| /* |
| * kernel/cpuset.c |
| * |
| * Processor and Memory placement constraints for sets of tasks. |
| * |
| * Copyright (C) 2003 BULL SA. |
| * Copyright (C) 2004-2006 Silicon Graphics, Inc. |
| * |
| * Portions derived from Patrick Mochel's sysfs code. |
| * sysfs is Copyright (c) 2001-3 Patrick Mochel |
| * |
| * 2003-10-10 Written by Simon Derr. |
| * 2003-10-22 Updates by Stephen Hemminger. |
| * 2004 May-July Rework by Paul Jackson. |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file COPYING in the main directory of the Linux |
| * distribution for more details. |
| */ |
| |
| #include <linux/cpu.h> |
| #include <linux/cpumask.h> |
| #include <linux/cpuset.h> |
| #include <linux/err.h> |
| #include <linux/errno.h> |
| #include <linux/file.h> |
| #include <linux/fs.h> |
| #include <linux/init.h> |
| #include <linux/interrupt.h> |
| #include <linux/kernel.h> |
| #include <linux/kmod.h> |
| #include <linux/list.h> |
| #include <linux/mempolicy.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/mount.h> |
| #include <linux/namei.h> |
| #include <linux/pagemap.h> |
| #include <linux/proc_fs.h> |
| #include <linux/rcupdate.h> |
| #include <linux/sched.h> |
| #include <linux/seq_file.h> |
| #include <linux/security.h> |
| #include <linux/slab.h> |
| #include <linux/spinlock.h> |
| #include <linux/stat.h> |
| #include <linux/string.h> |
| #include <linux/time.h> |
| #include <linux/backing-dev.h> |
| #include <linux/sort.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/atomic.h> |
| #include <linux/mutex.h> |
| |
| #define CPUSET_SUPER_MAGIC 0x27e0eb |
| |
| /* |
| * Tracks how many cpusets are currently defined in system. |
| * When there is only one cpuset (the root cpuset) we can |
| * short circuit some hooks. |
| */ |
| int number_of_cpusets __read_mostly; |
| |
| /* See "Frequency meter" comments, below. */ |
| |
| struct fmeter { |
| int cnt; /* unprocessed events count */ |
| int val; /* most recent output value */ |
| time_t time; /* clock (secs) when val computed */ |
| spinlock_t lock; /* guards read or write of above */ |
| }; |
| |
| struct cpuset { |
| unsigned long flags; /* "unsigned long" so bitops work */ |
| cpumask_t cpus_allowed; /* CPUs allowed to tasks in cpuset */ |
| nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */ |
| |
| /* |
| * Count is atomic so can incr (fork) or decr (exit) without a lock. |
| */ |
| atomic_t count; /* count tasks using this cpuset */ |
| |
| /* |
| * We link our 'sibling' struct into our parents 'children'. |
| * Our children link their 'sibling' into our 'children'. |
| */ |
| struct list_head sibling; /* my parents children */ |
| struct list_head children; /* my children */ |
| |
| struct cpuset *parent; /* my parent */ |
| struct dentry *dentry; /* cpuset fs entry */ |
| |
| /* |
| * Copy of global cpuset_mems_generation as of the most |
| * recent time this cpuset changed its mems_allowed. |
| */ |
| int mems_generation; |
| |
| struct fmeter fmeter; /* memory_pressure filter */ |
| }; |
| |
| /* bits in struct cpuset flags field */ |
| typedef enum { |
| CS_CPU_EXCLUSIVE, |
| CS_MEM_EXCLUSIVE, |
| CS_MEMORY_MIGRATE, |
| CS_REMOVED, |
| CS_NOTIFY_ON_RELEASE, |
| CS_SPREAD_PAGE, |
| CS_SPREAD_SLAB, |
| } cpuset_flagbits_t; |
| |
| /* convenient tests for these bits */ |
| static inline int is_cpu_exclusive(const struct cpuset *cs) |
| { |
| return test_bit(CS_CPU_EXCLUSIVE, &cs->flags); |
| } |
| |
| static inline int is_mem_exclusive(const struct cpuset *cs) |
| { |
| return test_bit(CS_MEM_EXCLUSIVE, &cs->flags); |
| } |
| |
| static inline int is_removed(const struct cpuset *cs) |
| { |
| return test_bit(CS_REMOVED, &cs->flags); |
| } |
| |
| static inline int notify_on_release(const struct cpuset *cs) |
| { |
| return test_bit(CS_NOTIFY_ON_RELEASE, &cs->flags); |
| } |
| |
| static inline int is_memory_migrate(const struct cpuset *cs) |
| { |
| return test_bit(CS_MEMORY_MIGRATE, &cs->flags); |
| } |
| |
| static inline int is_spread_page(const struct cpuset *cs) |
| { |
| return test_bit(CS_SPREAD_PAGE, &cs->flags); |
| } |
| |
| static inline int is_spread_slab(const struct cpuset *cs) |
| { |
| return test_bit(CS_SPREAD_SLAB, &cs->flags); |
| } |
| |
| /* |
| * Increment this integer everytime any cpuset changes its |
| * mems_allowed value. Users of cpusets can track this generation |
| * number, and avoid having to lock and reload mems_allowed unless |
| * the cpuset they're using changes generation. |
| * |
| * A single, global generation is needed because attach_task() could |
| * reattach a task to a different cpuset, which must not have its |
| * generation numbers aliased with those of that tasks previous cpuset. |
| * |
| * Generations are needed for mems_allowed because one task cannot |
| * modify anothers memory placement. So we must enable every task, |
| * on every visit to __alloc_pages(), to efficiently check whether |
| * its current->cpuset->mems_allowed has changed, requiring an update |
| * of its current->mems_allowed. |
| * |
| * Since cpuset_mems_generation is guarded by manage_mutex, |
| * there is no need to mark it atomic. |
| */ |
| static int cpuset_mems_generation; |
| |
| static struct cpuset top_cpuset = { |
| .flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)), |
| .cpus_allowed = CPU_MASK_ALL, |
| .mems_allowed = NODE_MASK_ALL, |
| .count = ATOMIC_INIT(0), |
| .sibling = LIST_HEAD_INIT(top_cpuset.sibling), |
| .children = LIST_HEAD_INIT(top_cpuset.children), |
| }; |
| |
| static struct vfsmount *cpuset_mount; |
| static struct super_block *cpuset_sb; |
| |
| /* |
| * We have two global cpuset mutexes below. They can nest. |
| * It is ok to first take manage_mutex, then nest callback_mutex. We also |
| * require taking task_lock() when dereferencing a tasks cpuset pointer. |
| * See "The task_lock() exception", at the end of this comment. |
| * |
| * A task must hold both mutexes to modify cpusets. If a task |
| * holds manage_mutex, then it blocks others wanting that mutex, |
| * ensuring that it is the only task able to also acquire callback_mutex |
| * and be able to modify cpusets. It can perform various checks on |
| * the cpuset structure first, knowing nothing will change. It can |
| * also allocate memory while just holding manage_mutex. While it is |
| * performing these checks, various callback routines can briefly |
| * acquire callback_mutex to query cpusets. Once it is ready to make |
| * the changes, it takes callback_mutex, blocking everyone else. |
| * |
| * Calls to the kernel memory allocator can not be made while holding |
| * callback_mutex, as that would risk double tripping on callback_mutex |
| * from one of the callbacks into the cpuset code from within |
| * __alloc_pages(). |
| * |
| * If a task is only holding callback_mutex, then it has read-only |
| * access to cpusets. |
| * |
| * The task_struct fields mems_allowed and mems_generation may only |
| * be accessed in the context of that task, so require no locks. |
| * |
| * Any task can increment and decrement the count field without lock. |
| * So in general, code holding manage_mutex or callback_mutex can't rely |
| * on the count field not changing. However, if the count goes to |
| * zero, then only attach_task(), which holds both mutexes, can |
| * increment it again. Because a count of zero means that no tasks |
| * are currently attached, therefore there is no way a task attached |
| * to that cpuset can fork (the other way to increment the count). |
| * So code holding manage_mutex or callback_mutex can safely assume that |
| * if the count is zero, it will stay zero. Similarly, if a task |
| * holds manage_mutex or callback_mutex on a cpuset with zero count, it |
| * knows that the cpuset won't be removed, as cpuset_rmdir() needs |
| * both of those mutexes. |
| * |
| * The cpuset_common_file_write handler for operations that modify |
| * the cpuset hierarchy holds manage_mutex across the entire operation, |
| * single threading all such cpuset modifications across the system. |
| * |
| * The cpuset_common_file_read() handlers only hold callback_mutex across |
| * small pieces of code, such as when reading out possibly multi-word |
| * cpumasks and nodemasks. |
| * |
| * The fork and exit callbacks cpuset_fork() and cpuset_exit(), don't |
| * (usually) take either mutex. These are the two most performance |
| * critical pieces of code here. The exception occurs on cpuset_exit(), |
| * when a task in a notify_on_release cpuset exits. Then manage_mutex |
| * is taken, and if the cpuset count is zero, a usermode call made |
| * to /sbin/cpuset_release_agent with the name of the cpuset (path |
| * relative to the root of cpuset file system) as the argument. |
| * |
| * A cpuset can only be deleted if both its 'count' of using tasks |
| * is zero, and its list of 'children' cpusets is empty. Since all |
| * tasks in the system use _some_ cpuset, and since there is always at |
| * least one task in the system (init), therefore, top_cpuset |
| * always has either children cpusets and/or using tasks. So we don't |
| * need a special hack to ensure that top_cpuset cannot be deleted. |
| * |
| * The above "Tale of Two Semaphores" would be complete, but for: |
| * |
| * The task_lock() exception |
| * |
| * The need for this exception arises from the action of attach_task(), |
| * which overwrites one tasks cpuset pointer with another. It does |
| * so using both mutexes, however there are several performance |
| * critical places that need to reference task->cpuset without the |
| * expense of grabbing a system global mutex. Therefore except as |
| * noted below, when dereferencing or, as in attach_task(), modifying |
| * a tasks cpuset pointer we use task_lock(), which acts on a spinlock |
| * (task->alloc_lock) already in the task_struct routinely used for |
| * such matters. |
| * |
| * P.S. One more locking exception. RCU is used to guard the |
| * update of a tasks cpuset pointer by attach_task() and the |
| * access of task->cpuset->mems_generation via that pointer in |
| * the routine cpuset_update_task_memory_state(). |
| */ |
| |
| static DEFINE_MUTEX(manage_mutex); |
| static DEFINE_MUTEX(callback_mutex); |
| |
| /* |
| * A couple of forward declarations required, due to cyclic reference loop: |
| * cpuset_mkdir -> cpuset_create -> cpuset_populate_dir -> cpuset_add_file |
| * -> cpuset_create_file -> cpuset_dir_inode_operations -> cpuset_mkdir. |
| */ |
| |
| static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode); |
| static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry); |
| |
| static struct backing_dev_info cpuset_backing_dev_info = { |
| .ra_pages = 0, /* No readahead */ |
| .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, |
| }; |
| |
| static struct inode *cpuset_new_inode(mode_t mode) |
| { |
| struct inode *inode = new_inode(cpuset_sb); |
| |
| if (inode) { |
| inode->i_mode = mode; |
| inode->i_uid = current->fsuid; |
| inode->i_gid = current->fsgid; |
