| 1 | |
| 2 | * kernel/cpuset.c
|
| 3 | *
|
| 4 | * Processor and Memory placement constraints for sets of tasks.
|
| 5 | *
|
| 6 | * Copyright (C) 2003 BULL SA.
|
| 7 | * Copyright (C) 2004-2006 Silicon Graphics, Inc.
|
| 8 | *
|
| 9 | * Portions derived from Patrick Mochel's sysfs code.
|
| 10 | * sysfs is Copyright (c) 2001-3 Patrick Mochel
|
| 11 | *
|
| 12 | * 2003-10-10 Written by Simon Derr.
|
| 13 | * 2003-10-22 Updates by Stephen Hemminger.
|
| 14 | * 2004 May-July Rework by Paul Jackson.
|
| 15 | *
|
| 16 | * This file is subject to the terms and conditions of the GNU General Public
|
| 17 | * License. See the file COPYING in the main directory of the Linux
|
| 18 | * distribution for more details.
|
| 19 |
|
| 20 |
|
| 21 | #include <linux/cpu.h>
|
| 22 | #include <linux/cpumask.h>
|
| 23 | #include <linux/cpuset.h>
|
| 24 | #include <linux/err.h>
|
| 25 | #include <linux/errno.h>
|
| 26 | #include <linux/file.h>
|
| 27 | #include <linux/fs.h>
|
| 28 | #include <linux/init.h>
|
| 29 | #include <linux/interrupt.h>
|
| 30 | #include <linux/kernel.h>
|
| 31 | #include <linux/kmod.h>
|
| 32 | #include <linux/list.h>
|
| 33 | #include <linux/mempolicy.h>
|
| 34 | #include <linux/mm.h>
|
| 35 | #include <linux/module.h>
|
| 36 | #include <linux/mount.h>
|
| 37 | #include <linux/namei.h>
|
| 38 | #include <linux/pagemap.h>
|
| 39 | #include <linux/proc_fs.h>
|
| 40 | #include <linux/rcupdate.h>
|
| 41 | #include <linux/sched.h>
|
| 42 | #include <linux/seq_file.h>
|
| 43 | #include <linux/security.h>
|
| 44 | #include <linux/slab.h>
|
| 45 | #include <linux/smp_lock.h>
|
| 46 | #include <linux/spinlock.h>
|
| 47 | #include <linux/stat.h>
|
| 48 | #include <linux/string.h>
|
| 49 | #include <linux/time.h>
|
| 50 | #include <linux/backing-dev.h>
|
| 51 | #include <linux/sort.h>
|
| 52 |
|
| 53 | #include <asm/uaccess.h>
|
| 54 | #include <asm/atomic.h>
|
| 55 | #include <linux/mutex.h>
|
| 56 |
|
| 57 | #define CPUSET_SUPER_MAGIC 0x27e0eb
|
| 58 |
|
| 59 | |
| 60 | * Tracks how many cpusets are currently defined in system.
|
| 61 | * When there is only one cpuset (the root cpuset) we can
|
| 62 | * short circuit some hooks.
|
| 63 |
|
| 64 | int number_of_cpusets __read_mostly;
|
| 65 |
|
| 66 |
|
| 67 |
|
| 68 | struct fmeter {
|
| 69 | int cnt;
|
| 70 | int val;
|
| 71 | time_t time;
|
| 72 | spinlock_t lock;
|
| 73 | };
|
| 74 |
|
| 75 | struct cpuset {
|
| 76 | unsigned long flags;
|
| 77 | cpumask_t cpus_allowed;
|
| 78 | nodemask_t mems_allowed;
|
| 79 |
|
| 80 | |
| 81 | * Count is atomic so can incr (fork) or decr (exit) without a lock.
|
| 82 |
|
| 83 | atomic_t count;
|
| 84 |
|
| 85 | |
| 86 | * We link our 'sibling' struct into our parents 'children'.
|
| 87 | * Our children link their 'sibling' into our 'children'.
|
| 88 |
|
| 89 | struct list_head sibling;
|
| 90 | struct list_head children;
|
| 91 |
|
| 92 | struct cpuset *parent;
|
| 93 | struct dentry *dentry;
|
| 94 |
|
| 95 | |
| 96 | * Copy of global cpuset_mems_generation as of the most
|
| 97 | * recent time this cpuset changed its mems_allowed.
|
| 98 |
|
| 99 | int mems_generation;
|
| 100 |
|
| 101 | struct fmeter fmeter;
|
| 102 | };
|
| 103 |
|
| 104 |
|
| 105 | typedef enum {
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| 106 | CS_CPU_EXCLUSIVE,
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| 107 | CS_MEM_EXCLUSIVE,
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| 108 | CS_MEMORY_MIGRATE,
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| 109 | CS_REMOVED,
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| 110 | CS_NOTIFY_ON_RELEASE,
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| 111 | CS_SPREAD_PAGE,
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| 112 | CS_SPREAD_SLAB,
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| 113 | } cpuset_flagbits_t;
|
| 114 |
|
| 115 |
|
| 116 | static inline int is_cpu_exclusive(const struct cpuset *cs)
|
| 117 | {
|
| 118 | return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
|
| 119 | }
|
| 120 |
|
| 121 | static inline int is_mem_exclusive(const struct cpuset *cs)
|
| 122 | {
|
| 123 | return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
|
| 124 | }
|
| 125 |
|
| 126 | static inline int is_removed(const struct cpuset *cs)
|
| 127 | {
|
| 128 | return test_bit(CS_REMOVED, &cs->flags);
|
| 129 | }
|
| 130 |
|
| 131 | static inline int notify_on_release(const struct cpuset *cs)
|
| 132 | {
|
| 133 | return test_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
|
| 134 | }
|
| 135 |
|
| 136 | static inline int is_memory_migrate(const struct cpuset *cs)
|
| 137 | {
|
| 138 | return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
|
| 139 | }
|
| 140 |
|
| 141 | static inline int is_spread_page(const struct cpuset *cs)
|
| 142 | {
|
| 143 | return test_bit(CS_SPREAD_PAGE, &cs->flags);
|
| 144 | }
|
| 145 |
|
| 146 | static inline int is_spread_slab(const struct cpuset *cs)
|
| 147 | {
|
| 148 | return test_bit(CS_SPREAD_SLAB, &cs->flags);
|
| 149 | }
|
| 150 |
|
| 151 | |
| 152 | * Increment this integer everytime any cpuset changes its
|
| 153 | * mems_allowed value. Users of cpusets can track this generation
|
| 154 | * number, and avoid having to lock and reload mems_allowed unless
|
| 155 | * the cpuset they're using changes generation.
|
| 156 | *
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| 157 | * A single, global generation is needed because attach_task() could
|
| 158 | * reattach a task to a different cpuset, which must not have its
|
| 159 | * generation numbers aliased with those of that tasks previous cpuset.
|
| 160 | *
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| 161 | * Generations are needed for mems_allowed because one task cannot
|
| 162 | * modify anothers memory placement. So we must enable every task,
|
| 163 | * on every visit to __alloc_pages(), to efficiently check whether
|
| 164 | * its current->cpuset->mems_allowed has changed, requiring an update
|
| 165 | * of its current->mems_allowed.
|
| 166 | *
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| 167 | * Since cpuset_mems_generation is guarded by manage_mutex,
|
| 168 | * there is no need to mark it atomic.
|
| 169 |
|
| 170 | static int cpuset_mems_generation;
|
| 171 |
|
| 172 | static struct cpuset top_cpuset = {
|
| 173 | .flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
|
| 174 | .cpus_allowed = CPU_MASK_ALL,
|
| 175 | .mems_allowed = NODE_MASK_ALL,
|
| 176 | .count = ATOMIC_INIT(0),
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| 177 | .sibling = LIST_HEAD_INIT(top_cpuset.sibling),
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| 178 | .children = LIST_HEAD_INIT(top_cpuset.children),
|
| 179 | };
|
| 180 |
|
| 181 | static struct vfsmount *cpuset_mount;
|
| 182 | static struct super_block *cpuset_sb;
|
| 183 |
|
| 184 | |
| 185 | * We have two global cpuset mutexes below. They can nest.
|
| 186 | * It is ok to first take manage_mutex, then nest callback_mutex. We also
|
| 187 | * require taking task_lock() when dereferencing a tasks cpuset pointer.
|
| 188 | * See "The task_lock() exception", at the end of this comment.
|
| 189 | *
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| 190 | * A task must hold both mutexes to modify cpusets. If a task
|
| 191 | * holds manage_mutex, then it blocks others wanting that mutex,
|
| 192 | * ensuring that it is the only task able to also acquire callback_mutex
|
| 193 | * and be able to modify cpusets. It can perform various checks on
|
| 194 | * the cpuset structure first, knowing nothing will change. It can
|
| 195 | * also allocate memory while just holding manage_mutex. While it is
|
| 196 | * performing these checks, various callback routines can briefly
|
| 197 | * acquire callback_mutex to query cpusets. Once it is ready to make
|
| 198 | * the changes, it takes callback_mutex, blocking everyone else.
|
| 199 | *
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| 200 | * Calls to the kernel memory allocator can not be made while holding
|
| 201 | * callback_mutex, as that would risk double tripping on callback_mutex
|
| 202 | * from one of the callbacks into the cpuset code from within
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| 203 | * __alloc_pages().
|
| 204 | *
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| 205 | * If a task is only holding callback_mutex, then it has read-only
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| 206 | * access to cpusets.
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| 207 | *
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| 208 | * The task_struct fields mems_allowed and mems_generation may only
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| 209 | * be accessed in the context of that task, so require no locks.
|
| 210 | *
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| 211 | * Any task can increment and decrement the count field without lock.
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| 212 | * So in general, code holding manage_mutex or callback_mutex can't rely
|
| 213 | * on the count field not changing. However, if the count goes to
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| 214 | * zero, then only attach_task(), which holds both mutexes, can
|
| 215 | * increment it again. Because a count of zero means that no tasks
|
| 216 | * are currently attached, therefore there is no way a task attached
|
| 217 | * to that cpuset can fork (the other way to increment the count).
|
| 218 | * So code holding manage_mutex or callback_mutex can safely assume that
|
| 219 | * if the count is zero, it will stay zero. Similarly, if a task
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| 220 | * holds manage_mutex or callback_mutex on a cpuset with zero count, it
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| 221 | * knows that the cpuset won't be removed, as cpuset_rmdir() needs
|
| 222 | * both of those mutexes.
|
| 223 | *
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| 224 | * The cpuset_common_file_write handler for operations that modify
|
| 225 | * the cpuset hierarchy holds manage_mutex across the entire operation,
|
| 226 | * single threading all such cpuset modifications across the system.
|
| 227 | *
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| 228 | * The cpuset_common_file_read() handlers only hold callback_mutex across
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| 229 | * small pieces of code, such as when reading out possibly multi-word
|
| 230 | * cpumasks and nodemasks.
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| 231 | *
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| 232 | * The fork and exit callbacks cpuset_fork() and cpuset_exit(), don't
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| 233 | * (usually) take either mutex. These are the two most performance
|
| 234 | * critical pieces of code here. The exception occurs on cpuset_exit(),
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| 235 | * when a task in a notify_on_release cpuset exits. Then manage_mutex
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| 236 | * is taken, and if the cpuset count is zero, a usermode call made
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| 237 | * to /sbin/cpuset_release_agent with the name of the cpuset (path
|
| 238 | * relative to the root of cpuset file system) as the argument.
|
| 239 | *
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| 240 | * A cpuset can only be deleted if both its 'count' of using tasks
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| 241 | * is zero, and its list of 'children' cpusets is empty. Since all
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| 242 | * tasks in the system use _some_ cpuset, and since there is always at
|
| 243 | * least one task in the system (init), therefore, top_cpuset
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| 244 | * always has either children cpusets and/or using tasks. So we don't
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| 245 | * need a special hack to ensure that top_cpuset cannot be deleted.
|
| 246 | *
|
| 247 | * The above "Tale of Two Semaphores" would be complete, but for:
|
| 248 | *
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| 249 | * The task_lock() exception
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| 250 | *
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| 251 | * The need for this exception arises from the action of attach_task(),
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| 252 | * which overwrites one tasks cpuset pointer with another. It does
|
| 253 | * so using both mutexes, however there are several performance
|
| 254 | * critical places that need to reference task->cpuset without the
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| 255 | * expense of grabbing a system global mutex. Therefore except as
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| 256 | * noted below, when dereferencing or, as in attach_task(), modifying
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| 257 | * a tasks cpuset pointer we use task_lock(), which acts on a spinlock
|
| 258 | * (task->alloc_lock) already in the task_struct routinely used for
|
| 259 | * such matters.
|
| 260 | *
|
| 261 | * P.S. One more locking exception. RCU is used to guard the
|
| 262 | * update of a tasks cpuset pointer by attach_task() and the
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| 263 | * access of task->cpuset->mems_generation via that pointer in
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| 264 | * the routine cpuset_update_task_memory_state().
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| 265 |
|
| 266 |
|
| 267 | static DEFINE_MUTEX(manage_mutex);
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| 268 | static DEFINE_MUTEX(callback_mutex);
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| 269 |
|
| 270 | |
| 271 | * A couple of forward declarations required, due to cyclic reference loop:
|
| 272 | * cpuset_mkdir -> cpuset_create -> cpuset_populate_dir -> cpuset_add_file
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| 273 | * -> cpuset_create_file -> cpuset_dir_inode_operations -> cpuset_mkdir.
