470fd64644
When a cpu is disabled, move_task_off_dead_cpu() is called for tasks that have been running on that cpu. Currently, such a task is migrated: 1) to any cpu on the same node as the disabled cpu, which is both online and among that task's cpus_allowed 2) to any cpu which is both online and among that task's cpus_allowed It is typical of a multithreaded application running on a large NUMA system to have its tasks confined to a cpuset so as to cluster them near the memory that they share. Furthermore, it is typical to explicitly place such a task on a specific cpu in that cpuset. And in that case the task's cpus_allowed includes only a single cpu. This patch would insert a preference to migrate such a task to some cpu within its cpuset (and set its cpus_allowed to its entire cpuset). With this patch, migrate the task to: 1) to any cpu on the same node as the disabled cpu, which is both online and among that task's cpus_allowed 2) to any online cpu within the task's cpuset 3) to any cpu which is both online and among that task's cpus_allowed In order to do this, move_task_off_dead_cpu() must make a call to cpuset_cpus_allowed_locked(), a new subset of cpuset_cpus_allowed(), that will not block. (name change - per Oleg's suggestion) Calls are made to cpuset_lock() and cpuset_unlock() in migration_call() to set the cpuset mutex during the whole migrate_live_tasks() and migrate_dead_tasks() procedure. [akpm@linux-foundation.org: build fix] [pj@sgi.com: Fix indentation and spacing] Signed-off-by: Cliff Wickman <cpw@sgi.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Christoph Lameter <clameter@sgi.com> Cc: Paul Jackson <pj@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2232 lines
67 KiB
C
2232 lines
67 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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*
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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/module.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/prio_heap.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 <asm/atomic.h>
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#include <linux/mutex.h>
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#include <linux/kfifo.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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/* Retrieve the cpuset from a cgroup */
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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_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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struct cpuset *parent; /* my parent */
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/*
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* Copy of global cpuset_mems_generation as of the most
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* recent time this cpuset changed its mems_allowed.
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*/
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int mems_generation;
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struct fmeter fmeter; /* memory_pressure filter */
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/* partition number for rebuild_sched_domains() */
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int pn;
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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 *cont)
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{
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return container_of(cgroup_subsys_state(cont, 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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/* bits in struct cpuset flags field */
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typedef enum {
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CS_CPU_EXCLUSIVE,
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CS_MEM_EXCLUSIVE,
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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 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_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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/*
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* Increment this integer everytime any cpuset changes its
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* mems_allowed value. Users of cpusets can track this generation
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* number, and avoid having to lock and reload mems_allowed unless
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* the cpuset they're using changes generation.
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*
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* A single, global generation is needed because attach_task() could
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* reattach a task to a different cpuset, which must not have its
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* generation numbers aliased with those of that tasks previous cpuset.
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*
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* Generations are needed for mems_allowed because one task cannot
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* modify anothers memory placement. So we must enable every task,
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* on every visit to __alloc_pages(), to efficiently check whether
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* its current->cpuset->mems_allowed has changed, requiring an update
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* of its current->mems_allowed.
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*
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* Since cpuset_mems_generation is guarded by manage_mutex,
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* there is no need to mark it atomic.
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*/
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static int cpuset_mems_generation;
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static struct cpuset top_cpuset = {
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.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
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.cpus_allowed = CPU_MASK_ALL,
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.mems_allowed = NODE_MASK_ALL,
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};
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/*
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* We have two global cpuset mutexes below. They can nest.
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* It is ok to first take manage_mutex, then nest callback_mutex. We also
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* require taking task_lock() when dereferencing a tasks 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
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* holds manage_mutex, then it blocks others wanting that mutex,
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* ensuring that it is the only task able to also acquire callback_mutex
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* and be able to modify cpusets. It can perform various checks on
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* the cpuset structure first, knowing nothing will change. It can
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* also allocate memory while just holding manage_mutex. While it is
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* performing these checks, various callback routines can briefly
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* acquire callback_mutex to query cpusets. Once it is ready to make
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* the changes, it takes callback_mutex, blocking 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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* The task_struct fields mems_allowed and mems_generation may only
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* be accessed in the context of that task, so require no locks.
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*
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* Any task can increment and decrement the count field without lock.