| inode->i_blocks = 0; |
| inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| inode->i_mapping->backing_dev_info = &cpuset_backing_dev_info; |
| } |
| return inode; |
| } |
| |
| static void cpuset_diput(struct dentry *dentry, struct inode *inode) |
| { |
| /* is dentry a directory ? if so, kfree() associated cpuset */ |
| if (S_ISDIR(inode->i_mode)) { |
| struct cpuset *cs = dentry->d_fsdata; |
| BUG_ON(!(is_removed(cs))); |
| kfree(cs); |
| } |
| iput(inode); |
| } |
| |
| static struct dentry_operations cpuset_dops = { |
| .d_iput = cpuset_diput, |
| }; |
| |
| static struct dentry *cpuset_get_dentry(struct dentry *parent, const char *name) |
| { |
| struct dentry *d = lookup_one_len(name, parent, strlen(name)); |
| if (!IS_ERR(d)) |
| d->d_op = &cpuset_dops; |
| return d; |
| } |
| |
| static void remove_dir(struct dentry *d) |
| { |
| struct dentry *parent = dget(d->d_parent); |
| |
| d_delete(d); |
| simple_rmdir(parent->d_inode, d); |
| dput(parent); |
| } |
| |
| /* |
| * NOTE : the dentry must have been dget()'ed |
| */ |
| static void cpuset_d_remove_dir(struct dentry *dentry) |
| { |
| struct list_head *node; |
| |
| spin_lock(&dcache_lock); |
| node = dentry->d_subdirs.next; |
| while (node != &dentry->d_subdirs) { |
| struct dentry *d = list_entry(node, struct dentry, d_u.d_child); |
| list_del_init(node); |
| if (d->d_inode) { |
| d = dget_locked(d); |
| spin_unlock(&dcache_lock); |
| d_delete(d); |
| simple_unlink(dentry->d_inode, d); |
| dput(d); |
| spin_lock(&dcache_lock); |
| } |
| node = dentry->d_subdirs.next; |
| } |
| list_del_init(&dentry->d_u.d_child); |
| spin_unlock(&dcache_lock); |
| remove_dir(dentry); |
| } |
| |
| static struct super_operations cpuset_ops = { |
| .statfs = simple_statfs, |
| .drop_inode = generic_delete_inode, |
| }; |
| |
| static int cpuset_fill_super(struct super_block *sb, void *unused_data, |
| int unused_silent) |
| { |
| struct inode *inode; |
| struct dentry *root; |
| |
| sb->s_blocksize = PAGE_CACHE_SIZE; |
| sb->s_blocksize_bits = PAGE_CACHE_SHIFT; |
| sb->s_magic = CPUSET_SUPER_MAGIC; |
| sb->s_op = &cpuset_ops; |
| cpuset_sb = sb; |
| |
| inode = cpuset_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR); |
| if (inode) { |
| inode->i_op = &simple_dir_inode_operations; |
| inode->i_fop = &simple_dir_operations; |
| /* directories start off with i_nlink == 2 (for "." entry) */ |
| inc_nlink(inode); |
| } else { |
| return -ENOMEM; |
| } |
| |
| root = d_alloc_root(inode); |
| if (!root) { |
| iput(inode); |
| return -ENOMEM; |
| } |
| sb->s_root = root; |
| return 0; |
| } |
| |
| static int cpuset_get_sb(struct file_system_type *fs_type, |
| int flags, const char *unused_dev_name, |
| void *data, struct vfsmount *mnt) |
| { |
| return get_sb_single(fs_type, flags, data, cpuset_fill_super, mnt); |
| } |
| |
| static struct file_system_type cpuset_fs_type = { |
| .name = "cpuset", |
| .get_sb = cpuset_get_sb, |
| .kill_sb = kill_litter_super, |
| }; |
| |
| /* struct cftype: |
| * |
| * The files in the cpuset filesystem mostly have a very simple read/write |
| * handling, some common function will take care of it. Nevertheless some cases |
| * (read tasks) are special and therefore I define this structure for every |
| * kind of file. |
| * |
| * |
| * When reading/writing to a file: |
| * - the cpuset to use in file->f_path.dentry->d_parent->d_fsdata |
| * - the 'cftype' of the file is file->f_path.dentry->d_fsdata |
| */ |
| |
| struct cftype { |
| char *name; |
| int private; |
| int (*open) (struct inode *inode, struct file *file); |
| ssize_t (*read) (struct file *file, char __user *buf, size_t nbytes, |
| loff_t *ppos); |
| int (*write) (struct file *file, const char __user *buf, size_t nbytes, |
| loff_t *ppos); |
| int (*release) (struct inode *inode, struct file *file); |
| }; |
| |
| static inline struct cpuset *__d_cs(struct dentry *dentry) |
| { |
| return dentry->d_fsdata; |
| } |
| |
| static inline struct cftype *__d_cft(struct dentry *dentry) |
| { |
| return dentry->d_fsdata; |
| } |
| |
| /* |
| * Call with manage_mutex held. Writes path of cpuset into buf. |
| * Returns 0 on success, -errno on error. |
| */ |
| |
| static int cpuset_path(const struct cpuset *cs, char *buf, int buflen) |
| { |
| char *start; |
| |
| start = buf + buflen; |
| |
| *--start = '\0'; |
| for (;;) { |
| int len = cs->dentry->d_name.len; |
| if ((start -= len) < buf) |
| return -ENAMETOOLONG; |
| memcpy(start, cs->dentry->d_name.name, len); |
| cs = cs->parent; |
| if (!cs) |
| break; |
| if (!cs->parent) |
| continue; |
| if (--start < buf) |
| return -ENAMETOOLONG; |
| *start = '/'; |
| } |
| memmove(buf, start, buf + buflen - start); |
| return 0; |
| } |
| |
| /* |
| * Notify userspace when a cpuset is released, by running |
| * /sbin/cpuset_release_agent with the name of the cpuset (path |
| * relative to the root of cpuset file system) as the argument. |
| * |
| * Most likely, this user command will try to rmdir this cpuset. |
| * |
| * This races with the possibility that some other task will be |
| * attached to this cpuset before it is removed, or that some other |
| * user task will 'mkdir' a child cpuset of this cpuset. That's ok. |
| * The presumed 'rmdir' will fail quietly if this cpuset is no longer |
| * unused, and this cpuset will be reprieved from its death sentence, |
| * to continue to serve a useful existence. Next time it's released, |
| * we will get notified again, if it still has 'notify_on_release' set. |
| * |
| * The final arg to call_usermodehelper() is 0, which means don't |
| * wait. The separate /sbin/cpuset_release_agent task is forked by |
| * call_usermodehelper(), then control in this thread returns here, |
| * without waiting for the release agent task. We don't bother to |
| * wait because the caller of this routine has no use for the exit |
| * status of the /sbin/cpuset_release_agent task, so no sense holding |
| * our caller up for that. |
| * |
| * When we had only one cpuset mutex, we had to call this |
| * without holding it, to avoid deadlock when call_usermodehelper() |
| * allocated memory. With two locks, we could now call this while |
| * holding manage_mutex, but we still don't, so as to minimize |
| * the time manage_mutex is held. |
| */ |
| |
| static void cpuset_release_agent(const char *pathbuf) |
| { |
| char *argv[3], *envp[3]; |
| int i; |
| |
| if (!pathbuf) |
| return; |
| |
| i = 0; |
| argv[i++] = "/sbin/cpuset_release_agent"; |
| argv[i++] = (char *)pathbuf; |
| argv[i] = NULL; |
| |
| i = 0; |
| /* minimal command environment */ |
| envp[i++] = "HOME=/"; |
| envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; |
| envp[i] = NULL; |
| |
| call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); |
| kfree(pathbuf); |
| } |
| |
| /* |
| * Either cs->count of using tasks transitioned to zero, or the |
| * cs->children list of child cpusets just became empty. If this |
| * cs is notify_on_release() and now both the user count is zero and |
| * the list of children is empty, prepare cpuset path in a kmalloc'd |
| * buffer, to be returned via ppathbuf, so that the caller can invoke |
| * cpuset_release_agent() with it later on, once manage_mutex is dropped. |
| * Call here with manage_mutex held. |
| * |
| * This check_for_release() routine is responsible for kmalloc'ing |
| * pathbuf. The above cpuset_release_agent() is responsible for |
| * kfree'ing pathbuf. The caller of these routines is responsible |
| * for providing a pathbuf pointer, initialized to NULL, then |
| * calling check_for_release() with manage_mutex held and the address |
| * of the pathbuf pointer, then dropping manage_mutex, then calling |
| * cpuset_release_agent() with pathbuf, as set by check_for_release(). |
| */ |
| |
| static void check_for_release(struct cpuset *cs, char **ppathbuf) |
| { |
| if (notify_on_release(cs) && atomic_read(&cs->count) == 0 && |
| list_empty(&cs->children)) { |
| char *buf; |
| |
| buf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| if (!buf) |
| return; |
| if (cpuset_path(cs, buf, PAGE_SIZE) < 0) |
| kfree(buf); |
| else |
| *ppathbuf = buf; |
| } |
| } |
| |
| /* |
| * Return in *pmask the portion of a cpusets's cpus_allowed that |
| * are online. If none are online, walk up the cpuset hierarchy |
| * until we find one that does have some online cpus. If we get |
| * all the way to the top and still haven't found any online cpus, |
| * return cpu_online_map. Or if passed a NULL cs from an exit'ing |
| * task, return cpu_online_map. |
| * |
| * One way or another, we guarantee to return some non-empty subset |
| * of cpu_online_map. |
| * |
| * Call with callback_mutex held. |
| */ |
| |
| static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask) |
| { |
| while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map)) |
| cs = cs->parent; |
| if (cs) |
| cpus_and(*pmask, cs->cpus_allowed, cpu_online_map); |
| else |
| *pmask = cpu_online_map; |
| BUG_ON(!cpus_intersects(*pmask, cpu_online_map)); |
| } |
| |
| /* |
| * Return in *pmask the portion of a cpusets's mems_allowed that |
| * are online. If none are online, walk up the cpuset hierarchy |
| * until we find one that does have some online mems. If we get |
| * all the way to the top and still haven't found any online mems, |
| * return node_online_map. |
| * |
| * One way or another, we guarantee to return some non-empty subset |
| * of node_online_map. |
| * |
| * Call with callback_mutex held. |
| */ |
| |
| static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask) |
| { |
| while (cs && !nodes_intersects(cs->mems_allowed, node_online_map)) |
| cs = cs->parent; |
| if (cs) |
| nodes_and(*pmask, cs->mems_allowed, node_online_map); |
| else |
| *pmask = node_online_map; |
| BUG_ON(!nodes_intersects(*pmask, node_online_map)); |
| } |
| |
| /** |
| * cpuset_update_task_memory_state - update task memory placement |
| * |
| * If the current tasks cpusets mems_allowed changed behind our |
| * backs, update current->mems_allowed, mems_generation and task NUMA |
| * mempolicy to the new value. |
| * |
| * Task mempolicy is updated by rebinding it relative to the |
| * current->cpuset if a task has its memory placement changed. |
| * Do not call this routine if in_interrupt(). |
| * |
| * Call without callback_mutex or task_lock() held. May be |
| * called with or without manage_mutex held. Thanks in part to |
| * 'the_top_cpuset_hack', the tasks cpuset pointer will never |
| * be NULL. This routine also might acquire callback_mutex and |
| * current->mm->mmap_sem during call. |
| * |
| * Reading current->cpuset->mems_generation doesn't need task_lock |
| * to guard the current->cpuset derefence, because it is guarded |
| * from concurrent freeing of current->cpuset by attach_task(), |
| * using RCU. |
| * |
| * The rcu_dereference() is technically probably not needed, |
| * as I don't actually mind if I see a new cpuset pointer but |
| * an old value of mems_generation. However this really only |
