diff options
Diffstat (limited to 'kernel/cgroup/cpuset.c')
| -rw-r--r-- | kernel/cgroup/cpuset.c | 99 |
1 files changed, 63 insertions, 36 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 479743db6c37..863e434a6020 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -39,6 +39,7 @@ #include <linux/memory.h> #include <linux/export.h> #include <linux/mount.h> +#include <linux/fs_context.h> #include <linux/namei.h> #include <linux/pagemap.h> #include <linux/proc_fs.h> @@ -203,19 +204,6 @@ static inline struct cpuset *parent_cs(struct cpuset *cs) return css_cs(cs->css.parent); } -#ifdef CONFIG_NUMA -static inline bool task_has_mempolicy(struct task_struct *task) -{ - return task->mempolicy; -} -#else -static inline bool task_has_mempolicy(struct task_struct *task) -{ - return false; -} -#endif - - /* bits in struct cpuset flags field */ typedef enum { CS_ONLINE, @@ -372,25 +360,52 @@ static inline bool is_in_v2_mode(void) * users. If someone tries to mount the "cpuset" filesystem, we * silently switch it to mount "cgroup" instead */ -static struct dentry *cpuset_mount(struct file_system_type *fs_type, - int flags, const char *unused_dev_name, void *data) -{ - struct file_system_type *cgroup_fs = get_fs_type("cgroup"); - struct dentry *ret = ERR_PTR(-ENODEV); - if (cgroup_fs) { - char mountopts[] = - "cpuset,noprefix," - "release_agent=/sbin/cpuset_release_agent"; - ret = cgroup_fs->mount(cgroup_fs, flags, - unused_dev_name, mountopts); - put_filesystem(cgroup_fs); +static int cpuset_get_tree(struct fs_context *fc) +{ + struct file_system_type *cgroup_fs; + struct fs_context *new_fc; + int ret; + + cgroup_fs = get_fs_type("cgroup"); + if (!cgroup_fs) + return -ENODEV; + + new_fc = fs_context_for_mount(cgroup_fs, fc->sb_flags); + if (IS_ERR(new_fc)) { + ret = PTR_ERR(new_fc); + } else { + static const char agent_path[] = "/sbin/cpuset_release_agent"; + ret = vfs_parse_fs_string(new_fc, "cpuset", NULL, 0); + if (!ret) + ret = vfs_parse_fs_string(new_fc, "noprefix", NULL, 0); + if (!ret) + ret = vfs_parse_fs_string(new_fc, "release_agent", + agent_path, sizeof(agent_path) - 1); + if (!ret) + ret = vfs_get_tree(new_fc); + if (!ret) { /* steal the result */ + fc->root = new_fc->root; + new_fc->root = NULL; + } + put_fs_context(new_fc); } + put_filesystem(cgroup_fs); return ret; } +static const struct fs_context_operations cpuset_fs_context_ops = { + .get_tree = cpuset_get_tree, +}; + +static int cpuset_init_fs_context(struct fs_context *fc) +{ + fc->ops = &cpuset_fs_context_ops; + return 0; +} + static struct file_system_type cpuset_fs_type = { - .name = "cpuset", - .mount = cpuset_mount, + .name = "cpuset", + .init_fs_context = cpuset_init_fs_context, }; /* @@ -714,7 +729,7 @@ static inline int nr_cpusets(void) * load balancing domains (sched domains) as specified by that partial * partition. * - * See "What is sched_load_balance" in Documentation/cgroup-v1/cpusets.txt + * See "What is sched_load_balance" in Documentation/admin-guide/cgroup-v1/cpusets.rst * for a background explanation of this. * * Does not return errors, on the theory that the callers of this @@ -725,11 +740,10 @@ static inline int nr_cpusets(void) * Must be called with cpuset_mutex held. * * The three key local variables below are: - * q - a linked-list 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. + * cp - cpuset pointer, used (together with pos_css) to perform a + * top-down scan of all cpusets. 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, @@ -760,7 +774,7 @@ static inline int nr_cpusets(void) static int generate_sched_domains(cpumask_var_t **domains, struct sched_domain_attr **attributes) { - struct cpuset *cp; /* scans q */ + struct cpuset *cp; /* top-down scan of cpusets */ 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 */ @@ -2815,7 +2829,7 @@ static void cpuset_fork(struct task_struct *task) if (task_css_is_root(task, cpuset_cgrp_id)) return; - set_cpus_allowed_ptr(task, ¤t->cpus_allowed); + set_cpus_allowed_ptr(task, current->cpus_ptr); task->mems_allowed = current->mems_allowed; } @@ -3240,10 +3254,23 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) spin_unlock_irqrestore(&callback_lock, flags); } +/** + * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe. + * @tsk: pointer to task_struct with which the scheduler is struggling + * + * Description: In the case that the scheduler cannot find an allowed cpu in + * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy + * mode however, this value is the same as task_cs(tsk)->effective_cpus, + * which will not contain a sane cpumask during cases such as cpu hotplugging. + * This is the absolute last resort for the scheduler and it is only used if + * _every_ other avenue has been traveled. + **/ + void cpuset_cpus_allowed_fallback(struct task_struct *tsk) { rcu_read_lock(); - do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus); + do_set_cpus_allowed(tsk, is_in_v2_mode() ? + task_cs(tsk)->cpus_allowed : cpu_possible_mask); rcu_read_unlock(); /* |