -1954,6 +1955,22 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
}
EXPORT_SYMBOL(blk_mq_init_queue);
+/*
+ * We have no quick way of doing reverse lookups. This is only used at
+ * queue init time, so runtime isn't important.
+ */
+static int blk_mq_hw_queue_to_node(unsigned int *mq_map, unsigned int index)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ if (index == mq_map[i])
+ return local_memory_node(cpu_to_node(i));
+ }
+
+ return NUMA_NO_NODE;
+}
+
static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
struct request_queue *q)
{
@@ -2253,6 +2270,30 @@ struct cpumask *blk_mq_tags_cpumask(struct blk_mq_tags *tags)
}
EXPORT_SYMBOL_GPL(blk_mq_tags_cpumask);
+static int blk_mq_create_mq_map(struct blk_mq_tag_set *set,
+ const struct cpumask *affinity_mask)
+{
+ int queue = -1, cpu = 0;
+
+ set->mq_map = kzalloc_node(sizeof(*set->mq_map) * nr_cpu_ids,
+ GFP_KERNEL, set->numa_node);
+ if (!set->mq_map)
+ return -ENOMEM;
+
+ if (!affinity_mask)
+ return 0; /* map all cpus to queue 0 */
+
+ /* If cpus are offline, map them to first hctx */
+ for_each_online_cpu(cpu) {
+ if (cpumask_test_cpu(cpu, affinity_mask))
+ queue++;
+ if (queue > 0)
+ set->mq_map[cpu] = queue;
+ }
+
+ return 0;
+}
+
/*
* Alloc a tag set to be associated with one or more request queues.
* May fail with EINVAL for various error conditions. May adjust the
@@ -2261,6 +2302,8 @@ EXPORT_SYMBOL_GPL(blk_mq_tags_cpumask);
*/
int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
{
+ int ret;
+
BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
if (!set->nr_hw_queues)
@@ -2299,11 +2342,26 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
if (!set->tags)
return -ENOMEM;
- set->mq_map = blk_mq_make_queue_map(set);
- if (!set->mq_map)
- goto out_free_tags;
+ /*
+ * Use the passed in affinity mask if the driver provided one.
+ */
+ if (set->affinity_mask) {
+ ret = blk_mq_create_mq_map(set, set->affinity_mask);
+ if (!set->mq_map)
+ goto out_free_tags;
+ } else {
+ struct cpumask *affinity_mask;
+
+ affinity_mask = irq_create_affinity_mask(&set->nr_hw_queues);
+ ret = blk_mq_create_mq_map(set, affinity_mask);
+ kfree(affinity_mask);
+
+ if (!set->mq_map)
+ goto out_free_tags;
+ }
- if (blk_mq_alloc_rq_maps(set))
+ ret = blk_mq_alloc_rq_maps(set);
+ if (ret)
goto out_free_mq_map;
mutex_init(&set->tag_list_lock);
@@ -2317,7 +2375,7 @@ out_free_mq_map:
out_free_tags:
kfree(set->tags);
set->tags = NULL;
- return -ENOMEM;
+ return ret;
}
EXPORT_SYMBOL(blk_mq_alloc_tag_set);
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 9087b11..fe7e21f 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -45,14 +45,6 @@ void blk_mq_enable_hotplug(void);
void blk_mq_disable_hotplug(void);
/*
- * CPU -> queue mappings
- */
-extern unsigned int *blk_mq_make_queue_map(struct blk_mq_tag_set *set);
-extern int blk_mq_update_queue_map(unsigned int *map, unsigned int nr_queues,
- const struct cpumask *online_mask);
-extern int blk_mq_hw_queue_to_node(unsigned int *map, unsigned int);
-
-/*
* sysfs helpers
*/
extern int blk_mq_sysfs_register(struct request_queue *q);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 0a3b138..404cc86 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -75,6 +75,7 @@ struct blk_mq_tag_set {
unsigned int timeout;
unsigned int flags; /* BLK_MQ_F_* */
void *driver_data;
+ struct cpumask *affinity_mask;
struct blk_mq_tags **tags;
--
2.1.4
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