forked from Minki/linux
0b0585c3e1
Pull cpuset changes from Tejun Heo:
"cpuset has always been rather odd about its configurations - a cgroup
right after creation didn't allow any task executions before
configuration, changing configuration in the parent modifies the
descendants irreversibly and so on. These behaviors are inherently
nasty and almost hostile against sharing the hierarchy with other
controllers making it very difficult to use in unified hierarchy.
Li is currently in the process of updating the behaviors for
__DEVEL__sane_behavior which is the bulk of changes in this pull
request. It isn't complete yet and the behaviors will change further
but all changes are gated behind sane_behavior. In the process, the
rather hairy work-item punting which was used to work around the
limitations of cgroup descendant iterator was simplified."
* 'for-3.11-cpuset' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cpuset: rename @cont to @cgrp
cpuset: fix to migrate mm correctly in a corner case
cpuset: allow to move tasks to empty cpusets
cpuset: allow to keep tasks in empty cpusets
cpuset: introduce effective_{cpumask|nodemask}_cpuset()
cpuset: record old_mems_allowed in struct cpuset
cpuset: remove async hotplug propagation work
cpuset: let hotplug propagation work wait for task attaching
cpuset: re-structure update_cpumask() a bit
cpuset: remove cpuset_test_cpumask()
cpuset: remove unnecessary variable in cpuset_attach()
cpuset: cleanup guarantee_online_{cpus|mems}()
cpuset: remove redundant check in cpuset_cpus_allowed_fallback()
2754 lines
78 KiB
C
2754 lines
78 KiB
C
/*
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* kernel/cpuset.c
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*
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* Processor and Memory placement constraints for sets of tasks.
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*
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* Copyright (C) 2003 BULL SA.
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* Copyright (C) 2004-2007 Silicon Graphics, Inc.
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* Copyright (C) 2006 Google, Inc
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*
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* Portions derived from Patrick Mochel's sysfs code.
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* sysfs is Copyright (c) 2001-3 Patrick Mochel
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*
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* 2003-10-10 Written by Simon Derr.
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* 2003-10-22 Updates by Stephen Hemminger.
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* 2004 May-July Rework by Paul Jackson.
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* 2006 Rework by Paul Menage to use generic cgroups
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* 2008 Rework of the scheduler domains and CPU hotplug handling
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* by Max Krasnyansky
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of the Linux
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* distribution for more details.
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*/
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#include <linux/cpu.h>
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#include <linux/cpumask.h>
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#include <linux/cpuset.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/kmod.h>
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#include <linux/list.h>
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#include <linux/mempolicy.h>
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#include <linux/mm.h>
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#include <linux/memory.h>
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#include <linux/export.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/pagemap.h>
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#include <linux/proc_fs.h>
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#include <linux/rcupdate.h>
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#include <linux/sched.h>
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#include <linux/seq_file.h>
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#include <linux/security.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/time.h>
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#include <linux/backing-dev.h>
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#include <linux/sort.h>
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#include <asm/uaccess.h>
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#include <linux/atomic.h>
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#include <linux/mutex.h>
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#include <linux/workqueue.h>
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#include <linux/cgroup.h>
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#include <linux/wait.h>
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/*
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* Tracks how many cpusets are currently defined in system.
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* When there is only one cpuset (the root cpuset) we can
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* short circuit some hooks.
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*/
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int number_of_cpusets __read_mostly;
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/* Forward declare cgroup structures */
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struct cgroup_subsys cpuset_subsys;
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struct cpuset;
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/* See "Frequency meter" comments, below. */
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struct fmeter {
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int cnt; /* unprocessed events count */
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int val; /* most recent output value */
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time_t time; /* clock (secs) when val computed */
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spinlock_t lock; /* guards read or write of above */
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};
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struct cpuset {
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struct cgroup_subsys_state css;
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unsigned long flags; /* "unsigned long" so bitops work */
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cpumask_var_t cpus_allowed; /* CPUs allowed to tasks in cpuset */
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nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */
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/*
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* This is old Memory Nodes tasks took on.
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*
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* - top_cpuset.old_mems_allowed is initialized to mems_allowed.
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* - A new cpuset's old_mems_allowed is initialized when some
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* task is moved into it.
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* - old_mems_allowed is used in cpuset_migrate_mm() when we change
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* cpuset.mems_allowed and have tasks' nodemask updated, and
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* then old_mems_allowed is updated to mems_allowed.
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*/
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nodemask_t old_mems_allowed;
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struct fmeter fmeter; /* memory_pressure filter */
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/*
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* Tasks are being attached to this cpuset. Used to prevent
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* zeroing cpus/mems_allowed between ->can_attach() and ->attach().
