Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Common Block IO controller cgroup interface |
| 3 | * |
| 4 | * Based on ideas and code from CFQ, CFS and BFQ: |
| 5 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
| 6 | * |
| 7 | * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> |
| 8 | * Paolo Valente <paolo.valente@unimore.it> |
| 9 | * |
| 10 | * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> |
| 11 | * Nauman Rafique <nauman@google.com> |
| 12 | */ |
| 13 | #include <linux/ioprio.h> |
Vivek Goyal | 2208419 | 2009-12-03 12:59:49 -0500 | [diff] [blame] | 14 | #include <linux/kdev_t.h> |
Vivek Goyal | 9d6a986 | 2009-12-04 10:36:41 -0500 | [diff] [blame] | 15 | #include <linux/module.h> |
Stephen Rothwell | accee78 | 2009-12-07 19:29:39 +1100 | [diff] [blame] | 16 | #include <linux/err.h> |
Divyesh Shah | 9195291 | 2010-04-01 15:01:41 -0700 | [diff] [blame] | 17 | #include <linux/blkdev.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 18 | #include <linux/slab.h> |
Gui Jianfeng | 34d0f17 | 2010-04-13 16:05:49 +0800 | [diff] [blame] | 19 | #include <linux/genhd.h> |
Tejun Heo | 72e06c2 | 2012-03-05 13:15:00 -0800 | [diff] [blame] | 20 | #include <linux/delay.h> |
Tejun Heo | 9a9e8a2 | 2012-03-19 15:10:56 -0700 | [diff] [blame] | 21 | #include <linux/atomic.h> |
Tejun Heo | 72e06c2 | 2012-03-05 13:15:00 -0800 | [diff] [blame] | 22 | #include "blk-cgroup.h" |
Tejun Heo | 5efd611 | 2012-03-05 13:15:12 -0800 | [diff] [blame] | 23 | #include "blk.h" |
Vivek Goyal | 3e25206 | 2009-12-04 10:36:42 -0500 | [diff] [blame] | 24 | |
Divyesh Shah | 84c124d | 2010-04-09 08:31:19 +0200 | [diff] [blame] | 25 | #define MAX_KEY_LEN 100 |
| 26 | |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 27 | static DEFINE_MUTEX(blkcg_pol_mutex); |
Tejun Heo | 923adde | 2012-03-05 13:15:13 -0800 | [diff] [blame] | 28 | |
Tejun Heo | e71357e | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 29 | struct blkcg blkcg_root = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT, |
| 30 | .cfq_leaf_weight = 2 * CFQ_WEIGHT_DEFAULT, }; |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 31 | EXPORT_SYMBOL_GPL(blkcg_root); |
Vivek Goyal | 9d6a986 | 2009-12-04 10:36:41 -0500 | [diff] [blame] | 32 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 33 | static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS]; |
Tejun Heo | 035d10b | 2012-03-05 13:15:04 -0800 | [diff] [blame] | 34 | |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 35 | static bool blkcg_policy_enabled(struct request_queue *q, |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 36 | const struct blkcg_policy *pol) |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 37 | { |
| 38 | return pol && test_bit(pol->plid, q->blkcg_pols); |
| 39 | } |
| 40 | |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 41 | /** |
| 42 | * blkg_free - free a blkg |
| 43 | * @blkg: blkg to free |
| 44 | * |
| 45 | * Free @blkg which may be partially allocated. |
| 46 | */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 47 | static void blkg_free(struct blkcg_gq *blkg) |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 48 | { |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 49 | int i; |
Tejun Heo | 549d3aa | 2012-03-05 13:15:16 -0800 | [diff] [blame] | 50 | |
| 51 | if (!blkg) |
| 52 | return; |
| 53 | |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 54 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 55 | struct blkcg_policy *pol = blkcg_policy[i]; |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 56 | struct blkg_policy_data *pd = blkg->pd[i]; |
| 57 | |
Tejun Heo | 9ade5ea | 2012-04-01 14:38:44 -0700 | [diff] [blame] | 58 | if (!pd) |
| 59 | continue; |
| 60 | |
Tejun Heo | f9fcc2d | 2012-04-16 13:57:27 -0700 | [diff] [blame] | 61 | if (pol && pol->pd_exit_fn) |
| 62 | pol->pd_exit_fn(blkg); |
Tejun Heo | 9ade5ea | 2012-04-01 14:38:44 -0700 | [diff] [blame] | 63 | |
Tejun Heo | 9ade5ea | 2012-04-01 14:38:44 -0700 | [diff] [blame] | 64 | kfree(pd); |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 65 | } |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 66 | |
Tejun Heo | a051661 | 2012-06-26 15:05:44 -0700 | [diff] [blame] | 67 | blk_exit_rl(&blkg->rl); |
Tejun Heo | 549d3aa | 2012-03-05 13:15:16 -0800 | [diff] [blame] | 68 | kfree(blkg); |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 69 | } |
| 70 | |
| 71 | /** |
| 72 | * blkg_alloc - allocate a blkg |
| 73 | * @blkcg: block cgroup the new blkg is associated with |
| 74 | * @q: request_queue the new blkg is associated with |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 75 | * @gfp_mask: allocation mask to use |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 76 | * |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 77 | * Allocate a new blkg assocating @blkcg and @q. |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 78 | */ |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 79 | static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q, |
| 80 | gfp_t gfp_mask) |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 81 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 82 | struct blkcg_gq *blkg; |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 83 | int i; |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 84 | |
| 85 | /* alloc and init base part */ |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 86 | blkg = kzalloc_node(sizeof(*blkg), gfp_mask, q->node); |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 87 | if (!blkg) |
| 88 | return NULL; |
| 89 | |
Tejun Heo | c875f4d | 2012-03-05 13:15:22 -0800 | [diff] [blame] | 90 | blkg->q = q; |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 91 | INIT_LIST_HEAD(&blkg->q_node); |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 92 | blkg->blkcg = blkcg; |
Tejun Heo | 1adaf3d | 2012-03-05 13:15:15 -0800 | [diff] [blame] | 93 | blkg->refcnt = 1; |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 94 | |
Tejun Heo | a051661 | 2012-06-26 15:05:44 -0700 | [diff] [blame] | 95 | /* root blkg uses @q->root_rl, init rl only for !root blkgs */ |
| 96 | if (blkcg != &blkcg_root) { |
| 97 | if (blk_init_rl(&blkg->rl, q, gfp_mask)) |
| 98 | goto err_free; |
| 99 | blkg->rl.blkg = blkg; |
| 100 | } |
| 101 | |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 102 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 103 | struct blkcg_policy *pol = blkcg_policy[i]; |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 104 | struct blkg_policy_data *pd; |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 105 | |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 106 | if (!blkcg_policy_enabled(q, pol)) |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 107 | continue; |
Tejun Heo | 549d3aa | 2012-03-05 13:15:16 -0800 | [diff] [blame] | 108 | |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 109 | /* alloc per-policy data and attach it to blkg */ |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 110 | pd = kzalloc_node(pol->pd_size, gfp_mask, q->node); |
Tejun Heo | a051661 | 2012-06-26 15:05:44 -0700 | [diff] [blame] | 111 | if (!pd) |
| 112 | goto err_free; |
Tejun Heo | 549d3aa | 2012-03-05 13:15:16 -0800 | [diff] [blame] | 113 | |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 114 | blkg->pd[i] = pd; |
| 115 | pd->blkg = blkg; |
Tejun Heo | b276a87 | 2013-01-09 08:05:12 -0800 | [diff] [blame] | 116 | pd->plid = i; |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 117 | |
Tejun Heo | 9b2ea86 | 2012-06-04 15:21:00 +0900 | [diff] [blame] | 118 | /* invoke per-policy init */ |
Tejun Heo | 356d2e5 | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 119 | if (pol->pd_init_fn) |
