b211e9d7c8
Pull cgroup updates from Tejun Heo: "Nothing too interesting. Just a handful of cleanup patches" * 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: Revert "cgroup: remove redundant variable in cgroup_mount()" cgroup: remove redundant variable in cgroup_mount() cgroup: fix missing unlock in cgroup_release_agent() cgroup: remove CGRP_RELEASABLE flag perf/cgroup: Remove perf_put_cgroup() cgroup: remove redundant check in cgroup_ino() cpuset: simplify proc_cpuset_show() cgroup: simplify proc_cgroup_show() cgroup: use a per-cgroup work for release agent cgroup: remove bogus comments cgroup: remove redundant code in cgroup_rmdir() cgroup: remove some useless forward declarations cgroup: fix a typo in comment.
2772 lines
78 KiB
C
2772 lines
78 KiB
C
/*
|
|
* kernel/cpuset.c
|
|
*
|
|
* Processor and Memory placement constraints for sets of tasks.
|
|
*
|
|
* Copyright (C) 2003 BULL SA.
|
|
* 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
|
|
*
|
|
* 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
|
|
* 2008 Rework of the scheduler domains and CPU hotplug handling
|
|
* by Max Krasnyansky
|
|
*
|
|
* 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/memory.h>
|
|
#include <linux/export.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 <linux/atomic.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/cgroup.h>
|
|
#include <linux/wait.h>
|
|
|
|
struct static_key cpusets_enabled_key __read_mostly = STATIC_KEY_INIT_FALSE;
|
|
|
|
/* 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 {
|
|
struct cgroup_subsys_state css;
|
|
|
|
unsigned long flags; /* "unsigned long" so bitops work */
|
|
|
|
/*
|
|
* On default hierarchy:
|
|
*
|
|
* The user-configured masks can only be changed by writing to
|
|
* cpuset.cpus and cpuset.mems, and won't be limited by the
|
|
* parent masks.
|
|
*
|
|
* The effective masks is the real masks that apply to the tasks
|
|
* in the cpuset. They may be changed if the configured masks are
|
|
* changed or hotplug happens.
|
|
*
|
|
* effective_mask == configured_mask & parent's effective_mask,
|
|
* and if it ends up empty, it will inherit the parent's mask.
|
|
*
|
|
*
|
|
* On legacy hierachy:
|
|
*
|
|
* The user-configured masks are always the same with effective masks.
|
|
*/
|
|
|
|
/* user-configured CPUs and Memory Nodes allow to tasks */
|
|
cpumask_var_t cpus_allowed;
|
|
nodemask_t mems_allowed;
|
|
|
|
/* effective CPUs and Memory Nodes allow to tasks */
|
|
cpumask_var_t effective_cpus;
|
|
nodemask_t effective_mems;
|
|
|
|
/*
|
|
* This is old Memory Nodes tasks took on.
|
|
*
|
|
* - top_cpuset.old_mems_allowed is initialized to mems_allowed.
|
|
* - A new cpuset's old_mems_allowed is initialized when some
|
|
* task is moved into it.
|
|
* - old_mems_allowed is used in cpuset_migrate_mm() when we change
|
|
* cpuset.mems_allowed and have tasks' nodemask updated, and
|
|
* then old_mems_allowed is updated to mems_allowed.
|
|
*/
|
|
nodemask_t old_mems_allowed;
|
|
|
|
struct fmeter fmeter; /* memory_pressure filter */
|
|
|
|
/*
|
|
* Tasks are being attached to this cpuset. Used to prevent
|
|
* zeroing cpus/mems_allowed between ->can_attach() and ->attach().
|
|
*/
|
|
int attach_in_progress;
|
|
|
|
/* partition number for rebuild_sched_domains() */
|
|
int pn;
|
|
|
|
/* for custom sched domain */
|
|
int relax_domain_level;
|
|
};
|
|
|
|
static inline struct cpuset *css_cs(struct cgroup_subsys_state *css)
|
|
{
|
|
return css ? container_of(css, struct cpuset, css) : NULL;
|
|
}
|
|
|
|
/* Retrieve the cpuset for a task */
|
|
static inline struct cpuset *task_cs(struct task_struct *task)
|
|
{
|
|
return css_cs(task_css(task, cpuset_cgrp_id));
|
|
}
|
|
|
|
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,
|
|
CS_CPU_EXCLUSIVE,
|
|
CS_MEM_EXCLUSIVE,
|
|
CS_MEM_HARDWALL,
|
|
CS_MEMORY_MIGRATE,
|
|
CS_SCHED_LOAD_BALANCE,
|
|
CS_SPREAD_PAGE,
|
|
CS_SPREAD_SLAB,
|
|
} cpuset_flagbits_t;
|
|
|
|
/* convenient tests for these bits */
|
|
static inline bool is_cpuset_online(const struct cpuset *cs)
|
|
{
|
|
return test_bit(CS_ONLINE, &cs->flags);
|
|
}
|
|
|
|
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_mem_hardwall(const struct cpuset *cs)
|
|
{
|
|
return test_bit(CS_MEM_HARDWALL, &cs->flags);
|
|
}
|
|
|
|
static inline int is_sched_load_balance(const struct cpuset *cs)
|
|
{
|
|
return test_bit(CS_SCHED_LOAD_BALANCE, &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);
|
|
}
|
|
|
|
static struct cpuset top_cpuset = {
|
|
.flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
|
|
(1 << CS_MEM_EXCLUSIVE)),
|
|
};
|
|
|
|
/**
|
|
* cpuset_for_each_child - traverse online children of a cpuset
|
|
* @child_cs: loop cursor pointing to the current child
|
|
* @pos_css: used for iteration
|
|
* @parent_cs: target cpuset to walk children of
|
|
*
|
|
* Walk @child_cs through the online children of @parent_cs. Must be used
|
|
* with RCU read locked.
|
|
*/
|
|
#define cpuset_for_each_child(child_cs, pos_css, parent_cs) \
|
|
css_for_each_child((pos_css), &(parent_cs)->css) \
|
|
if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
|
|
|
|
/**
|
|
* cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
|
|
* @des_cs: loop cursor pointing to the current descendant
|
|
* @pos_css: used for iteration
|
|
* @root_cs: target cpuset to walk ancestor of
|
|
*
|
|
* Walk @des_cs through the online descendants of @root_cs. Must be used
|
|
* with RCU read locked. The caller may modify @pos_css by calling
|
|
* css_rightmost_descendant() to skip subtree. @root_cs is included in the
|
|
* iteration and the first node to be visited.
|
|
*/
|
|
#define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \
|
|
css_for_each_descendant_pre((pos_css), &(root_cs)->css) \
|
|
if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
|
|
|
|
/*
|
|
* There are two global mutexes guarding cpuset structures - cpuset_mutex
|
|
* and callback_mutex. The latter may nest inside the former. We also
|
|
* require taking task_lock() when dereferencing a task's 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
|
|
* cpuset_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 cpuset_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.
|
|
*
|
|
* Now, the task_struct fields mems_allowed and mempolicy may be changed
|
|
* by other task, we use alloc_lock in the task_struct fields to protect
|
|
* them.
|
|
*
|
|
* 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.
|
|
*
|
|
* Accessing a task's cpuset should be done in accordance with the
|
|
* guidelines for accessing subsystem state in kernel/cgroup.c
|
|
*/
|
|
|
|
static DEFINE_MUTEX(cpuset_mutex);
|
|
static DEFINE_MUTEX(callback_mutex);
|
|
|
|
/*
|
|
* CPU / memory hotplug is handled asynchronously.
|
|
*/
|
|
static void cpuset_hotplug_workfn(struct work_struct *work);
|
|
static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
|
|
|
|
static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
|
|
|
|
/*
|
|
* 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 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);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static struct file_system_type cpuset_fs_type = {
|
|
.name = "cpuset",
|
|
.mount = cpuset_mount,
|
|
};
|
|
|
|
/*
|
|
* 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. The top
|
|
* cpuset always has some cpus online.
|
|
*
|
|
* One way or another, we guarantee to return some non-empty subset
|
|
* of cpu_online_mask.
|
|
*
|
|
* Call with callback_mutex held.
|
|
*/
|
|
static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask)
|
|
{
|
|
while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask))
|
|
cs = parent_cs(cs);
|
|
cpumask_and(pmask, cs->effective_cpus, cpu_online_mask);
|
|
}
|
|
|
|
/*
|
|
* Return in *pmask the portion of a cpusets's mems_allowed that
|
|
* 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. The top cpuset always has some mems online.
|
|
*
|
|
* One way or another, we guarantee to return some non-empty subset
|
|
* of node_states[N_MEMORY].
|
|
*
|
|
* Call with callback_mutex held.
|
|
*/
|
|
static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
|
|
{
|
|
while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY]))
|
|
cs = parent_cs(cs);
|
|
nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);
|
|
}
|
|
|
|
/*
|
|
* update task's spread flag if cpuset's page/slab spread flag is set
|
|
*
|
|
* Called with callback_mutex/cpuset_mutex held
|
|
*/
|
|
static void cpuset_update_task_spread_flag(struct cpuset *cs,
|
|
struct task_struct *tsk)
|
|
{
|
|
if (is_spread_page(cs))
|
|
task_set_spread_page(tsk);
|
|
else
|
|
task_clear_spread_page(tsk);
|
|
|
|
if (is_spread_slab(cs))
|
|
task_set_spread_slab(tsk);
|
|
else
|
|
task_clear_spread_slab(tsk);
|
|
}
|
|
|
|
/*
|
|
* 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 cpuset_mutex.