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*/
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int attach_in_progress;
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/* partition number for rebuild_sched_domains() */
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int pn;
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/* for custom sched domain */
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int relax_domain_level;
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};
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/* Retrieve the cpuset for a cgroup */
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static inline struct cpuset *cgroup_cs(struct cgroup *cgrp)
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{
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return container_of(cgroup_subsys_state(cgrp, cpuset_subsys_id),
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struct cpuset, css);
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}
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/* Retrieve the cpuset for a task */
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static inline struct cpuset *task_cs(struct task_struct *task)
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{
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return container_of(task_subsys_state(task, cpuset_subsys_id),
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struct cpuset, css);
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}
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static inline struct cpuset *parent_cs(const struct cpuset *cs)
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{
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struct cgroup *pcgrp = cs->css.cgroup->parent;
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if (pcgrp)
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return cgroup_cs(pcgrp);
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return NULL;
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}
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#ifdef CONFIG_NUMA
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static inline bool task_has_mempolicy(struct task_struct *task)
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{
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return task->mempolicy;
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}
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#else
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static inline bool task_has_mempolicy(struct task_struct *task)
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{
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return false;
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}
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#endif
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/* bits in struct cpuset flags field */
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typedef enum {
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CS_ONLINE,
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CS_CPU_EXCLUSIVE,
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CS_MEM_EXCLUSIVE,
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CS_MEM_HARDWALL,
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CS_MEMORY_MIGRATE,
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CS_SCHED_LOAD_BALANCE,
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CS_SPREAD_PAGE,
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CS_SPREAD_SLAB,
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} cpuset_flagbits_t;
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/* convenient tests for these bits */
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static inline bool is_cpuset_online(const struct cpuset *cs)
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{
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return test_bit(CS_ONLINE, &cs->flags);
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}
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static inline int is_cpu_exclusive(const struct cpuset *cs)
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{
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return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
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}
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static inline int is_mem_exclusive(const struct cpuset *cs)
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{
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return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
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}
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static inline int is_mem_hardwall(const struct cpuset *cs)
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{
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return test_bit(CS_MEM_HARDWALL, &cs->flags);
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}
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static inline int is_sched_load_balance(const struct cpuset *cs)
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{
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return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
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}
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static inline int is_memory_migrate(const struct cpuset *cs)
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{
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return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
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}
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static inline int is_spread_page(const struct cpuset *cs)
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{
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return test_bit(CS_SPREAD_PAGE, &cs->flags);
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}
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static inline int is_spread_slab(const struct cpuset *cs)
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{
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return test_bit(CS_SPREAD_SLAB, &cs->flags);
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}
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static struct cpuset top_cpuset = {
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.flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
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(1 << CS_MEM_EXCLUSIVE)),
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};
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/**
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* cpuset_for_each_child - traverse online children of a cpuset
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* @child_cs: loop cursor pointing to the current child
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* @pos_cgrp: used for iteration
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* @parent_cs: target cpuset to walk children of
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*
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* Walk @child_cs through the online children of @parent_cs. Must be used
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* with RCU read locked.
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*/
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#define cpuset_for_each_child(child_cs, pos_cgrp, parent_cs) \
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cgroup_for_each_child((pos_cgrp), (parent_cs)->css.cgroup) \
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if (is_cpuset_online(((child_cs) = cgroup_cs((pos_cgrp)))))
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/**
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* cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
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* @des_cs: loop cursor pointing to the current descendant
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* @pos_cgrp: used for iteration
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* @root_cs: target cpuset to walk ancestor of
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*
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* Walk @des_cs through the online descendants of @root_cs. Must be used
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* with RCU read locked. The caller may modify @pos_cgrp by calling
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* cgroup_rightmost_descendant() to skip subtree.
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*/
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#define cpuset_for_each_descendant_pre(des_cs, pos_cgrp, root_cs) \
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cgroup_for_each_descendant_pre((pos_cgrp), (root_cs)->css.cgroup) \
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if (is_cpuset_online(((des_cs) = cgroup_cs((pos_cgrp)))))
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/*
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* There are two global mutexes guarding cpuset structures - cpuset_mutex
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* and callback_mutex. The latter may nest inside the former. We also
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* require taking task_lock() when dereferencing a task's cpuset pointer.
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* See "The task_lock() exception", at the end of this comment.
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*
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* A task must hold both mutexes to modify cpusets. If a task holds
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* cpuset_mutex, then it blocks others wanting that mutex, ensuring that it
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* is the only task able to also acquire callback_mutex and be able to
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* modify cpusets. It can perform various checks on the cpuset structure
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* first, knowing nothing will change. It can also allocate memory while
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* just holding cpuset_mutex. While it is performing these checks, various
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* callback routines can briefly acquire callback_mutex to query cpusets.
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* Once it is ready to make the changes, it takes callback_mutex, blocking
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* everyone else.
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*
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* Calls to the kernel memory allocator can not be made while holding
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* callback_mutex, as that would risk double tripping on callback_mutex
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* from one of the callbacks into the cpuset code from within
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* __alloc_pages().
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*
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* If a task is only holding callback_mutex, then it has read-only
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* access to cpusets.
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*
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* Now, the task_struct fields mems_allowed and mempolicy may be changed
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* by other task, we use alloc_lock in the task_struct fields to protect
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* them.
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*
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* The cpuset_common_file_read() handlers only hold callback_mutex across
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* small pieces of code, such as when reading out possibly multi-word
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* cpumasks and nodemasks.
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*
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* Accessing a task's cpuset should be done in accordance with the
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* guidelines for accessing subsystem state in kernel/cgroup.c
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*/
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static DEFINE_MUTEX(cpuset_mutex);
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static DEFINE_MUTEX(callback_mutex);
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/*
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* CPU / memory hotplug is handled asynchronously.