Tejun Heo | f9fcc2d | 2012-04-16 13:57:27 -0700 | [diff] [blame] | 120 | pol->pd_init_fn(blkg); |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 121 | } |
| 122 | |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 123 | return blkg; |
Tejun Heo | a051661 | 2012-06-26 15:05:44 -0700 | [diff] [blame] | 124 | |
| 125 | err_free: |
| 126 | blkg_free(blkg); |
| 127 | return NULL; |
Tejun Heo | 0381411 | 2012-03-05 13:15:14 -0800 | [diff] [blame] | 128 | } |
| 129 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 130 | static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 131 | struct request_queue *q, bool update_hint) |
Tejun Heo | 80fd997 | 2012-04-13 14:50:53 -0700 | [diff] [blame] | 132 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 133 | struct blkcg_gq *blkg; |
Tejun Heo | 80fd997 | 2012-04-13 14:50:53 -0700 | [diff] [blame] | 134 | |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 135 | blkg = rcu_dereference(blkcg->blkg_hint); |
| 136 | if (blkg && blkg->q == q) |
| 137 | return blkg; |
| 138 | |
| 139 | /* |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 140 | * Hint didn't match. Look up from the radix tree. Note that the |
| 141 | * hint can only be updated under queue_lock as otherwise @blkg |
| 142 | * could have already been removed from blkg_tree. The caller is |
| 143 | * responsible for grabbing queue_lock if @update_hint. |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 144 | */ |
| 145 | blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id); |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 146 | if (blkg && blkg->q == q) { |
| 147 | if (update_hint) { |
| 148 | lockdep_assert_held(q->queue_lock); |
| 149 | rcu_assign_pointer(blkcg->blkg_hint, blkg); |
| 150 | } |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 151 | return blkg; |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 152 | } |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 153 | |
Tejun Heo | 80fd997 | 2012-04-13 14:50:53 -0700 | [diff] [blame] | 154 | return NULL; |
| 155 | } |
| 156 | |
| 157 | /** |
| 158 | * blkg_lookup - lookup blkg for the specified blkcg - q pair |
| 159 | * @blkcg: blkcg of interest |
| 160 | * @q: request_queue of interest |
| 161 | * |
| 162 | * Lookup blkg for the @blkcg - @q pair. This function should be called |
| 163 | * under RCU read lock and is guaranteed to return %NULL if @q is bypassing |
| 164 | * - see blk_queue_bypass_start() for details. |
| 165 | */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 166 | struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q) |
Tejun Heo | 80fd997 | 2012-04-13 14:50:53 -0700 | [diff] [blame] | 167 | { |
| 168 | WARN_ON_ONCE(!rcu_read_lock_held()); |
| 169 | |
| 170 | if (unlikely(blk_queue_bypass(q))) |
| 171 | return NULL; |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 172 | return __blkg_lookup(blkcg, q, false); |
Tejun Heo | 80fd997 | 2012-04-13 14:50:53 -0700 | [diff] [blame] | 173 | } |
| 174 | EXPORT_SYMBOL_GPL(blkg_lookup); |
| 175 | |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 176 | /* |
| 177 | * If @new_blkg is %NULL, this function tries to allocate a new one as |
| 178 | * necessary using %GFP_ATOMIC. @new_blkg is always consumed on return. |
| 179 | */ |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 180 | static struct blkcg_gq *blkg_create(struct blkcg *blkcg, |
| 181 | struct request_queue *q, |
| 182 | struct blkcg_gq *new_blkg) |
Vivek Goyal | 5624a4e | 2011-05-19 15:38:28 -0400 | [diff] [blame] | 183 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 184 | struct blkcg_gq *blkg; |
Tejun Heo | f427d90 | 2013-01-09 08:05:12 -0800 | [diff] [blame] | 185 | int i, ret; |
Vivek Goyal | 5624a4e | 2011-05-19 15:38:28 -0400 | [diff] [blame] | 186 | |
Tejun Heo | cd1604f | 2012-03-05 13:15:06 -0800 | [diff] [blame] | 187 | WARN_ON_ONCE(!rcu_read_lock_held()); |
| 188 | lockdep_assert_held(q->queue_lock); |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 189 | |
Tejun Heo | 7ee9c56 | 2012-03-05 13:15:11 -0800 | [diff] [blame] | 190 | /* blkg holds a reference to blkcg */ |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 191 | if (!css_tryget(&blkcg->css)) { |
Tejun Heo | 93e6d5d | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 192 | ret = -EINVAL; |
| 193 | goto err_free_blkg; |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 194 | } |
Tejun Heo | cd1604f | 2012-03-05 13:15:06 -0800 | [diff] [blame] | 195 | |
Tejun Heo | 496fb78 | 2012-04-19 16:29:23 -0700 | [diff] [blame] | 196 | /* allocate */ |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 197 | if (!new_blkg) { |
| 198 | new_blkg = blkg_alloc(blkcg, q, GFP_ATOMIC); |
| 199 | if (unlikely(!new_blkg)) { |
Tejun Heo | 93e6d5d | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 200 | ret = -ENOMEM; |
| 201 | goto err_put_css; |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 202 | } |
| 203 | } |
| 204 | blkg = new_blkg; |
Tejun Heo | cd1604f | 2012-03-05 13:15:06 -0800 | [diff] [blame] | 205 | |
Tejun Heo | 3c54786 | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 206 | /* link parent and insert */ |
| 207 | if (blkcg_parent(blkcg)) { |
| 208 | blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false); |
| 209 | if (WARN_ON_ONCE(!blkg->parent)) { |
| 210 | blkg = ERR_PTR(-EINVAL); |
| 211 | goto err_put_css; |
| 212 | } |
| 213 | blkg_get(blkg->parent); |
| 214 | } |
| 215 | |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 216 | spin_lock(&blkcg->lock); |
| 217 | ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg); |
| 218 | if (likely(!ret)) { |
| 219 | hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); |
| 220 | list_add(&blkg->q_node, &q->blkg_list); |
Tejun Heo | f427d90 | 2013-01-09 08:05:12 -0800 | [diff] [blame] | 221 | |
| 222 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
| 223 | struct blkcg_policy *pol = blkcg_policy[i]; |
| 224 | |
| 225 | if (blkg->pd[i] && pol->pd_online_fn) |
| 226 | pol->pd_online_fn(blkg); |
| 227 | } |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 228 | } |
Tejun Heo | f427d90 | 2013-01-09 08:05:12 -0800 | [diff] [blame] | 229 | blkg->online = true; |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 230 | spin_unlock(&blkcg->lock); |
| 231 | |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 232 | if (!ret) |
| 233 | return blkg; |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 234 | |
Tejun Heo | 3c54786 | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 235 | /* @blkg failed fully initialized, use the usual release path */ |
| 236 | blkg_put(blkg); |
| 237 | return ERR_PTR(ret); |
| 238 | |
Tejun Heo | 93e6d5d | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 239 | err_put_css: |
Tejun Heo | 496fb78 | 2012-04-19 16:29:23 -0700 | [diff] [blame] | 240 | css_put(&blkcg->css); |
Tejun Heo | 93e6d5d | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 241 | err_free_blkg: |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 242 | blkg_free(new_blkg); |
Tejun Heo | 93e6d5d | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 243 | return ERR_PTR(ret); |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 244 | } |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 245 | |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 246 | /** |
| 247 | * blkg_lookup_create - lookup blkg, try to create one if not there |
| 248 | * @blkcg: blkcg of interest |
| 249 | * @q: request_queue of interest |
| 250 | * |
| 251 | * Lookup blkg for the @blkcg - @q pair. If it doesn't exist, try to |
Tejun Heo | 3c54786 | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 252 | * create one. blkg creation is performed recursively from blkcg_root such |
| 253 | * that all non-root blkg's have access to the parent blkg. This function |