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| 274 |
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| 275 |
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| 276 | static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode);
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| 277 | static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry);
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| 278 |
|
| 279 | static struct backing_dev_info cpuset_backing_dev_info = {
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| 280 | .ra_pages = 0,
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| 281 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
|
| 282 | };
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| 283 |
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| 284 | static struct inode *cpuset_new_inode(mode_t mode)
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| 285 | {
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| 286 | struct inode *inode = new_inode(cpuset_sb);
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| 287 |
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| 288 | if (inode) {
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| 289 | inode->i_mode = mode;
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| 290 | inode->i_uid = current->fsuid;
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| 291 | inode->i_gid = current->fsgid;
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| 292 | inode->i_blocks = 0;
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| 293 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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| 294 | inode->i_mapping->backing_dev_info = &cpuset_backing_dev_info;
|
| 295 | }
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| 296 | return inode;
|
| 297 | }
|
| 298 |
|
| 299 | static void cpuset_diput(struct dentry *dentry, struct inode *inode)
|
| 300 | {
|
| 301 |
|
| 302 | if (S_ISDIR(inode->i_mode)) {
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| 303 | struct cpuset *cs = dentry->d_fsdata;
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| 304 | BUG_ON(!(is_removed(cs)));
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| 305 | kfree(cs);
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| 306 | }
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| 307 | iput(inode);
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| 308 | }
|
| 309 |
|
| 310 | static struct dentry_operations cpuset_dops = {
|
| 311 | .d_iput = cpuset_diput,
|
| 312 | };
|
| 313 |
|
| 314 | static struct dentry *cpuset_get_dentry(struct dentry *parent, const char *name)
|
| 315 | {
|
| 316 | struct dentry *d = lookup_one_len(name, parent, strlen(name));
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| 317 | if (!IS_ERR(d))
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| 318 | d->d_op = &cpuset_dops;
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| 319 | return d;
|
| 320 | }
|
| 321 |
|
| 322 | static void remove_dir(struct dentry *d)
|
| 323 | {
|
| 324 | struct dentry *parent = dget(d->d_parent);
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| 325 |
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| 326 | d_delete(d);
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| 327 | simple_rmdir(parent->d_inode, d);
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| 328 | dput(parent);
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| 329 | }
|
| 330 |
|
| 331 | |
| 332 | * NOTE : the dentry must have been dget()'ed
|
| 333 |
|
| 334 | static void cpuset_d_remove_dir(struct dentry *dentry)
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| 335 | {
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| 336 | struct list_head *node;
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| 337 |
|
| 338 | spin_lock(&dcache_lock);
|
| 339 | node = dentry->d_subdirs.next;
|
| 340 | while (node != &dentry->d_subdirs) {
|
| 341 | struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
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| 342 | list_del_init(node);
|
| 343 | if (d->d_inode) {
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| 344 | d = dget_locked(d);
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| 345 | spin_unlock(&dcache_lock);
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| 346 | d_delete(d);
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| 347 | simple_unlink(dentry->d_inode, d);
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| 348 | dput(d);
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| 349 | spin_lock(&dcache_lock);
|
| 350 | }
|
| 351 | node = dentry->d_subdirs.next;
|
| 352 | }
|
| 353 | list_del_init(&dentry->d_u.d_child);
|
| 354 | spin_unlock(&dcache_lock);
|
| 355 | remove_dir(dentry);
|
| 356 | }
|
| 357 |
|
| 358 | static struct super_operations cpuset_ops = {
|
| 359 | .statfs = simple_statfs,
|
| 360 | .drop_inode = generic_delete_inode,
|
| 361 | };
|
| 362 |
|
| 363 | static int cpuset_fill_super(struct super_block *sb, void *unused_data,
|
| 364 | int unused_silent)
|
| 365 | {
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| 366 | struct inode *inode;
|
| 367 | struct dentry *root;
|
| 368 |
|
| 369 | sb->s_blocksize = PAGE_CACHE_SIZE;
|
| 370 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
|
| 371 | sb->s_magic = CPUSET_SUPER_MAGIC;
|
| 372 | sb->s_op = &cpuset_ops;
|
| 373 | cpuset_sb = sb;
|
| 374 |
|
| 375 | inode = cpuset_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR);
|
| 376 | if (inode) {
|
| 377 | inode->i_op = &simple_dir_inode_operations;
|
| 378 | inode->i_fop = &simple_dir_operations;
|
| 379 |
|
| 380 | inc_nlink(inode);
|
| 381 | } else {
|
| 382 | return -ENOMEM;
|
| 383 | }
|
| 384 |
|
| 385 | root = d_alloc_root(inode);
|
| 386 | if (!root) {
|
| 387 | iput(inode);
|
| 388 | return -ENOMEM;
|
| 389 | }
|
| 390 | sb->s_root = root;
|
| 391 | return 0;
|
| 392 | }
|
| 393 |
|
| 394 | static int cpuset_get_sb(struct file_system_type *fs_type,
|
| 395 | int flags, const char *unused_dev_name,
|
| 396 | void *data, struct vfsmount *mnt)
|
| 397 | {
|
| 398 | return get_sb_single(fs_type, flags, data, cpuset_fill_super, mnt);
|
| 399 | }
|
| 400 |
|
| 401 | static struct file_system_type cpuset_fs_type = {
|
| 402 | .name = "cpuset",
|
| 403 | .get_sb = cpuset_get_sb,
|
| 404 | .kill_sb = kill_litter_super,
|
| 405 | };
|
| 406 |
|
| 407 | |
| 408 | *
|
| 409 | * The files in the cpuset filesystem mostly have a very simple read/write
|
| 410 | * handling, some common function will take care of it. Nevertheless some cases
|
| 411 | * (read tasks) are special and therefore I define this structure for every
|
| 412 | * kind of file.
|
| 413 | *
|
| 414 | *
|
| 415 | * When reading/writing to a file:
|
| 416 | * - the cpuset to use in file->f_path.dentry->d_parent->d_fsdata
|
| 417 | * - the 'cftype' of the file is file->f_path.dentry->d_fsdata
|
| 418 |
|
| 419 |
|
| 420 | struct cftype {
|
| 421 | char *name;
|
| 422 | int private;
|
| 423 | int (*open) (struct inode *inode, struct file *file);
|
| 424 | ssize_t (*read) (struct file *file, char __user *buf, size_t nbytes,
|
| 425 | loff_t *ppos);
|
| 426 | int (*write) (struct file *file, const char __user *buf, size_t nbytes,
|
| 427 | loff_t *ppos);
|
| 428 | int (*release) (struct inode *inode, struct file *file);
|
| 429 | };
|
| 430 |
|
| 431 | static inline struct cpuset *__d_cs(struct dentry *dentry)
|
| 432 | {
|
| 433 | return dentry->d_fsdata;
|
| 434 | }
|
| 435 |
|
| 436 | static inline struct cftype *__d_cft(struct dentry *dentry)
|
| 437 | {
|
| 438 | return dentry->d_fsdata;
|
| 439 | }
|
| 440 |
|
| 441 | |
| 442 | * Call with manage_mutex held. Writes path of cpuset into buf.
|
| 443 | * Returns 0 on success, -errno on error.
|
| 444 |
|
| 445 |
|
| 446 | static int cpuset_path(const struct cpuset *cs, char *buf, int buflen)
|
| 447 | {
|
| 448 | char *start;
|
| 449 |
|
| 450 | start = buf + buflen;
|
| 451 |
|
| 452 | *--start = '\0';
|
| 453 | for (;;) {
|
| 454 | int len = cs->dentry->d_name.len;
|
| 455 | if ((start -= len) < buf)
|
| 456 | return -ENAMETOOLONG;
|
| 457 | memcpy(start, cs->dentry->d_name.name, len);
|
| 458 | cs = cs->parent;
|
| 459 | if (!cs)
|
| 460 | break;
|
| 461 | if (!cs->parent)
|
| 462 | continue;
|
| 463 | if (--start < buf)
|
| 464 | return -ENAMETOOLONG;
|
| 465 | *start = '/';
|
| 466 | }
|
| 467 | memmove(buf, start, buf + buflen - start);
|
| 468 | return 0;
|
| 469 | }
|
| 470 |
|
| 471 | |
| 472 | * Notify userspace when a cpuset is released, by running
|
| 473 | * /sbin/cpuset_release_agent with the name of the cpuset (path
|
| 474 | * relative to the root of cpuset file system) as the argument.
|
| 475 | *
|
| 476 | * Most likely, this user command will try to rmdir this cpuset.
|
| 477 | *
|
| 478 | * This races with the possibility that some other task will be
|
| 479 | * attached to this cpuset before it is removed, or that some other
|
| 480 | * user task will 'mkdir' a child cpuset of this cpuset. That's ok.
|
| 481 | * The presumed 'rmdir' will fail quietly if this cpuset is no longer
|
| 482 | * unused, and this cpuset will be reprieved from its death sentence,
|
| 483 | * to continue to serve a useful existence. Next time it's released,
|
| 484 | * we will get notified again, if it still has 'notify_on_release' set.
|
| 485 | *
|
| 486 | * The final arg to call_usermodehelper() is 0, which means don't
|
| 487 | * wait. The separate /sbin/cpuset_release_agent task is forked by
|
| 488 | * call_usermodehelper(), then control in this thread returns here,
|
| 489 | * without waiting for the release agent task. We don't bother to
|
| 490 | * wait because the caller of this routine has no use for the exit
|
| 491 | * status of the /sbin/cpuset_release_agent task, so no sense holding
|
| 492 | * our caller up for that.
|
| 493 | *
|
| 494 | * When we had only one cpuset mutex, we had to call this
|
| 495 | * without holding it, to avoid deadlock when call_usermodehelper()
|
| 496 | * allocated memory. With two locks, we could now call this while
|
| 497 | * holding manage_mutex, but we still don't, so as to minimize
|
| 498 | * the time manage_mutex is held.
|
| 499 |
|
| 500 |
|
| 501 | static void cpuset_release_agent(const char *pathbuf)
|
| 502 | {
|
| 503 | char *argv[3], *envp[3];
|
| 504 | int i;
|
| 505 |
|
| 506 | if (!pathbuf)
|
| 507 | return;
|
| 508 |
|
| 509 | i = 0;
|
| 510 | argv[i++] = "/sbin/cpuset_release_agent";
|
| 511 | argv[i++] = (char *)pathbuf;
|
| 512 | argv[i] = NULL;
|
| 513 |
|
| 514 | i = 0;
|
| 515 |
|
| 516 | envp[i++] = "HOME=/";
|
| 517 | envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
|
| 518 | envp[i] = NULL;
|
| 519 |
|
| 520 | call_usermodehelper(argv[0], argv, envp, 0);
|
| 521 | kfree(pathbuf);
|
| 522 | }
|
| 523 |
|
| 524 | |
| 525 | * Either cs->count of using tasks transitioned to zero, or the
|
| 526 | * cs->children list of child cpusets just became empty. If this
|
| 527 | * cs is notify_on_release() and now both the user count is zero and
|
| 528 | * the list of children is empty, prepare cpuset path in a kmalloc'd
|
| 529 | * buffer, to be returned via ppathbuf, so that the caller can invoke
|
| 530 | * cpuset_release_agent() with it later on, once manage_mutex is dropped.
|
| 531 | * Call here with manage_mutex held.
|
| 532 | *
|
| 533 | * This check_for_release() routine is responsible for kmalloc'ing
|
| 534 | * pathbuf. The above cpuset_release_agent() is responsible for
|
| 535 | * kfree'ing pathbuf. The caller of these routines is responsible
|
| 536 | * for providing a pathbuf pointer, initialized to NULL, then
|
| 537 | * calling check_for_release() with manage_mutex held and the address
|
| 538 | * of the pathbuf pointer, then dropping manage_mutex, then calling
|
| 539 | * cpuset_release_agent() with pathbuf, as set by check_for_release().
|
| 540 |
|
| 541 |
|
| 542 | static void check_for_release(struct cpuset *cs, char **ppathbuf)
|
| 543 | {
|
| 544 | if (notify_on_release(cs) && atomic_read(&cs->count) == 0 &&
|
| 545 | list_empty(&cs->children)) {
|
| 546 | char *buf;
|
| 547 |
|
| 548 | buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
|
| 549 | if (!buf)
|
| 550 | return;
|
| 551 | if (cpuset_path(cs, buf, PAGE_SIZE) < 0)
|
| 552 | kfree(buf);
|
| 553 | else
|
| 554 | *ppathbuf = buf;
|
| 555 | }
|
| 556 | }
|
| 557 |
|
| 558 | |
| 559 | * Return in *pmask the portion of a cpusets's cpus_allowed that
|
| 560 | * are online. If none are online, walk up the cpuset hierarchy
|
| 561 | * until we find one that does have some online cpus. If we get
|
| 562 | * all the way to the top and still haven't found any online cpus,
|
| 563 | * return cpu_online_map. Or if passed a NULL cs from an exit'ing
|
| 564 | * task, return cpu_online_map.
|
| 565 | *
|
| 566 | * One way or another, we guarantee to return some non-empty subset
|
| 567 | * of cpu_online_map.
|
| 568 | *
|
| 569 | * Call with callback_mutex held.
|
| 570 |
|
| 571 |
|
| 572 | static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask)
|
| 573 | {
|
| 574 | while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map))
|
| 575 | cs = cs->parent;
|
| 576 | if (cs)
|
| 577 | cpus_and(*pmask, cs->cpus_allowed, cpu_online_map);
|
| 578 | else
|
| 579 | *pmask = cpu_online_map;
|
| 580 | BUG_ON(!cpus_intersects(*pmask, cpu_online_map));
|
| 581 | }
|
| 582 |
|
| 583 | |
| 584 | * Return in *pmask the portion of a cpusets's mems_allowed that
|
| 585 | * are online. If none are online, walk up the cpuset hierarchy
|
| 586 | * until we find one that does have some online mems. If we get
|
| 587 | * all the way to the top and still haven't found any online mems,
|
| 588 | * return node_online_map.
|
| 589 | *
|
| 590 | * One way or another, we guarantee to return some non-empty subset
|
| 591 | * of node_online_map.
|
| 592 | *
|
| 593 | * Call with callback_mutex held.
|
| 594 |
|
| 595 |
|
| 596 | static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
|
| 597 | {
|
| 598 | while (cs && !nodes_intersects(cs->mems_allowed, node_online_map))
|
| 599 | cs = cs->parent;
|
| 600 | if (cs)
|
| 601 | nodes_and(*pmask, cs->mems_allowed, node_online_map);
|
| 602 | else
|
| 603 | *pmask = node_online_map;
|
| 604 | BUG_ON(!nodes_intersects(*pmask, node_online_map));
|
| 605 | }
|
| 606 |
|
| 607 | |
| 608 | * cpuset_update_task_memory_state - update task memory placement
|
| 609 | *
|
| 610 | * If the current tasks cpusets mems_allowed changed behind our
|
| 611 | * backs, update current->mems_allowed, mems_generation and task NUMA
|
| 612 | * mempolicy to the new value.
|
| 613 | *
|
| 614 | * Task mempolicy is updated by rebinding it relative to the
|
| 615 | * current->cpuset if a task has its memory placement changed.
|
| 616 | * Do not call this routine if in_interrupt().
|
| 617 | *
|
| 618 | * Call without callback_mutex or task_lock() held. May be
|
| 619 | * called with or without manage_mutex held. Thanks in part to
|
| 620 | * 'the_top_cpuset_hack', the tasks cpuset pointer will never
|
| 621 | * be NULL. This routine also might acquire callback_mutex and
|
| 622 | * current->mm->mmap_sem during call.
|
| 623 | *
|
| 624 | * Reading current->cpuset->mems_generation doesn't need task_lock
|
| 625 | * to guard the current->cpuset derefence, because it is guarded
|
| 626 | * from concurrent freeing of current->cpuset by attach_task(),
|
| 627 | * using RCU.
|
| 628 | *
|
| 629 | * The rcu_dereference() is technically probably not needed,
|
| 630 | * as I don't actually mind if I see a new cpuset pointer but
|
| 631 | * an old value of mems_generation. However this really only
|
| 632 | * matters on alpha systems using cpusets heavily. If I dropped
|
| 633 | * that rcu_dereference(), it would save them a memory barrier.
|
| 634 | * For all other arch's, rcu_dereference is a no-op anyway, and for
|
| 635 | * alpha systems not using cpusets, another planned optimization,
|
| 636 | * avoiding the rcu critical section for tasks in the root cpuset
|
| 637 | * which is statically allocated, so can't vanish, will make this
|
| 638 | * irrelevant. Better to use RCU as intended, than to engage in
|
| 639 | * some cute trick to save a memory barrier that is impossible to
|
| 640 | * test, for alpha systems using cpusets heavily, which might not
|
| 641 | * even exist.
|
| 642 | *
|
| 643 | * This routine is needed to update the per-task mems_allowed data,
|
| 644 | * within the tasks context, when it is trying to allocate memory
|
| 645 | * (in various mm/mempolicy.c routines) and notices that some other
|
| 646 | * task has been modifying its cpuset.
|
| 647 |
|
| 648 |
|
| 649 | void cpuset_update_task_memory_state(void)
|
| 650 | {
|
| 651 | int my_cpusets_mem_gen;
|
| 652 | struct task_struct *tsk = current;
|
| 653 | struct cpuset *cs;
|
| 654 |
|
| 655 | if (tsk->cpuset == &top_cpuset) {
|
| 656 |
|
| 657 | my_cpusets_mem_gen = top_cpuset.mems_generation;
|
| 658 | } else {
|
| 659 | rcu_read_lock();
|
| 660 | cs = rcu_dereference(tsk->cpuset);
|
| 661 | my_cpusets_mem_gen = cs->mems_generation;
|
| 662 | rcu_read_unlock();
|
| 663 | }
|
| 664 |
|
| 665 | if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
|
| 666 | mutex_lock(&callback_mutex);
|
| 667 | task_lock(tsk);
|
| 668 | cs = tsk->cpuset;
|
| 669 | guarantee_online_mems(cs, &tsk->mems_allowed);
|
| 670 | tsk->cpuset_mems_generation = cs->mems_generation;
|
| 671 | if (is_spread_page(cs))
|
| 672 | tsk->flags |= PF_SPREAD_PAGE;
|
| 673 | else
|
| 674 | tsk->flags &= ~PF_SPREAD_PAGE;
|
| 675 | if (is_spread_slab(cs))
|
| 676 | tsk->flags |= PF_SPREAD_SLAB;
|
| 677 | else
|
| 678 | tsk->flags &= ~PF_SPREAD_SLAB;
|
| 679 | task_unlock(tsk);
|
| 680 | mutex_unlock(&callback_mutex);
|
| 681 | mpol_rebind_task(tsk, &tsk->mems_allowed);
|
| 682 | }
|
| 683 | }
|
| 684 |
|
| 685 | |
| 686 | * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
|
| 687 | *
|
| 688 | * One cpuset is a subset of another if all its allowed CPUs and
|
| 689 | * Memory Nodes are a subset of the other, and its exclusive flags
|
| 690 | * are only set if the other's are set. Call holding manage_mutex.
