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author | 2015-08-04 12:17:53 -0700 | |
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committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/block/blk-mq-cpumap.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/block/blk-mq-cpumap.c')
-rw-r--r-- | kernel/block/blk-mq-cpumap.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/kernel/block/blk-mq-cpumap.c b/kernel/block/blk-mq-cpumap.c new file mode 100644 index 000000000..5f13f4d0b --- /dev/null +++ b/kernel/block/blk-mq-cpumap.c @@ -0,0 +1,119 @@ +/* + * 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_thread_cpumask(cpu)); + if (ret < nr_cpu_ids) + return ret; + + return cpu; +} + +int blk_mq_update_queue_map(unsigned int *map, unsigned int nr_queues) +{ + 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_online_cpu(i) { + 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 (!cpu_online(i)) { + 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)) + 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 cpu_to_node(i); + } + + return NUMA_NO_NODE; +} |