| 254 | * should be called under RCU read lock and @q->queue_lock. |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 255 | * |
| 256 | * Returns pointer to the looked up or created blkg on success, ERR_PTR() |
| 257 | * value on error. If @q is dead, returns ERR_PTR(-EINVAL). If @q is not |
| 258 | * dead and bypassing, returns ERR_PTR(-EBUSY). |
| 259 | */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 260 | struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, |
| 261 | struct request_queue *q) |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 262 | { |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 263 | struct blkcg_gq *blkg; |
| 264 | |
| 265 | WARN_ON_ONCE(!rcu_read_lock_held()); |
| 266 | lockdep_assert_held(q->queue_lock); |
| 267 | |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 268 | /* |
| 269 | * This could be the first entry point of blkcg implementation and |
| 270 | * we shouldn't allow anything to go through for a bypassing queue. |
| 271 | */ |
| 272 | if (unlikely(blk_queue_bypass(q))) |
Bart Van Assche | 3f3299d | 2012-11-28 13:42:38 +0100 | [diff] [blame] | 273 | return ERR_PTR(blk_queue_dying(q) ? -EINVAL : -EBUSY); |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 274 | |
| 275 | blkg = __blkg_lookup(blkcg, q, true); |
| 276 | if (blkg) |
| 277 | return blkg; |
| 278 | |
Tejun Heo | 3c54786 | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 279 | /* |
| 280 | * Create blkgs walking down from blkcg_root to @blkcg, so that all |
| 281 | * non-root blkgs have access to their parents. |
| 282 | */ |
| 283 | while (true) { |
| 284 | struct blkcg *pos = blkcg; |
| 285 | struct blkcg *parent = blkcg_parent(blkcg); |
| 286 | |
| 287 | while (parent && !__blkg_lookup(parent, q, false)) { |
| 288 | pos = parent; |
| 289 | parent = blkcg_parent(parent); |
| 290 | } |
| 291 | |
| 292 | blkg = blkg_create(pos, q, NULL); |
| 293 | if (pos == blkcg || IS_ERR(blkg)) |
| 294 | return blkg; |
| 295 | } |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 296 | } |
Tejun Heo | cd1604f | 2012-03-05 13:15:06 -0800 | [diff] [blame] | 297 | EXPORT_SYMBOL_GPL(blkg_lookup_create); |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 298 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 299 | static void blkg_destroy(struct blkcg_gq *blkg) |
Tejun Heo | 72e06c2 | 2012-03-05 13:15:00 -0800 | [diff] [blame] | 300 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 301 | struct blkcg *blkcg = blkg->blkcg; |
Tejun Heo | f427d90 | 2013-01-09 08:05:12 -0800 | [diff] [blame] | 302 | int i; |
Tejun Heo | 03aa264 | 2012-03-05 13:15:19 -0800 | [diff] [blame] | 303 | |
Tejun Heo | 27e1f9d | 2012-06-05 13:36:44 +0200 | [diff] [blame] | 304 | lockdep_assert_held(blkg->q->queue_lock); |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 305 | lockdep_assert_held(&blkcg->lock); |
Tejun Heo | 03aa264 | 2012-03-05 13:15:19 -0800 | [diff] [blame] | 306 | |
| 307 | /* Something wrong if we are trying to remove same group twice */ |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 308 | WARN_ON_ONCE(list_empty(&blkg->q_node)); |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 309 | WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node)); |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 310 | |
Tejun Heo | f427d90 | 2013-01-09 08:05:12 -0800 | [diff] [blame] | 311 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
| 312 | struct blkcg_policy *pol = blkcg_policy[i]; |
| 313 | |
| 314 | if (blkg->pd[i] && pol->pd_offline_fn) |
| 315 | pol->pd_offline_fn(blkg); |
| 316 | } |
| 317 | blkg->online = false; |
| 318 | |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 319 | radix_tree_delete(&blkcg->blkg_tree, blkg->q->id); |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 320 | list_del_init(&blkg->q_node); |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 321 | hlist_del_init_rcu(&blkg->blkcg_node); |
Tejun Heo | 03aa264 | 2012-03-05 13:15:19 -0800 | [diff] [blame] | 322 | |
Tejun Heo | 03aa264 | 2012-03-05 13:15:19 -0800 | [diff] [blame] | 323 | /* |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 324 | * Both setting lookup hint to and clearing it from @blkg are done |
| 325 | * under queue_lock. If it's not pointing to @blkg now, it never |
| 326 | * will. Hint assignment itself can race safely. |
| 327 | */ |
| 328 | if (rcu_dereference_raw(blkcg->blkg_hint) == blkg) |
| 329 | rcu_assign_pointer(blkcg->blkg_hint, NULL); |
| 330 | |
| 331 | /* |
Tejun Heo | 03aa264 | 2012-03-05 13:15:19 -0800 | [diff] [blame] | 332 | * Put the reference taken at the time of creation so that when all |
| 333 | * queues are gone, group can be destroyed. |
| 334 | */ |
| 335 | blkg_put(blkg); |
| 336 | } |
| 337 | |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 338 | /** |
| 339 | * blkg_destroy_all - destroy all blkgs associated with a request_queue |
| 340 | * @q: request_queue of interest |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 341 | * |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 342 | * Destroy all blkgs associated with @q. |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 343 | */ |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 344 | static void blkg_destroy_all(struct request_queue *q) |
Tejun Heo | 03aa264 | 2012-03-05 13:15:19 -0800 | [diff] [blame] | 345 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 346 | struct blkcg_gq *blkg, *n; |
Tejun Heo | 72e06c2 | 2012-03-05 13:15:00 -0800 | [diff] [blame] | 347 | |
Tejun Heo | 6d18b00 | 2012-04-13 13:11:35 -0700 | [diff] [blame] | 348 | lockdep_assert_held(q->queue_lock); |
Tejun Heo | 72e06c2 | 2012-03-05 13:15:00 -0800 | [diff] [blame] | 349 | |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 350 | list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 351 | struct blkcg *blkcg = blkg->blkcg; |
Tejun Heo | 72e06c2 | 2012-03-05 13:15:00 -0800 | [diff] [blame] | 352 | |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 353 | spin_lock(&blkcg->lock); |
| 354 | blkg_destroy(blkg); |
| 355 | spin_unlock(&blkcg->lock); |
Tejun Heo | 72e06c2 | 2012-03-05 13:15:00 -0800 | [diff] [blame] | 356 | } |
Jun'ichi Nomura | 65635cb | 2012-10-17 17:45:36 +0900 | [diff] [blame] | 357 | |
| 358 | /* |
| 359 | * root blkg is destroyed. Just clear the pointer since |
| 360 | * root_rl does not take reference on root blkg. |
| 361 | */ |
| 362 | q->root_blkg = NULL; |
| 363 | q->root_rl.blkg = NULL; |
Tejun Heo | 72e06c2 | 2012-03-05 13:15:00 -0800 | [diff] [blame] | 364 | } |
| 365 | |
Tejun Heo | 1adaf3d | 2012-03-05 13:15:15 -0800 | [diff] [blame] | 366 | static void blkg_rcu_free(struct rcu_head *rcu_head) |
| 367 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 368 | blkg_free(container_of(rcu_head, struct blkcg_gq, rcu_head)); |
Tejun Heo | 1adaf3d | 2012-03-05 13:15:15 -0800 | [diff] [blame] | 369 | } |
| 370 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 371 | void __blkg_release(struct blkcg_gq *blkg) |
Tejun Heo | 1adaf3d | 2012-03-05 13:15:15 -0800 | [diff] [blame] | 372 | { |
Tejun Heo | 3c54786 | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 373 | /* release the blkcg and parent blkg refs this blkg has been holding */ |
Tejun Heo | 1adaf3d | 2012-03-05 13:15:15 -0800 | [diff] [blame] | 374 | css_put(&blkg->blkcg->css); |
Tejun Heo | 3c54786 | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 375 | if (blkg->parent) |
| 376 | blkg_put(blkg->parent); |
Tejun Heo | 1adaf3d | 2012-03-05 13:15:15 -0800 | [diff] [blame] | 377 | |
| 378 | /* |
| 379 | * A group is freed in rcu manner. But having an rcu lock does not |
| 380 | * mean that one can access all the fields of blkg and assume these |
| 381 | * are valid. For example, don't try to follow throtl_data and |
| 382 | * request queue links. |
