diff options
Diffstat (limited to 'kernel/cpuset.c')
| -rw-r--r-- | kernel/cpuset.c | 1736 |
1 files changed, 628 insertions, 1108 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 57e6448b171..50f5dc46368 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -4,7 +4,8 @@ * Processor and Memory placement constraints for sets of tasks. * * Copyright (C) 2003 BULL SA. - * Copyright (C) 2004-2006 Silicon Graphics, Inc. + * Copyright (C) 2004-2007 Silicon Graphics, Inc. + * Copyright (C) 2006 Google, Inc * * Portions derived from Patrick Mochel's sysfs code. * sysfs is Copyright (c) 2001-3 Patrick Mochel @@ -12,6 +13,7 @@ * 2003-10-10 Written by Simon Derr. * 2003-10-22 Updates by Stephen Hemminger. * 2004 May-July Rework by Paul Jackson. + * 2006 Rework by Paul Menage to use generic cgroups * * 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 @@ -36,6 +38,7 @@ #include <linux/mount.h> #include <linux/namei.h> #include <linux/pagemap.h> +#include <linux/prio_heap.h> #include <linux/proc_fs.h> #include <linux/rcupdate.h> #include <linux/sched.h> @@ -52,8 +55,7 @@ #include <asm/uaccess.h> #include <asm/atomic.h> #include <linux/mutex.h> - -#define CPUSET_SUPER_MAGIC 0x27e0eb +#include <linux/kfifo.h> /* * Tracks how many cpusets are currently defined in system. @@ -62,6 +64,10 @@ */ int number_of_cpusets __read_mostly; +/* Retrieve the cpuset from a cgroup */ +struct cgroup_subsys cpuset_subsys; +struct cpuset; + /* See "Frequency meter" comments, below. */ struct fmeter { @@ -72,24 +78,13 @@ struct fmeter { }; struct cpuset { + struct cgroup_subsys_state css; + 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 @@ -98,15 +93,32 @@ struct cpuset { int mems_generation; struct fmeter fmeter; /* memory_pressure filter */ + + /* partition number for rebuild_sched_domains() */ + int pn; }; +/* Retrieve the cpuset for a cgroup */ +static inline struct cpuset *cgroup_cs(struct cgroup *cont) +{ + return container_of(cgroup_subsys_state(cont, cpuset_subsys_id), + struct cpuset, css); +} + +/* Retrieve the cpuset for a task */ +static inline struct cpuset *task_cs(struct task_struct *task) +{ + return container_of(task_subsys_state(task, cpuset_subsys_id), + struct cpuset, css); +} + + /* bits in struct cpuset flags field */ typedef enum { CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE, CS_MEMORY_MIGRATE, - CS_REMOVED, - CS_NOTIFY_ON_RELEASE, + CS_SCHED_LOAD_BALANCE, CS_SPREAD_PAGE, CS_SPREAD_SLAB, } cpuset_flagbits_t; @@ -122,14 +134,9 @@ 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) +static inline int is_sched_load_balance(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); + return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); } static inline int is_memory_migrate(const struct cpuset *cs) @@ -172,14 +179,8 @@ 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 @@ -263,297 +264,33 @@ static struct super_block *cpuset_sb; * 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; -} - +/* This is ugly, but preserves the userspace API for existing cpuset + * users. If someone tries to mount the "cpuset" filesystem, we + * silently switch it to mount "cgroup" instead */ 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); + struct file_system_type *cgroup_fs = get_fs_type("cgroup"); + int ret = -ENODEV; + if (cgroup_fs) { + char mountopts[] = + "cpuset,noprefix," + "release_agent=/sbin/cpuset_release_agent"; + ret = cgroup_fs->get_sb(cgroup_fs, flags, + unused_dev_name, mountopts, mnt); + put_filesystem(cgroup_fs); + } + return ret; } 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 @@ -581,26 +318,28 @@ static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask) /* * 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. + * are online, with memory. If none are online with memory, 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_states[N_HIGH_MEMORY]. * * One way or another, we guarantee to return some non-empty subset - * of node_online_map. + * of node_states[N_HIGH_MEMORY]. * * 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)) + while (cs && !nodes_intersects(cs->mems_allowed, + node_states[N_HIGH_MEMORY])) cs = cs->parent; if (cs) - nodes_and(*pmask, cs->mems_allowed, node_online_map); + nodes_and(*pmask, cs->mems_allowed, + node_states[N_HIGH_MEMORY]); else - *pmask = node_online_map; - BUG_ON(!nodes_intersects(*pmask, node_online_map)); + *pmask = node_states[N_HIGH_MEMORY]; + BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY])); } /** @@ -651,20 +390,19 @@ void cpuset_update_task_memory_state(void) struct task_struct *tsk = current; struct cpuset *cs; - if (tsk->cpuset == &top_cpuset) { + if (task_cs(tsk) == &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; + my_cpusets_mem_gen = task_cs(current)->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 */ + cs = task_cs(tsk); /* 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)) @@ -719,11 +457,12 @@ static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) static int validate_change(const struct cpuset *cur, const struct cpuset *trial) { + struct cgroup *cont; 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)) + list_for_each_entry(cont, &cur->css.cgroup->children, sibling) { + if (!is_cpuset_subset(cgroup_cs(cont), trial)) return -EBUSY; } @@ -738,7 +477,8 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial) return -EACCES; /* If either I or some sibling (!