|
|
*/
|
|
|
|
static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
|
|
{
|
|
return cpumask_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);
|
|
}
|
|
|
|
/**
|
|
* alloc_trial_cpuset - allocate a trial cpuset
|
|
* @cs: the cpuset that the trial cpuset duplicates
|
|
*/
|
|
static struct cpuset *alloc_trial_cpuset(struct cpuset *cs)
|
|
{
|
|
struct cpuset *trial;
|
|
|
|
trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
|
|
if (!trial)
|
|
return NULL;
|
|
|
|
if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL))
|
|
goto free_cs;
|
|
if (!alloc_cpumask_var(&trial->effective_cpus, GFP_KERNEL))
|
|
goto free_cpus;
|
|
|
|
cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);
|
|
cpumask_copy(trial->effective_cpus, cs->effective_cpus);
|
|
return trial;
|
|
|
|
free_cpus:
|
|
free_cpumask_var(trial->cpus_allowed);
|
|
free_cs:
|
|
kfree(trial);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* free_trial_cpuset - free the trial cpuset
|
|
* @trial: the trial cpuset to be freed
|
|
*/
|
|
static void free_trial_cpuset(struct cpuset *trial)
|
|
{
|
|
free_cpumask_var(trial->effective_cpus);
|
|
free_cpumask_var(trial->cpus_allowed);
|
|
kfree(trial);
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
* cpuset_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(struct cpuset *cur, struct cpuset *trial)
|
|
{
|
|
struct cgroup_subsys_state *css;
|
|
struct cpuset *c, *par;
|
|
int ret;
|
|
|
|
rcu_read_lock();
|
|
|
|
/* Each of our child cpusets must be a subset of us */
|
|
ret = -EBUSY;
|
|
cpuset_for_each_child(c, css, cur)
|
|
if (!is_cpuset_subset(c, trial))
|
|
goto out;
|
|
|
|
/* Remaining checks don't apply to root cpuset */
|
|
ret = 0;
|
|
if (cur == &top_cpuset)
|
|
goto out;
|
|
|
|
par = parent_cs(cur);
|
|
|
|
/* On legacy hiearchy, we must be a subset of our parent cpuset. */
|
|
ret = -EACCES;
|
|
if (!cgroup_on_dfl(cur->css.cgroup) && !is_cpuset_subset(trial, par))
|
|
goto out;
|
|
|
|
/*
|
|
* If either I or some sibling (!= me) is exclusive, we can't
|
|
* overlap
|
|
*/
|
|
ret = -EINVAL;
|
|
cpuset_for_each_child(c, css, par) {
|
|
if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
|
|
c != cur &&
|
|
cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
|
|
goto out;
|
|
if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
|
|
c != cur &&
|
|
nodes_intersects(trial->mems_allowed, c->mems_allowed))
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Cpusets with tasks - existing or newly being attached - can't
|
|
* be changed to have empty cpus_allowed or mems_allowed.
|
|
*/
|
|
ret = -ENOSPC;
|
|
if ((cgroup_has_tasks(cur->css.cgroup) || cur->attach_in_progress)) {
|
|
if (!cpumask_empty(cur->cpus_allowed) &&
|
|
cpumask_empty(trial->cpus_allowed))
|
|
goto out;
|
|
if (!nodes_empty(cur->mems_allowed) &&
|
|
nodes_empty(trial->mems_allowed))
|
|
goto out;
|
|
}
|
|
|
|
ret = 0;
|
|
out:
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
/*
|
|
* Helper routine for generate_sched_domains().
|
|
* Do cpusets a, b have overlapping effective cpus_allowed masks?
|
|
*/
|
|
static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
|
|
{
|
|
return cpumask_intersects(a->effective_cpus, b->effective_cpus);
|
|
}
|
|
|
|
static void
|
|
update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
|
|
{
|
|
if (dattr->relax_domain_level < c->relax_domain_level)
|
|
dattr->relax_domain_level = c->relax_domain_level;
|
|
return;
|
|
}
|
|
|
|
static void update_domain_attr_tree(struct sched_domain_attr *dattr,
|
|
struct cpuset *root_cs)
|
|
{
|
|
struct cpuset *cp;
|
|
struct cgroup_subsys_state *pos_css;
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
|
|
if (cp == root_cs)
|
|
continue;
|
|
|
|
/* skip the whole subtree if @cp doesn't have any CPU */
|
|
if (cpumask_empty(cp->cpus_allowed)) {
|
|
pos_css = css_rightmost_descendant(pos_css);
|
|
continue;
|
|
}
|
|
|
|
if (is_sched_load_balance(cp))
|
|
update_domain_attr(dattr, cp);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/*
|
|
* generate_sched_domains()
|
|
*
|
|
* This function builds a partial partition of the systems CPUs
|
|
* A 'partial partition' is a set of non-overlapping subsets whose
|
|
* union is a subset of that set.
|
|
* The output of this function needs to be passed to kernel/sched/core.c
|
|
* partition_sched_domains() routine, which will rebuild the scheduler's
|
|
* load balancing domains (sched domains) as specified by that partial
|
|
* partition.
|
|
*
|
|
* See "What is sched_load_balance" in Documentation/cgroups/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.
|
|
*
|
|
* 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.
|
|
* 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/core.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().
|
|
*/
|
|
static int generate_sched_domains(cpumask_var_t **domains,
|
|
struct sched_domain_attr **attributes)
|
|
{
|
|
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_var_t *doms; /* resulting partition; i.e. sched domains */
|
|
struct sched_domain_attr *dattr; /* attributes for custom domains */
|
|
int ndoms = 0; /* number of sched domains in result */
|
|
int nslot; /* next empty doms[] struct cpumask slot */
|
|
struct cgroup_subsys_state *pos_css;
|
|
|
|
doms = NULL;
|
|
dattr = NULL;
|
|
csa = NULL;
|
|
|
|
/* Special case for the 99% of systems with one, full, sched domain */
|
|
if (is_sched_load_balance(&top_cpuset)) {
|
|
ndoms = 1;
|
|
doms = alloc_sched_domains(ndoms);
|
|
if (!doms)
|
|
goto done;
|
|
|
|
dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
|
|
if (dattr) {
|
|
*dattr = SD_ATTR_INIT;
|
|
update_domain_attr_tree(dattr, &top_cpuset);
|
|
}
|
|
cpumask_copy(doms[0], top_cpuset.effective_cpus);
|
|
|
|
goto done;
|
|
}
|
|
|
|
csa = kmalloc(nr_cpusets() * sizeof(cp), GFP_KERNEL);
|
|
if (!csa)
|
|
goto done;
|
|
csn = 0;
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) {
|
|
if (cp == &top_cpuset)
|
|
continue;
|
|
/*
|
|
* Continue traversing beyond @cp iff @cp has some CPUs and
|
|
* isn't load balancing. The former is obvious. The
|
|
* latter: All child cpusets contain a subset of the
|
|
* parent's cpus, so just skip them, and then we call
|
|
* update_domain_attr_tree() to calc relax_domain_level of
|
|
* the corresponding sched domain.
|
|
*/
|
|
if (!cpumask_empty(cp->cpus_allowed) &&
|
|
!is_sched_load_balance(cp))
|
|
continue;
|
|
|
|
if (is_sched_load_balance(cp))
|
|
csa[csn++] = cp;
|
|
|
|
/* skip @cp's subtree */
|
|
pos_css = css_rightmost_descendant(pos_css);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Now we know how many domains to create.
|
|
* Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
|
|
*/
|
|
doms = alloc_sched_domains(ndoms);
|
|
if (!doms)
|
|
goto done;
|
|
|
|
/*
|
|
* The rest of the code, including the scheduler, can deal with
|
|
* dattr==NULL case. No need to abort if alloc fails.
|
|
*/
|
|
dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL);
|
|
|
|
for (nslot = 0, i = 0; i < csn; i++) {
|
|
struct cpuset *a = csa[i];
|
|
struct cpumask *dp;
|
|
int apn = a->pn;
|
|
|
|
if (apn < 0) {
|
|
/* Skip completed partitions */
|
|
continue;
|
|
}
|
|
|
|
dp = doms[nslot];
|
|
|
|
if (nslot == ndoms) {
|
|
static int warnings = 10;
|
|
if (warnings) {
|
|
pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
|
|
nslot, ndoms, csn, i, apn);
|
|
warnings--;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
cpumask_clear(dp);
|
|
if (dattr)
|
|
*(dattr + nslot) = SD_ATTR_INIT;
|
|
for (j = i; j < csn; j++) {
|
|
struct cpuset *b = csa[j];
|
|
|
|
if (apn == b->pn) {
|
|
cpumask_or(dp, dp, b->effective_cpus);
|
|
if (dattr)
|
|
update_domain_attr_tree(dattr + nslot, b);
|
|
|
|
/* Done with this partition */
|
|
b->pn = -1;
|
|
}
|
|
}
|
|
nslot++;
|
|
}
|
|
BUG_ON(nslot != ndoms);
|
|
|
|
done:
|
|
kfree(csa);
|
|
|
|
/*
|
|
* Fallback to the default domain if kmalloc() failed.
|
|
* See comments in partition_sched_domains().