| 383 | * |
| 384 | * Having a reference to blkg under an rcu allows acess to only |
| 385 | * values local to groups like group stats and group rate limits |
| 386 | */ |
| 387 | call_rcu(&blkg->rcu_head, blkg_rcu_free); |
| 388 | } |
| 389 | EXPORT_SYMBOL_GPL(__blkg_release); |
| 390 | |
Tejun Heo | a051661 | 2012-06-26 15:05:44 -0700 | [diff] [blame] | 391 | /* |
| 392 | * The next function used by blk_queue_for_each_rl(). It's a bit tricky |
| 393 | * because the root blkg uses @q->root_rl instead of its own rl. |
| 394 | */ |
| 395 | struct request_list *__blk_queue_next_rl(struct request_list *rl, |
| 396 | struct request_queue *q) |
| 397 | { |
| 398 | struct list_head *ent; |
| 399 | struct blkcg_gq *blkg; |
| 400 | |
| 401 | /* |
| 402 | * Determine the current blkg list_head. The first entry is |
| 403 | * root_rl which is off @q->blkg_list and mapped to the head. |
| 404 | */ |
| 405 | if (rl == &q->root_rl) { |
| 406 | ent = &q->blkg_list; |
Jun'ichi Nomura | 65c77fd | 2012-10-22 10:15:37 +0900 | [diff] [blame] | 407 | /* There are no more block groups, hence no request lists */ |
| 408 | if (list_empty(ent)) |
| 409 | return NULL; |
Tejun Heo | a051661 | 2012-06-26 15:05:44 -0700 | [diff] [blame] | 410 | } else { |
| 411 | blkg = container_of(rl, struct blkcg_gq, rl); |
| 412 | ent = &blkg->q_node; |
| 413 | } |
| 414 | |
| 415 | /* walk to the next list_head, skip root blkcg */ |
| 416 | ent = ent->next; |
| 417 | if (ent == &q->root_blkg->q_node) |
| 418 | ent = ent->next; |
| 419 | if (ent == &q->blkg_list) |
| 420 | return NULL; |
| 421 | |
| 422 | blkg = container_of(ent, struct blkcg_gq, q_node); |
| 423 | return &blkg->rl; |
| 424 | } |
| 425 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 426 | static int blkcg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, |
| 427 | u64 val) |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 428 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 429 | struct blkcg *blkcg = cgroup_to_blkcg(cgroup); |
| 430 | struct blkcg_gq *blkg; |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 431 | struct hlist_node *n; |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 432 | int i; |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 433 | |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 434 | mutex_lock(&blkcg_pol_mutex); |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 435 | spin_lock_irq(&blkcg->lock); |
Tejun Heo | 997a026 | 2012-03-08 10:53:58 -0800 | [diff] [blame] | 436 | |
| 437 | /* |
| 438 | * Note that stat reset is racy - it doesn't synchronize against |
| 439 | * stat updates. This is a debug feature which shouldn't exist |
| 440 | * anyway. If you get hit by a race, retry. |
| 441 | */ |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 442 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 443 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 444 | struct blkcg_policy *pol = blkcg_policy[i]; |
Tejun Heo | 549d3aa | 2012-03-05 13:15:16 -0800 | [diff] [blame] | 445 | |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 446 | if (blkcg_policy_enabled(blkg->q, pol) && |
Tejun Heo | f9fcc2d | 2012-04-16 13:57:27 -0700 | [diff] [blame] | 447 | pol->pd_reset_stats_fn) |
| 448 | pol->pd_reset_stats_fn(blkg); |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 449 | } |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 450 | } |
Vivek Goyal | f0bdc8c | 2011-05-19 15:38:30 -0400 | [diff] [blame] | 451 | |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 452 | spin_unlock_irq(&blkcg->lock); |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 453 | mutex_unlock(&blkcg_pol_mutex); |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 454 | return 0; |
| 455 | } |
| 456 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 457 | static const char *blkg_dev_name(struct blkcg_gq *blkg) |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 458 | { |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 459 | /* some drivers (floppy) instantiate a queue w/o disk registered */ |
| 460 | if (blkg->q->backing_dev_info.dev) |
| 461 | return dev_name(blkg->q->backing_dev_info.dev); |
| 462 | return NULL; |
Divyesh Shah | 303a3ac | 2010-04-01 15:01:24 -0700 | [diff] [blame] | 463 | } |
| 464 | |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 465 | /** |
| 466 | * blkcg_print_blkgs - helper for printing per-blkg data |
| 467 | * @sf: seq_file to print to |
| 468 | * @blkcg: blkcg of interest |
| 469 | * @prfill: fill function to print out a blkg |
| 470 | * @pol: policy in question |
| 471 | * @data: data to be passed to @prfill |
| 472 | * @show_total: to print out sum of prfill return values or not |
| 473 | * |
| 474 | * This function invokes @prfill on each blkg of @blkcg if pd for the |
| 475 | * policy specified by @pol exists. @prfill is invoked with @sf, the |
| 476 | * policy data and @data. If @show_total is %true, the sum of the return |
| 477 | * values from @prfill is printed with "Total" label at the end. |
| 478 | * |
| 479 | * This is to be used to construct print functions for |
| 480 | * cftype->read_seq_string method. |
| 481 | */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 482 | void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg, |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 483 | u64 (*prfill)(struct seq_file *, |
| 484 | struct blkg_policy_data *, int), |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 485 | const struct blkcg_policy *pol, int data, |
Tejun Heo | ec39934 | 2012-04-13 13:11:27 -0700 | [diff] [blame] | 486 | bool show_total) |
Vivek Goyal | 5624a4e | 2011-05-19 15:38:28 -0400 | [diff] [blame] | 487 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 488 | struct blkcg_gq *blkg; |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 489 | struct hlist_node *n; |
| 490 | u64 total = 0; |
| 491 | |
| 492 | spin_lock_irq(&blkcg->lock); |
| 493 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 494 | if (blkcg_policy_enabled(blkg->q, pol)) |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 495 | total += prfill(sf, blkg->pd[pol->plid], data); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 496 | spin_unlock_irq(&blkcg->lock); |
| 497 | |
| 498 | if (show_total) |
| 499 | seq_printf(sf, "Total %llu\n", (unsigned long long)total); |
| 500 | } |
Tejun Heo | 829fdb5 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 501 | EXPORT_SYMBOL_GPL(blkcg_print_blkgs); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 502 | |
| 503 | /** |
| 504 | * __blkg_prfill_u64 - prfill helper for a single u64 value |
| 505 | * @sf: seq_file to print to |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 506 | * @pd: policy private data of interest |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 507 | * @v: value to print |
| 508 | * |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 509 | * Print @v to @sf for the device assocaited with @pd. |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 510 | */ |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 511 | u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v) |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 512 | { |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 513 | const char *dname = blkg_dev_name(pd->blkg); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 514 | |
| 515 | if (!dname) |
| 516 | return 0; |
| 517 | |
| 518 | seq_printf(sf, "%s %llu\n", dname, (unsigned long long)v); |
| 519 | return v; |
| 520 | } |
Tejun Heo | 829fdb5 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 521 | EXPORT_SYMBOL_GPL(__blkg_prfill_u64); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 522 | |
| 523 | /** |
| 524 | * __blkg_prfill_rwstat - prfill helper for a blkg_rwstat |