|
| 691 |
|
| 692 |
|
| 693 | static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
|
| 694 | {
|
| 695 | return cpus_subset(p->cpus_allowed, q->cpus_allowed) &&
|
| 696 | nodes_subset(p->mems_allowed, q->mems_allowed) &&
|
| 697 | is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
|
| 698 | is_mem_exclusive(p) <= is_mem_exclusive(q);
|
| 699 | }
|
| 700 |
|
| 701 | |
| 702 | * validate_change() - Used to validate that any proposed cpuset change
|
| 703 | * follows the structural rules for cpusets.
|
| 704 | *
|
| 705 | * If we replaced the flag and mask values of the current cpuset
|
| 706 | * (cur) with those values in the trial cpuset (trial), would
|
| 707 | * our various subset and exclusive rules still be valid? Presumes
|
| 708 | * manage_mutex held.
|
| 709 | *
|
| 710 | * 'cur' is the address of an actual, in-use cpuset. Operations
|
| 711 | * such as list traversal that depend on the actual address of the
|
| 712 | * cpuset in the list must use cur below, not trial.
|
| 713 | *
|
| 714 | * 'trial' is the address of bulk structure copy of cur, with
|
| 715 | * perhaps one or more of the fields cpus_allowed, mems_allowed,
|
| 716 | * or flags changed to new, trial values.
|
| 717 | *
|
| 718 | * Return 0 if valid, -errno if not.
|
| 719 |
|
| 720 |
|
| 721 | static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
|
| 722 | {
|
| 723 | struct cpuset *c, *par;
|
| 724 |
|
| 725 |
|
| 726 | list_for_each_entry(c, &cur->children, sibling) {
|
| 727 | if (!is_cpuset_subset(c, trial))
|
| 728 | return -EBUSY;
|
| 729 | }
|
| 730 |
|
| 731 |
|
| 732 | if (cur == &top_cpuset)
|
| 733 | return 0;
|
| 734 |
|
| 735 | par = cur->parent;
|
| 736 |
|
| 737 |
|
| 738 | if (!is_cpuset_subset(trial, par))
|
| 739 | return -EACCES;
|
| 740 |
|
| 741 |
|
| 742 | list_for_each_entry(c, &par->children, sibling) {
|
| 743 | if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
|
| 744 | c != cur &&
|
| 745 | cpus_intersects(trial->cpus_allowed, c->cpus_allowed))
|
| 746 | return -EINVAL;
|
| 747 | if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
|
| 748 | c != cur &&
|
| 749 | nodes_intersects(trial->mems_allowed, c->mems_allowed))
|
| 750 | return -EINVAL;
|
| 751 | }
|
| 752 |
|
| 753 | return 0;
|
| 754 | }
|
| 755 |
|
| 756 | |
| 757 | * For a given cpuset cur, partition the system as follows
|
| 758 | * a. All cpus in the parent cpuset's cpus_allowed that are not part of any
|
| 759 | * exclusive child cpusets
|
| 760 | * b. All cpus in the current cpuset's cpus_allowed that are not part of any
|
| 761 | * exclusive child cpusets
|
| 762 | * Build these two partitions by calling partition_sched_domains
|
| 763 | *
|
| 764 | * Call with manage_mutex held. May nest a call to the
|
| 765 | * lock_cpu_hotplug()/unlock_cpu_hotplug() pair.
|
| 766 | * Must not be called holding callback_mutex, because we must
|
| 767 | * not call lock_cpu_hotplug() while holding callback_mutex.
|
| 768 |
|
| 769 |
|
| 770 | static void update_cpu_domains(struct cpuset *cur)
|
| 771 | {
|
| 772 | struct cpuset *c, *par = cur->parent;
|
| 773 | cpumask_t pspan, cspan;
|
| 774 |
|
| 775 | if (par == NULL || cpus_empty(cur->cpus_allowed))
|
| 776 | return;
|
| 777 |
|
| 778 | |
| 779 | * Get all cpus from parent's cpus_allowed not part of exclusive
|
| 780 | * children
|
| 781 |
|
| 782 | pspan = par->cpus_allowed;
|
| 783 | list_for_each_entry(c, &par->children, sibling) {
|
| 784 | if (is_cpu_exclusive(c))
|
| 785 | cpus_andnot(pspan, pspan, c->cpus_allowed);
|
| 786 | }
|
| 787 | if (!is_cpu_exclusive(cur)) {
|
| 788 | cpus_or(pspan, pspan, cur->cpus_allowed);
|
| 789 | if (cpus_equal(pspan, cur->cpus_allowed))
|
| 790 | return;
|
| 791 | cspan = CPU_MASK_NONE;
|
| 792 | } else {
|
| 793 | if (cpus_empty(pspan))
|
| 794 | return;
|
| 795 | cspan = cur->cpus_allowed;
|
| 796 | |
| 797 | * Get all cpus from current cpuset's cpus_allowed not part
|
| 798 | * of exclusive children
|
| 799 |
|
| 800 | list_for_each_entry(c, &cur->children, sibling) {
|
| 801 | if (is_cpu_exclusive(c))
|
| 802 | cpus_andnot(cspan, cspan, c->cpus_allowed);
|
| 803 | }
|
| 804 | }
|
| 805 |
|
| 806 | lock_cpu_hotplug();
|
| 807 | partition_sched_domains(&pspan, &cspan);
|
| 808 | unlock_cpu_hotplug();
|
| 809 | }
|
| 810 |
|
| 811 | |
| 812 | * Call with manage_mutex held. May take callback_mutex during call.
|
| 813 |
|
| 814 |
|
| 815 | static int update_cpumask(struct cpuset *cs, char *buf)
|
| 816 | {
|
| 817 | struct cpuset trialcs;
|
| 818 | int retval, cpus_unchanged;
|
| 819 |
|
| 820 |
|
| 821 | if (cs == &top_cpuset)
|
| 822 | return -EACCES;
|
| 823 |
|
| 824 | trialcs = *cs;
|
| 825 | retval = cpulist_parse(buf, trialcs.cpus_allowed);
|
| 826 | if (retval < 0)
|
| 827 | return retval;
|
| 828 | cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
|
| 829 | if (cpus_empty(trialcs.cpus_allowed))
|
| 830 | return -ENOSPC;
|
| 831 | retval = validate_change(cs, &trialcs);
|
| 832 | if (retval < 0)
|
| 833 | return retval;
|
| 834 | cpus_unchanged = cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed);
|
| 835 | mutex_lock(&callback_mutex);
|
| 836 | cs->cpus_allowed = trialcs.cpus_allowed;
|
| 837 | mutex_unlock(&callback_mutex);
|
| 838 | if (is_cpu_exclusive(cs) && !cpus_unchanged)
|
| 839 | update_cpu_domains(cs);
|
| 840 | return 0;
|
| 841 | }
|
| 842 |
|
| 843 | |
| 844 | * cpuset_migrate_mm
|
| 845 | *
|
| 846 | * Migrate memory region from one set of nodes to another.
|
| 847 | *
|
| 848 | * Temporarilly set tasks mems_allowed to target nodes of migration,
|
| 849 | * so that the migration code can allocate pages on these nodes.
|
| 850 | *
|
| 851 | * Call holding manage_mutex, so our current->cpuset won't change
|
| 852 | * during this call, as manage_mutex holds off any attach_task()
|
| 853 | * calls. Therefore we don't need to take task_lock around the
|
| 854 | * call to guarantee_online_mems(), as we know no one is changing
|
| 855 | * our tasks cpuset.
|
| 856 | *
|
| 857 | * Hold callback_mutex around the two modifications of our tasks
|
| 858 | * mems_allowed to synchronize with cpuset_mems_allowed().
|
| 859 | *
|
| 860 | * While the mm_struct we are migrating is typically from some
|
| 861 | * other task, the task_struct mems_allowed that we are hacking
|
| 862 | * is for our current task, which must allocate new pages for that
|
| 863 | * migrating memory region.
|
| 864 | *
|
| 865 | * We call cpuset_update_task_memory_state() before hacking
|
| 866 | * our tasks mems_allowed, so that we are assured of being in
|
| 867 | * sync with our tasks cpuset, and in particular, callbacks to
|
| 868 | * cpuset_update_task_memory_state() from nested page allocations
|
| 869 | * won't see any mismatch of our cpuset and task mems_generation
|
| 870 | * values, so won't overwrite our hacked tasks mems_allowed
|
| 871 | * nodemask.
|
| 872 |
|
| 873 |
|
| 874 | static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
|
| 875 | const nodemask_t *to)
|
| 876 | {
|
| 877 | struct task_struct *tsk = current;
|
| 878 |
|
| 879 | cpuset_update_task_memory_state();
|
| 880 |
|
| 881 | mutex_lock(&callback_mutex);
|
| 882 | tsk->mems_allowed = *to;
|
| 883 | mutex_unlock(&callback_mutex);
|
| 884 |
|
| 885 | do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
|
| 886 |
|
| 887 | mutex_lock(&callback_mutex);
|
| 888 | guarantee_online_mems(tsk->cpuset, &tsk->mems_allowed);
|
| 889 | mutex_unlock(&callback_mutex);
|
| 890 | }
|
| 891 |
|
| 892 | |
| 893 | * Handle user request to change the 'mems' memory placement
|
| 894 | * of a cpuset. Needs to validate the request, update the
|
| 895 | * cpusets mems_allowed and mems_generation, and for each
|
| 896 | * task in the cpuset, rebind any vma mempolicies and if
|
| 897 | * the cpuset is marked 'memory_migrate', migrate the tasks
|
| 898 | * pages to the new memory.
|
| 899 | *
|
| 900 | * Call with manage_mutex held. May take callback_mutex during call.
|
| 901 | * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
|
| 902 | * lock each such tasks mm->mmap_sem, scan its vma's and rebind
|
| 903 | * their mempolicies to the cpusets new mems_allowed.
|
| 904 |
|
| 905 |
|
| 906 | static int update_nodemask(struct cpuset *cs, char *buf)
|
| 907 | {
|
| 908 | struct cpuset trialcs;
|
| 909 | nodemask_t oldmem;
|
| 910 | struct task_struct *g, *p;
|
| 911 | struct mm_struct **mmarray;
|
| 912 | int i, n, ntasks;
|
| 913 | int migrate;
|
| 914 | int fudge;
|
| 915 | int retval;
|
| 916 |
|
| 917 |
|
| 918 | if (cs == &top_cpuset)
|
| 919 | return -EACCES;
|
| 920 |
|
| 921 | trialcs = *cs;
|
| 922 | retval = nodelist_parse(buf, trialcs.mems_allowed);
|
| 923 | if (retval < 0)
|
| 924 | goto done;
|
| 925 | nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map);
|
| 926 | oldmem = cs->mems_allowed;
|
| 927 | if (nodes_equal(oldmem, trialcs.mems_allowed)) {
|
| 928 | retval = 0;
|
| 929 | goto done;
|
| 930 | }
|
| 931 | if (nodes_empty(trialcs.mems_allowed)) {
|
| 932 | retval = -ENOSPC;
|
| 933 | goto done;
|
| 934 | }
|
| 935 | retval = validate_change(cs, &trialcs);
|
| 936 | if (retval < 0)
|
| 937 | goto done;
|
| 938 |
|
| 939 | mutex_lock(&callback_mutex);
|
| 940 | cs->mems_allowed = trialcs.mems_allowed;
|
| 941 | cs->mems_generation = cpuset_mems_generation++;
|
| 942 | mutex_unlock(&callback_mutex);
|
| 943 |
|
| 944 | set_cpuset_being_rebound(cs);
|
| 945 |
|
| 946 | fudge = 10;
|
| 947 | fudge += cpus_weight(cs->cpus_allowed);
|
| 948 | retval = -ENOMEM;
|
| 949 |
|
| 950 | |
| 951 | * Allocate mmarray[] to hold mm reference for each task
|
| 952 | * in cpuset cs. Can't kmalloc GFP_KERNEL while holding
|
| 953 | * tasklist_lock. We could use GFP_ATOMIC, but with a
|
| 954 | * few more lines of code, we can retry until we get a big
|
| 955 | * enough mmarray[] w/o using GFP_ATOMIC.
|
| 956 |
|
| 957 | while (1) {
|
| 958 | ntasks = atomic_read(&cs->count);
|
| 959 | ntasks += fudge;
|
| 960 | mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
|
| 961 | if (!mmarray)
|
| 962 | goto done;
|
| 963 | write_lock_irq(&tasklist_lock);
|
| 964 | if (atomic_read(&cs->count) <= ntasks)
|
| 965 | break;
|
| 966 | write_unlock_irq(&tasklist_lock);
|
| 967 | kfree(mmarray);
|
| 968 | }
|
| 969 |
|
| 970 | n = 0;
|
| 971 |
|
| 972 |
|
| 973 | do_each_thread(g, p) {
|
| 974 | struct mm_struct *mm;
|
| 975 |
|
| 976 | if (n >= ntasks) {
|
| 977 | printk(KERN_WARNING
|
| 978 | "Cpuset mempolicy rebind incomplete.\n");
|
| 979 | continue;
|
| 980 | }
|
| 981 | if (p->cpuset != cs)
|
| 982 | continue;
|
| 983 | mm = get_task_mm(p);
|
| 984 | if (!mm)
|
| 985 | continue;
|
| 986 | mmarray[n++] = mm;
|
| 987 | } while_each_thread(g, p);
|
| 988 | write_unlock_irq(&tasklist_lock);
|
| 989 |
|
| 990 | |
| 991 | * Now that we've dropped the tasklist spinlock, we can
|
| 992 | * rebind the vma mempolicies of each mm in mmarray[] to their
|
| 993 | * new cpuset, and release that mm. The mpol_rebind_mm()
|
| 994 | * call takes mmap_sem, which we couldn't take while holding
|
| 995 | * tasklist_lock. Forks can happen again now - the mpol_copy()
|
| 996 | * cpuset_being_rebound check will catch such forks, and rebind
|
| 997 | * their vma mempolicies too. Because we still hold the global
|
| 998 | * cpuset manage_mutex, we know that no other rebind effort will
|
| 999 | * be contending for the global variable cpuset_being_rebound.
|
| 1000 | * It's ok if we rebind the same mm twice; mpol_rebind_mm()
|
| 1001 | * is idempotent. Also migrate pages in each mm to new nodes.
|
| 1002 |
|
| 1003 | migrate = is_memory_migrate(cs);
|
| 1004 | for (i = 0; i < n; i++) {
|
| 1005 | struct mm_struct *mm = mmarray[i];
|
| 1006 |
|
| 1007 | mpol_rebind_mm(mm, &cs->mems_allowed);
|
| 1008 | if (migrate)
|
| 1009 | cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed);
|
| 1010 | mmput(mm);
|
| 1011 | }
|
| 1012 |
|
| 1013 |
|
| 1014 | kfree(mmarray);
|
| 1015 | set_cpuset_being_rebound(NULL);
|
| 1016 | retval = 0;
|
| 1017 | done:
|
| 1018 | return retval;
|
| 1019 | }
|
| 1020 |
|
| 1021 | |
| 1022 | * Call with manage_mutex held.