| * matters on alpha systems using cpusets heavily. If I dropped |
| * that rcu_dereference(), it would save them a memory barrier. |
| * For all other arch's, rcu_dereference is a no-op anyway, and for |
| * alpha systems not using cpusets, another planned optimization, |
| * avoiding the rcu critical section for tasks in the root cpuset |
| * which is statically allocated, so can't vanish, will make this |
| * irrelevant. Better to use RCU as intended, than to engage in |
| * some cute trick to save a memory barrier that is impossible to |
| * test, for alpha systems using cpusets heavily, which might not |
| * even exist. |
| * |
| * This routine is needed to update the per-task mems_allowed data, |
| * within the tasks context, when it is trying to allocate memory |
| * (in various mm/mempolicy.c routines) and notices that some other |
| * task has been modifying its cpuset. |
| */ |
| |
| void cpuset_update_task_memory_state(void) |
| { |
| int my_cpusets_mem_gen; |
| struct task_struct *tsk = current; |
| struct cpuset *cs; |
| |
| if (tsk->cpuset == &top_cpuset) { |
| /* Don't need rcu for top_cpuset. It's never freed. */ |
| my_cpusets_mem_gen = top_cpuset.mems_generation; |
| } else { |
| rcu_read_lock(); |
| cs = rcu_dereference(tsk->cpuset); |
| my_cpusets_mem_gen = cs->mems_generation; |
| rcu_read_unlock(); |
| } |
| |
| if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) { |
| mutex_lock(&callback_mutex); |
| task_lock(tsk); |
| cs = tsk->cpuset; /* Maybe changed when task not locked */ |
| guarantee_online_mems(cs, &tsk->mems_allowed); |
| tsk->cpuset_mems_generation = cs->mems_generation; |
| if (is_spread_page(cs)) |
| tsk->flags |= PF_SPREAD_PAGE; |
| else |
| tsk->flags &= ~PF_SPREAD_PAGE; |
| if (is_spread_slab(cs)) |
| tsk->flags |= PF_SPREAD_SLAB; |
| else |
| tsk->flags &= ~PF_SPREAD_SLAB; |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| mpol_rebind_task(tsk, &tsk->mems_allowed); |
| } |
| } |
| |
| /* |
| * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q? |
| * |
| * One cpuset is a subset of another if all its allowed CPUs and |
| * Memory Nodes are a subset of the other, and its exclusive flags |
| * are only set if the other's are set. Call holding manage_mutex. |
| */ |
| |
| static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) |
| { |
| return cpus_subset(p->cpus_allowed, q->cpus_allowed) && |
| nodes_subset(p->mems_allowed, q->mems_allowed) && |
| is_cpu_exclusive(p) <= is_cpu_exclusive(q) && |
| is_mem_exclusive(p) <= is_mem_exclusive(q); |
| } |
| |
| /* |
| * validate_change() - Used to validate that any proposed cpuset change |
| * follows the structural rules for cpusets. |
| * |
| * If we replaced the flag and mask values of the current cpuset |
| * (cur) with those values in the trial cpuset (trial), would |
| * our various subset and exclusive rules still be valid? Presumes |
| * manage_mutex held. |
| * |
| * 'cur' is the address of an actual, in-use cpuset. Operations |
| * such as list traversal that depend on the actual address of the |
| * cpuset in the list must use cur below, not trial. |
| * |
| * 'trial' is the address of bulk structure copy of cur, with |
| * perhaps one or more of the fields cpus_allowed, mems_allowed, |
| * or flags changed to new, trial values. |
| * |
| * Return 0 if valid, -errno if not. |
| */ |
| |
| static int validate_change(const struct cpuset *cur, const struct cpuset *trial) |
| { |
| struct cpuset *c, *par; |
| |
| /* Each of our child cpusets must be a subset of us */ |
| list_for_each_entry(c, &cur->children, sibling) { |
| if (!is_cpuset_subset(c, trial)) |
| return -EBUSY; |
| } |
| |
| /* Remaining checks don't apply to root cpuset */ |
| if (cur == &top_cpuset) |
| return 0; |
| |
| par = cur->parent; |
| |
| /* We must be a subset of our parent cpuset */ |
| if (!is_cpuset_subset(trial, par)) |
| return -EACCES; |
| |
| /* If either I or some sibling (!= me) is exclusive, we can't overlap */ |
| list_for_each_entry(c, &par->children, sibling) { |
| if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && |
| c != cur && |
| cpus_intersects(trial->cpus_allowed, c->cpus_allowed)) |
| return -EINVAL; |
| if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) && |
| c != cur && |
| nodes_intersects(trial->mems_allowed, c->mems_allowed)) |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * For a given cpuset cur, partition the system as follows |
| * a. All cpus in the parent cpuset's cpus_allowed that are not part of any |
| * exclusive child cpusets |
| * b. All cpus in the current cpuset's cpus_allowed that are not part of any |
| * exclusive child cpusets |
| * Build these two partitions by calling partition_sched_domains |
| * |
| * Call with manage_mutex held. May nest a call to the |
| * lock_cpu_hotplug()/unlock_cpu_hotplug() pair. |
| * Must not be called holding callback_mutex, because we must |
| * not call lock_cpu_hotplug() while holding callback_mutex. |
| */ |
| |
| static void update_cpu_domains(struct cpuset *cur) |
| { |
| struct cpuset *c, *par = cur->parent; |
| cpumask_t pspan, cspan; |
| |
| if (par == NULL || cpus_empty(cur->cpus_allowed)) |
| return; |
| |
| /* |
| * Get all cpus from parent's cpus_allowed not part of exclusive |
| * children |
| */ |
| pspan = par->cpus_allowed; |
| list_for_each_entry(c, &par->children, sibling) { |
| if (is_cpu_exclusive(c)) |
| cpus_andnot(pspan, pspan, c->cpus_allowed); |
| } |
| if (!is_cpu_exclusive(cur)) { |
| cpus_or(pspan, pspan, cur->cpus_allowed); |
| if (cpus_equal(pspan, cur->cpus_allowed)) |
| return; |
| cspan = CPU_MASK_NONE; |
| } else { |
| if (cpus_empty(pspan)) |
| return; |
| cspan = cur->cpus_allowed; |
| /* |
| * Get all cpus from current cpuset's cpus_allowed not part |
| * of exclusive children |
| */ |
| list_for_each_entry(c, &cur->children, sibling) { |
| if (is_cpu_exclusive(c)) |
| cpus_andnot(cspan, cspan, c->cpus_allowed); |
| } |
| } |
| |
| lock_cpu_hotplug(); |
| partition_sched_domains(&pspan, &cspan); |
| unlock_cpu_hotplug(); |
| } |
| |
| /* |
| * Call with manage_mutex held. May take callback_mutex during call. |
| */ |
| |
| static int update_cpumask(struct cpuset *cs, char *buf) |
| { |
| struct cpuset trialcs; |
| int retval, cpus_unchanged; |
| |
| /* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */ |
| if (cs == &top_cpuset) |
| return -EACCES; |
| |
| trialcs = *cs; |
| |
| /* |
| * We allow a cpuset's cpus_allowed to be empty; if it has attached |
| * tasks, we'll catch it later when we validate the change and return |
| * -ENOSPC. |
| */ |
| if (!buf[0] || (buf[0] == '\n' && !buf[1])) { |
| cpus_clear(trialcs.cpus_allowed); |
| } else { |
| retval = cpulist_parse(buf, trialcs.cpus_allowed); |
| if (retval < 0) |
| return retval; |
| } |
| cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map); |
| /* cpus_allowed cannot be empty for a cpuset with attached tasks. */ |
| if (atomic_read(&cs->count) && cpus_empty(trialcs.cpus_allowed)) |
| return -ENOSPC; |
| retval = validate_change(cs, &trialcs); |
| if (retval < 0) |
| return retval; |
| cpus_unchanged = cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed); |
| mutex_lock(&callback_mutex); |
| cs->cpus_allowed = trialcs.cpus_allowed; |
| mutex_unlock(&callback_mutex); |
| if (is_cpu_exclusive(cs) && !cpus_unchanged) |
| update_cpu_domains(cs); |
| return 0; |
| } |
| |
| /* |
| * cpuset_migrate_mm |
| * |
| * Migrate memory region from one set of nodes to another. |
| * |
| * Temporarilly set tasks mems_allowed to target nodes of migration, |
| * so that the migration code can allocate pages on these nodes. |
| * |
| * Call holding manage_mutex, so our current->cpuset won't change |
| * during this call, as manage_mutex holds off any attach_task() |
| * calls. Therefore we don't need to take task_lock around the |
| * call to guarantee_online_mems(), as we know no one is changing |
| * our tasks cpuset. |
| * |
| * Hold callback_mutex around the two modifications of our tasks |
| * mems_allowed to synchronize with cpuset_mems_allowed(). |
| * |
| * While the mm_struct we are migrating is typically from some |
| * other task, the task_struct mems_allowed that we are hacking |
| * is for our current task, which must allocate new pages for that |
| * migrating memory region. |
| * |
| * We call cpuset_update_task_memory_state() before hacking |
| * our tasks mems_allowed, so that we are assured of being in |
| * sync with our tasks cpuset, and in particular, callbacks to |
| * cpuset_update_task_memory_state() from nested page allocations |
| * won't see any mismatch of our cpuset and task mems_generation |
| * values, so won't overwrite our hacked tasks mems_allowed |
| * nodemask. |
| */ |
| |
| static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, |
| const nodemask_t *to) |
| { |
| struct task_struct *tsk = current; |
| |
| cpuset_update_task_memory_state(); |
| |
| mutex_lock(&callback_mutex); |
| tsk->mems_allowed = *to; |
| mutex_unlock(&callback_mutex); |
| |
| do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL); |
| |
| mutex_lock(&callback_mutex); |
| guarantee_online_mems(tsk->cpuset, &tsk->mems_allowed); |
| mutex_unlock(&callback_mutex); |
| } |
| |
| /* |
| * Handle user request to change the 'mems' memory placement |
| * of a cpuset. Needs to validate the request, update the |
| * cpusets mems_allowed and mems_generation, and for each |
| * task in the cpuset, rebind any vma mempolicies and if |
| * the cpuset is marked 'memory_migrate', migrate the tasks |
| * pages to the new memory. |
| * |
| * Call with manage_mutex held. May take callback_mutex during call. |
| * Will take tasklist_lock, scan tasklist for tasks in cpuset cs, |
| * lock each such tasks mm->mmap_sem, scan its vma's and rebind |
| * their mempolicies to the cpusets new mems_allowed. |
| */ |
| |
| static int update_nodemask(struct cpuset *cs, char *buf) |
| { |
| struct cpuset trialcs; |
| nodemask_t oldmem; |
| struct task_struct *g, *p; |
| struct mm_struct **mmarray; |
| int i, n, ntasks; |
| int migrate; |
| int fudge; |
| int retval; |
| |
| /* top_cpuset.mems_allowed tracks node_online_map; it's read-only */ |
| if (cs == &top_cpuset) |
| return -EACCES; |
| |
| trialcs = *cs; |
| |
| /* |
| * We allow a cpuset's mems_allowed to be empty; if it has attached |
| * tasks, we'll catch it later when we validate the change and return |
| * -ENOSPC. |
| */ |
| if (!buf[0] || (buf[0] == '\n' && !buf[1])) { |
| nodes_clear(trialcs.mems_allowed); |
| } else { |
| retval = nodelist_parse(buf, trialcs.mems_allowed); |
| if (retval < 0) |
| goto done; |
| } |
| nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map); |
| oldmem = cs->mems_allowed; |
| if (nodes_equal(oldmem, trialcs.mems_allowed)) { |
| retval = 0; /* Too easy - nothing to do */ |
| goto done; |
| } |
| /* mems_allowed cannot be empty for a cpuset with attached tasks. */ |
| if (atomic_read(&cs->count) && nodes_empty(trialcs.mems_allowed)) { |