| 525 | * @sf: seq_file to print to |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 526 | * @pd: policy private data of interest |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 527 | * @rwstat: rwstat to print |
| 528 | * |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 529 | * Print @rwstat to @sf for the device assocaited with @pd. |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 530 | */ |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 531 | u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, |
Tejun Heo | 829fdb5 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 532 | const struct blkg_rwstat *rwstat) |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 533 | { |
| 534 | static const char *rwstr[] = { |
| 535 | [BLKG_RWSTAT_READ] = "Read", |
| 536 | [BLKG_RWSTAT_WRITE] = "Write", |
| 537 | [BLKG_RWSTAT_SYNC] = "Sync", |
| 538 | [BLKG_RWSTAT_ASYNC] = "Async", |
| 539 | }; |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 540 | const char *dname = blkg_dev_name(pd->blkg); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 541 | u64 v; |
| 542 | int i; |
| 543 | |
| 544 | if (!dname) |
| 545 | return 0; |
| 546 | |
| 547 | for (i = 0; i < BLKG_RWSTAT_NR; i++) |
| 548 | seq_printf(sf, "%s %s %llu\n", dname, rwstr[i], |
| 549 | (unsigned long long)rwstat->cnt[i]); |
| 550 | |
| 551 | v = rwstat->cnt[BLKG_RWSTAT_READ] + rwstat->cnt[BLKG_RWSTAT_WRITE]; |
| 552 | seq_printf(sf, "%s Total %llu\n", dname, (unsigned long long)v); |
| 553 | return v; |
| 554 | } |
Tejun Heo | b50da39 | 2013-01-09 08:05:12 -0800 | [diff] [blame^] | 555 | EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 556 | |
Tejun Heo | 5bc4afb1 | 2012-04-01 14:38:45 -0700 | [diff] [blame] | 557 | /** |
| 558 | * blkg_prfill_stat - prfill callback for blkg_stat |
| 559 | * @sf: seq_file to print to |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 560 | * @pd: policy private data of interest |
| 561 | * @off: offset to the blkg_stat in @pd |
Tejun Heo | 5bc4afb1 | 2012-04-01 14:38:45 -0700 | [diff] [blame] | 562 | * |
| 563 | * prfill callback for printing a blkg_stat. |
| 564 | */ |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 565 | u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off) |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 566 | { |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 567 | return __blkg_prfill_u64(sf, pd, blkg_stat_read((void *)pd + off)); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 568 | } |
Tejun Heo | 5bc4afb1 | 2012-04-01 14:38:45 -0700 | [diff] [blame] | 569 | EXPORT_SYMBOL_GPL(blkg_prfill_stat); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 570 | |
Tejun Heo | 5bc4afb1 | 2012-04-01 14:38:45 -0700 | [diff] [blame] | 571 | /** |
| 572 | * blkg_prfill_rwstat - prfill callback for blkg_rwstat |
| 573 | * @sf: seq_file to print to |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 574 | * @pd: policy private data of interest |
| 575 | * @off: offset to the blkg_rwstat in @pd |
Tejun Heo | 5bc4afb1 | 2012-04-01 14:38:45 -0700 | [diff] [blame] | 576 | * |
| 577 | * prfill callback for printing a blkg_rwstat. |
| 578 | */ |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 579 | u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, |
| 580 | int off) |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 581 | { |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 582 | struct blkg_rwstat rwstat = blkg_rwstat_read((void *)pd + off); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 583 | |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 584 | return __blkg_prfill_rwstat(sf, pd, &rwstat); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 585 | } |
Tejun Heo | 5bc4afb1 | 2012-04-01 14:38:45 -0700 | [diff] [blame] | 586 | EXPORT_SYMBOL_GPL(blkg_prfill_rwstat); |
Tejun Heo | d3d32e6 | 2012-04-01 14:38:42 -0700 | [diff] [blame] | 587 | |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 588 | /** |
| 589 | * blkg_conf_prep - parse and prepare for per-blkg config update |
| 590 | * @blkcg: target block cgroup |
Tejun Heo | da8b066 | 2012-04-13 13:11:29 -0700 | [diff] [blame] | 591 | * @pol: target policy |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 592 | * @input: input string |
| 593 | * @ctx: blkg_conf_ctx to be filled |
| 594 | * |
| 595 | * Parse per-blkg config update from @input and initialize @ctx with the |
| 596 | * result. @ctx->blkg points to the blkg to be updated and @ctx->v the new |
Tejun Heo | da8b066 | 2012-04-13 13:11:29 -0700 | [diff] [blame] | 597 | * value. This function returns with RCU read lock and queue lock held and |
| 598 | * must be paired with blkg_conf_finish(). |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 599 | */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 600 | int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, |
| 601 | const char *input, struct blkg_conf_ctx *ctx) |
Tejun Heo | da8b066 | 2012-04-13 13:11:29 -0700 | [diff] [blame] | 602 | __acquires(rcu) __acquires(disk->queue->queue_lock) |
Gui Jianfeng | 34d0f17 | 2010-04-13 16:05:49 +0800 | [diff] [blame] | 603 | { |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 604 | struct gendisk *disk; |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 605 | struct blkcg_gq *blkg; |
Tejun Heo | 726fa69 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 606 | unsigned int major, minor; |
| 607 | unsigned long long v; |
| 608 | int part, ret; |
Gui Jianfeng | 34d0f17 | 2010-04-13 16:05:49 +0800 | [diff] [blame] | 609 | |
Tejun Heo | 726fa69 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 610 | if (sscanf(input, "%u:%u %llu", &major, &minor, &v) != 3) |
| 611 | return -EINVAL; |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 612 | |
Tejun Heo | 726fa69 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 613 | disk = get_gendisk(MKDEV(major, minor), &part); |
Tejun Heo | 4bfd482 | 2012-03-05 13:15:08 -0800 | [diff] [blame] | 614 | if (!disk || part) |
Tejun Heo | 726fa69 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 615 | return -EINVAL; |
Tejun Heo | e56da7e | 2012-03-05 13:15:07 -0800 | [diff] [blame] | 616 | |
| 617 | rcu_read_lock(); |
Tejun Heo | 4bfd482 | 2012-03-05 13:15:08 -0800 | [diff] [blame] | 618 | spin_lock_irq(disk->queue->queue_lock); |
Tejun Heo | da8b066 | 2012-04-13 13:11:29 -0700 | [diff] [blame] | 619 | |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 620 | if (blkcg_policy_enabled(disk->queue, pol)) |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 621 | blkg = blkg_lookup_create(blkcg, disk->queue); |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 622 | else |
| 623 | blkg = ERR_PTR(-EINVAL); |
Tejun Heo | e56da7e | 2012-03-05 13:15:07 -0800 | [diff] [blame] | 624 | |
Tejun Heo | 4bfd482 | 2012-03-05 13:15:08 -0800 | [diff] [blame] | 625 | if (IS_ERR(blkg)) { |
| 626 | ret = PTR_ERR(blkg); |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 627 | rcu_read_unlock(); |
Tejun Heo | da8b066 | 2012-04-13 13:11:29 -0700 | [diff] [blame] | 628 | spin_unlock_irq(disk->queue->queue_lock); |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 629 | put_disk(disk); |
| 630 | /* |
| 631 | * If queue was bypassing, we should retry. Do so after a |
| 632 | * short msleep(). It isn't strictly necessary but queue |
| 633 | * can be bypassing for some time and it's always nice to |
| 634 | * avoid busy looping. |
| 635 | */ |
| 636 | if (ret == -EBUSY) { |
| 637 | msleep(10); |
| 638 | ret = restart_syscall(); |
Vivek Goyal | 7702e8f | 2010-09-15 17:06:36 -0400 | [diff] [blame] | 639 | } |
Tejun Heo | 726fa69 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 640 | return ret; |
Vivek Goyal | 062a644 | 2010-09-15 17:06:33 -0400 | [diff] [blame] | 641 | } |