|
|
*/
|
|
if (doms == NULL)
|
|
ndoms = 1;
|
|
|
|
*domains = doms;
|
|
*attributes = dattr;
|
|
return ndoms;
|
|
}
|
|
|
|
/*
|
|
* Rebuild scheduler 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.
|
|
*
|
|
* Call with cpuset_mutex held. Takes get_online_cpus().
|
|
*/
|
|
static void rebuild_sched_domains_locked(void)
|
|
{
|
|
struct sched_domain_attr *attr;
|
|
cpumask_var_t *doms;
|
|
int ndoms;
|
|
|
|
lockdep_assert_held(&cpuset_mutex);
|
|
get_online_cpus();
|
|
|
|
/*
|
|
* We have raced with CPU hotplug. Don't do anything to avoid
|
|
* passing doms with offlined cpu to partition_sched_domains().
|
|
* Anyways, hotplug work item will rebuild sched domains.
|
|
*/
|
|
if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
|
|
goto out;
|
|
|
|
/* Generate domain masks and attrs */
|
|
ndoms = generate_sched_domains(&doms, &attr);
|
|
|
|
/* Have scheduler rebuild the domains */
|
|
partition_sched_domains(ndoms, doms, attr);
|
|
out:
|
|
put_online_cpus();
|
|
}
|
|
#else /* !CONFIG_SMP */
|
|
static void rebuild_sched_domains_locked(void)
|
|
{
|
|
}
|
|
#endif /* CONFIG_SMP */
|
|
|
|
void rebuild_sched_domains(void)
|
|
{
|
|
mutex_lock(&cpuset_mutex);
|
|
rebuild_sched_domains_locked();
|
|
mutex_unlock(&cpuset_mutex);
|
|
}
|
|
|
|
/**
|
|
* update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
|
|
* @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
|
|
*
|
|
* Iterate through each task of @cs updating its cpus_allowed to the
|
|
* effective cpuset's. As this function is called with cpuset_mutex held,
|
|
* cpuset membership stays stable.
|
|
*/
|
|
static void update_tasks_cpumask(struct cpuset *cs)
|
|
{
|
|
struct css_task_iter it;
|
|
struct task_struct *task;
|
|
|
|
css_task_iter_start(&cs->css, &it);
|
|
while ((task = css_task_iter_next(&it)))
|
|
set_cpus_allowed_ptr(task, cs->effective_cpus);
|
|
css_task_iter_end(&it);
|
|
}
|
|
|
|
/*
|
|
* update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
|
|
* @cs: the cpuset to consider
|
|
* @new_cpus: temp variable for calculating new effective_cpus
|
|
*
|
|
* When congifured cpumask is changed, the effective cpumasks of this cpuset
|
|
* and all its descendants need to be updated.
|
|
*
|
|
* On legacy hierachy, effective_cpus will be the same with cpu_allowed.
|
|
*
|
|
* Called with cpuset_mutex held
|
|
*/
|
|
static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
|
|
{
|
|
struct cpuset *cp;
|
|
struct cgroup_subsys_state *pos_css;
|
|
bool need_rebuild_sched_domains = false;
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cp, pos_css, cs) {
|
|
struct cpuset *parent = parent_cs(cp);
|
|
|
|
cpumask_and(new_cpus, cp->cpus_allowed, parent->effective_cpus);
|
|
|
|
/*
|
|
* If it becomes empty, inherit the effective mask of the
|
|
* parent, which is guaranteed to have some CPUs.
|
|
*/
|
|
if (cpumask_empty(new_cpus))
|
|
cpumask_copy(new_cpus, parent->effective_cpus);
|
|
|
|
/* Skip the whole subtree if the cpumask remains the same. */
|
|
if (cpumask_equal(new_cpus, cp->effective_cpus)) {
|
|
pos_css = css_rightmost_descendant(pos_css);
|
|
continue;
|
|
}
|
|
|
|
if (!css_tryget_online(&cp->css))
|
|
continue;
|
|
rcu_read_unlock();
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cpumask_copy(cp->effective_cpus, new_cpus);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
WARN_ON(!cgroup_on_dfl(cp->css.cgroup) &&
|
|
!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
|
|
|
|
update_tasks_cpumask(cp);
|
|
|
|
/*
|
|
* If the effective cpumask of any non-empty cpuset is changed,
|
|
* we need to rebuild sched domains.
|
|
*/
|
|
if (!cpumask_empty(cp->cpus_allowed) &&
|
|
is_sched_load_balance(cp))
|
|
need_rebuild_sched_domains = true;
|
|
|
|
rcu_read_lock();
|
|
css_put(&cp->css);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
if (need_rebuild_sched_domains)
|
|
rebuild_sched_domains_locked();
|
|
}
|
|
|
|
/**
|
|
* update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
|
|
* @cs: the cpuset to consider
|
|
* @trialcs: trial cpuset
|
|
* @buf: buffer of cpu numbers written to this cpuset
|
|
*/
|
|
static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
|
|
const char *buf)
|
|
{
|
|
int retval;
|
|
|
|
/* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
|
|
if (cs == &top_cpuset)
|
|
return -EACCES;
|
|
|
|
/*
|
|
* An empty cpus_allowed is ok only if the cpuset has no tasks.
|
|
* 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) {
|
|
cpumask_clear(trialcs->cpus_allowed);
|
|
} else {
|
|
retval = cpulist_parse(buf, trialcs->cpus_allowed);
|
|
if (retval < 0)
|
|
return retval;
|
|
|
|
if (!cpumask_subset(trialcs->cpus_allowed,
|
|
top_cpuset.cpus_allowed))
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Nothing to do if the cpus didn't change */
|
|
if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
|
|
return 0;
|
|
|
|
retval = validate_change(cs, trialcs);
|
|
if (retval < 0)
|
|
return retval;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
/* use trialcs->cpus_allowed as a temp variable */
|
|
update_cpumasks_hier(cs, trialcs->cpus_allowed);
|
|
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.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
|
|
const nodemask_t *to)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
tsk->mems_allowed = *to;
|
|
|
|
do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
|
|
|
|
rcu_read_lock();
|
|
guarantee_online_mems(task_cs(tsk), &tsk->mems_allowed);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/*
|
|
* cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
|
|
* @tsk: the task to change
|
|
* @newmems: new nodes that the task will be set
|
|
*
|
|
* In order to avoid seeing no nodes if the old and new nodes are disjoint,
|
|
* we structure updates as setting all new allowed nodes, then clearing newly
|
|
* disallowed ones.
|
|
*/
|
|
static void cpuset_change_task_nodemask(struct task_struct *tsk,
|
|
nodemask_t *newmems)
|
|
{
|
|
bool need_loop;
|
|
|
|
/*
|
|
* 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;
|
|
if (current->flags & PF_EXITING) /* Let dying task have memory */
|
|
return;
|
|
|
|
task_lock(tsk);
|
|
/*
|
|
* Determine if a loop is necessary if another thread is doing
|
|
* read_mems_allowed_begin(). If at least one node remains unchanged and
|
|
* tsk does not have a mempolicy, then an empty nodemask will not be
|
|
* possible when mems_allowed is larger than a word.
|
|
*/
|
|
need_loop = task_has_mempolicy(tsk) ||
|
|
!nodes_intersects(*newmems, tsk->mems_allowed);
|
|
|
|
if (need_loop) {
|
|
local_irq_disable();
|
|
write_seqcount_begin(&tsk->mems_allowed_seq);
|
|
}
|
|
|
|
nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
|
|
mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
|
|
|
|
mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2);
|
|
tsk->mems_allowed = *newmems;
|
|
|
|
if (need_loop) {
|
|
write_seqcount_end(&tsk->mems_allowed_seq);
|
|
local_irq_enable();
|
|
}
|
|
|
|
task_unlock(tsk);
|
|
}
|
|
|
|
static void *cpuset_being_rebound;
|
|
|
|
/**
|
|
* update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
|
|
* @cs: the cpuset in which each task's mems_allowed mask needs to be changed
|
|
*
|
|
* Iterate through each task of @cs updating its mems_allowed to the
|
|
* effective cpuset's. As this function is called with cpuset_mutex held,
|
|
* cpuset membership stays stable.
|
|
*/
|
|
static void update_tasks_nodemask(struct cpuset *cs)
|
|
{
|
|
static nodemask_t newmems; /* protected by cpuset_mutex */
|
|
struct css_task_iter it;
|
|
struct task_struct *task;
|
|
|
|
cpuset_being_rebound = cs; /* causes mpol_dup() rebind */
|
|
|
|
guarantee_online_mems(cs, &newmems);
|
|
|
|
/*
|
|
* The mpol_rebind_mm() call takes mmap_sem, which we couldn't
|
|
* take while holding tasklist_lock. Forks can happen - the
|
|
* mpol_dup() cpuset_being_rebound check will catch such forks,
|
|
* and rebind their vma mempolicies too. Because we still hold
|
|
* the global cpuset_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.
|
|
*/
|
|
css_task_iter_start(&cs->css, &it);
|
|
while ((task = css_task_iter_next(&it))) {
|
|
struct mm_struct *mm;
|
|
bool migrate;
|
|
|
|
cpuset_change_task_nodemask(task, &newmems);
|
|
|
|
mm = get_task_mm(task);
|
|
if (!mm)
|
|
continue;
|
|
|
|
migrate = is_memory_migrate(cs);
|
|
|
|
mpol_rebind_mm(mm, &cs->mems_allowed);
|
|
if (migrate)
|
|
cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
|
|
mmput(mm);
|
|
}
|
|
css_task_iter_end(&it);
|
|
|
|
/*
|
|
* All the tasks' nodemasks have been updated, update
|
|
* cs->old_mems_allowed.