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*/
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static void cpuset_hotplug_workfn(struct work_struct *work);
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static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
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static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
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/*
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* This is ugly, but preserves the userspace API for existing cpuset
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* users. If someone tries to mount the "cpuset" filesystem, we
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* silently switch it to mount "cgroup" instead
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*/
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static struct dentry *cpuset_mount(struct file_system_type *fs_type,
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int flags, const char *unused_dev_name, void *data)
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{
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struct file_system_type *cgroup_fs = get_fs_type("cgroup");
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struct dentry *ret = ERR_PTR(-ENODEV);
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if (cgroup_fs) {
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char mountopts[] =
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"cpuset,noprefix,"
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"release_agent=/sbin/cpuset_release_agent";
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ret = cgroup_fs->mount(cgroup_fs, flags,
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unused_dev_name, mountopts);
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put_filesystem(cgroup_fs);
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}
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return ret;
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}
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static struct file_system_type cpuset_fs_type = {
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.name = "cpuset",
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.mount = cpuset_mount,
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};
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/*
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* Return in pmask the portion of a cpusets's cpus_allowed that
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* are online. If none are online, walk up the cpuset hierarchy
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* until we find one that does have some online cpus. The top
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* cpuset always has some cpus online.
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*
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* One way or another, we guarantee to return some non-empty subset
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* of cpu_online_mask.
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*
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* Call with callback_mutex held.
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*/
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static void guarantee_online_cpus(const struct cpuset *cs,
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struct cpumask *pmask)
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{
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while (!cpumask_intersects(cs->cpus_allowed, cpu_online_mask))
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cs = parent_cs(cs);
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cpumask_and(pmask, cs->cpus_allowed, cpu_online_mask);
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}
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/*
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* Return in *pmask the portion of a cpusets's mems_allowed that
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* are online, with memory. If none are online with memory, walk
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* up the cpuset hierarchy until we find one that does have some
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* online mems. The top cpuset always has some mems online.
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*
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* One way or another, we guarantee to return some non-empty subset
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* of node_states[N_MEMORY].
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*
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* Call with callback_mutex held.
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*/
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static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
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{
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while (!nodes_intersects(cs->mems_allowed, node_states[N_MEMORY]))
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cs = parent_cs(cs);
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nodes_and(*pmask, cs->mems_allowed, node_states[N_MEMORY]);
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}
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|
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/*
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* update task's spread flag if cpuset's page/slab spread flag is set
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*
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* Called with callback_mutex/cpuset_mutex held
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*/
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static void cpuset_update_task_spread_flag(struct cpuset *cs,
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struct task_struct *tsk)
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{
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if (is_spread_page(cs))
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tsk->flags |= PF_SPREAD_PAGE;
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else
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tsk->flags &= ~PF_SPREAD_PAGE;
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if (is_spread_slab(cs))
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tsk->flags |= PF_SPREAD_SLAB;
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else
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tsk->flags &= ~PF_SPREAD_SLAB;
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}
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|
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/*
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* is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
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*
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* One cpuset is a subset of another if all its allowed CPUs and
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* Memory Nodes are a subset of the other, and its exclusive flags
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* are only set if the other's are set. Call holding cpuset_mutex.
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*/
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static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
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{
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return cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&
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nodes_subset(p->mems_allowed, q->mems_allowed) &&
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is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
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is_mem_exclusive(p) <= is_mem_exclusive(q);
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}
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|
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/**
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* alloc_trial_cpuset - allocate a trial cpuset
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* @cs: the cpuset that the trial cpuset duplicates
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*/
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static struct cpuset *alloc_trial_cpuset(const struct cpuset *cs)
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{
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struct cpuset *trial;
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|
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trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
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if (!trial)
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return NULL;
|
|
|
|
if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL)) {
|
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kfree(trial);
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return NULL;
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}
|
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cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);
|
|
|
|
return trial;
|
|
}
|
|
|
|
/**
|
|
* free_trial_cpuset - free the trial cpuset
|
|
* @trial: the trial cpuset to be freed
|
|
*/
|
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static void free_trial_cpuset(struct cpuset *trial)
|
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{
|
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free_cpumask_var(trial->cpus_allowed);
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kfree(trial);
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}
|
|
|
|
/*
|
|
* 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,
|
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* or flags changed to new, trial values.
|
|
*
|
|
* Return 0 if valid, -errno if not.
|
|
*/
|
|
|
|
static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
|
|
{
|
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struct cgroup *cgrp;
|
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struct cpuset *c, *par;
|
|
int ret;
|
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|
|
rcu_read_lock();
|
|
|
|
/* Each of our child cpusets must be a subset of us */
|
|
ret = -EBUSY;
|
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cpuset_for_each_child(c, cgrp, 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);
|
|
|
|
/* We must be a subset of our parent cpuset */
|
|
ret = -EACCES;
|
|
if (!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, cgrp, 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
|
|
* have empty cpus_allowed or mems_allowed.
|
|
*/
|
|
ret = -ENOSPC;
|
|
if ((cgroup_task_count(cur->css.cgroup) || cur->attach_in_progress) &&
|
|
(cpumask_empty(trial->cpus_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 cpus_allowed masks?
