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