|
|
*/
|
|
cs->old_mems_allowed = newmems;
|
|
|
|
/* We're done rebinding vmas to this cpuset's new mems_allowed. */
|
|
cpuset_being_rebound = NULL;
|
|
}
|
|
|
|
/*
|
|
* update_nodemasks_hier - Update effective nodemasks and tasks in the subtree
|
|
* @cs: the cpuset to consider
|
|
* @new_mems: a temp variable for calculating new effective_mems
|
|
*
|
|
* When configured nodemask is changed, the effective nodemasks of this cpuset
|
|
* and all its descendants need to be updated.
|
|
*
|
|
* On legacy hiearchy, effective_mems will be the same with mems_allowed.
|
|
*
|
|
* Called with cpuset_mutex held
|
|
*/
|
|
static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
|
|
{
|
|
struct cpuset *cp;
|
|
struct cgroup_subsys_state *pos_css;
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cp, pos_css, cs) {
|
|
struct cpuset *parent = parent_cs(cp);
|
|
|
|
nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems);
|
|
|
|
/*
|
|
* If it becomes empty, inherit the effective mask of the
|
|
* parent, which is guaranteed to have some MEMs.
|
|
*/
|
|
if (nodes_empty(*new_mems))
|
|
*new_mems = parent->effective_mems;
|
|
|
|
/* Skip the whole subtree if the nodemask remains the same. */
|
|
if (nodes_equal(*new_mems, cp->effective_mems)) {
|
|
pos_css = css_rightmost_descendant(pos_css);
|
|
continue;
|
|
}
|
|
|
|
if (!css_tryget_online(&cp->css))
|
|
continue;
|
|
rcu_read_unlock();
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cp->effective_mems = *new_mems;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
WARN_ON(!cgroup_on_dfl(cp->css.cgroup) &&
|
|
!nodes_equal(cp->mems_allowed, cp->effective_mems));
|
|
|
|
update_tasks_nodemask(cp);
|
|
|
|
rcu_read_lock();
|
|
css_put(&cp->css);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/*
|
|
* Handle user request to change the 'mems' memory placement
|
|
* of a cpuset. Needs to validate the request, update the
|
|
* cpusets mems_allowed, and for each task in the cpuset,
|
|
* update mems_allowed and rebind task's mempolicy and any vma
|
|
* mempolicies and if the cpuset is marked 'memory_migrate',
|
|
* migrate the tasks pages to the new memory.
|
|
*
|
|
* Call with cpuset_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, struct cpuset *trialcs,
|
|
const char *buf)
|
|
{
|
|
int retval;
|
|
|
|
/*
|
|
* top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
|
|
* it's read-only
|
|
*/
|
|
if (cs == &top_cpuset) {
|
|
retval = -EACCES;
|
|
goto done;
|
|
}
|
|
|
|
/*
|
|
* 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) {
|
|
nodes_clear(trialcs->mems_allowed);
|
|
} else {
|
|
retval = nodelist_parse(buf, trialcs->mems_allowed);
|
|
if (retval < 0)
|
|
goto done;
|
|
|
|
if (!nodes_subset(trialcs->mems_allowed,
|
|
top_cpuset.mems_allowed)) {
|
|
retval = -EINVAL;
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) {
|
|
retval = 0; /* Too easy - nothing to do */
|
|
goto done;
|
|
}
|
|
retval = validate_change(cs, trialcs);
|
|
if (retval < 0)
|
|
goto done;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cs->mems_allowed = trialcs->mems_allowed;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
/* use trialcs->mems_allowed as a temp variable */
|
|
update_nodemasks_hier(cs, &cs->mems_allowed);
|
|
done:
|
|
return retval;
|
|
}
|
|
|
|
int current_cpuset_is_being_rebound(void)
|
|
{
|
|
int ret;
|
|
|
|
rcu_read_lock();
|
|
ret = task_cs(current) == cpuset_being_rebound;
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int update_relax_domain_level(struct cpuset *cs, s64 val)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
if (val < -1 || val >= sched_domain_level_max)
|
|
return -EINVAL;
|
|
#endif
|
|
|
|
if (val != cs->relax_domain_level) {
|
|
cs->relax_domain_level = val;
|
|
if (!cpumask_empty(cs->cpus_allowed) &&
|
|
is_sched_load_balance(cs))
|
|
rebuild_sched_domains_locked();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* update_tasks_flags - update the spread flags of tasks in the cpuset.
|
|
* @cs: the cpuset in which each task's spread flags needs to be changed
|
|
*
|
|
* Iterate through each task of @cs updating its spread flags. As this
|
|
* function is called with cpuset_mutex held, cpuset membership stays
|
|
* stable.
|
|
*/
|
|
static void update_tasks_flags(struct cpuset *cs)
|
|
{
|
|
struct css_task_iter it;
|
|
struct task_struct *task;
|
|
|
|
css_task_iter_start(&cs->css, &it);
|
|
while ((task = css_task_iter_next(&it)))
|
|
cpuset_update_task_spread_flag(cs, task);
|
|
css_task_iter_end(&it);
|
|
}
|
|
|
|
/*
|
|
* update_flag - read a 0 or a 1 in a file and update associated flag
|
|
* bit: the bit to update (see cpuset_flagbits_t)
|
|
* cs: the cpuset to update
|
|
* turning_on: whether the flag is being set or cleared
|
|
*
|
|
* Call with cpuset_mutex held.
|
|
*/
|
|
|
|
static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
|
|
int turning_on)
|
|
{
|
|
struct cpuset *trialcs;
|
|
int balance_flag_changed;
|
|
int spread_flag_changed;
|
|
int err;
|
|
|
|
trialcs = alloc_trial_cpuset(cs);
|
|
if (!trialcs)
|
|
return -ENOMEM;
|
|
|
|
if (turning_on)
|
|
set_bit(bit, &trialcs->flags);
|
|
else
|
|
clear_bit(bit, &trialcs->flags);
|
|
|
|
err = validate_change(cs, trialcs);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
balance_flag_changed = (is_sched_load_balance(cs) !=
|
|
is_sched_load_balance(trialcs));
|
|
|
|
spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
|
|
|| (is_spread_page(cs) != is_spread_page(trialcs)));
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cs->flags = trialcs->flags;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
|
|
rebuild_sched_domains_locked();
|
|
|
|
if (spread_flag_changed)
|
|
update_tasks_flags(cs);
|
|
out:
|
|
free_trial_cpuset(trialcs);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
static struct cpuset *cpuset_attach_old_cs;
|
|
|
|
/* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */
|
|
static int cpuset_can_attach(struct cgroup_subsys_state *css,
|
|
struct cgroup_taskset *tset)
|
|
{
|
|
struct cpuset *cs = css_cs(css);
|
|
struct task_struct *task;
|
|
int ret;
|
|
|
|
/* used later by cpuset_attach() */
|
|
cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset));
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
/* allow moving tasks into an empty cpuset if on default hierarchy */
|
|
ret = -ENOSPC;
|
|
if (!cgroup_on_dfl(css->cgroup) &&
|
|
(cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
|
|
goto out_unlock;
|
|
|
|
cgroup_taskset_for_each(task, tset) {
|
|
/*
|
|
* Kthreads which disallow setaffinity shouldn't be moved
|
|
* to a new cpuset; we don't want to change their cpu
|
|
* affinity and isolating such threads by their set of
|
|
* allowed nodes is unnecessary. Thus, cpusets are not
|
|
* applicable for such threads. This prevents checking for
|
|
* success of set_cpus_allowed_ptr() on all attached tasks
|
|
* before cpus_allowed may be changed.
|
|
*/
|
|
ret = -EINVAL;
|
|
if (task->flags & PF_NO_SETAFFINITY)
|
|
goto out_unlock;
|
|
ret = security_task_setscheduler(task);
|
|
if (ret)
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* Mark attach is in progress. This makes validate_change() fail
|
|
* changes which zero cpus/mems_allowed.
|
|
*/
|
|
cs->attach_in_progress++;
|
|
ret = 0;
|
|
out_unlock:
|
|
mutex_unlock(&cpuset_mutex);
|
|
return ret;
|
|
}
|
|
|
|
static void cpuset_cancel_attach(struct cgroup_subsys_state *css,
|
|
struct cgroup_taskset *tset)
|
|
{
|
|
mutex_lock(&cpuset_mutex);
|
|
css_cs(css)->attach_in_progress--;
|
|
mutex_unlock(&cpuset_mutex);
|
|
}
|
|
|
|
/*
|
|
* Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach()
|
|
* but we can't allocate it dynamically there. Define it global and
|
|
* allocate from cpuset_init().