|
|
*/
|
|
static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
|
|
{
|
|
return cpumask_intersects(a->cpus_allowed, b->cpus_allowed);
|
|
}
|
|
|
|
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 *pos_cgrp;
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) {
|
|
/* skip the whole subtree if @cp doesn't have any CPU */
|
|
if (cpumask_empty(cp->cpus_allowed)) {
|
|
pos_cgrp = cgroup_rightmost_descendant(pos_cgrp);
|
|
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 *pos_cgrp;
|
|
|
|
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.cpus_allowed);
|
|
|
|
goto done;
|
|
}
|
|
|
|
csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);
|
|
if (!csa)
|
|
goto done;
|
|
csn = 0;
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cp, pos_cgrp, &top_cpuset) {
|
|
/*
|
|
* 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_cgrp = cgroup_rightmost_descendant(pos_cgrp);
|
|
}
|
|
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) {
|
|
printk(KERN_WARNING
|
|
"rebuild_sched_domains confused:"
|
|
" nslot %d, ndoms %d, csn %d, i %d,"
|
|
" apn %d\n",
|
|
nslot, ndoms, csn, i, apn);
|
|
warnings--;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
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->cpus_allowed);
|
|
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.cpus_allowed, 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);
|
|
}
|
|
|
|
/*
|
|
* effective_cpumask_cpuset - return nearest ancestor with non-empty cpus
|
|
* @cs: the cpuset in interest
|
|
*
|
|
* A cpuset's effective cpumask is the cpumask of the nearest ancestor
|
|
* with non-empty cpus. We use effective cpumask whenever:
|
|
* - we update tasks' cpus_allowed. (they take on the ancestor's cpumask
|
|
* if the cpuset they reside in has no cpus)
|
|
* - we want to retrieve task_cs(tsk)'s cpus_allowed.
|
|
*
|
|
* Called with cpuset_mutex held. cpuset_cpus_allowed_fallback() is an
|
|
* exception. See comments there.
|
|
*/
|
|
static struct cpuset *effective_cpumask_cpuset(struct cpuset *cs)
|
|
{
|
|
while (cpumask_empty(cs->cpus_allowed))
|
|
cs = parent_cs(cs);
|
|
return cs;
|
|
}
|
|
|
|
/*
|
|
* effective_nodemask_cpuset - return nearest ancestor with non-empty mems
|
|
* @cs: the cpuset in interest
|
|
*
|
|
* A cpuset's effective nodemask is the nodemask of the nearest ancestor
|
|
* with non-empty memss. We use effective nodemask whenever:
|
|
* - we update tasks' mems_allowed. (they take on the ancestor's nodemask
|
|
* if the cpuset they reside in has no mems)
|
|
* - we want to retrieve task_cs(tsk)'s mems_allowed.
|
|
*
|
|
* Called with cpuset_mutex held.
|
|
*/
|
|
static struct cpuset *effective_nodemask_cpuset(struct cpuset *cs)
|
|
{
|
|
while (nodes_empty(cs->mems_allowed))
|
|
cs = parent_cs(cs);
|
|
return cs;
|
|
}
|
|
|
|
/**
|
|
* cpuset_change_cpumask - make a task's cpus_allowed the same as its cpuset's
|
|
* @tsk: task to test
|
|
* @scan: struct cgroup_scanner containing the cgroup of the task
|
|
*
|
|
* Called by cgroup_scan_tasks() for each task in a cgroup whose
|
|
* cpus_allowed mask needs to be changed.
|
|
*
|
|
* We don't need to re-check for the cgroup/cpuset membership, since we're
|
|
* holding cpuset_mutex at this point.
|
|
*/
|
|
static void cpuset_change_cpumask(struct task_struct *tsk,
|
|
struct cgroup_scanner *scan)
|
|
{
|
|
struct cpuset *cpus_cs;
|
|
|
|
cpus_cs = effective_cpumask_cpuset(cgroup_cs(scan->cg));
|
|
set_cpus_allowed_ptr(tsk, cpus_cs->cpus_allowed);
|
|
}
|
|
|
|
/**
|
|
* 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
|
|
* @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
|
|
*
|
|
* Called with cpuset_mutex held
|
|
*
|
|
* The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
|
|
* calling callback functions for each.
|
|
*
|
|
* No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
|
|
* if @heap != NULL.
|
|
*/
|
|
static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap)
|
|
{
|
|
struct cgroup_scanner scan;
|
|
|
|
scan.cg = cs->css.cgroup;
|
|
scan.test_task = NULL;
|
|
scan.process_task = cpuset_change_cpumask;
|
|
scan.heap = heap;
|
|
cgroup_scan_tasks(&scan);
|
|
}
|
|
|
|
/*
|
|
* update_tasks_cpumask_hier - Update the cpumasks of tasks in the hierarchy.
|
|
* @root_cs: the root cpuset of the hierarchy
|
|
* @update_root: update root cpuset or not?
|
|
* @heap: the heap used by cgroup_scan_tasks()
|
|
*
|
|
* This will update cpumasks of tasks in @root_cs and all other empty cpusets
|
|
* which take on cpumask of @root_cs.