Tejun Heo | e56da7e | 2012-03-05 13:15:07 -0800 | [diff] [blame] | 642 | |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 643 | ctx->disk = disk; |
| 644 | ctx->blkg = blkg; |
Tejun Heo | 726fa69 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 645 | ctx->v = v; |
| 646 | return 0; |
Gui Jianfeng | 34d0f17 | 2010-04-13 16:05:49 +0800 | [diff] [blame] | 647 | } |
Tejun Heo | 829fdb5 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 648 | EXPORT_SYMBOL_GPL(blkg_conf_prep); |
Gui Jianfeng | 34d0f17 | 2010-04-13 16:05:49 +0800 | [diff] [blame] | 649 | |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 650 | /** |
| 651 | * blkg_conf_finish - finish up per-blkg config update |
| 652 | * @ctx: blkg_conf_ctx intiailized by blkg_conf_prep() |
| 653 | * |
| 654 | * Finish up after per-blkg config update. This function must be paired |
| 655 | * with blkg_conf_prep(). |
| 656 | */ |
Tejun Heo | 829fdb5 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 657 | void blkg_conf_finish(struct blkg_conf_ctx *ctx) |
Tejun Heo | da8b066 | 2012-04-13 13:11:29 -0700 | [diff] [blame] | 658 | __releases(ctx->disk->queue->queue_lock) __releases(rcu) |
Gui Jianfeng | 34d0f17 | 2010-04-13 16:05:49 +0800 | [diff] [blame] | 659 | { |
Tejun Heo | da8b066 | 2012-04-13 13:11:29 -0700 | [diff] [blame] | 660 | spin_unlock_irq(ctx->disk->queue->queue_lock); |
Tejun Heo | 3a8b31d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 661 | rcu_read_unlock(); |
| 662 | put_disk(ctx->disk); |
Gui Jianfeng | 34d0f17 | 2010-04-13 16:05:49 +0800 | [diff] [blame] | 663 | } |
Tejun Heo | 829fdb5 | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 664 | EXPORT_SYMBOL_GPL(blkg_conf_finish); |
Gui Jianfeng | 34d0f17 | 2010-04-13 16:05:49 +0800 | [diff] [blame] | 665 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 666 | struct cftype blkcg_files[] = { |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 667 | { |
Divyesh Shah | 84c124d | 2010-04-09 08:31:19 +0200 | [diff] [blame] | 668 | .name = "reset_stats", |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 669 | .write_u64 = blkcg_reset_stats, |
Vivek Goyal | 2208419 | 2009-12-03 12:59:49 -0500 | [diff] [blame] | 670 | }, |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 671 | { } /* terminate */ |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 672 | }; |
| 673 | |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 674 | /** |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 675 | * blkcg_css_offline - cgroup css_offline callback |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 676 | * @cgroup: cgroup of interest |
| 677 | * |
| 678 | * This function is called when @cgroup is about to go away and responsible |
| 679 | * for shooting down all blkgs associated with @cgroup. blkgs should be |
| 680 | * removed while holding both q and blkcg locks. As blkcg lock is nested |
| 681 | * inside q lock, this function performs reverse double lock dancing. |
| 682 | * |
| 683 | * This is the blkcg counterpart of ioc_release_fn(). |
| 684 | */ |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 685 | static void blkcg_css_offline(struct cgroup *cgroup) |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 686 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 687 | struct blkcg *blkcg = cgroup_to_blkcg(cgroup); |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 688 | |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 689 | spin_lock_irq(&blkcg->lock); |
Tejun Heo | 7ee9c56 | 2012-03-05 13:15:11 -0800 | [diff] [blame] | 690 | |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 691 | while (!hlist_empty(&blkcg->blkg_list)) { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 692 | struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first, |
| 693 | struct blkcg_gq, blkcg_node); |
Tejun Heo | c875f4d | 2012-03-05 13:15:22 -0800 | [diff] [blame] | 694 | struct request_queue *q = blkg->q; |
Vivek Goyal | b1c3576 | 2009-12-03 12:59:47 -0500 | [diff] [blame] | 695 | |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 696 | if (spin_trylock(q->queue_lock)) { |
| 697 | blkg_destroy(blkg); |
| 698 | spin_unlock(q->queue_lock); |
| 699 | } else { |
| 700 | spin_unlock_irq(&blkcg->lock); |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 701 | cpu_relax(); |
Dan Carpenter | a556793 | 2012-03-29 20:57:08 +0200 | [diff] [blame] | 702 | spin_lock_irq(&blkcg->lock); |
Jens Axboe | 0f3942a | 2010-05-03 14:28:55 +0200 | [diff] [blame] | 703 | } |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 704 | } |
Jens Axboe | 0f3942a | 2010-05-03 14:28:55 +0200 | [diff] [blame] | 705 | |
Tejun Heo | 9f13ef6 | 2012-03-05 13:15:21 -0800 | [diff] [blame] | 706 | spin_unlock_irq(&blkcg->lock); |
Tejun Heo | 7ee9c56 | 2012-03-05 13:15:11 -0800 | [diff] [blame] | 707 | } |
| 708 | |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 709 | static void blkcg_css_free(struct cgroup *cgroup) |
Tejun Heo | 7ee9c56 | 2012-03-05 13:15:11 -0800 | [diff] [blame] | 710 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 711 | struct blkcg *blkcg = cgroup_to_blkcg(cgroup); |
Tejun Heo | 7ee9c56 | 2012-03-05 13:15:11 -0800 | [diff] [blame] | 712 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 713 | if (blkcg != &blkcg_root) |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 714 | kfree(blkcg); |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 715 | } |
| 716 | |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 717 | static struct cgroup_subsys_state *blkcg_css_alloc(struct cgroup *cgroup) |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 718 | { |
Tejun Heo | 9a9e8a2 | 2012-03-19 15:10:56 -0700 | [diff] [blame] | 719 | static atomic64_t id_seq = ATOMIC64_INIT(0); |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 720 | struct blkcg *blkcg; |
Li Zefan | 0341509 | 2010-05-07 08:57:00 +0200 | [diff] [blame] | 721 | struct cgroup *parent = cgroup->parent; |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 722 | |
Li Zefan | 0341509 | 2010-05-07 08:57:00 +0200 | [diff] [blame] | 723 | if (!parent) { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 724 | blkcg = &blkcg_root; |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 725 | goto done; |
| 726 | } |
| 727 | |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 728 | blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); |
| 729 | if (!blkcg) |
| 730 | return ERR_PTR(-ENOMEM); |
| 731 | |
Tejun Heo | 3381cb8 | 2012-04-01 14:38:44 -0700 | [diff] [blame] | 732 | blkcg->cfq_weight = CFQ_WEIGHT_DEFAULT; |
Tejun Heo | e71357e | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 733 | blkcg->cfq_leaf_weight = CFQ_WEIGHT_DEFAULT; |
Tejun Heo | 9a9e8a2 | 2012-03-19 15:10:56 -0700 | [diff] [blame] | 734 | blkcg->id = atomic64_inc_return(&id_seq); /* root is 0, start from 1 */ |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 735 | done: |
| 736 | spin_lock_init(&blkcg->lock); |
Tejun Heo | a637120 | 2012-04-19 16:29:24 -0700 | [diff] [blame] | 737 | INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC); |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 738 | INIT_HLIST_HEAD(&blkcg->blkg_list); |
| 739 | |
| 740 | return &blkcg->css; |
| 741 | } |
| 742 | |
Tejun Heo | 5efd611 | 2012-03-05 13:15:12 -0800 | [diff] [blame] | 743 | /** |
| 744 | * blkcg_init_queue - initialize blkcg part of request queue |
| 745 | * @q: request_queue to initialize |
| 746 | * |
| 747 | * Called from blk_alloc_queue_node(). Responsible for initializing blkcg |
| 748 | * part of new request_queue @q. |
| 749 | * |
| 750 | * RETURNS: |
| 751 | * 0 on success, -errno on failure. |
| 752 | */ |
| 753 | int blkcg_init_queue(struct request_queue *q) |
| 754 | { |
| 755 | might_sleep(); |