= me) is exclusive, we can't overlap */ - list_for_each_entry(c, &par->children, sibling) { + list_for_each_entry(cont, &par->css.cgroup->children, sibling) { + c = cgroup_cs(cont); if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && c != cur && cpus_intersects(trial->cpus_allowed, c->cpus_allowed)) @@ -749,62 +489,247 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial) return -EINVAL; } + /* Cpusets with tasks can't have empty cpus_allowed or mems_allowed */ + if (cgroup_task_count(cur->css.cgroup)) { + if (cpus_empty(trial->cpus_allowed) || + nodes_empty(trial->mems_allowed)) { + return -ENOSPC; + } + } + 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. + * Helper routine for rebuild_sched_domains(). + * Do cpusets a, b have overlapping cpus_allowed masks? */ -static void update_cpu_domains(struct cpuset *cur) +static int cpusets_overlap(struct cpuset *a, struct cpuset *b) { - struct cpuset *c, *par = cur->parent; - cpumask_t pspan, cspan; + return cpus_intersects(a->cpus_allowed, b->cpus_allowed); +} - if (par == NULL || cpus_empty(cur->cpus_allowed)) - return; +/* + * rebuild_sched_domains() + * + * If the flag 'sched_load_balance' of any cpuset with non-empty + * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset + * which has that flag enabled, or if any cpuset with a non-empty + * 'cpus' is removed, then call this routine to rebuild the + * scheduler's dynamic sched domains. + * + * This routine builds a partial partition of the systems CPUs + * (the set of non-overlappping cpumask_t's in the array 'part' + * below), and passes that partial partition to the kernel/sched.c + * partition_sched_domains() routine, which will rebuild the + * schedulers load balancing domains (sched domains) as specified + * by that partial partition. A 'partial partition' is a set of + * non-overlapping subsets whose union is a subset of that set. + * + * See "What is sched_load_balance" in Documentation/cpusets.txt + * for a background explanation of this. + * + * Does not return errors, on the theory that the callers of this + * routine would rather not worry about failures to rebuild sched + * domains when operating in the severe memory shortage situations + * that could cause allocation failures below. + * + * Call with cgroup_mutex held. May take callback_mutex during + * call due to the kfifo_alloc() and kmalloc() calls. 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. Elsewhere + * the kernel nests callback_mutex inside lock_cpu_hotplug() calls. + * So the reverse nesting would risk an ABBA deadlock. + * + * The three key local variables below are: + * q - a kfifo queue of cpuset pointers, used to implement a + * top-down scan of all cpusets. This scan loads a pointer + * to each cpuset marked is_sched_load_balance into the + * array 'csa'. For our purposes, rebuilding the schedulers + * sched domains, we can ignore !is_sched_load_balance cpusets. + * csa - (for CpuSet Array) Array of pointers to all the cpusets + * that need to be load balanced, for convenient iterative + * access by the subsequent code that finds the best partition, + * i.e the set of domains (subsets) of CPUs such that the + * cpus_allowed of every cpuset marked is_sched_load_balance + * is a subset of one of these domains, while there are as + * many such domains as possible, each as small as possible. + * doms - Conversion of 'csa' to an array of cpumasks, for passing to + * the kernel/sched.c routine partition_sched_domains() in a + * convenient format, that can be easily compared to the prior + * value to determine what partition elements (sched domains) + * were changed (added or removed.) + * + * Finding the best partition (set of domains): + * The triple nested loops below over i, j, k scan over the + * load balanced cpusets (using the array of cpuset pointers in + * csa[]) looking for pairs of cpusets that have overlapping + * cpus_allowed, but which don't have the same 'pn' partition + * number and gives them in the same partition number. It keeps + * looping on the 'restart' label until it can no longer find + * any such pairs. + * + * The union of the cpus_allowed masks from the set of + * all cpusets having