|
| 1023 |
|
| 1024 |
|
| 1025 | static int update_memory_pressure_enabled(struct cpuset *cs, char *buf)
|
| 1026 | {
|
| 1027 | if (simple_strtoul(buf, NULL, 10) != 0)
|
| 1028 | cpuset_memory_pressure_enabled = 1;
|
| 1029 | else
|
| 1030 | cpuset_memory_pressure_enabled = 0;
|
| 1031 | return 0;
|
| 1032 | }
|
| 1033 |
|
| 1034 | |
| 1035 | * update_flag - read a 0 or a 1 in a file and update associated flag
|
| 1036 | * bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE,
|
| 1037 | * CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE,
|
| 1038 | * CS_SPREAD_PAGE, CS_SPREAD_SLAB)
|
| 1039 | * cs: the cpuset to update
|
| 1040 | * buf: the buffer where we read the 0 or 1
|
| 1041 | *
|
| 1042 | * Call with manage_mutex held.
|
| 1043 |
|
| 1044 |
|
| 1045 | static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf)
|
| 1046 | {
|
| 1047 | int turning_on;
|
| 1048 | struct cpuset trialcs;
|
| 1049 | int err, cpu_exclusive_changed;
|
| 1050 |
|
| 1051 | turning_on = (simple_strtoul(buf, NULL, 10) != 0);
|
| 1052 |
|
| 1053 | trialcs = *cs;
|
| 1054 | if (turning_on)
|
| 1055 | set_bit(bit, &trialcs.flags);
|
| 1056 | else
|
| 1057 | clear_bit(bit, &trialcs.flags);
|
| 1058 |
|
| 1059 | err = validate_change(cs, &trialcs);
|
| 1060 | if (err < 0)
|
| 1061 | return err;
|
| 1062 | cpu_exclusive_changed =
|
| 1063 | (is_cpu_exclusive(cs) != is_cpu_exclusive(&trialcs));
|
| 1064 | mutex_lock(&callback_mutex);
|
| 1065 | cs->flags = trialcs.flags;
|
| 1066 | mutex_unlock(&callback_mutex);
|
| 1067 |
|
| 1068 | if (cpu_exclusive_changed)
|
| 1069 | update_cpu_domains(cs);
|
| 1070 | return 0;
|
| 1071 | }
|
| 1072 |
|
| 1073 | |
| 1074 | * Frequency meter - How fast is some event occurring?
|
| 1075 | *
|
| 1076 | * These routines manage a digitally filtered, constant time based,
|
| 1077 | * event frequency meter. There are four routines:
|
| 1078 | * fmeter_init() - initialize a frequency meter.
|
| 1079 | * fmeter_markevent() - called each time the event happens.
|
| 1080 | * fmeter_getrate() - returns the recent rate of such events.
|
| 1081 | * fmeter_update() - internal routine used to update fmeter.
|
| 1082 | *
|
| 1083 | * A common data structure is passed to each of these routines,
|
| 1084 | * which is used to keep track of the state required to manage the
|
| 1085 | * frequency meter and its digital filter.
|
| 1086 | *
|
| 1087 | * The filter works on the number of events marked per unit time.
|
| 1088 | * The filter is single-pole low-pass recursive (IIR). The time unit
|
| 1089 | * is 1 second. Arithmetic is done using 32-bit integers scaled to
|
| 1090 | * simulate 3 decimal digits of precision (multiplied by 1000).
|
| 1091 | *
|
| 1092 | * With an FM_COEF of 933, and a time base of 1 second, the filter
|
| 1093 | * has a half-life of 10 seconds, meaning that if the events quit
|
| 1094 | * happening, then the rate returned from the fmeter_getrate()
|
| 1095 | * will be cut in half each 10 seconds, until it converges to zero.
|
| 1096 | *
|
| 1097 | * It is not worth doing a real infinitely recursive filter. If more
|
| 1098 | * than FM_MAXTICKS ticks have elapsed since the last filter event,
|
| 1099 | * just compute FM_MAXTICKS ticks worth, by which point the level
|
| 1100 | * will be stable.
|
| 1101 | *
|
| 1102 | * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
|
| 1103 | * arithmetic overflow in the fmeter_update() routine.
|
| 1104 | *
|
| 1105 | * Given the simple 32 bit integer arithmetic used, this meter works
|
| 1106 | * best for reporting rates between one per millisecond (msec) and
|
| 1107 | * one per 32 (approx) seconds. At constant rates faster than one
|
| 1108 | * per msec it maxes out at values just under 1,000,000. At constant
|
| 1109 | * rates between one per msec, and one per second it will stabilize
|
| 1110 | * to a value N*1000, where N is the rate of events per second.
|
| 1111 | * At constant rates between one per second and one per 32 seconds,
|
| 1112 | * it will be choppy, moving up on the seconds that have an event,
|
| 1113 | * and then decaying until the next event. At rates slower than
|
| 1114 | * about one in 32 seconds, it decays all the way back to zero between
|
| 1115 | * each event.
|
| 1116 |
|
| 1117 |
|
| 1118 | #define FM_COEF 933
|
| 1119 | #define FM_MAXTICKS ((time_t)99)
|
| 1120 | #define FM_MAXCNT 1000000
|
| 1121 | #define FM_SCALE 1000
|
| 1122 |
|
| 1123 |
|
| 1124 | static void fmeter_init(struct fmeter *fmp)
|
| 1125 | {
|
| 1126 | fmp->cnt = 0;
|
| 1127 | fmp->val = 0;
|
| 1128 | fmp->time = 0;
|
| 1129 | spin_lock_init(&fmp->lock);
|
| 1130 | }
|
| 1131 |
|
| 1132 |
|
| 1133 | static void fmeter_update(struct fmeter *fmp)
|
| 1134 | {
|
| 1135 | time_t now = get_seconds();
|
| 1136 | time_t ticks = now - fmp->time;
|
| 1137 |
|
| 1138 | if (ticks == 0)
|
| 1139 | return;
|
| 1140 |
|
| 1141 | ticks = min(FM_MAXTICKS, ticks);
|
| 1142 | while (ticks-- > 0)
|
| 1143 | fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
|
| 1144 | fmp->time = now;
|
| 1145 |
|
| 1146 | fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
|
| 1147 | fmp->cnt = 0;
|
| 1148 | }
|
| 1149 |
|
| 1150 |
|
| 1151 | static void fmeter_markevent(struct fmeter *fmp)
|
| 1152 | {
|
| 1153 | spin_lock(&fmp->lock);
|
| 1154 | fmeter_update(fmp);
|
| 1155 | fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
|
| 1156 | spin_unlock(&fmp->lock);
|
| 1157 | }
|
| 1158 |
|
| 1159 |
|
| 1160 | static int fmeter_getrate(struct fmeter *fmp)
|
| 1161 | {
|
| 1162 | int val;
|
| 1163 |
|
| 1164 | spin_lock(&fmp->lock);
|
| 1165 | fmeter_update(fmp);
|
| 1166 | val = fmp->val;
|
| 1167 | spin_unlock(&fmp->lock);
|
| 1168 | return val;
|
| 1169 | }
|
| 1170 |
|
| 1171 | |
| 1172 | * Attack task specified by pid in 'pidbuf' to cpuset 'cs', possibly
|
| 1173 | * writing the path of the old cpuset in 'ppathbuf' if it needs to be
|
| 1174 | * notified on release.
|
| 1175 | *
|
| 1176 | * Call holding manage_mutex. May take callback_mutex and task_lock of
|
| 1177 | * the task 'pid' during call.
|
| 1178 |
|
| 1179 |
|
| 1180 | static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf)
|
| 1181 | {
|
| 1182 | pid_t pid;
|
| 1183 | struct task_struct *tsk;
|
| 1184 | struct cpuset *oldcs;
|
| 1185 | cpumask_t cpus;
|
| 1186 | nodemask_t from, to;
|
| 1187 | struct mm_struct *mm;
|
| 1188 | int retval;
|
| 1189 |
|
| 1190 | if (sscanf(pidbuf, "%d", &pid) != 1)
|
| 1191 | return -EIO;
|
| 1192 | if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
|
| 1193 | return -ENOSPC;
|
| 1194 |
|
| 1195 | if (pid) {
|
| 1196 | read_lock(&tasklist_lock);
|
| 1197 |
|
| 1198 | tsk = find_task_by_pid(pid);
|
| 1199 | if (!tsk || tsk->flags & PF_EXITING) {
|
| 1200 | read_unlock(&tasklist_lock);
|
| 1201 | return -ESRCH;
|
| 1202 | }
|
| 1203 |
|
| 1204 | get_task_struct(tsk);
|
| 1205 | read_unlock(&tasklist_lock);
|
| 1206 |
|
| 1207 | if ((current->euid) && (current->euid != tsk->uid)
|
| 1208 | && (current->euid != tsk->suid)) {
|
| 1209 | put_task_struct(tsk);
|
| 1210 | return -EACCES;
|
| 1211 | }
|
| 1212 | } else {
|
| 1213 | tsk = current;
|
| 1214 | get_task_struct(tsk);
|
| 1215 | }
|
| 1216 |
|
| 1217 | retval = security_task_setscheduler(tsk, 0, NULL);
|
| 1218 | if (retval) {
|
| 1219 | put_task_struct(tsk);
|
| 1220 | return retval;
|
| 1221 | }
|
| 1222 |
|
| 1223 | mutex_lock(&callback_mutex);
|
| 1224 |
|
| 1225 | task_lock(tsk);
|
| 1226 | oldcs = tsk->cpuset;
|
| 1227 | |
| 1228 | * After getting 'oldcs' cpuset ptr, be sure still not exiting.
|
| 1229 | * If 'oldcs' might be the top_cpuset due to the_top_cpuset_hack
|
| 1230 | * then fail this attach_task(), to avoid breaking top_cpuset.count.
|
| 1231 |
|
| 1232 | if (tsk->flags & PF_EXITING) {
|
| 1233 | task_unlock(tsk);
|
| 1234 | mutex_unlock(&callback_mutex);
|
| 1235 | put_task_struct(tsk);
|
| 1236 | return -ESRCH;
|
| 1237 | }
|
| 1238 | atomic_inc(&cs->count);
|
| 1239 | rcu_assign_pointer(tsk->cpuset, cs);
|
| 1240 | task_unlock(tsk);
|
| 1241 |
|
| 1242 | guarantee_online_cpus(cs, &cpus);
|
| 1243 | set_cpus_allowed(tsk, cpus);
|
| 1244 |
|
| 1245 | from = oldcs->mems_allowed;
|
| 1246 | to = cs->mems_allowed;
|
| 1247 |
|
| 1248 | mutex_unlock(&callback_mutex);
|
| 1249 |
|
| 1250 | mm = get_task_mm(tsk);
|
| 1251 | if (mm) {
|
| 1252 | mpol_rebind_mm(mm, &to);
|
| 1253 | if (is_memory_migrate(cs))
|
| 1254 | cpuset_migrate_mm(mm, &from, &to);
|
| 1255 | mmput(mm);
|
| 1256 | }
|
| 1257 |
|
| 1258 | put_task_struct(tsk);
|
| 1259 | synchronize_rcu();
|
| 1260 | if (atomic_dec_and_test(&oldcs->count))
|
| 1261 | check_for_release(oldcs, ppathbuf);
|
| 1262 | return 0;
|
| 1263 | }
|
| 1264 |
|
| 1265 |
|
| 1266 |
|
| 1267 | typedef enum {
|
| 1268 | FILE_ROOT,
|
| 1269 | FILE_DIR,
|
| 1270 | FILE_MEMORY_MIGRATE,
|
| 1271 | FILE_CPULIST,
|
| 1272 | FILE_MEMLIST,
|
| 1273 | FILE_CPU_EXCLUSIVE,
|
| 1274 | FILE_MEM_EXCLUSIVE,
|
| 1275 | FILE_NOTIFY_ON_RELEASE,
|
| 1276 | FILE_MEMORY_PRESSURE_ENABLED,
|
| 1277 | FILE_MEMORY_PRESSURE,
|
| 1278 | FILE_SPREAD_PAGE,
|
| 1279 | FILE_SPREAD_SLAB,
|
| 1280 | FILE_TASKLIST,
|
| 1281 | } cpuset_filetype_t;
|
| 1282 |
|
| 1283 | static ssize_t cpuset_common_file_write(struct file *file,
|
| 1284 | const char __user *userbuf,
|
| 1285 | size_t nbytes, loff_t *unused_ppos)
|
| 1286 | {
|
| 1287 | struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
|
| 1288 | struct cftype *cft = __d_cft(file->f_path.dentry);
|
| 1289 | cpuset_filetype_t type = cft->private;
|
| 1290 | char *buffer;
|
| 1291 | char *pathbuf = NULL;
|
| 1292 | int retval = 0;
|
| 1293 |
|
| 1294 |
|
| 1295 | if (nbytes > 100 + 6 * max(NR_CPUS, MAX_NUMNODES))
|
| 1296 | return -E2BIG;
|
| 1297 |
|
| 1298 |
|
| 1299 | if ((buffer = kmalloc(nbytes + 1, GFP_KERNEL)) == 0)
|
| 1300 | return -ENOMEM;
|
| 1301 |
|
| 1302 | if (copy_from_user(buffer, userbuf, nbytes)) {
|
| 1303 | retval = -EFAULT;
|
| 1304 | goto out1;
|
| 1305 | }
|
| 1306 | buffer[nbytes] = 0;
|
| 1307 |
|
| 1308 | mutex_lock(&manage_mutex);
|
| 1309 |
|
| 1310 | if (is_removed(cs)) {
|
| 1311 | retval = -ENODEV;
|
| 1312 | goto out2;
|
| 1313 | }
|
| 1314 |
|
| 1315 | switch (type) {
|
| 1316 | case FILE_CPULIST:
|
| 1317 | retval = update_cpumask(cs, buffer);
|
| 1318 | break;
|
| 1319 | case FILE_MEMLIST:
|
| 1320 | retval = update_nodemask(cs, buffer);
|
| 1321 | break;
|
| 1322 | case FILE_CPU_EXCLUSIVE:
|
| 1323 | retval = update_flag(CS_CPU_EXCLUSIVE, cs, buffer);
|
| 1324 | break;
|
| 1325 | case FILE_MEM_EXCLUSIVE:
|
| 1326 | retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer);
|
| 1327 | break;
|
| 1328 | case FILE_NOTIFY_ON_RELEASE:
|
| 1329 | retval = update_flag(CS_NOTIFY_ON_RELEASE, cs, buffer);
|
| 1330 | break;
|
| 1331 | case FILE_MEMORY_MIGRATE:
|
| 1332 | retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer);
|
| 1333 | break;
|
| 1334 | case FILE_MEMORY_PRESSURE_ENABLED:
|
| 1335 | retval = update_memory_pressure_enabled(cs, buffer);
|
| 1336 | break;
|
| 1337 | case FILE_MEMORY_PRESSURE:
|
| 1338 | retval = -EACCES;
|
| 1339 | break;
|
| 1340 | case FILE_SPREAD_PAGE:
|
| 1341 | retval = update_flag(CS_SPREAD_PAGE, cs, buffer);
|
| 1342 | cs->mems_generation = cpuset_mems_generation++;
|
| 1343 | break;
|
| 1344 | case FILE_SPREAD_SLAB:
|
| 1345 | retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
|
| 1346 | cs->mems_generation = cpuset_mems_generation++;
|
| 1347 | break;
|
| 1348 | case FILE_TASKLIST:
|
| 1349 | retval = attach_task(cs, buffer, &pathbuf);
|
| 1350 | break;
|
| 1351 | default:
|
| 1352 | retval = -EINVAL;
|
| 1353 | goto out2;
|
| 1354 | }
|
| 1355 |
|
| 1356 | if (retval == 0)
|
| 1357 | retval = nbytes;
|
| 1358 | out2:
|
| 1359 | mutex_unlock(&manage_mutex);
|
| 1360 | cpuset_release_agent(pathbuf);
|
| 1361 | out1:
|
| 1362 | kfree(buffer);
|
| 1363 | return retval;
|
| 1364 | }
|
| 1365 |
|
| 1366 | static ssize_t cpuset_file_write(struct file *file, const char __user *buf,
|
| 1367 | size_t nbytes, loff_t *ppos)
|
| 1368 | {
|
| 1369 | ssize_t retval = 0;
|
| 1370 | struct cftype *cft = __d_cft(file->f_path.dentry);
|
| 1371 | if (!cft)
|
| 1372 | return -ENODEV;
|
| 1373 |
|
| 1374 |
|
| 1375 | if (cft->write)
|
| 1376 | retval = cft->write(file, buf, nbytes, ppos);
|
| 1377 | else
|
| 1378 | retval = cpuset_common_file_write(file, buf, nbytes, ppos);
|
| 1379 |
|
| 1380 | return retval;
|
| 1381 | }
|
| 1382 |
|
| 1383 | |
| 1384 | * These ascii lists should be read in a single call, by using a user
|
| 1385 | * buffer large enough to hold the entire map. If read in smaller
|
| 1386 | * chunks, there is no guarantee of atomicity. Since the display format
|
| 1387 | * used, list of ranges of sequential numbers, is variable length,
|
| 1388 | * and since these maps can change value dynamically, one could read
|
| 1389 | * gibberish by doing partial reads while a list was changing.