| 756 | |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 757 | return blk_throtl_init(q); |
Tejun Heo | 5efd611 | 2012-03-05 13:15:12 -0800 | [diff] [blame] | 758 | } |
| 759 | |
| 760 | /** |
| 761 | * blkcg_drain_queue - drain blkcg part of request_queue |
| 762 | * @q: request_queue to drain |
| 763 | * |
| 764 | * Called from blk_drain_queue(). Responsible for draining blkcg part. |
| 765 | */ |
| 766 | void blkcg_drain_queue(struct request_queue *q) |
| 767 | { |
| 768 | lockdep_assert_held(q->queue_lock); |
| 769 | |
| 770 | blk_throtl_drain(q); |
| 771 | } |
| 772 | |
| 773 | /** |
| 774 | * blkcg_exit_queue - exit and release blkcg part of request_queue |
| 775 | * @q: request_queue being released |
| 776 | * |
| 777 | * Called from blk_release_queue(). Responsible for exiting blkcg part. |
| 778 | */ |
| 779 | void blkcg_exit_queue(struct request_queue *q) |
| 780 | { |
Tejun Heo | 6d18b00 | 2012-04-13 13:11:35 -0700 | [diff] [blame] | 781 | spin_lock_irq(q->queue_lock); |
Tejun Heo | 3c96cb3 | 2012-04-13 13:11:34 -0700 | [diff] [blame] | 782 | blkg_destroy_all(q); |
Tejun Heo | 6d18b00 | 2012-04-13 13:11:35 -0700 | [diff] [blame] | 783 | spin_unlock_irq(q->queue_lock); |
| 784 | |
Tejun Heo | 5efd611 | 2012-03-05 13:15:12 -0800 | [diff] [blame] | 785 | blk_throtl_exit(q); |
| 786 | } |
| 787 | |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 788 | /* |
| 789 | * We cannot support shared io contexts, as we have no mean to support |
| 790 | * two tasks with the same ioc in two different groups without major rework |
| 791 | * of the main cic data structures. For now we allow a task to change |
| 792 | * its cgroup only if it's the only owner of its ioc. |
| 793 | */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 794 | static int blkcg_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 795 | { |
Tejun Heo | bb9d97b | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 796 | struct task_struct *task; |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 797 | struct io_context *ioc; |
| 798 | int ret = 0; |
| 799 | |
| 800 | /* task_lock() is needed to avoid races with exit_io_context() */ |
Tejun Heo | bb9d97b | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 801 | cgroup_taskset_for_each(task, cgrp, tset) { |
| 802 | task_lock(task); |
| 803 | ioc = task->io_context; |
| 804 | if (ioc && atomic_read(&ioc->nr_tasks) > 1) |
| 805 | ret = -EINVAL; |
| 806 | task_unlock(task); |
| 807 | if (ret) |
| 808 | break; |
| 809 | } |
Vivek Goyal | 31e4c28 | 2009-12-03 12:59:42 -0500 | [diff] [blame] | 810 | return ret; |
| 811 | } |
| 812 | |
Tejun Heo | 676f7c8 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 813 | struct cgroup_subsys blkio_subsys = { |
| 814 | .name = "blkio", |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 815 | .css_alloc = blkcg_css_alloc, |
| 816 | .css_offline = blkcg_css_offline, |
| 817 | .css_free = blkcg_css_free, |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 818 | .can_attach = blkcg_can_attach, |
Tejun Heo | 676f7c8 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 819 | .subsys_id = blkio_subsys_id, |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 820 | .base_cftypes = blkcg_files, |
Tejun Heo | 676f7c8 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 821 | .module = THIS_MODULE, |
Tejun Heo | 8c7f6ed | 2012-09-13 12:20:58 -0700 | [diff] [blame] | 822 | |
| 823 | /* |
| 824 | * blkio subsystem is utterly broken in terms of hierarchy support. |
| 825 | * It treats all cgroups equally regardless of where they're |
| 826 | * located in the hierarchy - all cgroups are treated as if they're |
| 827 | * right below the root. Fix it and remove the following. |
| 828 | */ |
| 829 | .broken_hierarchy = true, |
Tejun Heo | 676f7c8 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 830 | }; |
| 831 | EXPORT_SYMBOL_GPL(blkio_subsys); |
| 832 | |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 833 | /** |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 834 | * blkcg_activate_policy - activate a blkcg policy on a request_queue |
| 835 | * @q: request_queue of interest |
| 836 | * @pol: blkcg policy to activate |
| 837 | * |
| 838 | * Activate @pol on @q. Requires %GFP_KERNEL context. @q goes through |
| 839 | * bypass mode to populate its blkgs with policy_data for @pol. |
| 840 | * |
| 841 | * Activation happens with @q bypassed, so nobody would be accessing blkgs |
| 842 | * from IO path. Update of each blkg is protected by both queue and blkcg |
| 843 | * locks so that holding either lock and testing blkcg_policy_enabled() is |
| 844 | * always enough for dereferencing policy data. |
| 845 | * |
| 846 | * The caller is responsible for synchronizing [de]activations and policy |
| 847 | * [un]registerations. Returns 0 on success, -errno on failure. |
| 848 | */ |
| 849 | int blkcg_activate_policy(struct request_queue *q, |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 850 | const struct blkcg_policy *pol) |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 851 | { |
| 852 | LIST_HEAD(pds); |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 853 | struct blkcg_gq *blkg, *new_blkg; |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 854 | struct blkg_policy_data *pd, *n; |
| 855 | int cnt = 0, ret; |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 856 | bool preloaded; |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 857 | |
| 858 | if (blkcg_policy_enabled(q, pol)) |
| 859 | return 0; |
| 860 | |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 861 | /* preallocations for root blkg */ |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 862 | new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL); |
| 863 | if (!new_blkg) |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 864 | return -ENOMEM; |
| 865 | |
| 866 | preloaded = !radix_tree_preload(GFP_KERNEL); |
| 867 | |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 868 | blk_queue_bypass_start(q); |
| 869 | |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 870 | /* |
| 871 | * Make sure the root blkg exists and count the existing blkgs. As |
| 872 | * @q is bypassing at this point, blkg_lookup_create() can't be |
| 873 | * used. Open code it. |
| 874 | */ |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 875 | spin_lock_irq(q->queue_lock); |
| 876 | |
| 877 | rcu_read_lock(); |
Tejun Heo | 86cde6b | 2013-01-09 08:05:10 -0800 | [diff] [blame] | 878 | blkg = __blkg_lookup(&blkcg_root, q, false); |
| 879 | if (blkg) |
| 880 | blkg_free(new_blkg); |
| 881 | else |
| 882 | blkg = blkg_create(&blkcg_root, q, new_blkg); |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 883 | rcu_read_unlock(); |
| 884 | |
Tejun Heo | 1597499 | 2012-06-04 20:40:52 -0700 | [diff] [blame] | 885 | if (preloaded) |
| 886 | radix_tree_preload_end(); |
| 887 | |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 888 | if (IS_ERR(blkg)) { |
| 889 | ret = PTR_ERR(blkg); |
| 890 | goto out_unlock; |
| 891 | } |
| 892 | q->root_blkg = blkg; |
Tejun Heo | a051661 | 2012-06-26 15:05:44 -0700 | [diff] [blame] | 893 | q->root_rl.blkg = blkg; |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 894 | |
| 895 | list_for_each_entry(blkg, &q->blkg_list, q_node) |
| 896 | cnt++; |
| 897 | |
| 898 | spin_unlock_irq(q->queue_lock); |
| 899 | |
| 900 | /* allocate policy_data for all existing blkgs */ |
| 901 | while (cnt--) { |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 902 | pd = kzalloc_node(pol->pd_size, GFP_KERNEL, q->node); |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 903 | if (!pd) { |
| 904 | ret = -ENOMEM; |
| 905 | goto out_free; |
| 906 | } |
| 907 | list_add_tail(&pd->alloc_node, &pds); |
| 908 | } |
| 909 | |
| 910 | /* |
| 911 | * Install the allocated pds. With @q bypassing, no new blkg |