|
|
*/
|
|
static cpumask_var_t cpus_attach;
|
|
|
|
static void cpuset_attach(struct cgroup_subsys_state *css,
|
|
struct cgroup_taskset *tset)
|
|
{
|
|
/* static buf protected by cpuset_mutex */
|
|
static nodemask_t cpuset_attach_nodemask_to;
|
|
struct mm_struct *mm;
|
|
struct task_struct *task;
|
|
struct task_struct *leader = cgroup_taskset_first(tset);
|
|
struct cpuset *cs = css_cs(css);
|
|
struct cpuset *oldcs = cpuset_attach_old_cs;
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
/* prepare for attach */
|
|
if (cs == &top_cpuset)
|
|
cpumask_copy(cpus_attach, cpu_possible_mask);
|
|
else
|
|
guarantee_online_cpus(cs, cpus_attach);
|
|
|
|
guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
|
|
|
|
cgroup_taskset_for_each(task, tset) {
|
|
/*
|
|
* can_attach beforehand should guarantee that this doesn't
|
|
* fail. TODO: have a better way to handle failure here
|
|
*/
|
|
WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach));
|
|
|
|
cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);
|
|
cpuset_update_task_spread_flag(cs, task);
|
|
}
|
|
|
|
/*
|
|
* Change mm, possibly for multiple threads in a threadgroup. This is
|
|
* expensive and may sleep.
|
|
*/
|
|
cpuset_attach_nodemask_to = cs->effective_mems;
|
|
mm = get_task_mm(leader);
|
|
if (mm) {
|
|
mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
|
|
|
|
/*
|
|
* old_mems_allowed is the same with mems_allowed here, except
|
|
* if this task is being moved automatically due to hotplug.
|
|
* In that case @mems_allowed has been updated and is empty,
|
|
* so @old_mems_allowed is the right nodesets that we migrate
|
|
* mm from.
|
|
*/
|
|
if (is_memory_migrate(cs)) {
|
|
cpuset_migrate_mm(mm, &oldcs->old_mems_allowed,
|
|
&cpuset_attach_nodemask_to);
|
|
}
|
|
mmput(mm);
|
|
}
|
|
|
|
cs->old_mems_allowed = cpuset_attach_nodemask_to;
|
|
|
|
cs->attach_in_progress--;
|
|
if (!cs->attach_in_progress)
|
|
wake_up(&cpuset_attach_wq);
|
|
|
|
mutex_unlock(&cpuset_mutex);
|
|
}
|
|
|
|
/* The various types of files and directories in a cpuset file system */
|
|
|
|
typedef enum {
|
|
FILE_MEMORY_MIGRATE,
|
|
FILE_CPULIST,
|
|
FILE_MEMLIST,
|
|
FILE_EFFECTIVE_CPULIST,
|
|
FILE_EFFECTIVE_MEMLIST,
|
|
FILE_CPU_EXCLUSIVE,
|
|
FILE_MEM_EXCLUSIVE,
|
|
FILE_MEM_HARDWALL,
|
|
FILE_SCHED_LOAD_BALANCE,
|
|
FILE_SCHED_RELAX_DOMAIN_LEVEL,
|
|
FILE_MEMORY_PRESSURE_ENABLED,
|
|
FILE_MEMORY_PRESSURE,
|
|
FILE_SPREAD_PAGE,
|
|
FILE_SPREAD_SLAB,
|
|
} cpuset_filetype_t;
|
|
|
|
static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
|
|
u64 val)
|
|
{
|
|
struct cpuset *cs = css_cs(css);
|
|
cpuset_filetype_t type = cft->private;
|
|
int retval = 0;
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
if (!is_cpuset_online(cs)) {
|
|
retval = -ENODEV;
|
|
goto out_unlock;
|
|
}
|
|
|
|
switch (type) {
|
|
case FILE_CPU_EXCLUSIVE:
|
|
retval = update_flag(CS_CPU_EXCLUSIVE, cs, val);
|
|
break;
|
|
case FILE_MEM_EXCLUSIVE:
|
|
retval = update_flag(CS_MEM_EXCLUSIVE, cs, val);
|
|
break;
|
|
case FILE_MEM_HARDWALL:
|
|
retval = update_flag(CS_MEM_HARDWALL, cs, val);
|
|
break;
|
|
case FILE_SCHED_LOAD_BALANCE:
|
|
retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val);
|
|
break;
|
|
case FILE_MEMORY_MIGRATE:
|
|
retval = update_flag(CS_MEMORY_MIGRATE, cs, val);
|
|
break;
|
|
case FILE_MEMORY_PRESSURE_ENABLED:
|
|
cpuset_memory_pressure_enabled = !!val;
|
|
break;
|
|
case FILE_MEMORY_PRESSURE:
|
|
retval = -EACCES;
|
|
break;
|
|
case FILE_SPREAD_PAGE:
|
|
retval = update_flag(CS_SPREAD_PAGE, cs, val);
|
|
break;
|
|
case FILE_SPREAD_SLAB:
|
|
retval = update_flag(CS_SPREAD_SLAB, cs, val);
|
|
break;
|
|
default:
|
|
retval = -EINVAL;
|
|
break;
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&cpuset_mutex);
|
|
return retval;
|
|
}
|
|
|
|
static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
|
|
s64 val)
|
|
{
|
|
struct cpuset *cs = css_cs(css);
|
|
cpuset_filetype_t type = cft->private;
|
|
int retval = -ENODEV;
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
if (!is_cpuset_online(cs))
|
|
goto out_unlock;
|
|
|
|
switch (type) {
|
|
case FILE_SCHED_RELAX_DOMAIN_LEVEL:
|
|
retval = update_relax_domain_level(cs, val);
|
|
break;
|
|
default:
|
|
retval = -EINVAL;
|
|
break;
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&cpuset_mutex);
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* Common handling for a write to a "cpus" or "mems" file.
|
|
*/
|
|
static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
struct cpuset *cs = css_cs(of_css(of));
|
|
struct cpuset *trialcs;
|
|
int retval = -ENODEV;
|
|
|
|
buf = strstrip(buf);
|
|
|
|
/*
|
|
* CPU or memory hotunplug may leave @cs w/o any execution
|
|
* resources, in which case the hotplug code asynchronously updates
|
|
* configuration and transfers all tasks to the nearest ancestor
|
|
* which can execute.
|
|
*
|
|
* As writes to "cpus" or "mems" may restore @cs's execution
|
|
* resources, wait for the previously scheduled operations before
|
|
* proceeding, so that we don't end up keep removing tasks added
|
|
* after execution capability is restored.
|
|
*
|
|
* cpuset_hotplug_work calls back into cgroup core via
|
|
* cgroup_transfer_tasks() and waiting for it from a cgroupfs
|
|
* operation like this one can lead to a deadlock through kernfs
|
|
* active_ref protection. Let's break the protection. Losing the
|
|
* protection is okay as we check whether @cs is online after
|
|
* grabbing cpuset_mutex anyway. This only happens on the legacy
|
|
* hierarchies.