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* So in general, code holding manage_mutex or callback_mutex can't rely
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* on the count field not changing. However, if the count goes to
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* zero, then only attach_task(), which holds both mutexes, can
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* increment it again. Because a count of zero means that no tasks
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* are currently attached, therefore there is no way a task attached
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* to that cpuset can fork (the other way to increment the count).
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* So code holding manage_mutex or callback_mutex can safely assume that
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* if the count is zero, it will stay zero. Similarly, if a task
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* holds manage_mutex or callback_mutex on a cpuset with zero count, it
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* knows that the cpuset won't be removed, as cpuset_rmdir() needs
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* both of those mutexes.
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*
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* The cpuset_common_file_write handler for operations that modify
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* the cpuset hierarchy holds manage_mutex across the entire operation,
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* single threading all such cpuset modifications across the system.
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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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* The fork and exit callbacks cpuset_fork() and cpuset_exit(), don't
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* (usually) take either mutex. These are the two most performance
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* critical pieces of code here. The exception occurs on cpuset_exit(),
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* when a task in a notify_on_release cpuset exits. Then manage_mutex
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* is taken, and if the cpuset count is zero, a usermode call made
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* to /sbin/cpuset_release_agent with the name of the cpuset (path
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* relative to the root of cpuset file system) as the argument.
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*
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* A cpuset can only be deleted if both its 'count' of using tasks
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* is zero, and its list of 'children' cpusets is empty. Since all
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* tasks in the system use _some_ cpuset, and since there is always at
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* least one task in the system (init), therefore, top_cpuset
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* always has either children cpusets and/or using tasks. So we don't
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* need a special hack to ensure that top_cpuset cannot be deleted.
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*
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* The above "Tale of Two Semaphores" would be complete, but for:
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*
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* The task_lock() exception
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*
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* The need for this exception arises from the action of attach_task(),
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* which overwrites one tasks cpuset pointer with another. It does
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* so using both mutexes, however there are several performance
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* critical places that need to reference task->cpuset without the
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* expense of grabbing a system global mutex. Therefore except as
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* noted below, when dereferencing or, as in attach_task(), modifying
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* a tasks cpuset pointer we use task_lock(), which acts on a spinlock
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* (task->alloc_lock) already in the task_struct routinely used for
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* such matters.
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*
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* P.S. One more locking exception. RCU is used to guard the
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* update of a tasks cpuset pointer by attach_task() and the
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* access of task->cpuset->mems_generation via that pointer in
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* the routine cpuset_update_task_memory_state().
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*/
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static DEFINE_MUTEX(callback_mutex);
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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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static int cpuset_get_sb(struct file_system_type *fs_type,
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int flags, const char *unused_dev_name,
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void *data, struct vfsmount *mnt)
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{
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struct file_system_type *cgroup_fs = get_fs_type("cgroup");
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int ret = -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->get_sb(cgroup_fs, flags,
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unused_dev_name, mountopts, mnt);
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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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.get_sb = cpuset_get_sb,
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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. If we get
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* all the way to the top and still haven't found any online cpus,
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* return cpu_online_map. Or if passed a NULL cs from an exit'ing
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* task, return cpu_online_map.
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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_map.
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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, cpumask_t *pmask)
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{
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while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map))
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cs = cs->parent;
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if (cs)
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cpus_and(*pmask, cs->cpus_allowed, cpu_online_map);
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else
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*pmask = cpu_online_map;
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BUG_ON(!cpus_intersects(*pmask, cpu_online_map));
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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. If we get all the way to the top and still haven't
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* found any online mems, return node_states[N_HIGH_MEMORY].
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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_HIGH_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 (cs && !nodes_intersects(cs->mems_allowed,
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node_states[N_HIGH_MEMORY]))
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cs = cs->parent;
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if (cs)
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nodes_and(*pmask, cs->mems_allowed,
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node_states[N_HIGH_MEMORY]);
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else
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*pmask = node_states[N_HIGH_MEMORY];
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BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY]));
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}
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/**
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* cpuset_update_task_memory_state - update task memory placement
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*
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* If the current tasks cpusets mems_allowed changed behind our
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* backs, update current->mems_allowed, mems_generation and task NUMA
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* mempolicy to the new value.
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*
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* Task mempolicy is updated by rebinding it relative to the
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* current->cpuset if a task has its memory placement changed.