| retval = -ENOSPC; |
| goto done; |
| } |
| retval = validate_change(cs, &trialcs); |
| if (retval < 0) |
| goto done; |
| |
| mutex_lock(&callback_mutex); |
| cs->mems_allowed = trialcs.mems_allowed; |
| cs->mems_generation = cpuset_mems_generation++; |
| mutex_unlock(&callback_mutex); |
| |
| set_cpuset_being_rebound(cs); /* causes mpol_copy() rebind */ |
| |
| fudge = 10; /* spare mmarray[] slots */ |
| fudge += cpus_weight(cs->cpus_allowed); /* imagine one fork-bomb/cpu */ |
| retval = -ENOMEM; |
| |
| /* |
| * Allocate mmarray[] to hold mm reference for each task |
| * in cpuset cs. Can't kmalloc GFP_KERNEL while holding |
| * tasklist_lock. We could use GFP_ATOMIC, but with a |
| * few more lines of code, we can retry until we get a big |
| * enough mmarray[] w/o using GFP_ATOMIC. |
| */ |
| while (1) { |
| ntasks = atomic_read(&cs->count); /* guess */ |
| ntasks += fudge; |
| mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL); |
| if (!mmarray) |
| goto done; |
| read_lock(&tasklist_lock); /* block fork */ |
| if (atomic_read(&cs->count) <= ntasks) |
| break; /* got enough */ |
| read_unlock(&tasklist_lock); /* try again */ |
| kfree(mmarray); |
| } |
| |
| n = 0; |
| |
| /* Load up mmarray[] with mm reference for each task in cpuset. */ |
| do_each_thread(g, p) { |
| struct mm_struct *mm; |
| |
| if (n >= ntasks) { |
| printk(KERN_WARNING |
| "Cpuset mempolicy rebind incomplete.\n"); |
| continue; |
| } |
| if (p->cpuset != cs) |
| continue; |
| mm = get_task_mm(p); |
| if (!mm) |
| continue; |
| mmarray[n++] = mm; |
| } while_each_thread(g, p); |
| read_unlock(&tasklist_lock); |
| |
| /* |
| * Now that we've dropped the tasklist spinlock, we can |
| * rebind the vma mempolicies of each mm in mmarray[] to their |
| * new cpuset, and release that mm. The mpol_rebind_mm() |
| * call takes mmap_sem, which we couldn't take while holding |
| * tasklist_lock. Forks can happen again now - the mpol_copy() |
| * cpuset_being_rebound check will catch such forks, and rebind |
| * their vma mempolicies too. Because we still hold the global |
| * cpuset manage_mutex, we know that no other rebind effort will |
| * be contending for the global variable cpuset_being_rebound. |
| * It's ok if we rebind the same mm twice; mpol_rebind_mm() |
| * is idempotent. Also migrate pages in each mm to new nodes. |
| */ |
| migrate = is_memory_migrate(cs); |
| for (i = 0; i < n; i++) { |
| struct mm_struct *mm = mmarray[i]; |
| |
| mpol_rebind_mm(mm, &cs->mems_allowed); |
| if (migrate) |
| cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed); |
| mmput(mm); |
| } |
| |
| /* We're done rebinding vma's to this cpusets new mems_allowed. */ |
| kfree(mmarray); |
| set_cpuset_being_rebound(NULL); |
| retval = 0; |
| done: |
| return retval; |
| } |
| |
| /* |
| * Call with manage_mutex held. |
| */ |
| |
| static int update_memory_pressure_enabled(struct cpuset *cs, char *buf) |
| { |
| if (simple_strtoul(buf, NULL, 10) != 0) |
| cpuset_memory_pressure_enabled = 1; |
| else |
| cpuset_memory_pressure_enabled = 0; |
| return 0; |
| } |
| |
| /* |
| * update_flag - read a 0 or a 1 in a file and update associated flag |
| * bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE, |
| * CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE, |
| * CS_SPREAD_PAGE, CS_SPREAD_SLAB) |
| * cs: the cpuset to update |
| * buf: the buffer where we read the 0 or 1 |
| * |
| * Call with manage_mutex held. |
| */ |
| |
| static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf) |
| { |
| int turning_on; |
| struct cpuset trialcs; |
| int err, cpu_exclusive_changed; |
| |
| turning_on = (simple_strtoul(buf, NULL, 10) != 0); |
| |
| trialcs = *cs; |
| if (turning_on) |
| set_bit(bit, &trialcs.flags); |
| else |
| clear_bit(bit, &trialcs.flags); |
| |
| err = validate_change(cs, &trialcs); |
| if (err < 0) |
| return err; |
| cpu_exclusive_changed = |
| (is_cpu_exclusive(cs) != is_cpu_exclusive(&trialcs)); |
| mutex_lock(&callback_mutex); |
| cs->flags = trialcs.flags; |
| mutex_unlock(&callback_mutex); |
| |
| if (cpu_exclusive_changed) |
| update_cpu_domains(cs); |
| return 0; |
| } |
| |
| /* |
| * Frequency meter - How fast is some event occurring? |
| * |
| * These routines manage a digitally filtered, constant time based, |
| * event frequency meter. There are four routines: |
| * fmeter_init() - initialize a frequency meter. |
| * fmeter_markevent() - called each time the event happens. |
| * fmeter_getrate() - returns the recent rate of such events. |
| * fmeter_update() - internal routine used to update fmeter. |
| * |
| * A common data structure is passed to each of these routines, |
| * which is used to keep track of the state required to manage the |
| * frequency meter and its digital filter. |
| * |
| * The filter works on the number of events marked per unit time. |
| * The filter is single-pole low-pass recursive (IIR). The time unit |
| * is 1 second. Arithmetic is done using 32-bit integers scaled to |
| * simulate 3 decimal digits of precision (multiplied by 1000). |
| * |
| * With an FM_COEF of 933, and a time base of 1 second, the filter |
| * has a half-life of 10 seconds, meaning that if the events quit |
| * happening, then the rate returned from the fmeter_getrate() |
| * will be cut in half each 10 seconds, until it converges to zero. |
| * |
| * It is not worth doing a real infinitely recursive filter. If more |
| * than FM_MAXTICKS ticks have elapsed since the last filter event, |
| * just compute FM_MAXTICKS ticks worth, by which point the level |
| * will be stable. |
| * |
| * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid |
| * arithmetic overflow in the fmeter_update() routine. |
| * |
| * Given the simple 32 bit integer arithmetic used, this meter works |
| * best for reporting rates between one per millisecond (msec) and |
| * one per 32 (approx) seconds. At constant rates faster than one |
| * per msec it maxes out at values just under 1,000,000. At constant |
| * rates between one per msec, and one per second it will stabilize |
| * to a value N*1000, where N is the rate of events per second. |
| * At constant rates between one per second and one per 32 seconds, |
| * it will be choppy, moving up on the seconds that have an event, |
| * and then decaying until the next event. At rates slower than |
| * about one in 32 seconds, it decays all the way back to zero between |
| * each event. |
| */ |
| |
| #define FM_COEF 933 /* coefficient for half-life of 10 secs */ |
| #define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */ |
| #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */ |
| #define FM_SCALE 1000 /* faux fixed point scale */ |
| |
| /* Initialize a frequency meter */ |
| static void fmeter_init(struct fmeter *fmp) |
| { |
| fmp->cnt = 0; |
| fmp->val = 0; |
| fmp->time = 0; |
| spin_lock_init(&fmp->lock); |
| } |
| |
| /* Internal meter update - process cnt events and update value */ |
| static void fmeter_update(struct fmeter *fmp) |
| { |
| time_t now = get_seconds(); |
| time_t ticks = now - fmp->time; |
| |
| if (ticks == 0) |
| return; |
| |
| ticks = min(FM_MAXTICKS, ticks); |
| while (ticks-- > 0) |
| fmp->val = (FM_COEF * fmp->val) / FM_SCALE; |
| fmp->time = now; |
| |
| fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE; |
| fmp->cnt = 0; |
| } |
| |
| /* Process any previous ticks, then bump cnt by one (times scale). */ |
| static void fmeter_markevent(struct fmeter *fmp) |
| { |
| spin_lock(&fmp->lock); |
| fmeter_update(fmp); |
| fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE); |
| spin_unlock(&fmp->lock); |
| } |
| |
| /* Process any previous ticks, then return current value. */ |
| static int fmeter_getrate(struct fmeter *fmp) |
| { |
| int val; |
| |
| spin_lock(&fmp->lock); |
| fmeter_update(fmp); |
| val = fmp->val; |
| spin_unlock(&fmp->lock); |
| return val; |
| } |
| |
| /* |
| * Attack task specified by pid in 'pidbuf' to cpuset 'cs', possibly |
| * writing the path of the old cpuset in 'ppathbuf' if it needs to be |
| * notified on release. |
| * |
| * Call holding manage_mutex. May take callback_mutex and task_lock of |
| * the task 'pid' during call. |
| */ |
| |
| static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf) |
| { |
| pid_t pid; |
| struct task_struct *tsk; |
| struct cpuset *oldcs; |
| cpumask_t cpus; |
| nodemask_t from, to; |
| struct mm_struct *mm; |
| int retval; |
| |
| if (sscanf(pidbuf, "%d", &pid) != 1) |
| return -EIO; |
| if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)) |
| return -ENOSPC; |
| |
| if (pid) { |
| read_lock(&tasklist_lock); |
| |
| tsk = find_task_by_pid(pid); |
| if (!tsk || tsk->flags & PF_EXITING) { |
| read_unlock(&tasklist_lock); |
| return -ESRCH; |
| } |
| |
| get_task_struct(tsk); |
| read_unlock(&tasklist_lock); |
| |
| if ((current->euid) && (current->euid != tsk->uid) |
| && (current->euid != tsk->suid)) { |
| put_task_struct(tsk); |
| return -EACCES; |
| } |
| } else { |
| tsk = current; |
| get_task_struct(tsk); |
| } |
| |
| retval = security_task_setscheduler(tsk, 0, NULL); |
| if (retval) { |
| put_task_struct(tsk); |
| return retval; |
| } |
| |
| mutex_lock(&callback_mutex); |
| |
| task_lock(tsk); |
| oldcs = tsk->cpuset; |
| /* |
| * After getting 'oldcs' cpuset ptr, be sure still not exiting. |
| * If 'oldcs' might be the top_cpuset due to the_top_cpuset_hack |
| * then fail this attach_task(), to avoid breaking top_cpuset.count. |
| */ |
| if (tsk->flags & PF_EXITING) { |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| put_task_struct(tsk); |
| return -ESRCH; |
| } |
| atomic_inc(&cs->count); |
| rcu_assign_pointer(tsk->cpuset, cs); |
| task_unlock(tsk); |
| |
| guarantee_online_cpus(cs, &cpus); |
| set_cpus_allowed(tsk, cpus); |
| |
| from = oldcs->mems_allowed; |
| to = cs->mems_allowed; |
| |
| mutex_unlock(&callback_mutex); |
| |
| mm = get_task_mm(tsk); |
| if (mm) { |
| mpol_rebind_mm(mm, &to); |
| if (is_memory_migrate(cs)) |
| cpuset_migrate_mm(mm, &from, &to); |
| mmput(mm); |
| } |
| |
| put_task_struct(tsk); |
| synchronize_rcu(); |
| if (atomic_dec_and_test(&oldcs->count)) |
| check_for_release(oldcs, ppathbuf); |
| return 0; |
| } |
| |
| /* The various types of files and directories in a cpuset file system */ |
| |
| typedef enum { |
| FILE_ROOT, |
| FILE_DIR, |
| FILE_MEMORY_MIGRATE, |
| FILE_CPULIST, |
| FILE_MEMLIST, |
| FILE_CPU_EXCLUSIVE, |
| FILE_MEM_EXCLUSIVE, |
| FILE_NOTIFY_ON_RELEASE, |
| FILE_MEMORY_PRESSURE_ENABLED, |
| FILE_MEMORY_PRESSURE, |
| FILE_SPREAD_PAGE, |
| FILE_SPREAD_SLAB, |
| FILE_TASKLIST, |
| } cpuset_filetype_t; |
| |
| static ssize_t cpuset_common_file_write(struct file *file, |
| const char __user *userbuf, |
| size_t nbytes, loff_t *unused_ppos) |
| { |
| struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent); |
| struct cftype *cft = __d_cft(file->f_path.dentry); |
| cpuset_filetype_t type = cft->private; |
| char *buffer; |
| char *pathbuf = NULL; |