|
| 1390 | * A single large read to a buffer that crosses a page boundary is
|
| 1391 | * ok, because the result being copied to user land is not recomputed
|
| 1392 | * across a page fault.
|
| 1393 |
|
| 1394 |
|
| 1395 | static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
|
| 1396 | {
|
| 1397 | cpumask_t mask;
|
| 1398 |
|
| 1399 | mutex_lock(&callback_mutex);
|
| 1400 | mask = cs->cpus_allowed;
|
| 1401 | mutex_unlock(&callback_mutex);
|
| 1402 |
|
| 1403 | return cpulist_scnprintf(page, PAGE_SIZE, mask);
|
| 1404 | }
|
| 1405 |
|
| 1406 | static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
|
| 1407 | {
|
| 1408 | nodemask_t mask;
|
| 1409 |
|
| 1410 | mutex_lock(&callback_mutex);
|
| 1411 | mask = cs->mems_allowed;
|
| 1412 | mutex_unlock(&callback_mutex);
|
| 1413 |
|
| 1414 | return nodelist_scnprintf(page, PAGE_SIZE, mask);
|
| 1415 | }
|
| 1416 |
|
| 1417 | static ssize_t cpuset_common_file_read(struct file *file, char __user *buf,
|
| 1418 | size_t nbytes, loff_t *ppos)
|
| 1419 | {
|
| 1420 | struct cftype *cft = __d_cft(file->f_path.dentry);
|
| 1421 | struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
|
| 1422 | cpuset_filetype_t type = cft->private;
|
| 1423 | char *page;
|
| 1424 | ssize_t retval = 0;
|
| 1425 | char *s;
|
| 1426 |
|
| 1427 | if (!(page = (char *)__get_free_page(GFP_KERNEL)))
|
| 1428 | return -ENOMEM;
|
| 1429 |
|
| 1430 | s = page;
|
| 1431 |
|
| 1432 | switch (type) {
|
| 1433 | case FILE_CPULIST:
|
| 1434 | s += cpuset_sprintf_cpulist(s, cs);
|
| 1435 | break;
|
| 1436 | case FILE_MEMLIST:
|
| 1437 | s += cpuset_sprintf_memlist(s, cs);
|
| 1438 | break;
|
| 1439 | case FILE_CPU_EXCLUSIVE:
|
| 1440 | *s++ = is_cpu_exclusive(cs) ? '1' : '0';
|
| 1441 | break;
|
| 1442 | case FILE_MEM_EXCLUSIVE:
|
| 1443 | *s++ = is_mem_exclusive(cs) ? '1' : '0';
|
| 1444 | break;
|
| 1445 | case FILE_NOTIFY_ON_RELEASE:
|
| 1446 | *s++ = notify_on_release(cs) ? '1' : '0';
|
| 1447 | break;
|
| 1448 | case FILE_MEMORY_MIGRATE:
|
| 1449 | *s++ = is_memory_migrate(cs) ? '1' : '0';
|
| 1450 | break;
|
| 1451 | case FILE_MEMORY_PRESSURE_ENABLED:
|
| 1452 | *s++ = cpuset_memory_pressure_enabled ? '1' : '0';
|
| 1453 | break;
|
| 1454 | case FILE_MEMORY_PRESSURE:
|
| 1455 | s += sprintf(s, "%d", fmeter_getrate(&cs->fmeter));
|
| 1456 | break;
|
| 1457 | case FILE_SPREAD_PAGE:
|
| 1458 | *s++ = is_spread_page(cs) ? '1' : '0';
|
| 1459 | break;
|
| 1460 | case FILE_SPREAD_SLAB:
|
| 1461 | *s++ = is_spread_slab(cs) ? '1' : '0';
|
| 1462 | break;
|
| 1463 | default:
|
| 1464 | retval = -EINVAL;
|
| 1465 | goto out;
|
| 1466 | }
|
| 1467 | *s++ = '\n';
|
| 1468 |
|
| 1469 | retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
|
| 1470 | out:
|
| 1471 | free_page((unsigned long)page);
|
| 1472 | return retval;
|
| 1473 | }
|
| 1474 |
|
| 1475 | static ssize_t cpuset_file_read(struct file *file, char __user *buf, size_t nbytes,
|
| 1476 | loff_t *ppos)
|
| 1477 | {
|
| 1478 | ssize_t retval = 0;
|
| 1479 | struct cftype *cft = __d_cft(file->f_path.dentry);
|
| 1480 | if (!cft)
|
| 1481 | return -ENODEV;
|
| 1482 |
|
| 1483 |
|
| 1484 | if (cft->read)
|
| 1485 | retval = cft->read(file, buf, nbytes, ppos);
|
| 1486 | else
|
| 1487 | retval = cpuset_common_file_read(file, buf, nbytes, ppos);
|
| 1488 |
|
| 1489 | return retval;
|
| 1490 | }
|
| 1491 |
|
| 1492 | static int cpuset_file_open(struct inode *inode, struct file *file)
|
| 1493 | {
|
| 1494 | int err;
|
| 1495 | struct cftype *cft;
|
| 1496 |
|
| 1497 | err = generic_file_open(inode, file);
|
| 1498 | if (err)
|
| 1499 | return err;
|
| 1500 |
|
| 1501 | cft = __d_cft(file->f_path.dentry);
|
| 1502 | if (!cft)
|
| 1503 | return -ENODEV;
|
| 1504 | if (cft->open)
|
| 1505 | err = cft->open(inode, file);
|
| 1506 | else
|
| 1507 | err = 0;
|
| 1508 |
|
| 1509 | return err;
|
| 1510 | }
|
| 1511 |
|
| 1512 | static int cpuset_file_release(struct inode *inode, struct file *file)
|
| 1513 | {
|
| 1514 | struct cftype *cft = __d_cft(file->f_path.dentry);
|
| 1515 | if (cft->release)
|
| 1516 | return cft->release(inode, file);
|
| 1517 | return 0;
|
| 1518 | }
|
| 1519 |
|
| 1520 | |
| 1521 | * cpuset_rename - Only allow simple rename of directories in place.
|
| 1522 |
|
| 1523 | static int cpuset_rename(struct inode *old_dir, struct dentry *old_dentry,
|
| 1524 | struct inode *new_dir, struct dentry *new_dentry)
|
| 1525 | {
|
| 1526 | if (!S_ISDIR(old_dentry->d_inode->i_mode))
|
| 1527 | return -ENOTDIR;
|
| 1528 | if (new_dentry->d_inode)
|
| 1529 | return -EEXIST;
|
| 1530 | if (old_dir != new_dir)
|
| 1531 | return -EIO;
|
| 1532 | return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
|
| 1533 | }
|
| 1534 |
|
| 1535 | static const struct file_operations cpuset_file_operations = {
|
| 1536 | .read = cpuset_file_read,
|
| 1537 | .write = cpuset_file_write,
|
| 1538 | .llseek = generic_file_llseek,
|
| 1539 | .open = cpuset_file_open,
|
| 1540 | .release = cpuset_file_release,
|
| 1541 | };
|
| 1542 |
|
| 1543 | static const struct inode_operations cpuset_dir_inode_operations = {
|
| 1544 | .lookup = simple_lookup,
|
| 1545 | .mkdir = cpuset_mkdir,
|
| 1546 | .rmdir = cpuset_rmdir,
|
| 1547 | .rename = cpuset_rename,
|
| 1548 | };
|
| 1549 |
|
| 1550 | static int cpuset_create_file(struct dentry *dentry, int mode)
|
| 1551 | {
|
| 1552 | struct inode *inode;
|
| 1553 |
|
| 1554 | if (!dentry)
|
| 1555 | return -ENOENT;
|
| 1556 | if (dentry->d_inode)
|
| 1557 | return -EEXIST;
|
| 1558 |
|
| 1559 | inode = cpuset_new_inode(mode);
|
| 1560 | if (!inode)
|
| 1561 | return -ENOMEM;
|
| 1562 |
|
| 1563 | if (S_ISDIR(mode)) {
|
| 1564 | inode->i_op = &cpuset_dir_inode_operations;
|
| 1565 | inode->i_fop = &simple_dir_operations;
|
| 1566 |
|
| 1567 |
|
| 1568 | inc_nlink(inode);
|
| 1569 | } else if (S_ISREG(mode)) {
|
| 1570 | inode->i_size = 0;
|
| 1571 | inode->i_fop = &cpuset_file_operations;
|
| 1572 | }
|
| 1573 |
|
| 1574 | d_instantiate(dentry, inode);
|
| 1575 | dget(dentry);
|
| 1576 | return 0;
|
| 1577 | }
|
| 1578 |
|
| 1579 | |
| 1580 | * cpuset_create_dir - create a directory for an object.
|
| 1581 | * cs: the cpuset we create the directory for.
|
| 1582 | * It must have a valid ->parent field
|
| 1583 | * And we are going to fill its ->dentry field.
|
| 1584 | * name: The name to give to the cpuset directory. Will be copied.
|
| 1585 | * mode: mode to set on new directory.
|
| 1586 |
|
| 1587 |
|
| 1588 | static int cpuset_create_dir(struct cpuset *cs, const char *name, int mode)
|
| 1589 | {
|
| 1590 | struct dentry *dentry = NULL;
|
| 1591 | struct dentry *parent;
|
| 1592 | int error = 0;
|
| 1593 |
|
| 1594 | parent = cs->parent->dentry;
|
| 1595 | dentry = cpuset_get_dentry(parent, name);
|
| 1596 | if (IS_ERR(dentry))
|
| 1597 | return PTR_ERR(dentry);
|
| 1598 | error = cpuset_create_file(dentry, S_IFDIR | mode);
|
| 1599 | if (!error) {
|
| 1600 | dentry->d_fsdata = cs;
|
| 1601 | inc_nlink(parent->d_inode);
|
| 1602 | cs->dentry = dentry;
|
| 1603 | }
|
| 1604 | dput(dentry);
|
| 1605 |
|
| 1606 | return error;
|
| 1607 | }
|
| 1608 |
|
| 1609 | static int cpuset_add_file(struct dentry *dir, const struct cftype *cft)
|
| 1610 | {
|
| 1611 | struct dentry *dentry;
|
| 1612 | int error;
|
| 1613 |
|
| 1614 | mutex_lock(&dir->d_inode->i_mutex);
|
| 1615 | dentry = cpuset_get_dentry(dir, cft->name);
|
| 1616 | if (!IS_ERR(dentry)) {
|
| 1617 | error = cpuset_create_file(dentry, 0644 | S_IFREG);
|
| 1618 | if (!error)
|
| 1619 | dentry->d_fsdata = (void *)cft;
|
| 1620 | dput(dentry);
|
| 1621 | } else
|
| 1622 | error = PTR_ERR(dentry);
|
| 1623 | mutex_unlock(&dir->d_inode->i_mutex);
|
| 1624 | return error;
|
| 1625 | }
|
| 1626 |
|
| 1627 | |
| 1628 | * Stuff for reading the 'tasks' file.
|
| 1629 | *
|
| 1630 | * Reading this file can return large amounts of data if a cpuset has
|
| 1631 | * *lots* of attached tasks. So it may need several calls to read(),
|
| 1632 | * but we cannot guarantee that the information we produce is correct
|
| 1633 | * unless we produce it entirely atomically.
|
| 1634 | *
|
| 1635 | * Upon tasks file open(), a struct ctr_struct is allocated, that
|
| 1636 | * will have a pointer to an array (also allocated here). The struct
|
| 1637 | * ctr_struct * is stored in file->private_data. Its resources will
|
| 1638 | * be freed by release() when the file is closed. The array is used
|
| 1639 | * to sprintf the PIDs and then used by read().
|
| 1640 |
|
| 1641 |
|
| 1642 |
|
| 1643 |
|
| 1644 | struct ctr_struct {
|
| 1645 | char *buf;
|
| 1646 | int bufsz;
|
| 1647 | };
|
| 1648 |
|
| 1649 | |
| 1650 | * Load into 'pidarray' up to 'npids' of the tasks using cpuset 'cs'.
|
| 1651 | * Return actual number of pids loaded. No need to task_lock(p)
|
| 1652 | * when reading out p->cpuset, as we don't really care if it changes
|
| 1653 | * on the next cycle, and we are not going to try to dereference it.
|
| 1654 |
|
| 1655 | static int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs)
|
| 1656 | {
|
| 1657 | int n = 0;
|
| 1658 | struct task_struct *g, *p;
|
| 1659 |
|
| 1660 | read_lock(&tasklist_lock);
|
| 1661 |
|
| 1662 | do_each_thread(g, p) {
|
| 1663 | if (p->cpuset == cs) {
|
| 1664 | pidarray[n++] = p->pid;
|
| 1665 | if (unlikely(n == npids))
|
| 1666 | goto array_full;
|
| 1667 | }
|
| 1668 | } while_each_thread(g, p);
|
| 1669 |
|
| 1670 | array_full:
|
| 1671 | read_unlock(&tasklist_lock);
|
| 1672 | return n;
|
| 1673 | }
|
| 1674 |
|
| 1675 | static int cmppid(const void *a, const void *b)
|
| 1676 | {
|
| 1677 | return *(pid_t *)a - *(pid_t *)b;
|
| 1678 | }
|
| 1679 |
|
| 1680 | |
| 1681 | * Convert array 'a' of 'npids' pid_t's to a string of newline separated
|
| 1682 | * decimal pids in 'buf'. Don't write more than 'sz' chars, but return
|
| 1683 | * count 'cnt' of how many chars would be written if buf were large enough.
|
| 1684 |
|
| 1685 | static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids)
|
| 1686 | {
|
| 1687 | int cnt = 0;
|
| 1688 | int i;
|
| 1689 |
|
| 1690 | for (i = 0; i < npids; i++)
|
| 1691 | cnt += snprintf(buf + cnt, max(sz - cnt, 0), "%d\n", a[i]);
|
| 1692 | return cnt;
|
| 1693 | }
|
| 1694 |
|
| 1695 | |
| 1696 | * Handle an open on 'tasks' file. Prepare a buffer listing the
|
| 1697 | * process id's of tasks currently attached to the cpuset being opened.
|
| 1698 | *
|
| 1699 | * Does not require any specific cpuset mutexes, and does not take any.