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* Do not call this routine if in_interrupt().
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*
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* Call without callback_mutex or task_lock() held. May be
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* called with or without manage_mutex held. Thanks in part to
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* 'the_top_cpuset_hack', the tasks cpuset pointer will never
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* be NULL. This routine also might acquire callback_mutex and
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* current->mm->mmap_sem during call.
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*
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* Reading current->cpuset->mems_generation doesn't need task_lock
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* to guard the current->cpuset derefence, because it is guarded
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* from concurrent freeing of current->cpuset by attach_task(),
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* using RCU.
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*
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* The rcu_dereference() is technically probably not needed,
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* as I don't actually mind if I see a new cpuset pointer but
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* an old value of mems_generation. However this really only
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* matters on alpha systems using cpusets heavily. If I dropped
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* that rcu_dereference(), it would save them a memory barrier.
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* For all other arch's, rcu_dereference is a no-op anyway, and for
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* alpha systems not using cpusets, another planned optimization,
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* avoiding the rcu critical section for tasks in the root cpuset
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* which is statically allocated, so can't vanish, will make this
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* irrelevant. Better to use RCU as intended, than to engage in
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* some cute trick to save a memory barrier that is impossible to
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* test, for alpha systems using cpusets heavily, which might not
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* even exist.
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*
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* This routine is needed to update the per-task mems_allowed data,
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* within the tasks context, when it is trying to allocate memory
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* (in various mm/mempolicy.c routines) and notices that some other
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* task has been modifying its cpuset.
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*/
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void cpuset_update_task_memory_state(void)
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{
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int my_cpusets_mem_gen;
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struct task_struct *tsk = current;
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struct cpuset *cs;
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if (task_cs(tsk) == &top_cpuset) {
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/* Don't need rcu for top_cpuset. It's never freed. */
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my_cpusets_mem_gen = top_cpuset.mems_generation;
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} else {
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rcu_read_lock();
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my_cpusets_mem_gen = task_cs(current)->mems_generation;
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rcu_read_unlock();
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}
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if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
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mutex_lock(&callback_mutex);
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task_lock(tsk);
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cs = task_cs(tsk); /* Maybe changed when task not locked */
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guarantee_online_mems(cs, &tsk->mems_allowed);
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tsk->cpuset_mems_generation = cs->mems_generation;
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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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task_unlock(tsk);
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mutex_unlock(&callback_mutex);
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mpol_rebind_task(tsk, &tsk->mems_allowed);
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}
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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 manage_mutex.
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*/
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|
|
static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
|
|
{
|
|
return cpus_subset(p->cpus_allowed, q->cpus_allowed) &&
|
|
nodes_subset(p->mems_allowed, q->mems_allowed) &&
|
|
is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
|
|
is_mem_exclusive(p) <= is_mem_exclusive(q);
|
|
}
|
|
|
|
/*
|
|
* validate_change() - Used to validate that any proposed cpuset change
|
|
* follows the structural rules for cpusets.
|
|
*
|
|
* If we replaced the flag and mask values of the current cpuset
|
|
* (cur) with those values in the trial cpuset (trial), would
|
|
* our various subset and exclusive rules still be valid? Presumes
|
|
* manage_mutex held.
|
|
*
|
|
* 'cur' is the address of an actual, in-use cpuset. Operations
|
|
* such as list traversal that depend on the actual address of the
|
|
* cpuset in the list must use cur below, not trial.
|
|
*
|
|
* 'trial' is the address of bulk structure copy of cur, with
|
|
* perhaps one or more of the fields cpus_allowed, mems_allowed,
|
|
* or flags changed to new, trial values.
|
|
*
|
|
* Return 0 if valid, -errno if not.