| int retval = 0; |
| |
| /* Crude upper limit on largest legitimate cpulist user might write. */ |
| if (nbytes > 100 + 6 * max(NR_CPUS, MAX_NUMNODES)) |
| return -E2BIG; |
| |
| /* +1 for nul-terminator */ |
| if ((buffer = kmalloc(nbytes + 1, GFP_KERNEL)) == 0) |
| return -ENOMEM; |
| |
| if (copy_from_user(buffer, userbuf, nbytes)) { |
| retval = -EFAULT; |
| goto out1; |
| } |
| buffer[nbytes] = 0; /* nul-terminate */ |
| |
| mutex_lock(&manage_mutex); |
| |
| if (is_removed(cs)) { |
| retval = -ENODEV; |
| goto out2; |
| } |
| |
| switch (type) { |
| case FILE_CPULIST: |
| retval = update_cpumask(cs, buffer); |
| break; |
| case FILE_MEMLIST: |
| retval = update_nodemask(cs, buffer); |
| break; |
| case FILE_CPU_EXCLUSIVE: |
| retval = update_flag(CS_CPU_EXCLUSIVE, cs, buffer); |
| break; |
| case FILE_MEM_EXCLUSIVE: |
| retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer); |
| break; |
| case FILE_NOTIFY_ON_RELEASE: |
| retval = update_flag(CS_NOTIFY_ON_RELEASE, cs, buffer); |
| break; |
| case FILE_MEMORY_MIGRATE: |
| retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer); |
| break; |
| case FILE_MEMORY_PRESSURE_ENABLED: |
| retval = update_memory_pressure_enabled(cs, buffer); |
| break; |
| case FILE_MEMORY_PRESSURE: |
| retval = -EACCES; |
| break; |
| case FILE_SPREAD_PAGE: |
| retval = update_flag(CS_SPREAD_PAGE, cs, buffer); |
| cs->mems_generation = cpuset_mems_generation++; |
| break; |
| case FILE_SPREAD_SLAB: |
| retval = update_flag(CS_SPREAD_SLAB, cs, buffer); |
| cs->mems_generation = cpuset_mems_generation++; |
| break; |
| case FILE_TASKLIST: |
| retval = attach_task(cs, buffer, &pathbuf); |
| break; |
| default: |
| retval = -EINVAL; |
| goto out2; |
| } |
| |
| if (retval == 0) |
| retval = nbytes; |
| out2: |
| mutex_unlock(&manage_mutex); |
| cpuset_release_agent(pathbuf); |
| out1: |
| kfree(buffer); |
| return retval; |
| } |
| |
| static ssize_t cpuset_file_write(struct file *file, const char __user *buf, |
| size_t nbytes, loff_t *ppos) |
| { |
| ssize_t retval = 0; |
| struct cftype *cft = __d_cft(file->f_path.dentry); |
| if (!cft) |
| return -ENODEV; |
| |
| /* special function ? */ |
| if (cft->write) |
| retval = cft->write(file, buf, nbytes, ppos); |
| else |
| retval = cpuset_common_file_write(file, buf, nbytes, ppos); |
| |
| return retval; |
| } |
| |
| /* |
| * These ascii lists should be read in a single call, by using a user |
| * buffer large enough to hold the entire map. If read in smaller |
| * chunks, there is no guarantee of atomicity. Since the display format |
| * used, list of ranges of sequential numbers, is variable length, |
| * and since these maps can change value dynamically, one could read |
| * gibberish by doing partial reads while a list was changing. |
| * A single large read to a buffer that crosses a page boundary is |
| * ok, because the result being copied to user land is not recomputed |
| * across a page fault. |
| */ |
| |
| static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs) |
| { |
| cpumask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| mask = cs->cpus_allowed; |
| mutex_unlock(&callback_mutex); |
| |
| return cpulist_scnprintf(page, PAGE_SIZE, mask); |
| } |
| |
| static int cpuset_sprintf_memlist(char *page, struct cpuset *cs) |
| { |
| nodemask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| mask = cs->mems_allowed; |
| mutex_unlock(&callback_mutex); |
| |
| return nodelist_scnprintf(page, PAGE_SIZE, mask); |
| } |
| |
| static ssize_t cpuset_common_file_read(struct file *file, char __user *buf, |
| size_t nbytes, loff_t *ppos) |
| { |
| struct cftype *cft = __d_cft(file->f_path.dentry); |
| struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent); |
| cpuset_filetype_t type = cft->private; |
| char *page; |
| ssize_t retval = 0; |
| char *s; |
| |
| if (!(page = (char *)__get_free_page(GFP_KERNEL))) |
| return -ENOMEM; |
| |
| s = page; |
| |
| switch (type) { |
| case FILE_CPULIST: |
| s += cpuset_sprintf_cpulist(s, cs); |
| break; |
| case FILE_MEMLIST: |
| s += cpuset_sprintf_memlist(s, cs); |
| break; |
| case FILE_CPU_EXCLUSIVE: |
| *s++ = is_cpu_exclusive(cs) ? '1' : '0'; |
| break; |
| case FILE_MEM_EXCLUSIVE: |
| *s++ = is_mem_exclusive(cs) ? '1' : '0'; |
| break; |
| case FILE_NOTIFY_ON_RELEASE: |
| *s++ = notify_on_release(cs) ? '1' : '0'; |
| break; |
| case FILE_MEMORY_MIGRATE: |
| *s++ = is_memory_migrate(cs) ? '1' : '0'; |
| break; |
| case FILE_MEMORY_PRESSURE_ENABLED: |
| *s++ = cpuset_memory_pressure_enabled ? '1' : '0'; |
| break; |
| case FILE_MEMORY_PRESSURE: |
| s += sprintf(s, "%d", fmeter_getrate(&cs->fmeter)); |
| break; |
| case FILE_SPREAD_PAGE: |
| *s++ = is_spread_page(cs) ? '1' : '0'; |
| break; |
| case FILE_SPREAD_SLAB: |
| *s++ = is_spread_slab(cs) ? '1' : '0'; |
| break; |
| default: |
| retval = -EINVAL; |
| goto out; |
| } |
| *s++ = '\n'; |
| |
| retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page); |
| out: |
| free_page((unsigned long)page); |
| return retval; |
| } |
| |
| static ssize_t cpuset_file_read(struct file *file, char __user *buf, size_t nbytes, |
| loff_t *ppos) |
| { |
| ssize_t retval = 0; |
| struct cftype *cft = __d_cft(file->f_path.dentry); |
| if (!cft) |
| return -ENODEV; |
| |
| /* special function ? */ |
| if (cft->read) |
| retval = cft->read(file, buf, nbytes, ppos); |
| else |
| retval = cpuset_common_file_read(file, buf, nbytes, ppos); |
| |
| return retval; |
| } |
| |
| static int cpuset_file_open(struct inode *inode, struct file *file) |
| { |
| int err; |
| struct cftype *cft; |
| |
| err = generic_file_open(inode, file); |
| if (err) |
| return err; |
| |
| cft = __d_cft(file->f_path.dentry); |
| if (!cft) |
| return -ENODEV; |
| if (cft->open) |
| err = cft->open(inode, file); |
| else |
| err = 0; |
| |
| return err; |
| } |
| |
| static int cpuset_file_release(struct inode *inode, struct file *file) |
| { |
| struct cftype *cft = __d_cft(file->f_path.dentry); |
| if (cft->release) |
| return cft->release(inode, file); |
| return 0; |
| } |
| |
| /* |
| * cpuset_rename - Only allow simple rename of directories in place. |
| */ |
| static int cpuset_rename(struct inode *old_dir, struct dentry *old_dentry, |
| struct inode *new_dir, struct dentry *new_dentry) |
| { |
| if (!S_ISDIR(old_dentry->d_inode->i_mode)) |
| return -ENOTDIR; |
| if (new_dentry->d_inode) |
| return -EEXIST; |
| if (old_dir != new_dir) |
| return -EIO; |
| return simple_rename(old_dir, old_dentry, new_dir, new_dentry); |
| } |
| |
| static const struct file_operations cpuset_file_operations = { |
| .read = cpuset_file_read, |
| .write = cpuset_file_write, |
| .llseek = generic_file_llseek, |
| .open = cpuset_file_open, |
| .release = cpuset_file_release, |
| }; |
| |
| static const struct inode_operations cpuset_dir_inode_operations = { |
| .lookup = simple_lookup, |
| .mkdir = cpuset_mkdir, |
| .rmdir = cpuset_rmdir, |
| .rename = cpuset_rename, |
| }; |
| |
| static int cpuset_create_file(struct dentry *dentry, int mode) |
| { |
| struct inode *inode; |
| |
| if (!dentry) |
| return -ENOENT; |
| if (dentry->d_inode) |
| return -EEXIST; |
| |
| inode = cpuset_new_inode(mode); |
| if (!inode) |
| return -ENOMEM; |
| |
| if (S_ISDIR(mode)) { |
| inode->i_op = &cpuset_dir_inode_operations; |
| inode->i_fop = &simple_dir_operations; |
| |
| /* start off with i_nlink == 2 (for "." entry) */ |
| inc_nlink(inode); |
| } else if (S_ISREG(mode)) { |
| inode->i_size = 0; |
| inode->i_fop = &cpuset_file_operations; |
| } |
| |
| d_instantiate(dentry, inode); |
| dget(dentry); /* Extra count - pin the dentry in core */ |
| return 0; |
| } |
| |
| /* |
| * cpuset_create_dir - create a directory for an object. |
| * cs: the cpuset we create the directory for. |
| * It must have a valid ->parent field |
| * And we are going to fill its ->dentry field. |
| * name: The name to give to the cpuset directory. Will be copied. |
| * mode: mode to set on new directory. |
| */ |
| |
| static int cpuset_create_dir(struct cpuset *cs, const char *name, int mode) |
| { |
| struct dentry *dentry = NULL; |
| struct dentry *parent; |
| int error = 0; |
| |
| parent = cs->parent->dentry; |
| dentry = cpuset_get_dentry(parent, name); |
| if (IS_ERR(dentry)) |
| return PTR_ERR(dentry); |
| error = cpuset_create_file(dentry, S_IFDIR | mode); |
| if (!error) { |
| dentry->d_fsdata = cs; |
| inc_nlink(parent->d_inode); |
| cs->dentry = dentry; |
| } |
| dput(dentry); |
| |
| return error; |
| } |
| |
| static int cpuset_add_file(struct dentry *dir, const struct cftype *cft) |
| { |
| struct dentry *dentry; |
| int error; |
| |
| mutex_lock(&dir->d_inode->i_mutex); |
| dentry = cpuset_get_dentry(dir, cft->name); |
| if (!IS_ERR(dentry)) { |
| error = cpuset_create_file(dentry, 0644 | S_IFREG); |
| if (!error) |
| dentry->d_fsdata = (void *)cft; |
| dput(dentry); |
| } else |
| error = PTR_ERR(dentry); |
| mutex_unlock(&dir->d_inode->i_mutex); |
| return error; |
| } |
| |
| /* |
| * Stuff for reading the 'tasks' file. |
| * |
| * Reading this file can return large amounts of data if a cpuset has |
| * *lots* of attached tasks. So it may need several calls to read(), |
| * but we cannot guarantee that the information we produce is correct |
| * unless we produce it entirely atomically. |
| * |
| * Upon tasks file open(), a struct ctr_struct is allocated, that |
| * will have a pointer to an array (also allocated here). The struct |
| * ctr_struct * is stored in file->private_data. Its resources will |
| * be freed by release() when the file is closed. The array is used |
| * to sprintf the PIDs and then used by read(). |
| */ |
| |
| /* cpusets_tasks_read array */ |
| |
| struct ctr_struct { |
| char *buf; |
| int bufsz; |
| }; |
| |
| /* |
| * Load into 'pidarray' up to 'npids' of the tasks using cpuset 'cs'. |
| * Return actual number of pids loaded. No need to task_lock(p) |
| * when reading out p->cpuset, as we don't really care if it changes |
| * on the next cycle, and we are not going to try to dereference it. |
| */ |
| static int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs) |
| { |
| int n = 0; |
| struct task_struct *g, *p; |
| |
| read_lock(&tasklist_lock); |
| |
| do_each_thread(g, p) { |
| if (p->cpuset == cs) { |
| if (unlikely(n == npids)) |
| goto array_full; |
| pidarray[n++] = p->pid; |
| } |
| } while_each_thread(g, p); |
| |
| array_full: |
| read_unlock(&tasklist_lock); |
| return n; |
| } |
| |
| static int cmppid(const void *a, const void *b) |
| { |
| return *(pid_t *)a - *(pid_t *)b; |
| } |
| |
| /* |
| * Convert array 'a' of 'npids' pid_t's to a string of newline separated |
| * decimal pids in 'buf'. Don't write more than 'sz' chars, but return |
| * count 'cnt' of how many chars would be written if buf were large enough. |
| */ |
| static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids) |
| { |
| int cnt = 0; |
| int i; |
| |
| for (i = 0; i < npids; i++) |
| cnt += snprintf(buf + cnt, max(sz - cnt, 0), "%d\n", a[i]); |