|
| 1700 |
|
| 1701 | static int cpuset_tasks_open(struct inode *unused, struct file *file)
|
| 1702 | {
|
| 1703 | struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
|
| 1704 | struct ctr_struct *ctr;
|
| 1705 | pid_t *pidarray;
|
| 1706 | int npids;
|
| 1707 | char c;
|
| 1708 |
|
| 1709 | if (!(file->f_mode & FMODE_READ))
|
| 1710 | return 0;
|
| 1711 |
|
| 1712 | ctr = kmalloc(sizeof(*ctr), GFP_KERNEL);
|
| 1713 | if (!ctr)
|
| 1714 | goto err0;
|
| 1715 |
|
| 1716 | |
| 1717 | * If cpuset gets more users after we read count, we won't have
|
| 1718 | * enough space - tough. This race is indistinguishable to the
|
| 1719 | * caller from the case that the additional cpuset users didn't
|
| 1720 | * show up until sometime later on.
|
| 1721 |
|
| 1722 | npids = atomic_read(&cs->count);
|
| 1723 | pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
|
| 1724 | if (!pidarray)
|
| 1725 | goto err1;
|
| 1726 |
|
| 1727 | npids = pid_array_load(pidarray, npids, cs);
|
| 1728 | sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
|
| 1729 |
|
| 1730 |
|
| 1731 | ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1;
|
| 1732 | ctr->buf = kmalloc(ctr->bufsz, GFP_KERNEL);
|
| 1733 | if (!ctr->buf)
|
| 1734 | goto err2;
|
| 1735 | ctr->bufsz = pid_array_to_buf(ctr->buf, ctr->bufsz, pidarray, npids);
|
| 1736 |
|
| 1737 | kfree(pidarray);
|
| 1738 | file->private_data = ctr;
|
| 1739 | return 0;
|
| 1740 |
|
| 1741 | err2:
|
| 1742 | kfree(pidarray);
|
| 1743 | err1:
|
| 1744 | kfree(ctr);
|
| 1745 | err0:
|
| 1746 | return -ENOMEM;
|
| 1747 | }
|
| 1748 |
|
| 1749 | static ssize_t cpuset_tasks_read(struct file *file, char __user *buf,
|
| 1750 | size_t nbytes, loff_t *ppos)
|
| 1751 | {
|
| 1752 | struct ctr_struct *ctr = file->private_data;
|
| 1753 |
|
| 1754 | if (*ppos + nbytes > ctr->bufsz)
|
| 1755 | nbytes = ctr->bufsz - *ppos;
|
| 1756 | if (copy_to_user(buf, ctr->buf + *ppos, nbytes))
|
| 1757 | return -EFAULT;
|
| 1758 | *ppos += nbytes;
|
| 1759 | return nbytes;
|
| 1760 | }
|
| 1761 |
|
| 1762 | static int cpuset_tasks_release(struct inode *unused_inode, struct file *file)
|
| 1763 | {
|
| 1764 | struct ctr_struct *ctr;
|
| 1765 |
|
| 1766 | if (file->f_mode & FMODE_READ) {
|
| 1767 | ctr = file->private_data;
|
| 1768 | kfree(ctr->buf);
|
| 1769 | kfree(ctr);
|
| 1770 | }
|
| 1771 | return 0;
|
| 1772 | }
|
| 1773 |
|
| 1774 | |
| 1775 | * for the common functions, 'private' gives the type of file
|
| 1776 |
|
| 1777 |
|
| 1778 | static struct cftype cft_tasks = {
|
| 1779 | .name = "tasks",
|
| 1780 | .open = cpuset_tasks_open,
|
| 1781 | .read = cpuset_tasks_read,
|
| 1782 | .release = cpuset_tasks_release,
|
| 1783 | .private = FILE_TASKLIST,
|
| 1784 | };
|
| 1785 |
|
| 1786 | static struct cftype cft_cpus = {
|
| 1787 | .name = "cpus",
|
| 1788 | .private = FILE_CPULIST,
|
| 1789 | };
|
| 1790 |
|
| 1791 | static struct cftype cft_mems = {
|
| 1792 | .name = "mems",
|
| 1793 | .private = FILE_MEMLIST,
|
| 1794 | };
|
| 1795 |
|
| 1796 | static struct cftype cft_cpu_exclusive = {
|
| 1797 | .name = "cpu_exclusive",
|
| 1798 | .private = FILE_CPU_EXCLUSIVE,
|
| 1799 | };
|
| 1800 |
|
| 1801 | static struct cftype cft_mem_exclusive = {
|
| 1802 | .name = "mem_exclusive",
|
| 1803 | .private = FILE_MEM_EXCLUSIVE,
|
| 1804 | };
|
| 1805 |
|
| 1806 | static struct cftype cft_notify_on_release = {
|
| 1807 | .name = "notify_on_release",
|
| 1808 | .private = FILE_NOTIFY_ON_RELEASE,
|
| 1809 | };
|
| 1810 |
|
| 1811 | static struct cftype cft_memory_migrate = {
|
| 1812 | .name = "memory_migrate",
|
| 1813 | .private = FILE_MEMORY_MIGRATE,
|
| 1814 | };
|
| 1815 |
|
| 1816 | static struct cftype cft_memory_pressure_enabled = {
|
| 1817 | .name = "memory_pressure_enabled",
|
| 1818 | .private = FILE_MEMORY_PRESSURE_ENABLED,
|
| 1819 | };
|
| 1820 |
|
| 1821 | static struct cftype cft_memory_pressure = {
|
| 1822 | .name = "memory_pressure",
|
| 1823 | .private = FILE_MEMORY_PRESSURE,
|
| 1824 | };
|
| 1825 |
|
| 1826 | static struct cftype cft_spread_page = {
|
| 1827 | .name = "memory_spread_page",
|
| 1828 | .private = FILE_SPREAD_PAGE,
|
| 1829 | };
|
| 1830 |
|
| 1831 | static struct cftype cft_spread_slab = {
|
| 1832 | .name = "memory_spread_slab",
|
| 1833 | .private = FILE_SPREAD_SLAB,
|
| 1834 | };
|
| 1835 |
|
| 1836 | static int cpuset_populate_dir(struct dentry *cs_dentry)
|
| 1837 | {
|
| 1838 | int err;
|
| 1839 |
|
| 1840 | if ((err = cpuset_add_file(cs_dentry, &cft_cpus)) < 0)
|
| 1841 | return err;
|
| 1842 | if ((err = cpuset_add_file(cs_dentry, &cft_mems)) < 0)
|
| 1843 | return err;
|
| 1844 | if ((err = cpuset_add_file(cs_dentry, &cft_cpu_exclusive)) < 0)
|
| 1845 | return err;
|
| 1846 | if ((err = cpuset_add_file(cs_dentry, &cft_mem_exclusive)) < 0)
|
| 1847 | return err;
|
| 1848 | if ((err = cpuset_add_file(cs_dentry, &cft_notify_on_release)) < 0)
|
| 1849 | return err;
|
| 1850 | if ((err = cpuset_add_file(cs_dentry, &cft_memory_migrate)) < 0)
|
| 1851 | return err;
|
| 1852 | if ((err = cpuset_add_file(cs_dentry, &cft_memory_pressure)) < 0)
|
| 1853 | return err;
|
| 1854 | if ((err = cpuset_add_file(cs_dentry, &cft_spread_page)) < 0)
|
| 1855 | return err;
|
| 1856 | if ((err = cpuset_add_file(cs_dentry, &cft_spread_slab)) < 0)
|
| 1857 | return err;
|
| 1858 | if ((err = cpuset_add_file(cs_dentry, &cft_tasks)) < 0)
|
| 1859 | return err;
|
| 1860 | return 0;
|
| 1861 | }
|
| 1862 |
|
| 1863 | |
| 1864 | * cpuset_create - create a cpuset
|
| 1865 | * parent: cpuset that will be parent of the new cpuset.
|
| 1866 | * name: name of the new cpuset. Will be strcpy'ed.
|
| 1867 | * mode: mode to set on new inode
|
| 1868 | *
|
| 1869 | * Must be called with the mutex on the parent inode held
|
| 1870 |
|
| 1871 |
|
| 1872 | static long cpuset_create(struct cpuset *parent, const char *name, int mode)
|
| 1873 | {
|
| 1874 | struct cpuset *cs;
|
| 1875 | int err;
|
| 1876 |
|
| 1877 | cs = kmalloc(sizeof(*cs), GFP_KERNEL);
|
| 1878 | if (!cs)
|
| 1879 | return -ENOMEM;
|
| 1880 |
|
| 1881 | mutex_lock(&manage_mutex);
|
| 1882 | cpuset_update_task_memory_state();
|
| 1883 | cs->flags = 0;
|
| 1884 | if (notify_on_release(parent))
|
| 1885 | set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
|
| 1886 | if (is_spread_page(parent))
|
| 1887 | set_bit(CS_SPREAD_PAGE, &cs->flags);
|
| 1888 | if (is_spread_slab(parent))
|
| 1889 | set_bit(CS_SPREAD_SLAB, &cs->flags);
|
| 1890 | cs->cpus_allowed = CPU_MASK_NONE;
|
| 1891 | cs->mems_allowed = NODE_MASK_NONE;
|
| 1892 | atomic_set(&cs->count, 0);
|
| 1893 | INIT_LIST_HEAD(&cs->sibling);
|
| 1894 | INIT_LIST_HEAD(&cs->children);
|
| 1895 | cs->mems_generation = cpuset_mems_generation++;
|
| 1896 | fmeter_init(&cs->fmeter);
|
| 1897 |
|
| 1898 | cs->parent = parent;
|
| 1899 |
|
| 1900 | mutex_lock(&callback_mutex);
|
| 1901 | list_add(&cs->sibling, &cs->parent->children);
|
| 1902 | number_of_cpusets++;
|
| 1903 | mutex_unlock(&callback_mutex);
|
| 1904 |
|
| 1905 | err = cpuset_create_dir(cs, name, mode);
|
| 1906 | if (err < 0)
|
| 1907 | goto err;
|
| 1908 |
|
| 1909 | |
| 1910 | * Release manage_mutex before cpuset_populate_dir() because it
|
| 1911 | * will down() this new directory's i_mutex and if we race with
|
| 1912 | * another mkdir, we might deadlock.
|
| 1913 |
|
| 1914 | mutex_unlock(&manage_mutex);
|
| 1915 |
|
| 1916 | err = cpuset_populate_dir(cs->dentry);
|
| 1917 |
|
| 1918 | return 0;
|
| 1919 | err:
|
| 1920 | list_del(&cs->sibling);
|
| 1921 | mutex_unlock(&manage_mutex);
|
| 1922 | kfree(cs);
|
| 1923 | return err;
|
| 1924 | }
|
| 1925 |
|
| 1926 | static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode)
|
| 1927 | {
|
| 1928 | struct cpuset *c_parent = dentry->d_parent->d_fsdata;
|
| 1929 |
|
| 1930 |
|
| 1931 | return cpuset_create(c_parent, dentry->d_name.name, mode | S_IFDIR);
|
| 1932 | }
|
| 1933 |
|
| 1934 | |
| 1935 | * Locking note on the strange update_flag() call below:
|
| 1936 | *
|
| 1937 | * If the cpuset being removed is marked cpu_exclusive, then simulate
|
| 1938 | * turning cpu_exclusive off, which will call update_cpu_domains().
|
| 1939 | * The lock_cpu_hotplug() call in update_cpu_domains() must not be
|
| 1940 | * made while holding callback_mutex. Elsewhere the kernel nests
|
| 1941 | * callback_mutex inside lock_cpu_hotplug() calls. So the reverse
|
| 1942 | * nesting would risk an ABBA deadlock.
|
| 1943 |
|
| 1944 |
|
| 1945 | static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry)
|
| 1946 | {
|
| 1947 | struct cpuset *cs = dentry->d_fsdata;
|
| 1948 | struct dentry *d;
|
| 1949 | struct cpuset *parent;
|
| 1950 | char *pathbuf = NULL;
|
| 1951 |
|
| 1952 |
|
| 1953 |
|
| 1954 | mutex_lock(&manage_mutex);
|
| 1955 | cpuset_update_task_memory_state();
|
| 1956 | if (atomic_read(&cs->count) > 0) {
|
| 1957 | mutex_unlock(&manage_mutex);
|
| 1958 | return -EBUSY;
|
| 1959 | }
|
| 1960 | if (!list_empty(&cs->children)) {
|
| 1961 | mutex_unlock(&manage_mutex);
|
| 1962 | return -EBUSY;
|
| 1963 | }
|
| 1964 | if (is_cpu_exclusive(cs)) {
|
| 1965 | int retval = update_flag(CS_CPU_EXCLUSIVE, cs, "0");
|
| 1966 | if (retval < 0) {
|
| 1967 | mutex_unlock(&manage_mutex);
|
| 1968 | return retval;
|
| 1969 | }
|
| 1970 | }
|
| 1971 | parent = cs->parent;
|
| 1972 | mutex_lock(&callback_mutex);
|
| 1973 | set_bit(CS_REMOVED, &cs->flags);
|
| 1974 | list_del(&cs->sibling);
|
| 1975 | spin_lock(&cs->dentry->d_lock);
|
| 1976 | d = dget(cs->dentry);
|
| 1977 | cs->dentry = NULL;
|
| 1978 | spin_unlock(&d->d_lock);
|
| 1979 | cpuset_d_remove_dir(d);
|
| 1980 | dput(d);
|
| 1981 | number_of_cpusets--;
|
| 1982 | mutex_unlock(&callback_mutex);
|
| 1983 | if (list_empty(&parent->children))
|
| 1984 | check_for_release(parent, &pathbuf);
|
| 1985 | mutex_unlock(&manage_mutex);
|
| 1986 | cpuset_release_agent(pathbuf);
|
| 1987 | return 0;
|
| 1988 | }
|
| 1989 |
|
| 1990 | |
| 1991 | * cpuset_init_early - just enough so that the calls to
|
| 1992 | * cpuset_update_task_memory_state() in early init code
|
| 1993 | * are harmless.
|
| 1994 |
|
| 1995 |
|
| 1996 | int __init cpuset_init_early(void)
|
| 1997 | {
|
| 1998 | struct task_struct *tsk = current;
|
| 1999 |
|
| 2000 | tsk->cpuset = &top_cpuset;
|
| 2001 | tsk->cpuset->mems_generation = cpuset_mems_generation++;
|
| 2002 | return 0;
|
| 2003 | }
|
| 2004 |
|
| 2005 | |
| 2006 | * cpuset_init - initialize cpusets at system boot
|
| 2007 | *
|
| 2008 | * Description: Initialize top_cpuset and the cpuset internal file system,
|
| 2009 | *
|
| 2010 |
|
| 2011 | int __init cpuset_init(void)
|
| 2012 | {
|
| 2013 | struct dentry *root;
|
| 2014 | int err;
|
| 2015 |
|
| 2016 | top_cpuset.cpus_allowed = CPU_MASK_ALL;
|
| 2017 | top_cpuset.mems_allowed = NODE_MASK_ALL;
|
| 2018 |
|
| 2019 | fmeter_init(&top_cpuset.fmeter);
|
| 2020 | top_cpuset.mems_generation = cpuset_mems_generation++;
|
| 2021 |
|
| 2022 | init_task.cpuset = &top_cpuset;
|
| 2023 |
|
| 2024 | err = register_filesystem(&cpuset_fs_type);
|
| 2025 | if (err < 0)
|
| 2026 | goto out;
|
| 2027 | cpuset_mount = kern_mount(&cpuset_fs_type);
|
| 2028 | if (IS_ERR(cpuset_mount)) {
|
| 2029 | printk(KERN_ERR "cpuset: could not mount!\n");
|
| 2030 | err = PTR_ERR(cpuset_mount);
|
| 2031 | cpuset_mount = NULL;
|
| 2032 | goto out;
|
| 2033 | }
|
| 2034 | root = cpuset_mount->mnt_sb->s_root;
|
| 2035 | root->d_fsdata = &top_cpuset;
|
| 2036 | inc_nlink(root->d_inode);
|
| 2037 | top_cpuset.dentry = root;
|
| 2038 | root->d_inode->i_op = &cpuset_dir_inode_operations;
|
| 2039 | number_of_cpusets = 1;
|
| 2040 | err = cpuset_populate_dir(root);
|
| 2041 |
|
| 2042 | if (err == 0)
|
| 2043 | err = cpuset_add_file(root, &cft_memory_pressure_enabled);
|
| 2044 | out:
|
| 2045 | return err;
|
| 2046 | }
|
| 2047 |
|
| 2048 | |
| 2049 | * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
|
| 2050 | * or memory nodes, we need to walk over the cpuset hierarchy,
|
| 2051 | * removing that CPU or node from all cpusets. If this removes the
|
| 2052 | * last CPU or node from a cpuset, then the guarantee_online_cpus()
|
| 2053 | * or guarantee_online_mems() code will use that emptied cpusets
|
| 2054 | * parent online CPUs or nodes. Cpusets that were already empty of
|
| 2055 | * CPUs or nodes are left empty.