|
|
*/
|
|
css_get(&cs->css);
|
|
kernfs_break_active_protection(of->kn);
|
|
flush_work(&cpuset_hotplug_work);
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
if (!is_cpuset_online(cs))
|
|
goto out_unlock;
|
|
|
|
trialcs = alloc_trial_cpuset(cs);
|
|
if (!trialcs) {
|
|
retval = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
|
|
switch (of_cft(of)->private) {
|
|
case FILE_CPULIST:
|
|
retval = update_cpumask(cs, trialcs, buf);
|
|
break;
|
|
case FILE_MEMLIST:
|
|
retval = update_nodemask(cs, trialcs, buf);
|
|
break;
|
|
default:
|
|
retval = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
free_trial_cpuset(trialcs);
|
|
out_unlock:
|
|
mutex_unlock(&cpuset_mutex);
|
|
kernfs_unbreak_active_protection(of->kn);
|
|
css_put(&cs->css);
|
|
return retval ?: nbytes;
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
static int cpuset_common_seq_show(struct seq_file *sf, void *v)
|
|
{
|
|
struct cpuset *cs = css_cs(seq_css(sf));
|
|
cpuset_filetype_t type = seq_cft(sf)->private;
|
|
ssize_t count;
|
|
char *buf, *s;
|
|
int ret = 0;
|
|
|
|
count = seq_get_buf(sf, &buf);
|
|
s = buf;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
|
|
switch (type) {
|
|
case FILE_CPULIST:
|
|
s += cpulist_scnprintf(s, count, cs->cpus_allowed);
|
|
break;
|
|
case FILE_MEMLIST:
|
|
s += nodelist_scnprintf(s, count, cs->mems_allowed);
|
|
break;
|
|
case FILE_EFFECTIVE_CPULIST:
|
|
s += cpulist_scnprintf(s, count, cs->effective_cpus);
|
|
break;
|
|
case FILE_EFFECTIVE_MEMLIST:
|
|
s += nodelist_scnprintf(s, count, cs->effective_mems);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (s < buf + count - 1) {
|
|
*s++ = '\n';
|
|
seq_commit(sf, s - buf);
|
|
} else {
|
|
seq_commit(sf, -1);
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&callback_mutex);
|
|
return ret;
|
|
}
|
|
|
|
static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
|
|
{
|
|
struct cpuset *cs = css_cs(css);
|
|
cpuset_filetype_t type = cft->private;
|
|
switch (type) {
|
|
case FILE_CPU_EXCLUSIVE:
|
|
return is_cpu_exclusive(cs);
|
|
case FILE_MEM_EXCLUSIVE:
|
|
return is_mem_exclusive(cs);
|
|
case FILE_MEM_HARDWALL:
|
|
return is_mem_hardwall(cs);
|
|
case FILE_SCHED_LOAD_BALANCE:
|
|
return is_sched_load_balance(cs);
|
|
case FILE_MEMORY_MIGRATE:
|
|
return is_memory_migrate(cs);
|
|
case FILE_MEMORY_PRESSURE_ENABLED:
|
|
return cpuset_memory_pressure_enabled;
|
|
case FILE_MEMORY_PRESSURE:
|
|
return fmeter_getrate(&cs->fmeter);
|
|
case FILE_SPREAD_PAGE:
|
|
return is_spread_page(cs);
|
|
case FILE_SPREAD_SLAB:
|
|
return is_spread_slab(cs);
|
|
default:
|
|
BUG();
|
|
}
|
|
|
|
/* Unreachable but makes gcc happy */
|
|
return 0;
|
|
}
|
|
|
|
static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
|
|
{
|
|
struct cpuset *cs = css_cs(css);
|
|
cpuset_filetype_t type = cft->private;
|
|
switch (type) {
|
|
case FILE_SCHED_RELAX_DOMAIN_LEVEL:
|
|
return cs->relax_domain_level;
|
|
default:
|
|
BUG();
|
|
}
|
|
|
|
/* Unrechable but makes gcc happy */
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* for the common functions, 'private' gives the type of file
|
|
*/
|
|
|
|
static struct cftype files[] = {
|
|
{
|
|
.name = "cpus",
|
|
.seq_show = cpuset_common_seq_show,
|
|
.write = cpuset_write_resmask,
|
|
.max_write_len = (100U + 6 * NR_CPUS),
|
|
.private = FILE_CPULIST,
|
|
},
|
|
|
|
{
|
|
.name = "mems",
|
|
.seq_show = cpuset_common_seq_show,
|
|
.write = cpuset_write_resmask,
|
|
.max_write_len = (100U + 6 * MAX_NUMNODES),
|
|
.private = FILE_MEMLIST,
|
|
},
|
|
|
|
{
|
|
.name = "effective_cpus",
|
|
.seq_show = cpuset_common_seq_show,
|
|
.private = FILE_EFFECTIVE_CPULIST,
|
|
},
|
|
|
|
{
|
|
.name = "effective_mems",
|
|
.seq_show = cpuset_common_seq_show,
|
|
.private = FILE_EFFECTIVE_MEMLIST,
|
|
},
|
|
|
|
{
|
|
.name = "cpu_exclusive",
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_CPU_EXCLUSIVE,
|
|
},
|
|
|
|
{
|
|
.name = "mem_exclusive",
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_MEM_EXCLUSIVE,
|
|
},
|
|
|
|
{
|
|
.name = "mem_hardwall",
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_MEM_HARDWALL,
|
|
},
|
|
|
|
{
|
|
.name = "sched_load_balance",
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_SCHED_LOAD_BALANCE,
|
|
},
|
|
|
|
{
|
|
.name = "sched_relax_domain_level",
|
|
.read_s64 = cpuset_read_s64,
|
|
.write_s64 = cpuset_write_s64,
|
|
.private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
|
|
},
|
|
|
|
{
|
|
.name = "memory_migrate",
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_MEMORY_MIGRATE,
|
|
},
|
|
|
|
{
|
|
.name = "memory_pressure",
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_MEMORY_PRESSURE,
|
|
.mode = S_IRUGO,
|
|
},
|
|
|
|
{
|
|
.name = "memory_spread_page",
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_SPREAD_PAGE,
|
|
},
|
|
|
|
{
|
|
.name = "memory_spread_slab",
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_SPREAD_SLAB,
|
|
},
|
|
|
|
{
|
|
.name = "memory_pressure_enabled",
|
|
.flags = CFTYPE_ONLY_ON_ROOT,
|
|
.read_u64 = cpuset_read_u64,
|
|
.write_u64 = cpuset_write_u64,
|
|
.private = FILE_MEMORY_PRESSURE_ENABLED,
|
|
},
|
|
|
|
{ } /* terminate */
|
|
};
|
|
|
|
/*
|
|
* cpuset_css_alloc - allocate a cpuset css
|
|
* cgrp: control group that the new cpuset will be part of
|
|
*/
|
|
|
|
static struct cgroup_subsys_state *
|
|
cpuset_css_alloc(struct cgroup_subsys_state *parent_css)
|
|
{
|
|
struct cpuset *cs;
|
|
|
|
if (!parent_css)
|
|
return &top_cpuset.css;
|
|
|
|
cs = kzalloc(sizeof(*cs), GFP_KERNEL);
|
|
if (!cs)
|
|
return ERR_PTR(-ENOMEM);
|
|
if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL))
|
|
goto free_cs;
|
|
if (!alloc_cpumask_var(&cs->effective_cpus, GFP_KERNEL))
|
|
goto free_cpus;
|
|
|
|
set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
|
|
cpumask_clear(cs->cpus_allowed);
|
|
nodes_clear(cs->mems_allowed);
|
|
cpumask_clear(cs->effective_cpus);
|
|
nodes_clear(cs->effective_mems);
|
|
fmeter_init(&cs->fmeter);
|
|
cs->relax_domain_level = -1;
|
|
|
|
return &cs->css;
|
|
|
|
free_cpus:
|
|
free_cpumask_var(cs->cpus_allowed);
|
|
free_cs:
|
|
kfree(cs);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
static int cpuset_css_online(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cpuset *cs = css_cs(css);
|
|
struct cpuset *parent = parent_cs(cs);
|
|
struct cpuset *tmp_cs;
|
|
struct cgroup_subsys_state *pos_css;
|
|
|
|
if (!parent)
|
|
return 0;
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
set_bit(CS_ONLINE, &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);
|
|
|
|
cpuset_inc();
|
|
|
|
mutex_lock(&callback_mutex);
|
|
if (cgroup_on_dfl(cs->css.cgroup)) {
|
|
cpumask_copy(cs->effective_cpus, parent->effective_cpus);
|
|
cs->effective_mems = parent->effective_mems;
|
|
}
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
|
|
goto out_unlock;
|
|
|
|
/*
|
|
* Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
|
|
* set. This flag handling is implemented in cgroup core for
|
|
* histrical reasons - the flag may be specified during mount.
|
|
*
|
|
* Currently, if any sibling cpusets have exclusive cpus or mem, we
|
|
* refuse to clone the configuration - thereby refusing the task to
|
|
* be entered, and as a result refusing the sys_unshare() or
|
|
* clone() which initiated it. If this becomes a problem for some
|
|
* users who wish to allow that scenario, then this could be
|
|
* changed to grant parent->cpus_allowed-sibling_cpus_exclusive
|
|
* (and likewise for mems) to the new cgroup.
|
|
*/
|
|
rcu_read_lock();
|
|
cpuset_for_each_child(tmp_cs, pos_css, parent) {
|
|
if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) {
|
|
rcu_read_unlock();
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cs->mems_allowed = parent->mems_allowed;
|
|
cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
|
|
mutex_unlock(&callback_mutex);
|
|
out_unlock:
|
|
mutex_unlock(&cpuset_mutex);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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_locked().
|
|
*/
|
|
|
|
static void cpuset_css_offline(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cpuset *cs = css_cs(css);
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
if (is_sched_load_balance(cs))
|
|
update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
|
|
|
|
cpuset_dec();
|
|
clear_bit(CS_ONLINE, &cs->flags);
|
|
|
|
mutex_unlock(&cpuset_mutex);
|
|
}
|
|
|
|
static void cpuset_css_free(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cpuset *cs = css_cs(css);
|
|
|
|
free_cpumask_var(cs->effective_cpus);
|
|
free_cpumask_var(cs->cpus_allowed);
|
|
kfree(cs);
|
|
}
|
|
|
|
static void cpuset_bind(struct cgroup_subsys_state *root_css)
|
|
{
|
|
mutex_lock(&cpuset_mutex);
|
|
mutex_lock(&callback_mutex);
|
|
|
|
if (cgroup_on_dfl(root_css->cgroup)) {
|
|
cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
|
|
top_cpuset.mems_allowed = node_possible_map;
|
|
} else {
|
|
cpumask_copy(top_cpuset.cpus_allowed,
|
|
top_cpuset.effective_cpus);
|
|
top_cpuset.mems_allowed = top_cpuset.effective_mems;
|
|
}
|
|
|
|
mutex_unlock(&callback_mutex);
|
|
mutex_unlock(&cpuset_mutex);
|
|
}
|
|
|
|
struct cgroup_subsys cpuset_cgrp_subsys = {
|
|
.css_alloc = cpuset_css_alloc,
|
|
.css_online = cpuset_css_online,
|
|
.css_offline = cpuset_css_offline,
|
|
.css_free = cpuset_css_free,
|
|
.can_attach = cpuset_can_attach,
|
|
.cancel_attach = cpuset_cancel_attach,
|
|
.attach = cpuset_attach,
|
|
.bind = cpuset_bind,
|
|
.legacy_cftypes = files,
|
|
.early_init = 1,
|
|
};
|
|
|
|
/**
|
|
* cpuset_init - initialize cpusets at system boot
|
|
*
|
|
* Description: Initialize top_cpuset and the cpuset internal file system,
|
|
**/
|
|
|
|
int __init cpuset_init(void)
|
|
{
|
|
int err = 0;
|
|
|
|
if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL))
|
|
BUG();
|
|
if (!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL))
|
|
BUG();
|
|
|
|
cpumask_setall(top_cpuset.cpus_allowed);
|
|
nodes_setall(top_cpuset.mems_allowed);
|
|
cpumask_setall(top_cpuset.effective_cpus);
|
|
nodes_setall(top_cpuset.effective_mems);
|
|
|
|
fmeter_init(&top_cpuset.fmeter);
|
|
set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
|
|
top_cpuset.relax_domain_level = -1;
|
|
|
|
err = register_filesystem(&cpuset_fs_type);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL))
|
|
BUG();
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* If CPU and/or memory hotplug handlers, below, unplug 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 move the tasks in the empty
|
|
* cpuset to its next-highest non-empty parent.