|
|
*/
|
|
|
|
static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
|
|
{
|
|
struct cgroup *cont;
|
|
struct cpuset *c, *par;
|
|
|
|
/* Each of our child cpusets must be a subset of us */
|
|
list_for_each_entry(cont, &cur->css.cgroup->children, sibling) {
|
|
if (!is_cpuset_subset(cgroup_cs(cont), trial))
|
|
return -EBUSY;
|
|
}
|
|
|
|
/* Remaining checks don't apply to root cpuset */
|
|
if (cur == &top_cpuset)
|
|
return 0;
|
|
|
|
par = cur->parent;
|
|
|
|
/* We must be a subset of our parent cpuset */
|
|
if (!is_cpuset_subset(trial, par))
|
|
return -EACCES;
|
|
|
|
/* If either I or some sibling (!= me) is exclusive, we can't overlap */
|
|
list_for_each_entry(cont, &par->css.cgroup->children, sibling) {
|
|
c = cgroup_cs(cont);
|
|
if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
|
|
c != cur &&
|
|
cpus_intersects(trial->cpus_allowed, c->cpus_allowed))
|
|
return -EINVAL;
|
|
if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
|
|
c != cur &&
|
|
nodes_intersects(trial->mems_allowed, c->mems_allowed))
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Cpusets with tasks can't have empty cpus_allowed or mems_allowed */
|
|
if (cgroup_task_count(cur->css.cgroup)) {
|
|
if (cpus_empty(trial->cpus_allowed) ||
|
|
nodes_empty(trial->mems_allowed)) {
|
|
return -ENOSPC;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Helper routine for rebuild_sched_domains().
|
|
* Do cpusets a, b have overlapping cpus_allowed masks?
|
|
*/
|
|
|
|
static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
|
|
{
|
|
return cpus_intersects(a->cpus_allowed, b->cpus_allowed);
|
|
}
|
|
|
|
/*
|
|
* rebuild_sched_domains()
|
|
*
|
|
* If the flag 'sched_load_balance' of any cpuset with non-empty
|
|
* 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
|
|
* which has that flag enabled, or if any cpuset with a non-empty
|
|
* 'cpus' is removed, then call this routine to rebuild the
|
|
* scheduler's dynamic sched domains.
|
|
*
|
|
* This routine builds a partial partition of the systems CPUs
|
|
* (the set of non-overlappping cpumask_t's in the array 'part'
|
|
* below), and passes that partial partition to the kernel/sched.c
|
|
* partition_sched_domains() routine, which will rebuild the
|
|
* schedulers load balancing domains (sched domains) as specified
|
|
* by that partial partition. A 'partial partition' is a set of
|
|
* non-overlapping subsets whose union is a subset of that set.
|
|
*
|
|
* See "What is sched_load_balance" in Documentation/cpusets.txt
|
|
* for a background explanation of this.
|
|
*
|
|
* Does not return errors, on the theory that the callers of this
|
|
* routine would rather not worry about failures to rebuild sched
|
|
* domains when operating in the severe memory shortage situations
|
|
* that could cause allocation failures below.
|
|
*
|
|
* Call with cgroup_mutex held. May take callback_mutex during
|
|
* call due to the kfifo_alloc() and kmalloc() calls. May nest
|
|
* a call to the lock_cpu_hotplug()/unlock_cpu_hotplug() pair.
|
|
* Must not be called holding callback_mutex, because we must not
|
|
* call lock_cpu_hotplug() while holding callback_mutex. Elsewhere
|
|
* the kernel nests callback_mutex inside lock_cpu_hotplug() calls.
|
|
* So the reverse nesting would risk an ABBA deadlock.
|
|
*
|
|
* The three key local variables below are:
|
|
* q - a kfifo queue of cpuset pointers, used to implement a
|
|
* top-down scan of all cpusets. This scan loads a pointer
|
|
* to each cpuset marked is_sched_load_balance into the
|
|
* array 'csa'. For our purposes, rebuilding the schedulers
|
|
* sched domains, we can ignore !is_sched_load_balance cpusets.
|
|
* csa - (for CpuSet Array) Array of pointers to all the cpusets
|
|
* that need to be load balanced, for convenient iterative
|
|
* access by the subsequent code that finds the best partition,
|
|
* i.e the set of domains (subsets) of CPUs such that the
|
|
* cpus_allowed of every cpuset marked is_sched_load_balance
|
|
* is a subset of one of these domains, while there are as
|
|
* many such domains as possible, each as small as possible.
|
|
* doms - Conversion of 'csa' to an array of cpumasks, for passing to
|
|
* the kernel/sched.c routine partition_sched_domains() in a
|
|
* convenient format, that can be easily compared to the prior
|
|
* value to determine what partition elements (sched domains)
|
|
* were changed (added or removed.)