|
| 2056 | *
|
| 2057 | * This routine is intentionally inefficient in a couple of regards.
|
| 2058 | * It will check all cpusets in a subtree even if the top cpuset of
|
| 2059 | * the subtree has no offline CPUs or nodes. It checks both CPUs and
|
| 2060 | * nodes, even though the caller could have been coded to know that
|
| 2061 | * only one of CPUs or nodes needed to be checked on a given call.
|
| 2062 | * This was done to minimize text size rather than cpu cycles.
|
| 2063 | *
|
| 2064 | * Call with both manage_mutex and callback_mutex held.
|
| 2065 | *
|
| 2066 | * Recursive, on depth of cpuset subtree.
|
| 2067 |
|
| 2068 |
|
| 2069 | static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur)
|
| 2070 | {
|
| 2071 | struct cpuset *c;
|
| 2072 |
|
| 2073 |
|
| 2074 | list_for_each_entry(c, &cur->children, sibling) {
|
| 2075 | guarantee_online_cpus_mems_in_subtree(c);
|
| 2076 | if (!cpus_empty(c->cpus_allowed))
|
| 2077 | guarantee_online_cpus(c, &c->cpus_allowed);
|
| 2078 | if (!nodes_empty(c->mems_allowed))
|
| 2079 | guarantee_online_mems(c, &c->mems_allowed);
|
| 2080 | }
|
| 2081 | }
|
| 2082 |
|
| 2083 | |
| 2084 | * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
|
| 2085 | * cpu_online_map and node_online_map. Force the top cpuset to track
|
| 2086 | * whats online after any CPU or memory node hotplug or unplug event.
|
| 2087 | *
|
| 2088 | * To ensure that we don't remove a CPU or node from the top cpuset
|
| 2089 | * that is currently in use by a child cpuset (which would violate
|
| 2090 | * the rule that cpusets must be subsets of their parent), we first
|
| 2091 | * call the recursive routine guarantee_online_cpus_mems_in_subtree().
|
| 2092 | *
|
| 2093 | * Since there are two callers of this routine, one for CPU hotplug
|
| 2094 | * events and one for memory node hotplug events, we could have coded
|
| 2095 | * two separate routines here. We code it as a single common routine
|
| 2096 | * in order to minimize text size.
|
| 2097 |
|
| 2098 |
|
| 2099 | static void common_cpu_mem_hotplug_unplug(void)
|
| 2100 | {
|
| 2101 | mutex_lock(&manage_mutex);
|
| 2102 | mutex_lock(&callback_mutex);
|
| 2103 |
|
| 2104 | guarantee_online_cpus_mems_in_subtree(&top_cpuset);
|
| 2105 | top_cpuset.cpus_allowed = cpu_online_map;
|
| 2106 | top_cpuset.mems_allowed = node_online_map;
|
| 2107 |
|
| 2108 | mutex_unlock(&callback_mutex);
|
| 2109 | mutex_unlock(&manage_mutex);
|
| 2110 | }
|
| 2111 |
|
| 2112 | |
| 2113 | * The top_cpuset tracks what CPUs and Memory Nodes are online,
|
| 2114 | * period. This is necessary in order to make cpusets transparent
|
| 2115 | * (of no affect) on systems that are actively using CPU hotplug
|
| 2116 | * but making no active use of cpusets.
|
| 2117 | *
|
| 2118 | * This routine ensures that top_cpuset.cpus_allowed tracks
|
| 2119 | * cpu_online_map on each CPU hotplug (cpuhp) event.
|
| 2120 |
|
| 2121 |
|
| 2122 | static int cpuset_handle_cpuhp(struct notifier_block *nb,
|
| 2123 | unsigned long phase, void *cpu)
|
| 2124 | {
|
| 2125 | common_cpu_mem_hotplug_unplug();
|
| 2126 | return 0;
|
| 2127 | }
|
| 2128 |
|
| 2129 | #ifdef CONFIG_MEMORY_HOTPLUG
|
| 2130 | |
| 2131 | * Keep top_cpuset.mems_allowed tracking node_online_map.
|
| 2132 | * Call this routine anytime after you change node_online_map.
|
| 2133 | * See also the previous routine cpuset_handle_cpuhp().
|
| 2134 |
|
| 2135 |
|
| 2136 | void cpuset_track_online_nodes(void)
|
| 2137 | {
|
| 2138 | common_cpu_mem_hotplug_unplug();
|
| 2139 | }
|
| 2140 | #endif
|
| 2141 |
|
| 2142 | |
| 2143 | * cpuset_init_smp - initialize cpus_allowed
|
| 2144 | *
|
| 2145 | * Description: Finish top cpuset after cpu, node maps are initialized
|
| 2146 | *
|
| 2147 |
|
| 2148 | void __init cpuset_init_smp(void)
|
| 2149 | {
|
| 2150 | top_cpuset.cpus_allowed = cpu_online_map;
|
| 2151 | top_cpuset.mems_allowed = node_online_map;
|
| 2152 |
|
| 2153 | hotcpu_notifier(cpuset_handle_cpuhp, 0);
|
| 2154 | }
|
| 2155 |
|
| 2156 | |
| 2157 | * cpuset_fork - attach newly forked task to its parents cpuset.
|
| 2158 | * @tsk: pointer to task_struct of forking parent process.
|
| 2159 | *
|
| 2160 | * Description: A task inherits its parent's cpuset at fork().
|
| 2161 | *
|
| 2162 | * A pointer to the shared cpuset was automatically copied in fork.c
|
| 2163 | * by dup_task_struct(). However, we ignore that copy, since it was
|
| 2164 | * not made under the protection of task_lock(), so might no longer be
|
| 2165 | * a valid cpuset pointer. attach_task() might have already changed
|
| 2166 | * current->cpuset, allowing the previously referenced cpuset to
|
| 2167 | * be removed and freed. Instead, we task_lock(current) and copy
|
| 2168 | * its present value of current->cpuset for our freshly forked child.
|
| 2169 | *
|
| 2170 | * At the point that cpuset_fork() is called, 'current' is the parent
|
| 2171 | * task, and the passed argument 'child' points to the child task.
|
| 2172 | *
|
| 2173 |
|
| 2174 | void cpuset_fork(struct task_struct *child)
|
| 2175 | {
|
| 2176 | task_lock(current);
|
| 2177 | child->cpuset = current->cpuset;
|
| 2178 | atomic_inc(&child->cpuset->count);
|
| 2179 | task_unlock(current);
|
| 2180 | }
|
| 2181 |
|
| 2182 | |
| 2183 | * cpuset_exit - detach cpuset from exiting task
|
| 2184 | * @tsk: pointer to task_struct of exiting process
|
| 2185 | *
|
| 2186 | * Description: Detach cpuset from @tsk and release it.
|
| 2187 | *
|
| 2188 | * Note that cpusets marked notify_on_release force every task in
|
| 2189 | * them to take the global manage_mutex mutex when exiting.
|
| 2190 | * This could impact scaling on very large systems. Be reluctant to
|
| 2191 | * use notify_on_release cpusets where very high task exit scaling
|
| 2192 | * is required on large systems.
|
| 2193 | *
|
| 2194 | * Don't even think about derefencing 'cs' after the cpuset use count
|
| 2195 | * goes to zero, except inside a critical section guarded by manage_mutex
|
| 2196 | * or callback_mutex. Otherwise a zero cpuset use count is a license to
|
| 2197 | * any other task to nuke the cpuset immediately, via cpuset_rmdir().
|
| 2198 | *
|
| 2199 | * This routine has to take manage_mutex, not callback_mutex, because
|
| 2200 | * it is holding that mutex while calling check_for_release(),
|
| 2201 | * which calls kmalloc(), so can't be called holding callback_mutex().
|
| 2202 | *
|
| 2203 | * We don't need to task_lock() this reference to tsk->cpuset,
|
| 2204 | * because tsk is already marked PF_EXITING, so attach_task() won't
|
| 2205 | * mess with it, or task is a failed fork, never visible to attach_task.
|
| 2206 | *
|
| 2207 | * the_top_cpuset_hack:
|
| 2208 | *
|
| 2209 | * Set the exiting tasks cpuset to the root cpuset (top_cpuset).
|
| 2210 | *
|
| 2211 | * Don't leave a task unable to allocate memory, as that is an
|
| 2212 | * accident waiting to happen should someone add a callout in
|
| 2213 | * do_exit() after the cpuset_exit() call that might allocate.
|
| 2214 | * If a task tries to allocate memory with an invalid cpuset,
|
| 2215 | * it will oops in cpuset_update_task_memory_state().
|
| 2216 | *
|
| 2217 | * We call cpuset_exit() while the task is still competent to
|
| 2218 | * handle notify_on_release(), then leave the task attached to
|
| 2219 | * the root cpuset (top_cpuset) for the remainder of its exit.
|
| 2220 | *
|
| 2221 | * To do this properly, we would increment the reference count on
|
| 2222 | * top_cpuset, and near the very end of the kernel/exit.c do_exit()
|
| 2223 | * code we would add a second cpuset function call, to drop that
|
| 2224 | * reference. This would just create an unnecessary hot spot on
|
| 2225 | * the top_cpuset reference count, to no avail.
|
| 2226 | *
|
| 2227 | * Normally, holding a reference to a cpuset without bumping its
|
| 2228 | * count is unsafe. The cpuset could go away, or someone could
|
| 2229 | * attach us to a different cpuset, decrementing the count on
|
| 2230 | * the first cpuset that we never incremented. But in this case,
|
| 2231 | * top_cpuset isn't going away, and either task has PF_EXITING set,
|
| 2232 | * which wards off any attach_task() attempts, or task is a failed
|
| 2233 | * fork, never visible to attach_task.
|
| 2234 | *
|
| 2235 | * Another way to do this would be to set the cpuset pointer
|
| 2236 | * to NULL here, and check in cpuset_update_task_memory_state()
|
| 2237 | * for a NULL pointer. This hack avoids that NULL check, for no
|
| 2238 | * cost (other than this way too long comment ;).
|
| 2239 | *
|
| 2240 |
|
| 2241 | void cpuset_exit(struct task_struct *tsk)
|
| 2242 | {
|
| 2243 | struct cpuset *cs;
|
| 2244 |
|
| 2245 | cs = tsk->cpuset;
|
| 2246 | tsk->cpuset = &top_cpuset;
|
| 2247 |
|
| 2248 | if (notify_on_release(cs)) {
|
| 2249 | char *pathbuf = NULL;
|
| 2250 |
|
| 2251 | mutex_lock(&manage_mutex);
|
| 2252 | if (atomic_dec_and_test(&cs->count))
|
| 2253 | check_for_release(cs, &pathbuf);
|
| 2254 | mutex_unlock(&manage_mutex);
|
| 2255 | cpuset_release_agent(pathbuf);
|
| 2256 | } else {
|
| 2257 | atomic_dec(&cs->count);
|
| 2258 | }
|
| 2259 | }
|
| 2260 |
|
| 2261 | |
| 2262 | * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
|
| 2263 | * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
|
| 2264 | *
|
| 2265 | * Description: Returns the cpumask_t cpus_allowed of the cpuset
|
| 2266 | * attached to the specified @tsk. Guaranteed to return some non-empty
|
| 2267 | * subset of cpu_online_map, even if this means going outside the
|
| 2268 | * tasks cpuset.
|
| 2269 | *
|
| 2270 |
|
| 2271 | cpumask_t cpuset_cpus_allowed(struct task_struct *tsk)
|
| 2272 | {
|
| 2273 | cpumask_t mask;
|
| 2274 |
|
| 2275 | mutex_lock(&callback_mutex);
|
| 2276 | task_lock(tsk);
|
| 2277 | guarantee_online_cpus(tsk->cpuset, &mask);
|
| 2278 | task_unlock(tsk);
|
| 2279 | mutex_unlock(&callback_mutex);
|
| 2280 |
|
| 2281 | return mask;
|
| 2282 | }
|
| 2283 |
|
| 2284 | void cpuset_init_current_mems_allowed(void)
|
| 2285 | {
|
| 2286 | current->mems_allowed = NODE_MASK_ALL;
|
| 2287 | }
|
| 2288 |
|
| 2289 | |
| 2290 | * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
|
| 2291 | * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
|
| 2292 | *
|
| 2293 | * Description: Returns the nodemask_t mems_allowed of the cpuset
|
| 2294 | * attached to the specified @tsk. Guaranteed to return some non-empty
|
| 2295 | * subset of node_online_map, even if this means going outside the
|
| 2296 | * tasks cpuset.
|
| 2297 | *
|
| 2298 |
|
| 2299 | nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
|
| 2300 | {
|
| 2301 | nodemask_t mask;
|
| 2302 |
|
| 2303 | mutex_lock(&callback_mutex);
|
| 2304 | task_lock(tsk);
|
| 2305 | guarantee_online_mems(tsk->cpuset, &mask);
|
| 2306 | task_unlock(tsk);
|
| 2307 | mutex_unlock(&callback_mutex);
|
| 2308 |
|
| 2309 | return mask;
|
| 2310 | }
|
| 2311 |
|
| 2312 | |
| 2313 | * cpuset_zonelist_valid_mems_allowed - check zonelist vs. curremt mems_allowed
|
| 2314 | * @zl: the zonelist to be checked
|
| 2315 | *
|
| 2316 | * Are any of the nodes on zonelist zl allowed in current->mems_allowed?
|
| 2317 |
|
| 2318 | int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
|
| 2319 | {
|
| 2320 | int i;
|
| 2321 |
|
| 2322 | for (i = 0; zl->zones[i]; i++) {
|
| 2323 | int nid = zone_to_nid(zl->zones[i]);
|
| 2324 |
|
| 2325 | if (node_isset(nid, current->mems_allowed))
|
| 2326 | return 1;
|
| 2327 | }
|
| 2328 | return 0;
|
| 2329 | }
|
| 2330 |
|
| 2331 | |
| 2332 | * nearest_exclusive_ancestor() - Returns the nearest mem_exclusive
|
| 2333 | * ancestor to the specified cpuset. Call holding callback_mutex.
|
| 2334 | * If no ancestor is mem_exclusive (an unusual configuration), then
|
| 2335 | * returns the root cpuset.
|
| 2336 |
|
| 2337 | static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs)
|
| 2338 | {
|
| 2339 | while (!is_mem_exclusive(cs) && cs->parent)
|
| 2340 | cs = cs->parent;
|
| 2341 | return cs;
|
| 2342 | }
|
| 2343 |
|
| 2344 | |
| 2345 | * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node?
|
| 2346 | * @z: is this zone on an allowed node?