| return cnt; |
| } |
| |
| /* |
| * Handle an open on 'tasks' file. Prepare a buffer listing the |
| * process id's of tasks currently attached to the cpuset being opened. |
| * |
| * Does not require any specific cpuset mutexes, and does not take any. |
| */ |
| static int cpuset_tasks_open(struct inode *unused, struct file *file) |
| { |
| struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent); |
| struct ctr_struct *ctr; |
| pid_t *pidarray; |
| int npids; |
| char c; |
| |
| if (!(file->f_mode & FMODE_READ)) |
| return 0; |
| |
| ctr = kmalloc(sizeof(*ctr), GFP_KERNEL); |
| if (!ctr) |
| goto err0; |
| |
| /* |
| * If cpuset gets more users after we read count, we won't have |
| * enough space - tough. This race is indistinguishable to the |
| * caller from the case that the additional cpuset users didn't |
| * show up until sometime later on. |
| */ |
| npids = atomic_read(&cs->count); |
| pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL); |
| if (!pidarray) |
| goto err1; |
| |
| npids = pid_array_load(pidarray, npids, cs); |
| sort(pidarray, npids, sizeof(pid_t), cmppid, NULL); |
| |
| /* Call pid_array_to_buf() twice, first just to get bufsz */ |
| ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1; |
| ctr->buf = kmalloc(ctr->bufsz, GFP_KERNEL); |
| if (!ctr->buf) |
| goto err2; |
| ctr->bufsz = pid_array_to_buf(ctr->buf, ctr->bufsz, pidarray, npids); |
| |
| kfree(pidarray); |
| file->private_data = ctr; |
| return 0; |
| |
| err2: |
| kfree(pidarray); |
| err1: |
| kfree(ctr); |
| err0: |
| return -ENOMEM; |
| } |
| |
| static ssize_t cpuset_tasks_read(struct file *file, char __user *buf, |
| size_t nbytes, loff_t *ppos) |
| { |
| struct ctr_struct *ctr = file->private_data; |
| |
| return simple_read_from_buffer(buf, nbytes, ppos, ctr->buf, ctr->bufsz); |
| } |
| |
| static int cpuset_tasks_release(struct inode *unused_inode, struct file *file) |
| { |
| struct ctr_struct *ctr; |
| |
| if (file->f_mode & FMODE_READ) { |
| ctr = file->private_data; |
| kfree(ctr->buf); |
| kfree(ctr); |
| } |
| return 0; |
| } |
| |
| /* |
| * for the common functions, 'private' gives the type of file |
| */ |
| |
| static struct cftype cft_tasks = { |
| .name = "tasks", |
| .open = cpuset_tasks_open, |
| .read = cpuset_tasks_read, |
| .release = cpuset_tasks_release, |
| .private = FILE_TASKLIST, |
| }; |
| |
| static struct cftype cft_cpus = { |
| .name = "cpus", |
| .private = FILE_CPULIST, |
| }; |
| |
| static struct cftype cft_mems = { |
| .name = "mems", |
| .private = FILE_MEMLIST, |
| }; |
| |
| static struct cftype cft_cpu_exclusive = { |
| .name = "cpu_exclusive", |
| .private = FILE_CPU_EXCLUSIVE, |
| }; |
| |
| static struct cftype cft_mem_exclusive = { |
| .name = "mem_exclusive", |
| .private = FILE_MEM_EXCLUSIVE, |
| }; |
| |
| static struct cftype cft_notify_on_release = { |
| .name = "notify_on_release", |
| .private = FILE_NOTIFY_ON_RELEASE, |
| }; |
| |
| static struct cftype cft_memory_migrate = { |
| .name = "memory_migrate", |
| .private = FILE_MEMORY_MIGRATE, |
| }; |
| |
| static struct cftype cft_memory_pressure_enabled = { |
| .name = "memory_pressure_enabled", |
| .private = FILE_MEMORY_PRESSURE_ENABLED, |
| }; |
| |
| static struct cftype cft_memory_pressure = { |
| .name = "memory_pressure", |
| .private = FILE_MEMORY_PRESSURE, |
| }; |
| |
| static struct cftype cft_spread_page = { |
| .name = "memory_spread_page", |
| .private = FILE_SPREAD_PAGE, |
| }; |
| |
| static struct cftype cft_spread_slab = { |
| .name = "memory_spread_slab", |
| .private = FILE_SPREAD_SLAB, |
| }; |
| |
| static int cpuset_populate_dir(struct dentry *cs_dentry) |
| { |
| int err; |
| |
| if ((err = cpuset_add_file(cs_dentry, &cft_cpus)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_mems)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_cpu_exclusive)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_mem_exclusive)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_notify_on_release)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_memory_migrate)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_memory_pressure)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_spread_page)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_spread_slab)) < 0) |
| return err; |
| if ((err = cpuset_add_file(cs_dentry, &cft_tasks)) < 0) |
| return err; |
| return 0; |
| } |
| |
| /* |
| * cpuset_create - create a cpuset |
| * parent: cpuset that will be parent of the new cpuset. |
| * name: name of the new cpuset. Will be strcpy'ed. |
| * mode: mode to set on new inode |
| * |
| * Must be called with the mutex on the parent inode held |
| */ |
| |
| static long cpuset_create(struct cpuset *parent, const char *name, int mode) |
| { |
| struct cpuset *cs; |
| int err; |
| |
| cs = kmalloc(sizeof(*cs), GFP_KERNEL); |
| if (!cs) |
| return -ENOMEM; |
| |
| mutex_lock(&manage_mutex); |
| cpuset_update_task_memory_state(); |
| cs->flags = 0; |
| if (notify_on_release(parent)) |
| set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags); |
| if (is_spread_page(parent)) |
| set_bit(CS_SPREAD_PAGE, &cs->flags); |
| if (is_spread_slab(parent)) |
| set_bit(CS_SPREAD_SLAB, &cs->flags); |
| cs->cpus_allowed = CPU_MASK_NONE; |
| cs->mems_allowed = NODE_MASK_NONE; |
| atomic_set(&cs->count, 0); |
| INIT_LIST_HEAD(&cs->sibling); |
| INIT_LIST_HEAD(&cs->children); |
| cs->mems_generation = cpuset_mems_generation++; |
| fmeter_init(&cs->fmeter); |
| |
| cs->parent = parent; |
| |
| mutex_lock(&callback_mutex); |
| list_add(&cs->sibling, &cs->parent->children); |
| number_of_cpusets++; |
| mutex_unlock(&callback_mutex); |
| |
| err = cpuset_create_dir(cs, name, mode); |
| if (err < 0) |
| goto err; |
| |
| /* |
| * Release manage_mutex before cpuset_populate_dir() because it |
| * will down() this new directory's i_mutex and if we race with |
| * another mkdir, we might deadlock. |
| */ |
| mutex_unlock(&manage_mutex); |
| |
| err = cpuset_populate_dir(cs->dentry); |
| /* If err < 0, we have a half-filled directory - oh well ;) */ |
| return 0; |
| err: |
| list_del(&cs->sibling); |
| mutex_unlock(&manage_mutex); |
| kfree(cs); |
| return err; |
| } |
| |
| static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
| { |
| struct cpuset *c_parent = dentry->d_parent->d_fsdata; |
| |
| /* the vfs holds inode->i_mutex already */ |
| return cpuset_create(c_parent, dentry->d_name.name, mode | S_IFDIR); |
| } |
| |
| /* |
| * Locking note on the strange update_flag() call below: |
| * |
| * If the cpuset being removed is marked cpu_exclusive, then simulate |
| * turning cpu_exclusive off, which will call update_cpu_domains(). |
| * The lock_cpu_hotplug() call in update_cpu_domains() must not be |
| * made while holding callback_mutex. Elsewhere the kernel nests |
| * callback_mutex inside lock_cpu_hotplug() calls. So the reverse |
| * nesting would risk an ABBA deadlock. |
| */ |
| |
| static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry) |
| { |
| struct cpuset *cs = dentry->d_fsdata; |
| struct dentry *d; |
| struct cpuset *parent; |
| char *pathbuf = NULL; |
| |
| /* the vfs holds both inode->i_mutex already */ |
| |
| mutex_lock(&manage_mutex); |
| cpuset_update_task_memory_state(); |
| if (atomic_read(&cs->count) > 0) { |
| mutex_unlock(&manage_mutex); |
| return -EBUSY; |
| } |
| if (!list_empty(&cs->children)) { |
| mutex_unlock(&manage_mutex); |
| return -EBUSY; |
| } |
| if (is_cpu_exclusive(cs)) { |
| int retval = update_flag(CS_CPU_EXCLUSIVE, cs, "0"); |
| if (retval < 0) { |
| mutex_unlock(&manage_mutex); |
| return retval; |
| } |
| } |
| parent = cs->parent; |
| mutex_lock(&callback_mutex); |
| set_bit(CS_REMOVED, &cs->flags); |
| list_del(&cs->sibling); /* delete my sibling from parent->children */ |
| spin_lock(&cs->dentry->d_lock); |
| d = dget(cs->dentry); |
| cs->dentry = NULL; |
| spin_unlock(&d->d_lock); |
| cpuset_d_remove_dir(d); |
| dput(d); |
| number_of_cpusets--; |
| mutex_unlock(&callback_mutex); |
| if (list_empty(&parent->children)) |
| check_for_release(parent, &pathbuf); |
| mutex_unlock(&manage_mutex); |
| cpuset_release_agent(pathbuf); |
| return 0; |
| } |
| |
| /* |
| * cpuset_init_early - just enough so that the calls to |
| * cpuset_update_task_memory_state() in early init code |
| * are harmless. |
| */ |
| |
| int __init cpuset_init_early(void) |
| { |
| struct task_struct *tsk = current; |
| |
| tsk->cpuset = &top_cpuset; |
| tsk->cpuset->mems_generation = cpuset_mems_generation++; |
| return 0; |
| } |
| |
| /** |
| * cpuset_init - initialize cpusets at system boot |
| * |
| * Description: Initialize top_cpuset and the cpuset internal file system, |
| **/ |
| |
| int __init cpuset_init(void) |
| { |
| struct dentry *root; |
| int err; |
| |
| top_cpuset.cpus_allowed = CPU_MASK_ALL; |
| top_cpuset.mems_allowed = NODE_MASK_ALL; |
| |
| fmeter_init(&top_cpuset.fmeter); |
| top_cpuset.mems_generation = cpuset_mems_generation++; |
| |
| init_task.cpuset = &top_cpuset; |
| |
| err = register_filesystem(&cpuset_fs_type); |
| if (err < 0) |
| goto out; |
| cpuset_mount = kern_mount(&cpuset_fs_type); |
| if (IS_ERR(cpuset_mount)) { |
| printk(KERN_ERR "cpuset: could not mount!\n"); |
| err = PTR_ERR(cpuset_mount); |
| cpuset_mount = NULL; |
| goto out; |
| } |
| root = cpuset_mount->mnt_sb->s_root; |
| root->d_fsdata = &top_cpuset; |
| inc_nlink(root->d_inode); |
| top_cpuset.dentry = root; |
| root->d_inode->i_op = &cpuset_dir_inode_operations; |
| number_of_cpusets = 1; |
| err = cpuset_populate_dir(root); |
| /* memory_pressure_enabled is in root cpuset only */ |
| if (err == 0) |
| err = cpuset_add_file(root, &cft_memory_pressure_enabled); |
| out: |
| return err; |
| } |
| |
| /* |
| * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs |
| * or memory nodes, we need to walk over the cpuset hierarchy, |
| * removing that CPU or node from all cpusets. If this removes the |
| * last CPU or node from a cpuset, then the guarantee_online_cpus() |
| * or guarantee_online_mems() code will use that emptied cpusets |
| * parent online CPUs or nodes. Cpusets that were already empty of |
| * CPUs or nodes are left empty. |
| * |
| * This routine is intentionally inefficient in a couple of regards. |
| * It will check all cpusets in a subtree even if the top cpuset of |
| * the subtree has no offline CPUs or nodes. It checks both CPUs and |
| * nodes, even though the caller could have been coded to know that |
| * only one of CPUs or nodes needed to be checked on a given call. |
| * This was done to minimize text size rather than cpu cycles. |
| * |
| * Call with both manage_mutex and callback_mutex held. |
| * |
| * Recursive, on depth of cpuset subtree. |
| */ |
| |
| static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur) |
| { |
| struct cpuset *c; |
| |
| /* Each of our child cpusets mems must be online */ |
| list_for_each_entry(c, &cur->children, sibling) { |
| guarantee_online_cpus_mems_in_subtree(c); |