|
|
*/
|
|
static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
|
|
{
|
|
struct cpuset *parent;
|
|
|
|
/*
|
|
* Find its next-highest non-empty parent, (top cpuset
|
|
* has online cpus, so can't be empty).
|
|
*/
|
|
parent = parent_cs(cs);
|
|
while (cpumask_empty(parent->cpus_allowed) ||
|
|
nodes_empty(parent->mems_allowed))
|
|
parent = parent_cs(parent);
|
|
|
|
if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {
|
|
pr_err("cpuset: failed to transfer tasks out of empty cpuset ");
|
|
pr_cont_cgroup_name(cs->css.cgroup);
|
|
pr_cont("\n");
|
|
}
|
|
}
|
|
|
|
static void
|
|
hotplug_update_tasks_legacy(struct cpuset *cs,
|
|
struct cpumask *new_cpus, nodemask_t *new_mems,
|
|
bool cpus_updated, bool mems_updated)
|
|
{
|
|
bool is_empty;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cpumask_copy(cs->cpus_allowed, new_cpus);
|
|
cpumask_copy(cs->effective_cpus, new_cpus);
|
|
cs->mems_allowed = *new_mems;
|
|
cs->effective_mems = *new_mems;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
/*
|
|
* Don't call update_tasks_cpumask() if the cpuset becomes empty,
|
|
* as the tasks will be migratecd to an ancestor.
|
|
*/
|
|
if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
|
|
update_tasks_cpumask(cs);
|
|
if (mems_updated && !nodes_empty(cs->mems_allowed))
|
|
update_tasks_nodemask(cs);
|
|
|
|
is_empty = cpumask_empty(cs->cpus_allowed) ||
|
|
nodes_empty(cs->mems_allowed);
|
|
|
|
mutex_unlock(&cpuset_mutex);
|
|
|
|
/*
|
|
* Move tasks to the nearest ancestor with execution resources,
|
|
* This is full cgroup operation which will also call back into
|
|
* cpuset. Should be done outside any lock.
|
|
*/
|
|
if (is_empty)
|
|
remove_tasks_in_empty_cpuset(cs);
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
}
|
|
|
|
static void
|
|
hotplug_update_tasks(struct cpuset *cs,
|
|
struct cpumask *new_cpus, nodemask_t *new_mems,
|
|
bool cpus_updated, bool mems_updated)
|
|
{
|
|
if (cpumask_empty(new_cpus))
|
|
cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
|
|
if (nodes_empty(*new_mems))
|
|
*new_mems = parent_cs(cs)->effective_mems;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cpumask_copy(cs->effective_cpus, new_cpus);
|
|
cs->effective_mems = *new_mems;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
if (cpus_updated)
|
|
update_tasks_cpumask(cs);
|
|
if (mems_updated)
|
|
update_tasks_nodemask(cs);
|
|
}
|
|
|
|
/**
|
|
* cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
|
|
* @cs: cpuset in interest
|
|
*
|
|
* Compare @cs's cpu and mem masks against top_cpuset and if some have gone
|
|
* offline, update @cs accordingly. If @cs ends up with no CPU or memory,
|
|
* all its tasks are moved to the nearest ancestor with both resources.
|
|
*/
|
|
static void cpuset_hotplug_update_tasks(struct cpuset *cs)
|
|
{
|
|
static cpumask_t new_cpus;
|
|
static nodemask_t new_mems;
|
|
bool cpus_updated;
|
|
bool mems_updated;
|
|
retry:
|
|
wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
/*
|
|
* We have raced with task attaching. We wait until attaching
|
|
* is finished, so we won't attach a task to an empty cpuset.
|
|
*/
|
|
if (cs->attach_in_progress) {
|
|
mutex_unlock(&cpuset_mutex);
|
|
goto retry;
|
|
}
|
|
|
|
cpumask_and(&new_cpus, cs->cpus_allowed, parent_cs(cs)->effective_cpus);
|
|
nodes_and(new_mems, cs->mems_allowed, parent_cs(cs)->effective_mems);
|
|
|
|
cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
|
|
mems_updated = !nodes_equal(new_mems, cs->effective_mems);
|
|
|
|
if (cgroup_on_dfl(cs->css.cgroup))
|
|
hotplug_update_tasks(cs, &new_cpus, &new_mems,
|
|
cpus_updated, mems_updated);
|
|
else
|
|
hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems,
|
|
cpus_updated, mems_updated);
|
|
|
|
mutex_unlock(&cpuset_mutex);
|
|
}
|
|
|
|
/**
|
|
* cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset
|
|
*
|
|
* This function is called after either CPU or memory configuration has
|
|
* changed and updates cpuset accordingly. The top_cpuset is always
|
|
* synchronized to cpu_active_mask and N_MEMORY, which 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.
|
|
*
|
|
* Non-root cpusets are only affected by offlining. If any CPUs or memory
|
|
* nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on
|
|
* all descendants.
|
|
*
|
|
* Note that CPU offlining during suspend is ignored. We don't modify
|
|
* cpusets across suspend/resume cycles at all.
|
|
*/
|
|
static void cpuset_hotplug_workfn(struct work_struct *work)
|
|
{
|
|
static cpumask_t new_cpus;
|
|
static nodemask_t new_mems;
|
|
bool cpus_updated, mems_updated;
|
|
bool on_dfl = cgroup_on_dfl(top_cpuset.css.cgroup);
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
/* fetch the available cpus/mems and find out which changed how */
|
|
cpumask_copy(&new_cpus, cpu_active_mask);
|
|
new_mems = node_states[N_MEMORY];
|
|
|
|
cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
|
|
mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
|
|
|
|
/* synchronize cpus_allowed to cpu_active_mask */
|
|
if (cpus_updated) {
|
|
mutex_lock(&callback_mutex);
|
|
if (!on_dfl)
|
|
cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
|
|
cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
|
|
mutex_unlock(&callback_mutex);
|
|
/* we don't mess with cpumasks of tasks in top_cpuset */
|
|
}
|
|
|
|
/* synchronize mems_allowed to N_MEMORY */
|
|
if (mems_updated) {
|
|
mutex_lock(&callback_mutex);
|
|
if (!on_dfl)
|
|
top_cpuset.mems_allowed = new_mems;
|
|
top_cpuset.effective_mems = new_mems;
|
|
mutex_unlock(&callback_mutex);
|
|
update_tasks_nodemask(&top_cpuset);
|
|
}
|
|
|
|
mutex_unlock(&cpuset_mutex);
|
|
|
|
/* if cpus or mems changed, we need to propagate to descendants */
|
|
if (cpus_updated || mems_updated) {
|
|
struct cpuset *cs;
|
|
struct cgroup_subsys_state *pos_css;
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
|
|
if (cs == &top_cpuset || !css_tryget_online(&cs->css))
|
|
continue;
|
|
rcu_read_unlock();
|
|
|
|
cpuset_hotplug_update_tasks(cs);
|
|
|
|
rcu_read_lock();
|
|
css_put(&cs->css);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/* rebuild sched domains if cpus_allowed has changed */
|
|
if (cpus_updated)
|
|
rebuild_sched_domains();
|
|
}
|
|
|
|
void cpuset_update_active_cpus(bool cpu_online)
|
|
{
|
|
/*
|
|
* We're inside cpu hotplug critical region which usually nests
|
|
* inside cgroup synchronization. Bounce actual hotplug processing
|
|
* to a work item to avoid reverse locking order.
|
|
*
|
|
* We still need to do partition_sched_domains() synchronously;
|
|
* otherwise, the scheduler will get confused and put tasks to the
|
|
* dead CPU. Fall back to the default single domain.
|
|
* cpuset_hotplug_workfn() will rebuild it as necessary.
|
|
*/
|
|
partition_sched_domains(1, NULL, NULL);
|
|
schedule_work(&cpuset_hotplug_work);
|
|
}
|
|
|
|
/*
|
|
* Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY].
|
|
* Call this routine anytime after node_states[N_MEMORY] changes.
|
|
* See cpuset_update_active_cpus() for CPU hotplug handling.