|
| 2347 | * @gfp_mask: memory allocation flags
|
| 2348 | *
|
| 2349 | * If we're in interrupt, yes, we can always allocate. If
|
| 2350 | * __GFP_THISNODE is set, yes, we can always allocate. If zone
|
| 2351 | * z's node is in our tasks mems_allowed, yes. If it's not a
|
| 2352 | * __GFP_HARDWALL request and this zone's nodes is in the nearest
|
| 2353 | * mem_exclusive cpuset ancestor to this tasks cpuset, yes.
|
| 2354 | * Otherwise, no.
|
| 2355 | *
|
| 2356 | * If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall()
|
| 2357 | * reduces to cpuset_zone_allowed_hardwall(). Otherwise,
|
| 2358 | * cpuset_zone_allowed_softwall() might sleep, and might allow a zone
|
| 2359 | * from an enclosing cpuset.
|
| 2360 | *
|
| 2361 | * cpuset_zone_allowed_hardwall() only handles the simpler case of
|
| 2362 | * hardwall cpusets, and never sleeps.
|
| 2363 | *
|
| 2364 | * The __GFP_THISNODE placement logic is really handled elsewhere,
|
| 2365 | * by forcibly using a zonelist starting at a specified node, and by
|
| 2366 | * (in get_page_from_freelist()) refusing to consider the zones for
|
| 2367 | * any node on the zonelist except the first. By the time any such
|
| 2368 | * calls get to this routine, we should just shut up and say 'yes'.
|
| 2369 | *
|
| 2370 | * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
|
| 2371 | * and do not allow allocations outside the current tasks cpuset.
|
| 2372 | * GFP_KERNEL allocations are not so marked, so can escape to the
|
| 2373 | * nearest enclosing mem_exclusive ancestor cpuset.
|
| 2374 | *
|
| 2375 | * Scanning up parent cpusets requires callback_mutex. The
|
| 2376 | * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
|
| 2377 | * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
|
| 2378 | * current tasks mems_allowed came up empty on the first pass over
|
| 2379 | * the zonelist. So only GFP_KERNEL allocations, if all nodes in the
|
| 2380 | * cpuset are short of memory, might require taking the callback_mutex
|
| 2381 | * mutex.
|
| 2382 | *
|
| 2383 | * The first call here from mm/page_alloc:get_page_from_freelist()
|
| 2384 | * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
|
| 2385 | * so no allocation on a node outside the cpuset is allowed (unless
|
| 2386 | * in interrupt, of course).
|
| 2387 | *
|
| 2388 | * The second pass through get_page_from_freelist() doesn't even call
|
| 2389 | * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
|
| 2390 | * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
|
| 2391 | * in alloc_flags. That logic and the checks below have the combined
|
| 2392 | * affect that:
|
| 2393 | * in_interrupt - any node ok (current task context irrelevant)
|
| 2394 | * GFP_ATOMIC - any node ok
|
| 2395 | * GFP_KERNEL - any node in enclosing mem_exclusive cpuset ok
|
| 2396 | * GFP_USER - only nodes in current tasks mems allowed ok.
|
| 2397 | *
|
| 2398 | * Rule:
|
| 2399 | * Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you
|
| 2400 | * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables
|
| 2401 | * the code that might scan up ancestor cpusets and sleep.
|
| 2402 |
|
| 2403 |
|
| 2404 | int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
|
| 2405 | {
|
| 2406 | int node;
|
| 2407 | const struct cpuset *cs;
|
| 2408 | int allowed;
|
| 2409 |
|
| 2410 | if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
|
| 2411 | return 1;
|
| 2412 | node = zone_to_nid(z);
|
| 2413 | might_sleep_if(!(gfp_mask & __GFP_HARDWALL));
|
| 2414 | if (node_isset(node, current->mems_allowed))
|
| 2415 | return 1;
|
| 2416 | if (gfp_mask & __GFP_HARDWALL)
|
| 2417 | return 0;
|
| 2418 |
|
| 2419 | if (current->flags & PF_EXITING)
|
| 2420 | return 1;
|
| 2421 |
|
| 2422 |
|
| 2423 | mutex_lock(&callback_mutex);
|
| 2424 |
|
| 2425 | task_lock(current);
|
| 2426 | cs = nearest_exclusive_ancestor(current->cpuset);
|
| 2427 | task_unlock(current);
|
| 2428 |
|
| 2429 | allowed = node_isset(node, cs->mems_allowed);
|
| 2430 | mutex_unlock(&callback_mutex);
|
| 2431 | return allowed;
|
| 2432 | }
|
| 2433 |
|
| 2434 | |
| 2435 | * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node?
|
| 2436 | * @z: is this zone on an allowed node?
|
| 2437 | * @gfp_mask: memory allocation flags
|
| 2438 | *
|
| 2439 | * If we're in interrupt, yes, we can always allocate.
|
| 2440 | * If __GFP_THISNODE is set, yes, we can always allocate. If zone
|
| 2441 | * z's node is in our tasks mems_allowed, yes. Otherwise, no.
|
| 2442 | *
|
| 2443 | * The __GFP_THISNODE placement logic is really handled elsewhere,
|
| 2444 | * by forcibly using a zonelist starting at a specified node, and by
|
| 2445 | * (in get_page_from_freelist()) refusing to consider the zones for
|
| 2446 | * any node on the zonelist except the first. By the time any such
|
| 2447 | * calls get to this routine, we should just shut up and say 'yes'.
|
| 2448 | *
|
| 2449 | * Unlike the cpuset_zone_allowed_softwall() variant, above,
|
| 2450 | * this variant requires that the zone be in the current tasks
|
| 2451 | * mems_allowed or that we're in interrupt. It does not scan up the
|
| 2452 | * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset.
|
| 2453 | * It never sleeps.
|
| 2454 |
|
| 2455 |
|
| 2456 | int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
|
| 2457 | {
|
| 2458 | int node;
|
| 2459 |
|
| 2460 | if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
|
| 2461 | return 1;
|
| 2462 | node = zone_to_nid(z);
|
| 2463 | if (node_isset(node, current->mems_allowed))
|
| 2464 | return 1;
|
| 2465 | return 0;
|
| 2466 | }
|
| 2467 |
|
| 2468 | |
| 2469 | * cpuset_lock - lock out any changes to cpuset structures
|
| 2470 | *
|
| 2471 | * The out of memory (oom) code needs to mutex_lock cpusets
|
| 2472 | * from being changed while it scans the tasklist looking for a
|
| 2473 | * task in an overlapping cpuset. Expose callback_mutex via this
|
| 2474 | * cpuset_lock() routine, so the oom code can lock it, before
|
| 2475 | * locking the task list. The tasklist_lock is a spinlock, so
|
| 2476 | * must be taken inside callback_mutex.
|
| 2477 |
|
| 2478 |
|
| 2479 | void cpuset_lock(void)
|
| 2480 | {
|
| 2481 | mutex_lock(&callback_mutex);
|
| 2482 | }
|
| 2483 |
|
| 2484 | |
| 2485 | * cpuset_unlock - release lock on cpuset changes
|
| 2486 | *
|
| 2487 | * Undo the lock taken in a previous cpuset_lock() call.
|
| 2488 |
|
| 2489 |
|
| 2490 | void cpuset_unlock(void)
|
| 2491 | {
|
| 2492 | mutex_unlock(&callback_mutex);
|
| 2493 | }
|
| 2494 |
|
| 2495 | |
| 2496 | * cpuset_mem_spread_node() - On which node to begin search for a page
|
| 2497 | *
|
| 2498 | * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
|
| 2499 | * tasks in a cpuset with is_spread_page or is_spread_slab set),
|
| 2500 | * and if the memory allocation used cpuset_mem_spread_node()
|
| 2501 | * to determine on which node to start looking, as it will for
|
| 2502 | * certain page cache or slab cache pages such as used for file
|
| 2503 | * system buffers and inode caches, then instead of starting on the
|
| 2504 | * local node to look for a free page, rather spread the starting
|
| 2505 | * node around the tasks mems_allowed nodes.
|
| 2506 | *
|
| 2507 | * We don't have to worry about the returned node being offline
|
| 2508 | * because "it can't happen", and even if it did, it would be ok.
|
| 2509 | *
|
| 2510 | * The routines calling guarantee_online_mems() are careful to
|
| 2511 | * only set nodes in task->mems_allowed that are online. So it
|
| 2512 | * should not be possible for the following code to return an
|
| 2513 | * offline node. But if it did, that would be ok, as this routine
|
| 2514 | * is not returning the node where the allocation must be, only
|
| 2515 | * the node where the search should start. The zonelist passed to
|
| 2516 | * __alloc_pages() will include all nodes. If the slab allocator
|
| 2517 | * is passed an offline node, it will fall back to the local node.
|
| 2518 | * See kmem_cache_alloc_node().
|
| 2519 |
|
| 2520 |
|
| 2521 | int cpuset_mem_spread_node(void)
|
| 2522 | {
|
| 2523 | int node;
|
| 2524 |
|
| 2525 | node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed);
|
| 2526 | if (node == MAX_NUMNODES)
|
| 2527 | node = first_node(current->mems_allowed);
|
| 2528 | current->cpuset_mem_spread_rotor = node;
|
| 2529 | return node;
|
| 2530 | }
|
| 2531 | EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
|
| 2532 |
|
| 2533 | |
| 2534 | * cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors?
|
| 2535 | * @p: pointer to task_struct of some other task.
|
| 2536 | *
|
| 2537 | * Description: Return true if the nearest mem_exclusive ancestor
|
| 2538 | * cpusets of tasks @p and current overlap. Used by oom killer to
|
| 2539 | * determine if task @p's memory usage might impact the memory
|
| 2540 | * available to the current task.
|
| 2541 | *
|
| 2542 | * Call while holding callback_mutex.
|
| 2543 | *
|
| 2544 |
|
| 2545 | int cpuset_excl_nodes_overlap(const struct task_struct *p)
|
| 2546 | {
|
| 2547 | const struct cpuset *cs1, *cs2;
|
| 2548 | int overlap = 1;
|
| 2549 |
|
| 2550 | task_lock(current);
|
| 2551 | if (current->flags & PF_EXITING) {
|
| 2552 | task_unlock(current);
|
| 2553 | goto done;
|
| 2554 | }
|
| 2555 | cs1 = nearest_exclusive_ancestor(current->cpuset);
|
| 2556 | task_unlock(current);
|
| 2557 |
|
| 2558 | task_lock((struct task_struct *)p);
|
| 2559 | if (p->flags & PF_EXITING) {
|
| 2560 | task_unlock((struct task_struct *)p);
|
| 2561 | goto done;
|
| 2562 | }
|
| 2563 | cs2 = nearest_exclusive_ancestor(p->cpuset);
|
| 2564 | task_unlock((struct task_struct *)p);
|
| 2565 |
|
| 2566 | overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed);
|
| 2567 | done:
|
| 2568 | return overlap;
|
| 2569 | }
|
| 2570 |
|
| 2571 | |
| 2572 | * Collection of memory_pressure is suppressed unless
|
| 2573 | * this flag is enabled by writing "1" to the special
|
| 2574 | * cpuset file 'memory_pressure_enabled' in the root cpuset.
|
| 2575 |
|
| 2576 |
|
| 2577 | int cpuset_memory_pressure_enabled __read_mostly;
|
| 2578 |
|
| 2579 | |
| 2580 | * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
|
| 2581 | *
|
| 2582 | * Keep a running average of the rate of synchronous (direct)
|
| 2583 | * page reclaim efforts initiated by tasks in each cpuset.
|
| 2584 | *
|
| 2585 | * This represents the rate at which some task in the cpuset
|
| 2586 | * ran low on memory on all nodes it was allowed to use, and
|
| 2587 | * had to enter the kernels page reclaim code in an effort to
|
| 2588 | * create more free memory by tossing clean pages or swapping
|
| 2589 | * or writing dirty pages.
|
| 2590 | *
|
| 2591 | * Display to user space in the per-cpuset read-only file
|
| 2592 | * "memory_pressure". Value displayed is an integer
|
| 2593 | * representing the recent rate of entry into the synchronous
|
| 2594 | * (direct) page reclaim by any task attached to the cpuset.
|
| 2595 | *
|
| 2596 |
|
| 2597 | void __cpuset_memory_pressure_bump(void)
|
| 2598 | {
|
| 2599 | struct cpuset *cs;
|
| 2600 |
|
| 2601 | task_lock(current);
|
| 2602 | cs = current->cpuset;
|
| 2603 | fmeter_markevent(&cs->fmeter);
|
| 2604 | task_unlock(current);
|
| 2605 | }
|
| 2606 |
|
| 2607 | |
| 2608 | * proc_cpuset_show()
|
| 2609 | * - Print tasks cpuset path into seq_file.
|
| 2610 | * - Used for /proc/<pid>/cpuset.
|
| 2611 | * - No need to task_lock(tsk) on this tsk->cpuset reference, as it
|
| 2612 | * doesn't really matter if tsk->cpuset changes after we read it,
|
| 2613 | * and we take manage_mutex, keeping attach_task() from changing it
|
| 2614 | * anyway. No need to check that tsk->cpuset != NULL, thanks to
|
| 2615 | * the_top_cpuset_hack in cpuset_exit(), which sets an exiting tasks
|
| 2616 | * cpuset to top_cpuset.
|
| 2617 |
|
| 2618 | static int proc_cpuset_show(struct seq_file *m, void *v)
|
| 2619 | {
|
| 2620 | struct pid *pid;
|
| 2621 | struct task_struct *tsk;
|
| 2622 | char *buf;
|
| 2623 | int retval;
|
| 2624 |
|
| 2625 | retval = -ENOMEM;
|
| 2626 | buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
|
| 2627 | if (!buf)
|
| 2628 | goto out;
|
| 2629 |
|
| 2630 | retval = -ESRCH;
|
| 2631 | pid = m->private;
|
| 2632 | tsk = get_pid_task(pid, PIDTYPE_PID);
|
| 2633 | if (!tsk)
|
| 2634 | goto out_free;
|
| 2635 |
|
| 2636 | retval = -EINVAL;
|
| 2637 | mutex_lock(&manage_mutex);
|
| 2638 |
|
| 2639 | retval = cpuset_path(tsk->cpuset, buf, PAGE_SIZE);
|
| 2640 | if (retval < 0)
|
| 2641 | goto out_unlock;
|
| 2642 | seq_puts(m, buf);
|
| 2643 | seq_putc(m, '\n');
|
| 2644 | out_unlock:
|
| 2645 | mutex_unlock(&manage_mutex);
|
| 2646 | put_task_struct(tsk);
|
| 2647 | out_free:
|
| 2648 | kfree(buf);
|
| 2649 | out:
|
| 2650 | return retval;
|
| 2651 | }
|
| 2652 |
|
| 2653 | static int cpuset_open(struct inode *inode, struct file *file)
|
| 2654 | {
|
| 2655 | struct pid *pid = PROC_I(inode)->pid;
|
| 2656 | return single_open(file, proc_cpuset_show, pid);
|
| 2657 | }
|
| 2658 |
|
| 2659 | const struct file_operations proc_cpuset_operations = {
|
| 2660 | .open = cpuset_open,
|
| 2661 | .read = seq_read,
|
| 2662 | .llseek = seq_lseek,
|
| 2663 | .release = single_release,
|
| 2664 | };
|
| 2665 |
|
| 2666 |
|
| 2667 | char *cpuset_task_status_allowed(struct task_struct *task, char *buffer)
|
| 2668 | {
|
| 2669 | buffer += sprintf(buffer, "Cpus_allowed:\t");
|
| 2670 | buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed);
|
| 2671 | buffer += sprintf(buffer, "\n");
|
| 2672 | buffer += sprintf(buffer, "Mems_allowed:\t");
|
| 2673 | buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed);
|
| 2674 | buffer += sprintf(buffer, "\n");
|
| 2675 | return buffer;
|
| 2676 | }
|