the same 'pn' value then form the one + * element of the partition (one sched domain) to be passed to + * partition_sched_domains(). + */ - /* - * 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); +static void rebuild_sched_domains(void) +{ + struct kfifo *q; /* queue of cpusets to be scanned */ + struct cpuset *cp; /* scans q */ + struct cpuset **csa; /* array of all cpuset ptrs */ + int csn; /* how many cpuset ptrs in csa so far */ + int i, j, k; /* indices for partition finding loops */ + cpumask_t *doms; /* resulting partition; i.e. sched domains */ + int ndoms; /* number of sched domains in result */ + int nslot; /* next empty doms[] cpumask_t slot */ + + q = NULL; + csa = NULL; + doms = NULL; + + /* Special case for the 99% of systems with one, full, sched domain */ + if (is_sched_load_balance(&top_cpuset)) { + ndoms = 1; + doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL); + if (!doms) + goto rebuild; + *doms = top_cpuset.cpus_allowed; + goto rebuild; } - 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); + + q = kfifo_alloc(number_of_cpusets * sizeof(cp), GFP_KERNEL, NULL); + if (IS_ERR(q)) + goto done; + csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL); + if (!csa) + goto done; + csn = 0; + + cp = &top_cpuset; + __kfifo_put(q, (void *)&cp, sizeof(cp)); + while (__kfifo_get(q, (void *)&cp, sizeof(cp))) { + struct cgroup *cont; + struct cpuset *child; /* scans child cpusets of cp */ + if (is_sched_load_balance(cp)) + csa[csn++] = cp; + list_for_each_entry(cont, &cp->css.cgroup->children, sibling) { + child = cgroup_cs(cont); + __kfifo_put(q, (void *)&child, sizeof(cp)); + } + } + + for (i = 0; i < csn; i++) + csa[i]->pn = i; + ndoms = csn; + +restart: + /* Find the best partition (set of sched domains) */ + for (i = 0; i < csn; i++) { + struct cpuset *a = csa[i]; + int apn = a->pn; + + for (j = 0; j < csn; j++) { + struct cpuset *b = csa[j]; + int bpn = b->pn; + + if (apn != bpn && cpusets_overlap(a, b)) { + for (k = 0; k < csn; k++) { + struct cpuset *c = csa[k]; + + if (c->pn == bpn) + c->pn = apn; + } + ndoms--; /* one less element */ + goto restart; + } + } + } + + /* Convert <csn, csa> to <ndoms, doms> */ + doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL); + if (!doms) + goto rebuild; + + for (nslot = 0, i = 0; i < csn; i++) { + struct cpuset *a = csa[i]; + int apn = a->pn; + + if (apn >= 0) { + cpumask_t *dp = doms + nslot; + + if (nslot == ndoms) { + static int warnings = 10; + if (warnings) { + printk(KERN_WARNING + "rebuild_sched_domains confused:" + " nslot %d, ndoms %d, csn %d, i %d," + " apn %d\n", + nslot, ndoms, csn, i, apn); + warnings--; + } + continue; + } + + cpus_clear(*dp); + for (j = i; j < csn; j++) { + struct cpuset *b = csa[j]; + + if (apn == b->pn) { + cpus_or(*dp, *dp, b->cpus_allowed); + b->pn = -1; + } + } + nslot++; } } + BUG_ON(nslot != ndoms); +rebuild: + /* Have scheduler rebuild sched domains */ lock_cpu_hotplug(); - partition_sched_domains(&pspan, &cspan); + partition_sched_domains(ndoms, doms); unlock_cpu_hotplug(); + +done: + if (q && !IS_ERR(q)) + kfifo_free(q); + kfree(csa); + /* Don't kfree(doms) -- partition_sched_domains() does that. */ +} + +static inline int started_after_time(struct task_struct *t1, + struct timespec *time, + struct task_struct *t2) +{ + int start_diff = timespec_compare(&t1->start_time, time); + if (start_diff > 0) { + return 1; + } else if (start_diff < 0) { + return 0; + } else { + /* + * Arbitrarily, if two processes started at the same + * time, we'll say that the lower pointer value + * started first. Note that t2 may have exited by now + * so this may not be a valid pointer any longer, but + * that's fine - it still serves to distinguish + * between two tasks started (effectively) + * simultaneously. + */ + return t1 > t2; + } +} + +static inline int started_after(void *p1, void *p2) +{ + struct task_struct *t1 = p1; + struct task_struct *t2 = p2; + return started_after_time(t1, &t2->start_time, t2); } /* @@ -814,7 +739,15 @@ static void update_cpu_domains(struct cpuset *cur) static int update_cpumask(struct cpuset *cs, char *buf) { struct cpuset trialcs; - int retval, cpus_unchanged; + int retval, i; + int is_load_balanced; + struct cgroup_iter it; + struct cgroup *cgrp = cs->css.cgroup; + struct task_struct *p, *dropped; + /* Never dereference latest_task, since it's not refcounted */ + struct task_struct *latest_task = NULL; + struct ptr_heap heap; + struct timespec latest_time = { 0, 0 }; /* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */ if (cs == &top_cpuset) @@ -823,11 +756,13 @@ static int update_cpumask(struct cpuset *cs, char *buf) 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. + * An empty cpus_allowed is ok iff there are no tasks in the cpuset. + * Since cpulist_parse() fails on an empty mask, we special case + * that parsing. The validate_change() call ensures that cpusets + * with tasks have cpus. */ - if (!buf[0] || (buf[0] == '\n' && !buf[1])) { + buf = strstrip(buf); + if (!