| 912 | * should have been created while the queue lock was dropped. |
| 913 | */ |
| 914 | spin_lock_irq(q->queue_lock); |
| 915 | |
| 916 | list_for_each_entry(blkg, &q->blkg_list, q_node) { |
| 917 | if (WARN_ON(list_empty(&pds))) { |
| 918 | /* umm... this shouldn't happen, just abort */ |
| 919 | ret = -ENOMEM; |
| 920 | goto out_unlock; |
| 921 | } |
| 922 | pd = list_first_entry(&pds, struct blkg_policy_data, alloc_node); |
| 923 | list_del_init(&pd->alloc_node); |
| 924 | |
| 925 | /* grab blkcg lock too while installing @pd on @blkg */ |
| 926 | spin_lock(&blkg->blkcg->lock); |
| 927 | |
| 928 | blkg->pd[pol->plid] = pd; |
| 929 | pd->blkg = blkg; |
Tejun Heo | b276a87 | 2013-01-09 08:05:12 -0800 | [diff] [blame] | 930 | pd->plid = pol->plid; |
Tejun Heo | f9fcc2d | 2012-04-16 13:57:27 -0700 | [diff] [blame] | 931 | pol->pd_init_fn(blkg); |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 932 | |
| 933 | spin_unlock(&blkg->blkcg->lock); |
| 934 | } |
| 935 | |
| 936 | __set_bit(pol->plid, q->blkcg_pols); |
| 937 | ret = 0; |
| 938 | out_unlock: |
| 939 | spin_unlock_irq(q->queue_lock); |
| 940 | out_free: |
| 941 | blk_queue_bypass_end(q); |
| 942 | list_for_each_entry_safe(pd, n, &pds, alloc_node) |
| 943 | kfree(pd); |
| 944 | return ret; |
| 945 | } |
| 946 | EXPORT_SYMBOL_GPL(blkcg_activate_policy); |
| 947 | |
| 948 | /** |
| 949 | * blkcg_deactivate_policy - deactivate a blkcg policy on a request_queue |
| 950 | * @q: request_queue of interest |
| 951 | * @pol: blkcg policy to deactivate |
| 952 | * |
| 953 | * Deactivate @pol on @q. Follows the same synchronization rules as |
| 954 | * blkcg_activate_policy(). |
| 955 | */ |
| 956 | void blkcg_deactivate_policy(struct request_queue *q, |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 957 | const struct blkcg_policy *pol) |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 958 | { |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 959 | struct blkcg_gq *blkg; |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 960 | |
| 961 | if (!blkcg_policy_enabled(q, pol)) |
| 962 | return; |
| 963 | |
| 964 | blk_queue_bypass_start(q); |
| 965 | spin_lock_irq(q->queue_lock); |
| 966 | |
| 967 | __clear_bit(pol->plid, q->blkcg_pols); |
| 968 | |
Tejun Heo | 6d18b00 | 2012-04-13 13:11:35 -0700 | [diff] [blame] | 969 | /* if no policy is left, no need for blkgs - shoot them down */ |
| 970 | if (bitmap_empty(q->blkcg_pols, BLKCG_MAX_POLS)) |
| 971 | blkg_destroy_all(q); |
| 972 | |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 973 | list_for_each_entry(blkg, &q->blkg_list, q_node) { |
| 974 | /* grab blkcg lock too while removing @pd from @blkg */ |
| 975 | spin_lock(&blkg->blkcg->lock); |
| 976 | |
Tejun Heo | f427d90 | 2013-01-09 08:05:12 -0800 | [diff] [blame] | 977 | if (pol->pd_offline_fn) |
| 978 | pol->pd_offline_fn(blkg); |
Tejun Heo | f9fcc2d | 2012-04-16 13:57:27 -0700 | [diff] [blame] | 979 | if (pol->pd_exit_fn) |
| 980 | pol->pd_exit_fn(blkg); |
Tejun Heo | a2b1693 | 2012-04-13 13:11:33 -0700 | [diff] [blame] | 981 | |
| 982 | kfree(blkg->pd[pol->plid]); |
| 983 | blkg->pd[pol->plid] = NULL; |
| 984 | |
| 985 | spin_unlock(&blkg->blkcg->lock); |
| 986 | } |
| 987 | |
| 988 | spin_unlock_irq(q->queue_lock); |
| 989 | blk_queue_bypass_end(q); |
| 990 | } |
| 991 | EXPORT_SYMBOL_GPL(blkcg_deactivate_policy); |
| 992 | |
| 993 | /** |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 994 | * blkcg_policy_register - register a blkcg policy |
| 995 | * @pol: blkcg policy to register |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 996 | * |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 997 | * Register @pol with blkcg core. Might sleep and @pol may be modified on |
| 998 | * successful registration. Returns 0 on success and -errno on failure. |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 999 | */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1000 | int blkcg_policy_register(struct blkcg_policy *pol) |
Vivek Goyal | 3e25206 | 2009-12-04 10:36:42 -0500 | [diff] [blame] | 1001 | { |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1002 | int i, ret; |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 1003 | |
Tejun Heo | f95a04a | 2012-04-16 13:57:26 -0700 | [diff] [blame] | 1004 | if (WARN_ON(pol->pd_size < sizeof(struct blkg_policy_data))) |
| 1005 | return -EINVAL; |
| 1006 | |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 1007 | mutex_lock(&blkcg_pol_mutex); |
| 1008 | |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1009 | /* find an empty slot */ |
| 1010 | ret = -ENOSPC; |
| 1011 | for (i = 0; i < BLKCG_MAX_POLS; i++) |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1012 | if (!blkcg_policy[i]) |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1013 | break; |
| 1014 | if (i >= BLKCG_MAX_POLS) |
| 1015 | goto out_unlock; |
Tejun Heo | 035d10b | 2012-03-05 13:15:04 -0800 | [diff] [blame] | 1016 | |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1017 | /* register and update blkgs */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1018 | pol->plid = i; |
| 1019 | blkcg_policy[i] = pol; |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1020 | |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1021 | /* everything is in place, add intf files for the new policy */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1022 | if (pol->cftypes) |
| 1023 | WARN_ON(cgroup_add_cftypes(&blkio_subsys, pol->cftypes)); |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1024 | ret = 0; |
| 1025 | out_unlock: |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 1026 | mutex_unlock(&blkcg_pol_mutex); |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1027 | return ret; |
Vivek Goyal | 3e25206 | 2009-12-04 10:36:42 -0500 | [diff] [blame] | 1028 | } |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1029 | EXPORT_SYMBOL_GPL(blkcg_policy_register); |
Vivek Goyal | 3e25206 | 2009-12-04 10:36:42 -0500 | [diff] [blame] | 1030 | |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1031 | /** |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1032 | * blkcg_policy_unregister - unregister a blkcg policy |
| 1033 | * @pol: blkcg policy to unregister |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1034 | * |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1035 | * Undo blkcg_policy_register(@pol). Might sleep. |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1036 | */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1037 | void blkcg_policy_unregister(struct blkcg_policy *pol) |
Vivek Goyal | 3e25206 | 2009-12-04 10:36:42 -0500 | [diff] [blame] | 1038 | { |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 1039 | mutex_lock(&blkcg_pol_mutex); |
| 1040 | |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1041 | if (WARN_ON(blkcg_policy[pol->plid] != pol)) |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1042 | goto out_unlock; |
| 1043 | |
| 1044 | /* kill the intf files first */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1045 | if (pol->cftypes) |
| 1046 | cgroup_rm_cftypes(&blkio_subsys, pol->cftypes); |
Tejun Heo | 44ea53d | 2012-04-01 14:38:43 -0700 | [diff] [blame] | 1047 | |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1048 | /* unregister and update blkgs */ |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1049 | blkcg_policy[pol->plid] = NULL; |
Tejun Heo | 8bd435b | 2012-04-13 13:11:28 -0700 | [diff] [blame] | 1050 | out_unlock: |
Tejun Heo | bc0d650 | 2012-04-13 13:11:26 -0700 | [diff] [blame] | 1051 | mutex_unlock(&blkcg_pol_mutex); |
Vivek Goyal | 3e25206 | 2009-12-04 10:36:42 -0500 | [diff] [blame] | 1052 | } |
Tejun Heo | 3c79839 | 2012-04-16 13:57:25 -0700 | [diff] [blame] | 1053 | EXPORT_SYMBOL_GPL(blkcg_policy_unregister); |