|
|
*
|
|
* Called with cpuset_mutex held
|
|
*/
|
|
static void update_tasks_cpumask_hier(struct cpuset *root_cs,
|
|
bool update_root, struct ptr_heap *heap)
|
|
{
|
|
struct cpuset *cp;
|
|
struct cgroup *pos_cgrp;
|
|
|
|
if (update_root)
|
|
update_tasks_cpumask(root_cs, heap);
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) {
|
|
/* skip the whole subtree if @cp have some CPU */
|
|
if (!cpumask_empty(cp->cpus_allowed)) {
|
|
pos_cgrp = cgroup_rightmost_descendant(pos_cgrp);
|
|
continue;
|
|
}
|
|
if (!css_tryget(&cp->css))
|
|
continue;
|
|
rcu_read_unlock();
|
|
|
|
update_tasks_cpumask(cp, heap);
|
|
|
|
rcu_read_lock();
|
|
css_put(&cp->css);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/**
|
|
* update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
|
|
* @cs: the cpuset to consider
|
|
* @buf: buffer of cpu numbers written to this cpuset
|
|
*/
|
|
static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
|
|
const char *buf)
|
|
{
|
|
struct ptr_heap heap;
|
|
int retval;
|
|
int is_load_balanced;
|
|
|
|
/* 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, cpu_active_mask))
|
|
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;
|
|
|
|
retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
|
|
if (retval)
|
|
return retval;
|
|
|
|
is_load_balanced = is_sched_load_balance(trialcs);
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
update_tasks_cpumask_hier(cs, true, &heap);
|
|
|
|
heap_free(&heap);
|
|
|
|
if (is_load_balanced)
|
|
rebuild_sched_domains_locked();
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* cpuset_migrate_mm
|
|
*
|
|
* Migrate memory region from one set of nodes to another.
|
|
*
|
|
* Temporarilly set tasks mems_allowed to target nodes of migration,
|
|
* so that the migration code can allocate pages on these nodes.
|
|
*
|
|
* Call holding cpuset_mutex, so current's cpuset won't change
|
|
* during this call, as manage_mutex holds off any cpuset_attach()
|
|
* calls. Therefore we don't need to take task_lock around the
|
|
* call to guarantee_online_mems(), as we know no one is changing
|
|
* our task's cpuset.
|
|
*
|
|
* 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;
|
|
struct cpuset *mems_cs;
|
|
|
|
tsk->mems_allowed = *to;
|
|
|
|
do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
|
|
|
|
mems_cs = effective_nodemask_cpuset(task_cs(tsk));
|
|
guarantee_online_mems(mems_cs, &tsk->mems_allowed);
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
* get_mems_allowed(). 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)
|
|
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);
|
|
|
|
task_unlock(tsk);
|
|
}
|
|
|
|
/*
|
|
* Update task's mems_allowed and rebind its mempolicy and vmas' mempolicy
|
|
* of it to cpuset's new mems_allowed, and migrate pages to new nodes if
|
|
* memory_migrate flag is set. Called with cpuset_mutex held.
|
|
*/
|
|
static void cpuset_change_nodemask(struct task_struct *p,
|
|
struct cgroup_scanner *scan)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(scan->cg);
|
|
struct mm_struct *mm;
|
|
int migrate;
|
|
nodemask_t *newmems = scan->data;
|
|
|
|
cpuset_change_task_nodemask(p, newmems);
|
|
|
|
mm = get_task_mm(p);
|
|
if (!mm)
|
|
return;
|
|
|
|
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);
|
|
}
|
|
|
|
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
|
|
* @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
|
|
*
|
|
* Called with cpuset_mutex held
|
|
* No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
|
|
* if @heap != NULL.
|
|
*/
|
|
static void update_tasks_nodemask(struct cpuset *cs, struct ptr_heap *heap)
|
|
{
|
|
static nodemask_t newmems; /* protected by cpuset_mutex */
|
|
struct cgroup_scanner scan;
|
|
struct cpuset *mems_cs = effective_nodemask_cpuset(cs);
|
|
|
|
cpuset_being_rebound = cs; /* causes mpol_dup() rebind */
|
|
|
|
guarantee_online_mems(mems_cs, &newmems);
|
|
|
|
scan.cg = cs->css.cgroup;
|
|
scan.test_task = NULL;
|
|
scan.process_task = cpuset_change_nodemask;
|
|
scan.heap = heap;
|
|
scan.data = &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.
|
|
*/
|
|
cgroup_scan_tasks(&scan);
|
|
|
|
/*
|
|
* 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_tasks_nodemask_hier - Update the nodemasks of tasks in the hierarchy.
|
|
* @cs: the root cpuset of the hierarchy
|
|
* @update_root: update the root cpuset or not?
|
|
* @heap: the heap used by cgroup_scan_tasks()
|
|
*
|
|
* This will update nodemasks of tasks in @root_cs and all other empty cpusets
|
|
* which take on nodemask of @root_cs.