*buf) { cpus_clear(trialcs.cpus_allowed); } else { retval = cpulist_parse(buf, trialcs.cpus_allowed); @@ -835,18 +770,79 @@ static int update_cpumask(struct cpuset *cs, char *buf) 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); + + /* Nothing to do if the cpus didn't change */ + if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed)) + return 0; + retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, &started_after); + if (retval) + return retval; + + is_load_balanced = is_sched_load_balance(&trialcs); + 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); + + again: + /* + * Scan tasks in the cpuset, and update the cpumasks of any + * that need an update. Since we can't call set_cpus_allowed() + * while holding tasklist_lock, gather tasks to be processed + * in a heap structure. If the statically-sized heap fills up, + * overflow tasks that started later, and in future iterations + * only consider tasks that started after the latest task in + * the previous pass. This guarantees forward progress and + * that we don't miss any tasks + */ + heap.size = 0; + cgroup_iter_start(cgrp, &it); + while ((p = cgroup_iter_next(cgrp, &it))) { + /* Only affect tasks that don't have the right cpus_allowed */ + if (cpus_equal(p->cpus_allowed, cs->cpus_allowed)) + continue; + /* + * Only process tasks that started after the last task + * we processed + */ + if (!started_after_time(p, &latest_time, latest_task)) + continue; + dropped = heap_insert(&heap, p); + if (dropped == NULL) { + get_task_struct(p); + } else if (dropped != p) { + get_task_struct(p); + put_task_struct(dropped); + } + } + cgroup_iter_end(cgrp, &it); + if (heap.size) { + for (i = 0; i < heap.size; i++) { + struct task_struct *p = heap.ptrs[i]; + if (i == 0) { + latest_time = p->start_time; + latest_task = p; + } + set_cpus_allowed(p, cs->cpus_allowed); + put_task_struct(p); + } + /* + * If we had to process any tasks at all, scan again + * in case some of them were in the middle of forking + * children that didn't notice the new cpumask + * restriction. Not the most efficient way to do it, + * but it avoids having to take callback_mutex in the + * fork path + */ + goto again; + } + heap_free(&heap); + if (is_load_balanced) + rebuild_sched_domains(); + return 0; } @@ -895,7 +891,7 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL); mutex_lock(&callback_mutex); - guarantee_online_mems(tsk->cpuset, &tsk->mems_allowed); + guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed); mutex_unlock(&callback_mutex); } @@ -913,46 +909,50 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, * their mempolicies to the cpusets new mems_allowed. */ +static void *cpuset_being_rebound; + static int update_nodemask(struct cpuset *cs, char *buf) { struct cpuset trialcs; nodemask_t oldmem; - struct task_struct *g, *p; + struct task_struct *p; struct mm_struct **mmarray; int i, n, ntasks; int migrate; int fudge; int retval; + struct cgroup_iter it; - /* top_cpuset.mems_allowed tracks node_online_map; it's read-only */ + /* + * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY]; + * 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. + * An empty mems_allowed is ok iff there are no tasks in the cpuset. + * Since nodelist_parse() fails on an empty mask, we special case + * that parsing. The validate_change() call ensures that cpusets + * with tasks have memory. */ - if (!buf[0] || (buf[0] == '\n' && !buf[1])) { + buf = strstrip(buf); + if (!*buf) { 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); + nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, + node_states[N_HIGH_MEMORY]); 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; @@ -962,7 +962,7 @@ static int update_nodemask(struct cpuset *cs, char *buf) cs->mems_generation = cpuset_mems_generation++; mutex_unlock(&callback_mutex); - set_cpuset_being_rebound(cs); /* causes mpol_copy() rebind */ + cpuset_being_rebound = cs; /* causes mpol_copy() rebind */ fudge = 10; /* spare mmarray[] slots */ fudge += cpus_weight(cs->cpus_allowed); /* imagine one fork-bomb/cpu */ @@ -976,13 +976,13 @@ static int update_nodemask(struct cpuset *cs, char *buf) * enough mmarray[] w/o using GFP_ATOMIC. */ while (1) { - ntasks = atomic_read(&cs->count); /* guess */ + ntasks = cgroup_task_count(cs->css.cgroup); /* 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) + if (cgroup_task_count(cs->css.cgroup) <= ntasks) break; /* got enough */ read_unlock(&tasklist_lock); /* try again */ kfree(mmarray); @@ -991,21 +991,21 @@ static int update_nodemask(struct cpuset *cs, char *buf) n = 0; /* Load up mmarray[] with mm reference for each task in cpuset. */ - do_each_thread(g, p) { + cgroup_iter_start(cs->css.cgroup, &it); + while ((p = cgroup_iter_next(cs->css.cgroup, &it))) { struct mm_struct *mm; if (n >= ntasks) { printk(KERN_WARNING "Cpuset mempolicy rebind incomplete.