| if (!cpus_empty(c->cpus_allowed)) |
| guarantee_online_cpus(c, &c->cpus_allowed); |
| if (!nodes_empty(c->mems_allowed)) |
| guarantee_online_mems(c, &c->mems_allowed); |
| } |
| } |
| |
| /* |
| * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track |
| * cpu_online_map and node_online_map. Force the top cpuset to track |
| * whats online after any CPU or memory node hotplug or unplug event. |
| * |
| * To ensure that we don't remove a CPU or node from the top cpuset |
| * that is currently in use by a child cpuset (which would violate |
| * the rule that cpusets must be subsets of their parent), we first |
| * call the recursive routine guarantee_online_cpus_mems_in_subtree(). |
| * |
| * Since there are two callers of this routine, one for CPU hotplug |
| * events and one for memory node hotplug events, we could have coded |
| * two separate routines here. We code it as a single common routine |
| * in order to minimize text size. |
| */ |
| |
| static void common_cpu_mem_hotplug_unplug(void) |
| { |
| mutex_lock(&manage_mutex); |
| mutex_lock(&callback_mutex); |
| |
| guarantee_online_cpus_mems_in_subtree(&top_cpuset); |
| top_cpuset.cpus_allowed = cpu_online_map; |
| top_cpuset.mems_allowed = node_online_map; |
| |
| mutex_unlock(&callback_mutex); |
| mutex_unlock(&manage_mutex); |
| } |
| |
| /* |
| * The top_cpuset tracks what CPUs and Memory Nodes are online, |
| * period. This is necessary in order to make cpusets transparent |
| * (of no affect) on systems that are actively using CPU hotplug |
| * but making no active use of cpusets. |
| * |
| * This routine ensures that top_cpuset.cpus_allowed tracks |
| * cpu_online_map on each CPU hotplug (cpuhp) event. |
| */ |
| |
| static int cpuset_handle_cpuhp(struct notifier_block *nb, |
| unsigned long phase, void *cpu) |
| { |
| if (phase == CPU_DYING || phase == CPU_DYING_FROZEN) |
| return NOTIFY_DONE; |
| |
| common_cpu_mem_hotplug_unplug(); |
| return 0; |
| } |
| |
| #ifdef CONFIG_MEMORY_HOTPLUG |
| /* |
| * Keep top_cpuset.mems_allowed tracking node_online_map. |
| * Call this routine anytime after you change node_online_map. |
| * See also the previous routine cpuset_handle_cpuhp(). |
| */ |
| |
| void cpuset_track_online_nodes(void) |
| { |
| common_cpu_mem_hotplug_unplug(); |
| } |
| #endif |
| |
| /** |
| * cpuset_init_smp - initialize cpus_allowed |
| * |
| * Description: Finish top cpuset after cpu, node maps are initialized |
| **/ |
| |
| void __init cpuset_init_smp(void) |
| { |
| top_cpuset.cpus_allowed = cpu_online_map; |
| top_cpuset.mems_allowed = node_online_map; |
| |
| hotcpu_notifier(cpuset_handle_cpuhp, 0); |
| } |
| |
| /** |
| * cpuset_fork - attach newly forked task to its parents cpuset. |
| * @tsk: pointer to task_struct of forking parent process. |
| * |
| * Description: A task inherits its parent's cpuset at fork(). |
| * |
| * A pointer to the shared cpuset was automatically copied in fork.c |
| * by dup_task_struct(). However, we ignore that copy, since it was |
| * not made under the protection of task_lock(), so might no longer be |
| * a valid cpuset pointer. attach_task() might have already changed |
| * current->cpuset, allowing the previously referenced cpuset to |
| * be removed and freed. Instead, we task_lock(current) and copy |
| * its present value of current->cpuset for our freshly forked child. |
| * |
| * At the point that cpuset_fork() is called, 'current' is the parent |
| * task, and the passed argument 'child' points to the child task. |
| **/ |
| |
| void cpuset_fork(struct task_struct *child) |
| { |
| task_lock(current); |
| child->cpuset = current->cpuset; |
| atomic_inc(&child->cpuset->count); |
| task_unlock(current); |
| } |
| |
| /** |
| * cpuset_exit - detach cpuset from exiting task |
| * @tsk: pointer to task_struct of exiting process |
| * |
| * Description: Detach cpuset from @tsk and release it. |
| * |
| * Note that cpusets marked notify_on_release force every task in |
| * them to take the global manage_mutex mutex when exiting. |
| * This could impact scaling on very large systems. Be reluctant to |
| * use notify_on_release cpusets where very high task exit scaling |
| * is required on large systems. |
| * |
| * Don't even think about derefencing 'cs' after the cpuset use count |
| * goes to zero, except inside a critical section guarded by manage_mutex |
| * or callback_mutex. Otherwise a zero cpuset use count is a license to |
| * any other task to nuke the cpuset immediately, via cpuset_rmdir(). |
| * |
| * This routine has to take manage_mutex, not callback_mutex, because |
| * it is holding that mutex while calling check_for_release(), |
| * which calls kmalloc(), so can't be called holding callback_mutex(). |
| * |
| * the_top_cpuset_hack: |
| * |
| * Set the exiting tasks cpuset to the root cpuset (top_cpuset). |
| * |
| * Don't leave a task unable to allocate memory, as that is an |
| * accident waiting to happen should someone add a callout in |
| * do_exit() after the cpuset_exit() call that might allocate. |
| * If a task tries to allocate memory with an invalid cpuset, |
| * it will oops in cpuset_update_task_memory_state(). |
| * |
| * We call cpuset_exit() while the task is still competent to |
| * handle notify_on_release(), then leave the task attached to |
| * the root cpuset (top_cpuset) for the remainder of its exit. |
| * |
| * To do this properly, we would increment the reference count on |
| * top_cpuset, and near the very end of the kernel/exit.c do_exit() |
| * code we would add a second cpuset function call, to drop that |
| * reference. This would just create an unnecessary hot spot on |
| * the top_cpuset reference count, to no avail. |
| * |
| * Normally, holding a reference to a cpuset without bumping its |
| * count is unsafe. The cpuset could go away, or someone could |
| * attach us to a different cpuset, decrementing the count on |
| * the first cpuset that we never incremented. But in this case, |
| * top_cpuset isn't going away, and either task has PF_EXITING set, |
| * which wards off any attach_task() attempts, or task is a failed |
| * fork, never visible to attach_task. |
| * |
| * Another way to do this would be to set the cpuset pointer |
| * to NULL here, and check in cpuset_update_task_memory_state() |
| * for a NULL pointer. This hack avoids that NULL check, for no |
| * cost (other than this way too long comment ;). |
| **/ |
| |
| void cpuset_exit(struct task_struct *tsk) |
| { |
| struct cpuset *cs; |
| |
| task_lock(current); |
| cs = tsk->cpuset; |
| tsk->cpuset = &top_cpuset; /* the_top_cpuset_hack - see above */ |
| task_unlock(current); |
| |
| if (notify_on_release(cs)) { |
| char *pathbuf = NULL; |
| |
| mutex_lock(&manage_mutex); |
| if (atomic_dec_and_test(&cs->count)) |
| check_for_release(cs, &pathbuf); |
| mutex_unlock(&manage_mutex); |
| cpuset_release_agent(pathbuf); |
| } else { |
| atomic_dec(&cs->count); |
| } |
| } |
| |
| /** |
| * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset. |
| * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed. |
| * |
| * Description: Returns the cpumask_t cpus_allowed of the cpuset |
| * attached to the specified @tsk. Guaranteed to return some non-empty |
| * subset of cpu_online_map, even if this means going outside the |
| * tasks cpuset. |
| **/ |
| |
| cpumask_t cpuset_cpus_allowed(struct task_struct *tsk) |
| { |
| cpumask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| task_lock(tsk); |
| guarantee_online_cpus(tsk->cpuset, &mask); |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| |
| return mask; |
| } |
| |
| void cpuset_init_current_mems_allowed(void) |
| { |
| current->mems_allowed = NODE_MASK_ALL; |
| } |
| |
| /** |
| * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset. |
| * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed. |
| * |
| * Description: Returns the nodemask_t mems_allowed of the cpuset |
| * attached to the specified @tsk. Guaranteed to return some non-empty |
| * subset of node_online_map, even if this means going outside the |
| * tasks cpuset. |
| **/ |
| |
| nodemask_t cpuset_mems_allowed(struct task_struct *tsk) |
| { |
| nodemask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| task_lock(tsk); |
| guarantee_online_mems(tsk->cpuset, &mask); |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| |
| return mask; |
| } |
| |
| /** |
| * cpuset_zonelist_valid_mems_allowed - check zonelist vs. curremt mems_allowed |
| * @zl: the zonelist to be checked |
| * |
| * Are any of the nodes on zonelist zl allowed in current->mems_allowed? |
| */ |
| int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl) |
| { |
| int i; |
| |
| for (i = 0; zl->zones[i]; i++) { |
| int nid = zone_to_nid(zl->zones[i]); |
| |
| if (node_isset(nid, current->mems_allowed)) |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * nearest_exclusive_ancestor() - Returns the nearest mem_exclusive |
| * ancestor to the specified cpuset. Call holding callback_mutex. |
| * If no ancestor is mem_exclusive (an unusual configuration), then |
| * returns the root cpuset. |
| */ |
| static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs) |
| { |
| while (!is_mem_exclusive(cs) && cs->parent) |
| cs = cs->parent; |
| return cs; |
| } |
| |
| /** |
| * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node? |
| * @z: is this zone on an allowed node? |
| * @gfp_mask: memory allocation flags |
| * |
| * If we're in interrupt, yes, we can always allocate. If |
| * __GFP_THISNODE is set, yes, we can always allocate. If zone |
| * z's node is in our tasks mems_allowed, yes. If it's not a |
| * __GFP_HARDWALL request and this zone's nodes is in the nearest |
| * mem_exclusive cpuset ancestor to this tasks cpuset, yes. |
| * If the task has been OOM killed and has access to memory reserves |
| * as specified by the TIF_MEMDIE flag, yes. |
| * Otherwise, no. |
| * |
| * If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall() |
| * reduces to cpuset_zone_allowed_hardwall(). Otherwise, |
| * cpuset_zone_allowed_softwall() might sleep, and might allow a zone |
| * from an enclosing cpuset. |
| * |
| * cpuset_zone_allowed_hardwall() only handles the simpler case of |
| * hardwall cpusets, and never sleeps. |
| * |
| * The __GFP_THISNODE placement logic is really handled elsewhere, |
| * by forcibly using a zonelist starting at a specified node, and by |
| * (in get_page_from_freelist()) refusing to consider the zones for |
| * any node on the zonelist except the first. By the time any such |
| * calls get to this routine, we should just shut up and say 'yes'. |
| * |
| * GFP_USER allocations are marked with the __GFP_HARDWALL bit, |
| * and do not allow allocations outside the current tasks cpuset |
| * unless the task has been OOM killed as is marked TIF_MEMDIE. |
| * GFP_KERNEL allocations are not so marked, so can escape to the |
| * nearest enclosing mem_exclusive ancestor cpuset. |
| * |
| * Scanning up parent cpusets requires callback_mutex. The |