|
|
*
|
|
* Called with cpuset_mutex held
|
|
*/
|
|
static void update_tasks_nodemask_hier(struct cpuset *root_cs,
|
|
bool update_root, struct ptr_heap *heap)
|
|
{
|
|
struct cpuset *cp;
|
|
struct cgroup *pos_cgrp;
|
|
|
|
if (update_root)
|
|
update_tasks_nodemask(root_cs, heap);
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) {
|
|
/* skip the whole subtree if @cp have some CPU */
|
|
if (!nodes_empty(cp->mems_allowed)) {
|
|
pos_cgrp = cgroup_rightmost_descendant(pos_cgrp);
|
|
continue;
|
|
}
|
|
if (!css_tryget(&cp->css))
|
|
continue;
|
|
rcu_read_unlock();
|
|
|
|
update_tasks_nodemask(cp, heap);
|
|
|
|
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;
|
|
struct ptr_heap heap;
|
|
|
|
/*
|
|
* 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,
|
|
node_states[N_MEMORY])) {
|
|
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;
|
|
|
|
retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
|
|
if (retval < 0)
|
|
goto done;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cs->mems_allowed = trialcs->mems_allowed;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
update_tasks_nodemask_hier(cs, true, &heap);
|
|
|
|
heap_free(&heap);
|
|
done:
|
|
return retval;
|
|
}
|
|
|
|
int current_cpuset_is_being_rebound(void)
|
|
{
|
|
return task_cs(current) == cpuset_being_rebound;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* cpuset_change_flag - make a task's spread flags the same as its cpuset's
|
|
* @tsk: task to be updated
|
|
* @scan: struct cgroup_scanner containing the cgroup of the task
|
|
*
|
|
* Called by cgroup_scan_tasks() for each task in a cgroup.
|
|
*
|
|
* We don't need to re-check for the cgroup/cpuset membership, since we're
|
|
* holding cpuset_mutex at this point.
|
|
*/
|
|
static void cpuset_change_flag(struct task_struct *tsk,
|
|
struct cgroup_scanner *scan)
|
|
{
|
|
cpuset_update_task_spread_flag(cgroup_cs(scan->cg), tsk);
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
* @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
|
|
*
|
|
* Called with cpuset_mutex held
|
|
*
|
|
* The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
|
|
* calling callback functions for each.
|
|
*
|
|
* No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
|
|
* if @heap != NULL.
|
|
*/
|
|
static void update_tasks_flags(struct cpuset *cs, struct ptr_heap *heap)
|
|
{
|
|
struct cgroup_scanner scan;
|
|
|
|
scan.cg = cs->css.cgroup;
|
|
scan.test_task = NULL;
|
|
scan.process_task = cpuset_change_flag;
|
|
scan.heap = heap;
|
|
cgroup_scan_tasks(&scan);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
struct ptr_heap heap;
|
|
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;
|
|
|
|
err = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
|
|
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, &heap);
|
|
heap_free(&heap);
|
|
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;
|
|
}
|
|
|
|
/* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */
|
|
static int cpuset_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
struct task_struct *task;
|
|
int ret;
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
/*
|
|
* We allow to move tasks into an empty cpuset if sane_behavior
|
|
* flag is set.
|
|
*/
|
|
ret = -ENOSPC;
|
|
if (!cgroup_sane_behavior(cgrp) &&
|
|
(cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
|
|
goto out_unlock;
|
|
|
|
cgroup_taskset_for_each(task, cgrp, 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 *cgrp,
|
|
struct cgroup_taskset *tset)
|
|
{
|
|
mutex_lock(&cpuset_mutex);
|
|
cgroup_cs(cgrp)->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 *cgrp, 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 cgroup *oldcgrp = cgroup_taskset_cur_cgroup(tset);
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
struct cpuset *oldcs = cgroup_cs(oldcgrp);
|
|
struct cpuset *cpus_cs = effective_cpumask_cpuset(cs);
|
|
struct cpuset *mems_cs = effective_nodemask_cpuset(cs);
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
/* prepare for attach */
|
|
if (cs == &top_cpuset)
|
|
cpumask_copy(cpus_attach, cpu_possible_mask);
|
|
else
|
|
guarantee_online_cpus(cpus_cs, cpus_attach);
|
|
|
|
guarantee_online_mems(mems_cs, &cpuset_attach_nodemask_to);
|
|
|
|
cgroup_taskset_for_each(task, cgrp, 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->mems_allowed;
|
|
mm = get_task_mm(leader);
|
|
if (mm) {
|
|
struct cpuset *mems_oldcs = effective_nodemask_cpuset(oldcs);
|
|
|
|
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, &mems_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_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 *cgrp, struct cftype *cft, u64 val)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
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_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 *cgrp, struct cftype *cft, s64 val)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
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 int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft,
|
|
const char *buf)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
struct cpuset *trialcs;
|
|
int retval = -ENODEV;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
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 (cft->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);
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* These ascii lists should be read in a single call, by using a user
|
|
* buffer large enough to hold the entire map. If read in smaller
|
|
* chunks, there is no guarantee of atomicity. Since the display format
|
|
* used, list of ranges of sequential numbers, is variable length,
|
|
* and since these maps can change value dynamically, one could read
|
|
* gibberish by doing partial reads while a list was changing.
|
|
* A single large read to a buffer that crosses a page boundary is
|
|
* ok, because the result being copied to user land is not recomputed
|
|
* across a page fault.