\n"); - continue; + break; } - if (p->cpuset != cs) - continue; mm = get_task_mm(p); if (!mm) continue; mmarray[n++] = mm; - } while_each_thread(g, p); + } + cgroup_iter_end(cs->css.cgroup, &it); read_unlock(&tasklist_lock); /* @@ -1033,12 +1033,17 @@ static int update_nodemask(struct cpuset *cs, char *buf) /* We're done rebinding vma's to this cpusets new mems_allowed. */ kfree(mmarray); - set_cpuset_being_rebound(NULL); + cpuset_being_rebound = NULL; retval = 0; done: return retval; } +int current_cpuset_is_being_rebound(void) +{ + return task_cs(current) == cpuset_being_rebound; +} + /* * Call with manage_mutex held. */ @@ -1055,6 +1060,7 @@ static int update_memory_pressure_enabled(struct cpuset *cs, char *buf) /* * 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_SCHED_LOAD_BALANCE, * CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE, * CS_SPREAD_PAGE, CS_SPREAD_SLAB) * cs: the cpuset to update @@ -1067,7 +1073,8 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf) { int turning_on; struct cpuset trialcs; - int err, cpu_exclusive_changed; + int err; + int cpus_nonempty, balance_flag_changed; turning_on = (simple_strtoul(buf, NULL, 10) != 0); @@ -1080,14 +1087,18 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf) err = validate_change(cs, &trialcs); if (err < 0) return err; - cpu_exclusive_changed = - (is_cpu_exclusive(cs) != is_cpu_exclusive(&trialcs)); + + cpus_nonempty = !cpus_empty(trialcs.cpus_allowed); + balance_flag_changed = (is_sched_load_balance(cs) != + is_sched_load_balance(&trialcs)); + mutex_lock(&callback_mutex); cs->flags = trialcs.flags; mutex_unlock(&callback_mutex); - if (cpu_exclusive_changed) - update_cpu_domains(cs); + if (cpus_nonempty && balance_flag_changed) + rebuild_sched_domains(); + return 0; } @@ -1189,85 +1200,34 @@ static int fmeter_getrate(struct fmeter *fmp) 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) +static int cpuset_can_attach(struct cgroup_subsys *ss, + struct cgroup *cont, struct task_struct *tsk) { - pid_t pid; - struct task_struct *tsk; - struct cpuset *oldcs; - cpumask_t cpus; - nodemask_t from, to; - struct mm_struct *mm; - int retval; + struct cpuset *cs = cgroup_cs(cont); - 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); - } + return security_task_setscheduler(tsk, 0, NULL); +} - retval = security_task_setscheduler(tsk, 0, NULL); - if (retval) { - put_task_struct(tsk); - return retval; - } +static void cpuset_attach(struct cgroup_subsys *ss, + struct cgroup *cont, struct cgroup *oldcont, + struct task_struct *tsk) +{ + cpumask_t cpus; + nodemask_t from, to; + struct mm_struct *mm; + struct cpuset *cs = cgroup_cs(cont); + struct cpuset *oldcs = cgroup_cs(oldcont); 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); + mutex_unlock(&callback_mutex); from = oldcs->mems_allowed; to = cs->mems_allowed; - - mutex_unlock(&callback_mutex); - mm = get_task_mm(tsk); if (mm) { mpol_rebind_mm(mm, &to); @@ -1276,44 +1236,36 @@ static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf) 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_SCHED_LOAD_BALANCE, 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, +static ssize_t cpuset_common_file_write(struct cgroup *cont, + struct cftype *cft, + 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); + struct cpuset *cs = cgroup_cs(cont); 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)) + if (nbytes > 100U + 6 * max(NR_CPUS, MAX_NUMNODES)) return -E2BIG; /* +1 for nul-terminator */ @@ -1326,9 +1278,9 @@ static ssize_t cpuset_common_file_write(struct file *file, } buffer[nbytes] = 0; /* nul-terminate */ - mutex_lock(&manage_mutex); + cgroup_lock(); - if (is_removed(cs)) { + if (cgroup_is_removed(cont)) { retval = -ENODEV; goto out2; } @@ -1346,8 +1298,8 @@ static ssize_t cpuset_common_file_write(struct file *file, 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); + case FILE_SCHED_LOAD_BALANCE: + retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, buffer); break; case FILE_MEMORY_MIGRATE: retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer); @@ -1366,9 +1318,6 @@ static ssize_t cpuset_common_file_write(struct file *file, 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; @@ -1377,30 +1326,12 @@ static ssize_t cpuset_common_file_write(struct file *file, if (retval == 0) retval = nbytes; out2: - mutex_unlock(&manage_mutex); - cpuset_release_agent(pathbuf); + cgroup_unlock(); 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 @@ -1435,17 +1366,19 @@ static int cpuset_sprintf_memlist(char *page, struct cpuset *cs) 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) +static ssize_t cpuset_common_file_read(struct cgroup *cont, + struct cftype *cft, + 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); + struct cpuset *cs = cgroup_cs(cont); cpuset_filetype_t type = cft->private; char *page; ssize_t retval = 0; char *s; - if (!