From 298fb372984a808ccba9ca15a9cf0f393b3259b4 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 10 Nov 2020 13:41:53 -0500 Subject: dm: rename multipath path selector source files to have "dm-ps" prefix Additional prefix helps clarify that these source files implement path selectors. Required updating Makefile to still build modules _without_ the "dm-ps" prefix to preserve dm-multipath's ability to autoload path selector modules. While at it, cleaned up some DM whitespace in Makefile. Signed-off-by: Mike Snitzer --- drivers/md/dm-ps-io-affinity.c | 272 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 272 insertions(+) create mode 100644 drivers/md/dm-ps-io-affinity.c (limited to 'drivers/md/dm-ps-io-affinity.c') diff --git a/drivers/md/dm-ps-io-affinity.c b/drivers/md/dm-ps-io-affinity.c new file mode 100644 index 000000000000..077655cd4fae --- /dev/null +++ b/drivers/md/dm-ps-io-affinity.c @@ -0,0 +1,272 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 Oracle Corporation + * + * Module Author: Mike Christie + */ +#include "dm-path-selector.h" + +#include +#include + +#define DM_MSG_PREFIX "multipath io-affinity" + +struct path_info { + struct dm_path *path; + cpumask_var_t cpumask; + refcount_t refcount; + bool failed; +}; + +struct selector { + struct path_info **path_map; + cpumask_var_t path_mask; + atomic_t map_misses; +}; + +static void ioa_free_path(struct selector *s, unsigned int cpu) +{ + struct path_info *pi = s->path_map[cpu]; + + if (!pi) + return; + + if (refcount_dec_and_test(&pi->refcount)) { + cpumask_clear_cpu(cpu, s->path_mask); + free_cpumask_var(pi->cpumask); + kfree(pi); + + s->path_map[cpu] = NULL; + } +} + +static int ioa_add_path(struct path_selector *ps, struct dm_path *path, + int argc, char **argv, char **error) +{ + struct selector *s = ps->context; + struct path_info *pi = NULL; + unsigned int cpu; + int ret; + + if (argc != 1) { + *error = "io-affinity ps: invalid number of arguments"; + return -EINVAL; + } + + pi = kzalloc(sizeof(*pi), GFP_KERNEL); + if (!pi) { + *error = "io-affinity ps: Error allocating path context"; + return -ENOMEM; + } + + pi->path = path; + path->pscontext = pi; + refcount_set(&pi->refcount, 1); + + if (!zalloc_cpumask_var(&pi->cpumask, GFP_KERNEL)) { + *error = "io-affinity ps: Error allocating cpumask context"; + ret = -ENOMEM; + goto free_pi; + } + + ret = cpumask_parse(argv[0], pi->cpumask); + if (ret) { + *error = "io-affinity ps: invalid cpumask"; + ret = -EINVAL; + goto free_mask; + } + + for_each_cpu(cpu, pi->cpumask) { + if (cpu >= nr_cpu_ids) { + DMWARN_LIMIT("Ignoring mapping for CPU %u. Max CPU is %u", + cpu, nr_cpu_ids); + break; + } + + if (s->path_map[cpu]) { + DMWARN("CPU mapping for %u exists. Ignoring.", cpu); + continue; + } + + cpumask_set_cpu(cpu, s->path_mask); + s->path_map[cpu] = pi; + refcount_inc(&pi->refcount); + continue; + } + + if (refcount_dec_and_test(&pi->refcount)) { + *error = "io-affinity ps: No new/valid CPU mapping found"; + ret = -EINVAL; + goto free_mask; + } + + return 0; + +free_mask: + free_cpumask_var(pi->cpumask); +free_pi: + kfree(pi); + return ret; +} + +static int ioa_create(struct path_selector *ps, unsigned argc, char **argv) +{ + struct selector *s; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + + s->path_map = kzalloc(nr_cpu_ids * sizeof(struct path_info *), + GFP_KERNEL); + if (!s->path_map) + goto free_selector; + + if (!zalloc_cpumask_var(&s->path_mask, GFP_KERNEL)) + goto free_map; + + atomic_set(&s->map_misses, 0); + ps->context = s; + return 0; + +free_map: + kfree(s->path_map); +free_selector: + kfree(s); + return -ENOMEM; +} + +static void ioa_destroy(struct path_selector *ps) +{ + struct selector *s = ps->context; + unsigned cpu; + + for_each_cpu(cpu, s->path_mask) + ioa_free_path(s, cpu); + + free_cpumask_var(s->path_mask); + kfree(s->path_map); + kfree(s); + + ps->context = NULL; +} + +static int ioa_status(struct path_selector *ps, struct dm_path *path, + status_type_t type, char *result, unsigned int maxlen) +{ + struct selector *s = ps->context; + struct path_info *pi; + int sz = 0; + + if (!path) { + DMEMIT("0 "); + return sz; + } + + switch(type) { + case STATUSTYPE_INFO: + DMEMIT("%d ", atomic_read(&s->map_misses)); + break; + case STATUSTYPE_TABLE: + pi = path->pscontext; + DMEMIT("%*pb ", cpumask_pr_args(pi->cpumask)); + break; + } + + return sz; +} + +static void ioa_fail_path(struct path_selector *ps, struct dm_path *p) +{ + struct path_info *pi = p->pscontext; + + pi->failed = true; +} + +static int ioa_reinstate_path(struct path_selector *ps, struct dm_path *p) +{ + struct path_info *pi = p->pscontext; + + pi->failed = false; + return 0; +} + +static struct dm_path *ioa_select_path(struct path_selector *ps, + size_t nr_bytes) +{ + unsigned int cpu, node; + struct selector *s = ps->context; + const struct cpumask *cpumask; + struct path_info *pi; + int i; + + cpu = get_cpu(); + + pi = s->path_map[cpu]; + if (pi && !pi->failed) + goto done; + + /* + * Perf is not optimal, but we at least try the local node then just + * try not to fail. + */ + if (!pi) + atomic_inc(&s->map_misses); + + node = cpu_to_node(cpu); + cpumask = cpumask_of_node(node); + for_each_cpu(i, cpumask) { + pi = s->path_map[i]; + if (pi && !pi->failed) + goto done; + } + + for_each_cpu(i, s->path_mask) { + pi = s->path_map[i]; + if (pi && !pi->failed) + goto done; + } + pi = NULL; + +done: + put_cpu(); + return pi ? pi->path : NULL; +} + +static struct path_selector_type ioa_ps = { + .name = "io-affinity", + .module = THIS_MODULE, + .table_args = 1, + .info_args = 1, + .create = ioa_create, + .destroy = ioa_destroy, + .status = ioa_status, + .add_path = ioa_add_path, + .fail_path = ioa_fail_path, + .reinstate_path = ioa_reinstate_path, + .select_path = ioa_select_path, +}; + +static int __init dm_ioa_init(void) +{ + int ret = dm_register_path_selector(&ioa_ps); + + if (ret < 0) + DMERR("register failed %d", ret); + return ret; +} + +static void __exit dm_ioa_exit(void) +{ + int ret = dm_unregister_path_selector(&ioa_ps); + + if (ret < 0) + DMERR("unregister failed %d", ret); +} + +module_init(dm_ioa_init); +module_exit(dm_ioa_exit); + +MODULE_DESCRIPTION(DM_NAME " multipath path selector that selects paths based on the CPU IO is being executed on"); +MODULE_AUTHOR("Mike Christie "); +MODULE_LICENSE("GPL"); -- cgit v1.2.3-59-g8ed1b