|
|
*/
|
|
|
|
static size_t cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
|
|
{
|
|
size_t count;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
count = cpulist_scnprintf(page, PAGE_SIZE, cs->cpus_allowed);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
return count;
|
|
}
|
|
|
|
static size_t cpuset_sprintf_memlist(char *page, struct cpuset *cs)
|
|
{
|
|
size_t count;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
count = nodelist_scnprintf(page, PAGE_SIZE, cs->mems_allowed);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
return count;
|
|
}
|
|
|
|
static ssize_t cpuset_common_file_read(struct cgroup *cgrp,
|
|
struct cftype *cft,
|
|
struct file *file,
|
|
char __user *buf,
|
|
size_t nbytes, loff_t *ppos)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
cpuset_filetype_t type = cft->private;
|
|
char *page;
|
|
ssize_t retval = 0;
|
|
char *s;
|
|
|
|
if (!(page = (char *)__get_free_page(GFP_TEMPORARY)))
|
|
return -ENOMEM;
|
|
|
|
s = page;
|
|
|
|
switch (type) {
|
|
case FILE_CPULIST:
|
|
s += cpuset_sprintf_cpulist(s, cs);
|
|
break;
|
|
case FILE_MEMLIST:
|
|
s += cpuset_sprintf_memlist(s, cs);
|
|
break;
|
|
default:
|
|
retval = -EINVAL;
|
|
goto out;
|
|
}
|
|
*s++ = '\n';
|
|
|
|
retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
|
|
out:
|
|
free_page((unsigned long)page);
|
|
return retval;
|
|
}
|
|
|
|
static u64 cpuset_read_u64(struct cgroup *cgrp, struct cftype *cft)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
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 *cgrp, struct cftype *cft)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
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",
|
|
.read = cpuset_common_file_read,
|
|
.write_string = cpuset_write_resmask,
|
|
.max_write_len = (100U + 6 * NR_CPUS),
|
|
.private = FILE_CPULIST,
|
|
},
|
|
|
|
{
|
|
.name = "mems",
|
|
.read = cpuset_common_file_read,
|
|
.write_string = cpuset_write_resmask,
|
|
.max_write_len = (100U + 6 * MAX_NUMNODES),
|
|
.private = FILE_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 *cgrp)
|
|
{
|
|
struct cpuset *cs;
|
|
|
|
if (!cgrp->parent)
|
|
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)) {
|
|
kfree(cs);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
|
|
cpumask_clear(cs->cpus_allowed);
|
|
nodes_clear(cs->mems_allowed);
|
|
fmeter_init(&cs->fmeter);
|
|
cs->relax_domain_level = -1;
|
|
|
|
return &cs->css;
|
|
}
|
|
|
|
static int cpuset_css_online(struct cgroup *cgrp)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
struct cpuset *parent = parent_cs(cs);
|
|
struct cpuset *tmp_cs;
|
|
struct cgroup *pos_cg;
|
|
|
|
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);
|
|
|
|
number_of_cpusets++;
|
|
|
|
if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->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_cg, 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;
|
|
}
|
|
|
|
static void cpuset_css_offline(struct cgroup *cgrp)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
|
|
mutex_lock(&cpuset_mutex);
|
|
|
|
if (is_sched_load_balance(cs))
|
|
update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
|
|
|
|
number_of_cpusets--;
|
|
clear_bit(CS_ONLINE, &cs->flags);
|
|
|
|
mutex_unlock(&cpuset_mutex);
|
|
}
|
|
|
|
/*
|
|
* 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_free(struct cgroup *cgrp)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cgrp);
|
|
|
|
free_cpumask_var(cs->cpus_allowed);
|
|
kfree(cs);
|
|
}
|
|
|
|
struct cgroup_subsys cpuset_subsys = {
|
|
.name = "cpuset",
|
|
.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,
|
|
.subsys_id = cpuset_subsys_id,
|
|
.base_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();
|
|
|
|
cpumask_setall(top_cpuset.cpus_allowed);
|
|
nodes_setall(top_cpuset.mems_allowed);
|
|
|
|
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();
|
|
|
|
number_of_cpusets = 1;
|
|
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)) {
|
|
rcu_read_lock();
|
|
printk(KERN_ERR "cpuset: failed to transfer tasks out of empty cpuset %s\n",
|
|
cgroup_name(cs->css.cgroup));
|
|
rcu_read_unlock();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 off_cpus;
|
|
static nodemask_t off_mems;
|
|
bool is_empty;
|
|
bool sane = cgroup_sane_behavior(cs->css.cgroup);
|
|
|
|
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_andnot(&off_cpus, cs->cpus_allowed, top_cpuset.cpus_allowed);
|
|
nodes_andnot(off_mems, cs->mems_allowed, top_cpuset.mems_allowed);
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
/*
|
|
* If sane_behavior flag is set, we need to update tasks' cpumask
|
|
* for empty cpuset to take on ancestor's cpumask. Otherwise, don't
|
|
* call update_tasks_cpumask() if the cpuset becomes empty, as
|
|
* the tasks in it will be migrated to an ancestor.
|
|
*/
|
|
if ((sane && cpumask_empty(cs->cpus_allowed)) ||
|
|
(!cpumask_empty(&off_cpus) && !cpumask_empty(cs->cpus_allowed)))
|
|
update_tasks_cpumask(cs, NULL);
|
|
|
|
mutex_lock(&callback_mutex);
|
|
nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
/*
|
|
* If sane_behavior flag is set, we need to update tasks' nodemask
|
|
* for empty cpuset to take on ancestor's nodemask. Otherwise, don't
|
|
* call update_tasks_nodemask() if the cpuset becomes empty, as
|
|
* the tasks in it will be migratd to an ancestor.