(page = (char *)__get_free_page(GFP_KERNEL))) + if (!(page = (char *)__get_free_page(GFP_TEMPORARY))) return -ENOMEM; s = page; @@ -1463,8 +1396,8 @@ static ssize_t cpuset_common_file_read(struct file *file, char __user *buf, case FILE_MEM_EXCLUSIVE: *s++ = is_mem_exclusive(cs) ? '1' : '0'; break; - case FILE_NOTIFY_ON_RELEASE: - *s++ = notify_on_release(cs) ? '1' : '0'; + case FILE_SCHED_LOAD_BALANCE: + *s++ = is_sched_load_balance(cs) ? '1' : '0'; break; case FILE_MEMORY_MIGRATE: *s++ = is_memory_migrate(cs) ? '1' : '0'; @@ -1493,390 +1426,150 @@ out: 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", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_CPULIST, }; static struct cftype cft_mems = { .name = "mems", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_MEMLIST, }; static struct cftype cft_cpu_exclusive = { .name = "cpu_exclusive", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_CPU_EXCLUSIVE, }; static struct cftype cft_mem_exclusive = { .name = "mem_exclusive", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_MEM_EXCLUSIVE, }; -static struct cftype cft_notify_on_release = { - .name = "notify_on_release", - .private = FILE_NOTIFY_ON_RELEASE, +static struct cftype cft_sched_load_balance = { + .name = "sched_load_balance", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, + .private = FILE_SCHED_LOAD_BALANCE, }; static struct cftype cft_memory_migrate = { .name = "memory_migrate", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_MEMORY_MIGRATE, }; static struct cftype cft_memory_pressure_enabled = { .name = "memory_pressure_enabled", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_MEMORY_PRESSURE_ENABLED, }; static struct cftype cft_memory_pressure = { .name = "memory_pressure", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_MEMORY_PRESSURE, }; static struct cftype cft_spread_page = { .name = "memory_spread_page", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_SPREAD_PAGE, }; static struct cftype cft_spread_slab = { .name = "memory_spread_slab", + .read = cpuset_common_file_read, + .write = cpuset_common_file_write, .private = FILE_SPREAD_SLAB, }; -static int cpuset_populate_dir(struct dentry *cs_dentry) +static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont) { int err; - if ((err = cpuset_add_file(cs_dentry, &cft_cpus)) < 0) - return err; - if ((err = cpuset_add_file(cs_dentry, &cft_mems)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_cpus)) < 0) return err; - if ((err = cpuset_add_file(cs_dentry, &cft_cpu_exclusive)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_mems)) < 0) return err; - if ((err = cpuset_add_file(cs_dentry, &cft_mem_exclusive)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_cpu_exclusive)) < 0) return err; - if ((err = cpuset_add_file(cs_dentry, &cft_notify_on_release)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_mem_exclusive)) < 0) return err; - if ((err = cpuset_add_file(cs_dentry, &cft_memory_migrate)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_memory_migrate)) < 0) return err; - if ((err = cpuset_add_file(cs_dentry, &cft_memory_pressure)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_sched_load_balance)) < 0) return err; - if ((err = cpuset_add_file(cs_dentry, &cft_spread_page)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_memory_pressure)) < 0) return err; - if ((err = cpuset_add_file(cs_dentry, &cft_spread_slab)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_spread_page)) < 0) return err; - if ((err = cpuset_add_file(cs_dentry, &cft_tasks)) < 0) + if ((err = cgroup_add_file(cont, ss, &cft_spread_slab)) < 0) return err; + /* memory_pressure_enabled is in root cpuset only */ + if (err == 0 && !cont->parent) + err = cgroup_add_file(cont, ss, + &cft_memory_pressure_enabled); return 0; } /* + * post_clone() is called at the end of cgroup_clone(). + * 'cgroup' was just created automatically as a result of + * a cgroup_clone(), and the current task is about to + * be moved into 'cgroup'. + * + * Currently we refuse to set up the cgroup - thereby + * refusing the task to be entered, and as a result refusing + * the sys_unshare() or clone() which initiated it - if any + * sibling cpusets have exclusive cpus or mem. + * + * If this becomes a problem for some users who wish to + * allow that scenario, then cpuset_post_clone() could be + * changed to grant parent->cpus_allowed-sibling_cpus_exclusive + * (and likewise for mems) to the new cgroup. + */ +static void cpuset_post_clone(struct cgroup_subsys *ss, + struct cgroup *cgroup) +{ + struct cgroup *parent, *child; + struct cpuset *cs, *parent_cs; + + parent = cgroup->parent; + list_for_each_entry(child, &parent->children, sibling) { + cs = cgroup_cs(child); + if (is_mem_exclusive(cs) || is_cpu_exclusive(cs)) + return; + } + cs = cgroup_cs(cgroup); + parent_cs = cgroup_cs(parent); + + cs->mems_allowed = parent_cs->mems_allowed; + cs->cpus_allowed = parent_cs->cpus_allowed; + return; +} + +/* * 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. @@ -1885,124 +1578,77 @@ static int cpuset_populate_dir(struct dentry *cs_dentry) * Must be called with the mutex on the parent inode held */ -static long cpuset_create(struct cpuset *parent, const char *name, int mode) +static struct cgroup_subsys_state *cpuset_create( + struct cgroup_subsys *ss, + struct cgroup *cont) { struct cpuset *cs; - int err; + struct cpuset *parent; + if (!cont->parent) { + /* This is early initialization for the top cgroup */ + top_cpuset.mems_generation = cpuset_mems_generation++; + return &top_cpuset.css; + } + parent = cgroup_cs(cont->parent); cs = kmalloc(sizeof(*cs), GFP_KERNEL); if (!cs) - return -ENOMEM; + return ERR_PTR(-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); + set_bit(CS_SCHED_LOAD_BALANCE, &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); + return &cs->css ; } /* * 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. + * If the cpuset being removed has its flag 'sched_load_balance' + * enabled, then simulate turning sched_load_balance off, which + * will call rebuild_sched_domains(). The lock_cpu_hotplug() + * call in rebuild_sched_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) +static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { - struct cpuset *cs = dentry->d_fsdata; - struct dentry *d; - struct cpuset *parent; - char *pathbuf = NULL; - - /* the vfs holds both inode->i_mutex already */ + struct cpuset *cs = cgroup_cs(cont); - 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); + + if (is_sched_load_balance(cs)) + update_flag(CS_SCHED_LOAD_BALANCE, cs, "0"); + 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; + kfree(cs); } +struct cgroup_subsys cpuset_subsys = { + .name = "cpuset", + .create = cpuset_create, + .destroy = cpuset_destroy, + .can_attach = cpuset_can_attach, + .attach = cpuset_attach, + .populate = cpuset_populate, + .post_clone = cpuset_post_clone, + .subsys_id = cpuset_subsys_id, + .early_init = 1, +}; + /* * cpuset_init_early - just enough so that the calls to * cpuset_update_task_memory_state() in early init code @@ -2011,13 +1657,11 @@ static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry) int __init cpuset_init_early(void) { - struct task_struct *tsk = current; - - tsk->cpuset = &top_cpuset; - tsk->cpuset->mems_generation = cpuset_mems_generation++; + top_cpuset.mems_generation = cpuset_mems_generation++; return 0; } + /** * cpuset_init - initialize cpusets at system boot * @@ -2026,39 +1670,21 @@ int __init cpuset_init_early(void) int __init cpuset_init(void) { - struct dentry *root; - int err; + int err = 0; 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; + set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags); 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; + return err; + 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; + return 0; } /* @@ -2084,10 +1710,12 @@ out: static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur) { + struct cgroup *cont; struct cpuset *c; /* Each of our child cpusets mems must be online */ - list_for_each_entry(c, &cur->children, sibling) { + list_for_each_entry(cont, &cur->css.cgroup->children, sibling) { + c = cgroup_cs(cont); guarantee_online_cpus_mems_in_subtree(c); if (!cpus_empty(c->cpus_allowed)) guarantee_online_cpus(c, &c->cpus_allowed); @@ -2098,8 +1726,9 @@ static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur) /* * 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. + * cpu_online_map and node_states[N_HIGH_MEMORY]. Force the top cpuset to + * track what's 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 @@ -2114,15 +1743,15 @@ static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur) static void common_cpu_mem_hotplug_unplug(void) { - mutex_lock(&manage_mutex); + cgroup_lock(); 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; + top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; mutex_unlock(&callback_mutex); - mutex_unlock(&manage_mutex); + cgroup_unlock(); } /* @@ -2135,8 +1764,8 @@ static void common_cpu_mem_hotplug_unplug(void) * cpu_online_map on each CPU hotplug (cpuhp) event. */ -static int cpuset_handle_cpuhp(struct notifier_block *nb, - unsigned long phase, void *cpu) +static