| * __alloc_pages() routine only calls here with __GFP_HARDWALL bit |
| * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the |
| * current tasks mems_allowed came up empty on the first pass over |
| * the zonelist. So only GFP_KERNEL allocations, if all nodes in the |
| * cpuset are short of memory, might require taking the callback_mutex |
| * mutex. |
| * |
| * The first call here from mm/page_alloc:get_page_from_freelist() |
| * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, |
| * so no allocation on a node outside the cpuset is allowed (unless |
| * in interrupt, of course). |
| * |
| * The second pass through get_page_from_freelist() doesn't even call |
| * here for GFP_ATOMIC calls. For those calls, the __alloc_pages() |
| * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set |
| * in alloc_flags. That logic and the checks below have the combined |
| * affect that: |
| * in_interrupt - any node ok (current task context irrelevant) |
| * GFP_ATOMIC - any node ok |
| * TIF_MEMDIE - any node ok |
| * GFP_KERNEL - any node in enclosing mem_exclusive cpuset ok |
| * GFP_USER - only nodes in current tasks mems allowed ok. |
| * |
| * Rule: |
| * Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you |
| * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables |
| * the code that might scan up ancestor cpusets and sleep. |
| */ |
| |
| int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask) |
| { |
| int node; /* node that zone z is on */ |
| const struct cpuset *cs; /* current cpuset ancestors */ |
| int allowed; /* is allocation in zone z allowed? */ |
| |
| if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) |
| return 1; |
| node = zone_to_nid(z); |
| might_sleep_if(!(gfp_mask & __GFP_HARDWALL)); |
| if (node_isset(node, current->mems_allowed)) |
| return 1; |
| /* |
| * Allow tasks that have access to memory reserves because they have |
| * been OOM killed to get memory anywhere. |
| */ |
| if (unlikely(test_thread_flag(TIF_MEMDIE))) |
| return 1; |
| if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ |
| return 0; |
| |
| if (current->flags & PF_EXITING) /* Let dying task have memory */ |
| return 1; |
| |
| /* Not hardwall and node outside mems_allowed: scan up cpusets */ |
| mutex_lock(&callback_mutex); |
| |
| task_lock(current); |
| cs = nearest_exclusive_ancestor(current->cpuset); |
| task_unlock(current); |
| |
| allowed = node_isset(node, cs->mems_allowed); |
| mutex_unlock(&callback_mutex); |
| return allowed; |
| } |
| |
| /* |
| * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node? |
| * @z: is this zone on an allowed node? |
| * @gfp_mask: memory allocation flags |
| * |
| * If we're in interrupt, yes, we can always allocate. |
| * If __GFP_THISNODE is set, yes, we can always allocate. If zone |
| * z's node is in our tasks mems_allowed, yes. If the task has been |
| * OOM killed and has access to memory reserves as specified by the |
| * TIF_MEMDIE flag, yes. Otherwise, no. |
| * |
| * The __GFP_THISNODE placement logic is really handled elsewhere, |
| * by forcibly using a zonelist starting at a specified node, and by |
| * (in get_page_from_freelist()) refusing to consider the zones for |
| * any node on the zonelist except the first. By the time any such |
| * calls get to this routine, we should just shut up and say 'yes'. |
| * |
| * Unlike the cpuset_zone_allowed_softwall() variant, above, |
| * this variant requires that the zone be in the current tasks |
| * mems_allowed or that we're in interrupt. It does not scan up the |
| * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset. |
| * It never sleeps. |
| */ |
| |
| int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask) |
| { |
| int node; /* node that zone z is on */ |
| |
| if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) |
| return 1; |
| node = zone_to_nid(z); |
| if (node_isset(node, current->mems_allowed)) |
| return 1; |
| /* |
| * Allow tasks that have access to memory reserves because they have |
| * been OOM killed to get memory anywhere. |
| */ |
| if (unlikely(test_thread_flag(TIF_MEMDIE))) |
| return 1; |
| return 0; |
| } |
| |
| /** |
| * cpuset_lock - lock out any changes to cpuset structures |
| * |
| * The out of memory (oom) code needs to mutex_lock cpusets |
| * from being changed while it scans the tasklist looking for a |
| * task in an overlapping cpuset. Expose callback_mutex via this |
| * cpuset_lock() routine, so the oom code can lock it, before |
| * locking the task list. The tasklist_lock is a spinlock, so |
| * must be taken inside callback_mutex. |
| */ |
| |
| void cpuset_lock(void) |
| { |
| mutex_lock(&callback_mutex); |
| } |
| |
| /** |
| * cpuset_unlock - release lock on cpuset changes |
| * |
| * Undo the lock taken in a previous cpuset_lock() call. |
| */ |
| |
| void cpuset_unlock(void) |
| { |
| mutex_unlock(&callback_mutex); |
| } |
| |
| /** |
| * cpuset_mem_spread_node() - On which node to begin search for a page |
| * |
| * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for |
| * tasks in a cpuset with is_spread_page or is_spread_slab set), |
| * and if the memory allocation used cpuset_mem_spread_node() |
| * to determine on which node to start looking, as it will for |
| * certain page cache or slab cache pages such as used for file |
| * system buffers and inode caches, then instead of starting on the |
| * local node to look for a free page, rather spread the starting |
| * node around the tasks mems_allowed nodes. |
| * |
| * We don't have to worry about the returned node being offline |
| * because "it can't happen", and even if it did, it would be ok. |
| * |
| * The routines calling guarantee_online_mems() are careful to |
| * only set nodes in task->mems_allowed that are online. So it |
| * should not be possible for the following code to return an |
| * offline node. But if it did, that would be ok, as this routine |
| * is not returning the node where the allocation must be, only |
| * the node where the search should start. The zonelist passed to |
| * __alloc_pages() will include all nodes. If the slab allocator |
| * is passed an offline node, it will fall back to the local node. |
| * See kmem_cache_alloc_node(). |
| */ |
| |
| int cpuset_mem_spread_node(void) |
| { |
| int node; |
| |
| node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed); |
| if (node == MAX_NUMNODES) |
| node = first_node(current->mems_allowed); |
| current->cpuset_mem_spread_rotor = node; |
| return node; |
| } |
| EXPORT_SYMBOL_GPL(cpuset_mem_spread_node); |
| |
| /** |
| * cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors? |
| * @p: pointer to task_struct of some other task. |
| * |
| * Description: Return true if the nearest mem_exclusive ancestor |
| * cpusets of tasks @p and current overlap. Used by oom killer to |
| * determine if task @p's memory usage might impact the memory |
| * available to the current task. |
| * |
| * Call while holding callback_mutex. |
| **/ |
| |
| int cpuset_excl_nodes_overlap(const struct task_struct *p) |
| { |
| const struct cpuset *cs1, *cs2; /* my and p's cpuset ancestors */ |
| int overlap = 1; /* do cpusets overlap? */ |
| |
| task_lock(current); |
| if (current->flags & PF_EXITING) { |
| task_unlock(current); |
| goto done; |
| } |
| cs1 = nearest_exclusive_ancestor(current->cpuset); |
| task_unlock(current); |
| |
| task_lock((struct task_struct *)p); |
| if (p->flags & PF_EXITING) { |
| task_unlock((struct task_struct *)p); |
| goto done; |
| } |
| cs2 = nearest_exclusive_ancestor(p->cpuset); |
| task_unlock((struct task_struct *)p); |
| |
| overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed); |
| done: |
| return overlap; |
| } |
| |
| /* |
| * Collection of memory_pressure is suppressed unless |
| * this flag is enabled by writing "1" to the special |
| * cpuset file 'memory_pressure_enabled' in the root cpuset. |
| */ |
| |
| int cpuset_memory_pressure_enabled __read_mostly; |
| |
| /** |
| * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims. |
| * |
| * Keep a running average of the rate of synchronous (direct) |
| * page reclaim efforts initiated by tasks in each cpuset. |
| * |
| * This represents the rate at which some task in the cpuset |
| * ran low on memory on all nodes it was allowed to use, and |
| * had to enter the kernels page reclaim code in an effort to |
| * create more free memory by tossing clean pages or swapping |
| * or writing dirty pages. |
| * |
| * Display to user space in the per-cpuset read-only file |
| * "memory_pressure". Value displayed is an integer |
| * representing the recent rate of entry into the synchronous |
| * (direct) page reclaim by any task attached to the cpuset. |
| **/ |
| |
| void __cpuset_memory_pressure_bump(void) |
| { |
| struct cpuset *cs; |
| |
| task_lock(current); |
| cs = current->cpuset; |
| fmeter_markevent(&cs->fmeter); |
| task_unlock(current); |
| } |
| |
| /* |
| * proc_cpuset_show() |
| * - Print tasks cpuset path into seq_file. |
| * - Used for /proc/<pid>/cpuset. |
| * - No need to task_lock(tsk) on this tsk->cpuset reference, as it |
| * doesn't really matter if tsk->cpuset changes after we read it, |
| * and we take manage_mutex, keeping attach_task() from changing it |
| * anyway. No need to check that tsk->cpuset != NULL, thanks to |
| * the_top_cpuset_hack in cpuset_exit(), which sets an exiting tasks |
| * cpuset to top_cpuset. |
| */ |
| static int proc_cpuset_show(struct seq_file *m, void *v) |
| { |
| struct pid *pid; |
| struct task_struct *tsk; |
| char *buf; |
| int retval; |
| |
| retval = -ENOMEM; |
| buf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| if (!buf) |
| goto out; |
| |
| retval = -ESRCH; |
| pid = m->private; |
| tsk = get_pid_task(pid, PIDTYPE_PID); |
| if (!tsk) |
| goto out_free; |
| |
| retval = -EINVAL; |
| mutex_lock(&manage_mutex); |
| |
| retval = cpuset_path(tsk->cpuset, buf, PAGE_SIZE); |
| if (retval < 0) |
| goto out_unlock; |
| seq_puts(m, buf); |
| seq_putc(m, '\n'); |
| out_unlock: |
| mutex_unlock(&manage_mutex); |
| put_task_struct(tsk); |
| out_free: |
| kfree(buf); |
| out: |
| return retval; |
| } |
| |
| static int cpuset_open(struct inode *inode, struct file *file) |
| { |
| struct pid *pid = PROC_I(inode)->pid; |
| return single_open(file, proc_cpuset_show, pid); |
| } |
| |
| const struct file_operations proc_cpuset_operations = { |
| .open = cpuset_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = single_release, |
| }; |
| |
| /* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */ |
| char *cpuset_task_status_allowed(struct task_struct *task, char *buffer) |
| { |
| buffer += sprintf(buffer, "Cpus_allowed:\t"); |
| buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed); |
| buffer += sprintf(buffer, "\n"); |
| buffer += sprintf(buffer, "Mems_allowed:\t"); |
| buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed); |
| buffer += sprintf(buffer, "\n"); |
| return buffer; |
| } |