|
|
*/
|
|
if ((sane && nodes_empty(cs->mems_allowed)) ||
|
|
(!nodes_empty(off_mems) && !nodes_empty(cs->mems_allowed)))
|
|
update_tasks_nodemask(cs, NULL);
|
|
|
|
is_empty = cpumask_empty(cs->cpus_allowed) ||
|
|
nodes_empty(cs->mems_allowed);
|
|
|
|
mutex_unlock(&cpuset_mutex);
|
|
|
|
/*
|
|
* If sane_behavior flag is set, we'll keep tasks in empty cpusets.
|
|
*
|
|
* Otherwise 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 (!sane && is_empty)
|
|
remove_tasks_in_empty_cpuset(cs);
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
|
|
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.cpus_allowed, &new_cpus);
|
|
mems_updated = !nodes_equal(top_cpuset.mems_allowed, new_mems);
|
|
|
|
/* synchronize cpus_allowed to cpu_active_mask */
|
|
if (cpus_updated) {
|
|
mutex_lock(&callback_mutex);
|
|
cpumask_copy(top_cpuset.cpus_allowed, &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);
|
|
top_cpuset.mems_allowed = new_mems;
|
|
mutex_unlock(&callback_mutex);
|
|
update_tasks_nodemask(&top_cpuset, NULL);
|
|
}
|
|
|
|
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 *pos_cgrp;
|
|
|
|
rcu_read_lock();
|
|
cpuset_for_each_descendant_pre(cs, pos_cgrp, &top_cpuset) {
|
|
if (!css_tryget(&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;
|
|
|
|
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)
|
|
{
|
|
struct cpuset *cpus_cs;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
task_lock(tsk);
|
|
cpus_cs = effective_cpumask_cpuset(task_cs(tsk));
|
|
guarantee_online_cpus(cpus_cs, pmask);
|
|
task_unlock(tsk);
|
|
mutex_unlock(&callback_mutex);
|
|
}
|
|
|
|
void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
|
|
{
|
|
const struct cpuset *cpus_cs;
|
|
|
|
rcu_read_lock();
|
|
cpus_cs = effective_cpumask_cpuset(task_cs(tsk));
|
|
do_set_cpus_allowed(tsk, cpus_cs->cpus_allowed);
|
|
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)
|
|
{
|
|
struct cpuset *mems_cs;
|
|
nodemask_t mask;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
task_lock(tsk);
|
|
mems_cs = effective_nodemask_cpuset(task_cs(tsk));
|
|
guarantee_online_mems(mems_cs, &mask);
|
|
task_unlock(tsk);
|
|
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 const struct cpuset *nearest_hardwall_ancestor(const 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)
|
|
{
|
|
const 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);
|
|
|
|
task_lock(current);
|
|
cs = nearest_hardwall_ancestor(task_cs(current));
|
|
task_unlock(current);
|
|
|
|
allowed = node_isset(node, cs->mems_allowed);
|
|
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
|
|
* @task: 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. Must hold task_lock(task) to allow
|
|
* dereferencing task_cs(task).
|
|
*/
|
|
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 = task_cs(tsk)->css.cgroup;
|
|
|
|
rcu_read_lock();
|
|
spin_lock(&cpuset_buffer_lock);
|
|
|
|
nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
|
|
tsk->mems_allowed);
|
|
printk(KERN_INFO "%s cpuset=%s mems_allowed=%s\n",
|
|
tsk->comm, cgroup_name(cgrp), cpuset_nodelist);
|
|
|
|
spin_unlock(&cpuset_buffer_lock);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
task_lock(current);
|
|
fmeter_markevent(&task_cs(current)->fmeter);
|
|
task_unlock(current);
|
|
}
|
|
|
|
#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, void *unused_v)
|
|
{
|
|
struct pid *pid;
|
|
struct task_struct *tsk;
|
|
char *buf;
|
|
struct cgroup_subsys_state *css;
|
|
int retval;
|
|
|
|
retval = -ENOMEM;
|
|
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
|
|
if (!buf)
|
|
goto out;
|
|
|
|
retval = -ESRCH;
|
|
pid = m->private;
|
|
tsk = get_pid_task(pid, PIDTYPE_PID);
|
|
if (!tsk)
|
|
goto out_free;
|
|
|
|
rcu_read_lock();
|
|
css = task_subsys_state(tsk, cpuset_subsys_id);
|
|
retval = cgroup_path(css->cgroup, buf, PAGE_SIZE);
|
|
rcu_read_unlock();
|
|
if (retval < 0)
|
|
goto out_put_task;
|
|
seq_puts(m, buf);
|
|
seq_putc(m, '\n');
|
|
out_put_task:
|
|
put_task_struct(tsk);
|
|
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_printf(m, "Mems_allowed:\t");
|
|
seq_nodemask(m, &task->mems_allowed);
|
|
seq_printf(m, "\n");
|
|
seq_printf(m, "Mems_allowed_list:\t");
|
|
seq_nodemask_list(m, &task->mems_allowed);
|
|
seq_printf(m, "\n");
|
|
}
|