int cpuset_handle_cpuhp(struct notifier_block *unused_nb, + unsigned long phase, void *unused_cpu) { if (phase == CPU_DYING || phase == CPU_DYING_FROZEN) return NOTIFY_DONE; @@ -2147,8 +1776,9 @@ static int cpuset_handle_cpuhp(struct notifier_block *nb, #ifdef CONFIG_MEMORY_HOTPLUG /* - * Keep top_cpuset.mems_allowed tracking node_online_map. - * Call this routine anytime after you change node_online_map. + * Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY]. + * Call this routine anytime after you change + * node_states[N_HIGH_MEMORY]. * See also the previous routine cpuset_handle_cpuhp(). */ @@ -2167,115 +1797,13 @@ void cpuset_track_online_nodes(void) void __init cpuset_init_smp(void) { top_cpuset.cpus_allowed = cpu_online_map; - top_cpuset.mems_allowed = node_online_map; + top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; 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. * @@ -2290,10 +1818,23 @@ cpumask_t cpuset_cpus_allowed(struct task_struct *tsk) cpumask_t mask; mutex_lock(&callback_mutex); + mask = cpuset_cpus_allowed_locked(tsk); + mutex_unlock(&callback_mutex); + + return mask; +} + +/** + * cpuset_cpus_allowed_locked - return cpus_allowed mask from a tasks cpuset. + * Must be called with callback_mutex held. + **/ +cpumask_t cpuset_cpus_allowed_locked(struct task_struct *tsk) +{ + cpumask_t mask; + task_lock(tsk); - guarantee_online_cpus(tsk->cpuset, &mask); + guarantee_online_cpus(task_cs(tsk), &mask); task_unlock(tsk); - mutex_unlock(&callback_mutex); return mask; } @@ -2309,7 +1850,7 @@ void cpuset_init_current_mems_allowed(void) * * 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 + * subset of node_states[N_HIGH_MEMORY], even if this means going outside the * tasks cpuset. **/ @@ -2319,7 +1860,7 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk) mutex_lock(&callback_mutex); task_lock(tsk); - guarantee_online_mems(tsk->cpuset, &mask); + guarantee_online_mems(task_cs(tsk), &mask); task_unlock(tsk); mutex_unlock(&callback_mutex); @@ -2450,7 +1991,7 @@ int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask) mutex_lock(&callback_mutex); task_lock(current); - cs = nearest_exclusive_ancestor(current->cpuset); + cs = nearest_exclusive_ancestor(task_cs(current)); task_unlock(current); allowed = node_isset(node, cs->mems_allowed); @@ -2491,12 +2032,12 @@ int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask) 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; + /* + * 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; } @@ -2566,41 +2107,20 @@ int cpuset_mem_spread_node(void) 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. + * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's? + * @tsk1: pointer to task_struct of some task. + * @tsk2: pointer to task_struct of some other task. + * + * Description: Return true if @tsk1's mems_allowed intersects the + * mems_allowed of @tsk2. Used by the OOM killer to determine if + * one of the task's memory usage might impact the memory available + * to the other. **/ -int cpuset_excl_nodes_overlap(const struct task_struct *p) +int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, + const struct task_struct *tsk2) { - 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; + return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed); } /* @@ -2631,14 +2151,12 @@ int cpuset_memory_pressure_enabled __read_mostly; void __cpuset_memory_pressure_bump(void) { - struct cpuset *cs; - task_lock(current); - cs = current->cpuset; - fmeter_markevent(&cs->fmeter); + fmeter_markevent(&task_cs(current)->fmeter); task_unlock(current); } +#ifdef CONFIG_PROC_PID_CPUSET /* * proc_cpuset_show() * - Print tasks cpuset path into seq_file. @@ -2650,11 +2168,12 @@ void __cpuset_memory_pressure_bump(void) * 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) +static int proc_cpuset_show(struct seq_file *m, void *unused_v) { struct pid *pid; struct task_struct *tsk; char *buf; + struct cgroup_subsys_state *css; int retval; retval = -ENOMEM; @@ -2669,15 +2188,15 @@ static int proc_cpuset_show(struct seq_file *m, void *v) goto out_free; retval = -EINVAL; - mutex_lock(&manage_mutex); - - retval = cpuset_path(tsk->cpuset, buf, PAGE_SIZE); + cgroup_lock(); + css = task_subsys_state(tsk, cpuset_subsys_id); + retval = cgroup_path(css->cgroup, buf, PAGE_SIZE); if (retval < 0) goto out_unlock; seq_puts(m, buf); seq_putc(m, '\n'); out_unlock: - mutex_unlock(&manage_mutex); + cgroup_unlock(); put_task_struct(tsk); out_free: kfree(buf); @@ -2697,6 +2216,7 @@ const struct file_operations proc_cpuset_operations = { .llseek = seq_lseek, .release = single_release, }; +#endif /* CONFIG_PROC_PID_CPUSET */ /* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */ char *cpuset_task_status_allowed(struct task_struct *task, char *buffer) |