|
|
*/
|
|
static int cpuset_track_online_nodes(struct notifier_block *self,
|
|
unsigned long action, void *arg)
|
|
{
|
|
schedule_work(&cpuset_hotplug_work);
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block cpuset_track_online_nodes_nb = {
|
|
.notifier_call = cpuset_track_online_nodes,
|
|
.priority = 10, /* ??! */
|
|
};
|
|
|
|
/**
|
|
* cpuset_init_smp - initialize cpus_allowed
|
|
*
|
|
* Description: Finish top cpuset after cpu, node maps are initialized
|
|
*/
|
|
void __init cpuset_init_smp(void)
|
|
{
|
|
cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
|
|
top_cpuset.mems_allowed = node_states[N_MEMORY];
|
|
top_cpuset.old_mems_allowed = top_cpuset.mems_allowed;
|
|
|
|
cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);
|
|
top_cpuset.effective_mems = node_states[N_MEMORY];
|
|
|
|
register_hotmemory_notifier(&cpuset_track_online_nodes_nb);
|
|
}
|
|
|
|
/**
|
|
* cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
|
|
* @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
|
|
* @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
|
|
*
|
|
* Description: Returns the cpumask_var_t cpus_allowed of the cpuset
|
|
* attached to the specified @tsk. Guaranteed to return some non-empty
|
|
* subset of cpu_online_mask, even if this means going outside the
|
|
* tasks cpuset.
|
|
**/
|
|
|
|
void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
|
|
{
|
|
mutex_lock(&callback_mutex);
|
|
rcu_read_lock();
|
|
guarantee_online_cpus(task_cs(tsk), pmask);
|
|
rcu_read_unlock();
|
|
mutex_unlock(&callback_mutex);
|
|
}
|
|
|
|
void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
|
|
{
|
|
rcu_read_lock();
|
|
do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus);
|
|
rcu_read_unlock();
|
|
|
|
/*
|
|
* We own tsk->cpus_allowed, nobody can change it under us.
|
|
*
|
|
* But we used cs && cs->cpus_allowed lockless and thus can
|
|
* race with cgroup_attach_task() or update_cpumask() and get
|
|
* the wrong tsk->cpus_allowed. However, both cases imply the
|
|
* subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr()
|
|
* which takes task_rq_lock().
|
|
*
|
|
* If we are called after it dropped the lock we must see all
|
|
* changes in tsk_cs()->cpus_allowed. Otherwise we can temporary
|
|
* set any mask even if it is not right from task_cs() pov,
|
|
* the pending set_cpus_allowed_ptr() will fix things.
|
|
*
|
|
* select_fallback_rq() will fix things ups and set cpu_possible_mask
|
|
* if required.
|
|
*/
|
|
}
|
|
|
|
void cpuset_init_current_mems_allowed(void)
|
|
{
|
|
nodes_setall(current->mems_allowed);
|
|
}
|
|
|
|
/**
|
|
* 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_states[N_MEMORY], 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);
|
|
rcu_read_lock();
|
|
guarantee_online_mems(task_cs(tsk), &mask);
|
|
rcu_read_unlock();
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
return mask;
|
|
}
|
|
|
|
/**
|
|
* cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed
|
|
* @nodemask: the nodemask to be checked
|
|
*
|
|
* Are any of the nodes in the nodemask allowed in current->mems_allowed?
|
|
*/
|
|
int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
|
|
{
|
|
return nodes_intersects(*nodemask, current->mems_allowed);
|
|
}
|
|
|
|
/*
|
|
* nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
|
|
* mem_hardwall ancestor to the specified cpuset. Call holding
|
|
* callback_mutex. If no ancestor is mem_exclusive or mem_hardwall
|
|
* (an unusual configuration), then returns the root cpuset.
|
|
*/
|
|
static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
|
|
{
|
|
while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs))
|
|
cs = parent_cs(cs);
|
|
return cs;
|
|
}
|
|
|
|
/**
|
|
* cpuset_node_allowed_softwall - Can we allocate on a memory node?
|
|
* @node: is this 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 node is in our task's mems_allowed,
|
|
* yes. If it's not a __GFP_HARDWALL request and this node is in the nearest
|
|
* hardwalled cpuset ancestor to this task's 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_node_allowed_softwall() reduces to
|
|
* cpuset_node_allowed_hardwall(). Otherwise, cpuset_node_allowed_softwall()
|
|
* might sleep, and might allow a node from an enclosing cpuset.
|
|
*
|
|
* cpuset_node_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 hardwalled 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 hardwalled cpuset ok
|
|
* GFP_USER - only nodes in current tasks mems allowed ok.
|
|
*
|
|
* Rule:
|
|
* Don't call cpuset_node_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_node_allowed_softwall(int node, gfp_t gfp_mask)
|
|
{
|
|
struct cpuset *cs; /* current cpuset ancestors */
|
|
int allowed; /* is allocation in zone z allowed? */
|
|
|
|
if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
|
|
return 1;
|
|
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);
|
|
|
|
rcu_read_lock();
|
|
cs = nearest_hardwall_ancestor(task_cs(current));
|
|
allowed = node_isset(node, cs->mems_allowed);
|
|
rcu_read_unlock();
|
|
|
|
mutex_unlock(&callback_mutex);
|
|
return allowed;
|
|
}
|
|
|
|
/*
|
|
* cpuset_node_allowed_hardwall - Can we allocate on a memory node?
|
|
* @node: is this 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 node is in our task's 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_node_allowed_softwall() variant, above,
|
|
* this variant requires that the node be in the current task's
|
|
* 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_node_allowed_hardwall(int node, gfp_t gfp_mask)
|
|
{
|
|
if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
|
|
return 1;
|
|
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_mem_spread_node() - On which node to begin search for a file page
|
|
* cpuset_slab_spread_node() - On which node to begin search for a slab 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().
|
|
*/
|
|
|
|
static int cpuset_spread_node(int *rotor)
|
|
{
|
|
int node;
|
|
|
|
node = next_node(*rotor, current->mems_allowed);
|
|
if (node == MAX_NUMNODES)
|
|
node = first_node(current->mems_allowed);
|
|
*rotor = node;
|
|
return node;
|
|
}
|
|
|
|
int cpuset_mem_spread_node(void)
|
|
{
|
|
if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE)
|
|
current->cpuset_mem_spread_rotor =
|
|
node_random(¤t->mems_allowed);
|
|
|
|
return cpuset_spread_node(¤t->cpuset_mem_spread_rotor);
|
|
}
|
|
|
|
int cpuset_slab_spread_node(void)
|
|
{
|
|
if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE)
|
|
current->cpuset_slab_spread_rotor =
|
|
node_random(¤t->mems_allowed);
|
|
|
|
return cpuset_spread_node(¤t->cpuset_slab_spread_rotor);
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
|
|
|
|
/**
|
|
* 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_mems_allowed_intersects(const struct task_struct *tsk1,
|
|
const struct task_struct *tsk2)
|
|
{
|
|
return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
|
|
}
|
|
|
|
#define CPUSET_NODELIST_LEN (256)
|
|
|
|
/**
|
|
* cpuset_print_task_mems_allowed - prints task's cpuset and mems_allowed
|
|
* @tsk: pointer to task_struct of some task.
|
|
*
|
|
* Description: Prints @task's name, cpuset name, and cached copy of its
|
|
* mems_allowed to the kernel log.
|
|
*/
|
|
void cpuset_print_task_mems_allowed(struct task_struct *tsk)
|
|
{
|
|
/* Statically allocated to prevent using excess stack. */
|
|
static char cpuset_nodelist[CPUSET_NODELIST_LEN];
|
|
static DEFINE_SPINLOCK(cpuset_buffer_lock);
|
|
struct cgroup *cgrp;
|
|
|
|
spin_lock(&cpuset_buffer_lock);
|
|
rcu_read_lock();
|
|
|
|
cgrp = task_cs(tsk)->css.cgroup;
|
|
nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
|
|
tsk->mems_allowed);
|
|
pr_info("%s cpuset=", tsk->comm);
|
|
pr_cont_cgroup_name(cgrp);
|
|
pr_cont(" mems_allowed=%s\n", cpuset_nodelist);
|
|
|
|
rcu_read_unlock();
|
|
spin_unlock(&cpuset_buffer_lock);
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
rcu_read_lock();
|
|
fmeter_markevent(&task_cs(current)->fmeter);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
#ifdef CONFIG_PROC_PID_CPUSET
|
|
/*
|
|
* 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 cpuset_mutex, keeping cpuset_attach() from changing it
|
|
* anyway.
|
|
*/
|
|
int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
|
|
struct pid *pid, struct task_struct *tsk)
|
|
{
|
|
char *buf, *p;
|
|
struct cgroup_subsys_state *css;
|
|
int retval;
|
|
|
|
retval = -ENOMEM;
|
|
buf = kmalloc(PATH_MAX, GFP_KERNEL);
|
|
if (!buf)
|
|
goto out;
|
|
|
|
retval = -ENAMETOOLONG;
|
|
rcu_read_lock();
|
|
css = task_css(tsk, cpuset_cgrp_id);
|
|
p = cgroup_path(css->cgroup, buf, PATH_MAX);
|
|
rcu_read_unlock();
|
|
if (!p)
|
|
goto out_free;
|
|
seq_puts(m, p);
|
|
seq_putc(m, '\n');
|
|
retval = 0;
|
|
out_free:
|
|
kfree(buf);
|
|
out:
|
|
return retval;
|
|
}
|
|
#endif /* CONFIG_PROC_PID_CPUSET */
|
|
|
|
/* Display task mems_allowed in /proc/<pid>/status file. */
|
|
void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
|
|
{
|
|
seq_puts(m, "Mems_allowed:\t");
|
|
seq_nodemask(m, &task->mems_allowed);
|
|
seq_puts(m, "\n");
|
|
seq_puts(m, "Mems_allowed_list:\t");
|
|
seq_nodemask_list(m, &task->mems_allowed);
|
|
seq_puts(m, "\n");
|
|
}
|