|
|
*
|
|
* Finding the best partition (set of domains):
|
|
* The triple nested loops below over i, j, k scan over the
|
|
* load balanced cpusets (using the array of cpuset pointers in
|
|
* csa[]) looking for pairs of cpusets that have overlapping
|
|
* cpus_allowed, but which don't have the same 'pn' partition
|
|
* number and gives them in the same partition number. It keeps
|
|
* looping on the 'restart' label until it can no longer find
|
|
* any such pairs.
|
|
*
|
|
* The union of the cpus_allowed masks from the set of
|
|
* all cpusets having the same 'pn' value then form the one
|
|
* element of the partition (one sched domain) to be passed to
|
|
* partition_sched_domains().
|
|
*/
|
|
|
|
static void rebuild_sched_domains(void)
|
|
{
|
|
struct kfifo *q; /* queue of cpusets to be scanned */
|
|
struct cpuset *cp; /* scans q */
|
|
struct cpuset **csa; /* array of all cpuset ptrs */
|
|
int csn; /* how many cpuset ptrs in csa so far */
|
|
int i, j, k; /* indices for partition finding loops */
|
|
cpumask_t *doms; /* resulting partition; i.e. sched domains */
|
|
int ndoms; /* number of sched domains in result */
|
|
int nslot; /* next empty doms[] cpumask_t slot */
|
|
|
|
q = NULL;
|
|
csa = NULL;
|
|
doms = NULL;
|
|
|
|
/* Special case for the 99% of systems with one, full, sched domain */
|
|
if (is_sched_load_balance(&top_cpuset)) {
|
|
ndoms = 1;
|
|
doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
|
|
if (!doms)
|
|
goto rebuild;
|
|
*doms = top_cpuset.cpus_allowed;
|
|
goto rebuild;
|
|
}
|
|
|
|
q = kfifo_alloc(number_of_cpusets * sizeof(cp), GFP_KERNEL, NULL);
|
|
if (IS_ERR(q))
|
|
goto done;
|
|
csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);
|
|
if (!csa)
|
|
goto done;
|
|
csn = 0;
|
|
|
|
cp = &top_cpuset;
|
|
__kfifo_put(q, (void *)&cp, sizeof(cp));
|
|
while (__kfifo_get(q, (void *)&cp, sizeof(cp))) {
|
|
struct cgroup *cont;
|
|
struct cpuset *child; /* scans child cpusets of cp */
|
|
if (is_sched_load_balance(cp))
|
|
csa[csn++] = cp;
|
|
list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
|
|
child = cgroup_cs(cont);
|
|
__kfifo_put(q, (void *)&child, sizeof(cp));
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < csn; i++)
|
|
csa[i]->pn = i;
|
|
ndoms = csn;
|
|
|
|
restart:
|
|
/* Find the best partition (set of sched domains) */
|
|
for (i = 0; i < csn; i++) {
|
|
struct cpuset *a = csa[i];
|
|
int apn = a->pn;
|
|
|
|
for (j = 0; j < csn; j++) {
|
|
struct cpuset *b = csa[j];
|
|
int bpn = b->pn;
|
|
|
|
if (apn != bpn && cpusets_overlap(a, b)) {
|
|
for (k = 0; k < csn; k++) {
|
|
struct cpuset *c = csa[k];
|
|
|
|
if (c->pn == bpn)
|
|
c->pn = apn;
|
|
}
|
|
ndoms--; /* one less element */
|
|
goto restart;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Convert <csn, csa> to <ndoms, doms> */
|
|
doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
|
|
if (!doms)
|
|
goto rebuild;
|
|
|
|
for (nslot = 0, i = 0; i < csn; i++) {
|
|
struct cpuset *a = csa[i];
|
|
int apn = a->pn;
|
|
|
|
if (apn >= 0) {
|
|
cpumask_t *dp = doms + nslot;
|
|
|
|
if (nslot == ndoms) {
|
|
static int warnings = 10;
|
|
if (warnings) {
|
|
printk(KERN_WARNING
|
|
"rebuild_sched_domains confused:"
|
|
" nslot %d, ndoms %d, csn %d, i %d,"
|
|
" apn %d\n",
|
|
nslot, ndoms, csn, i, apn);
|
|
warnings--;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
cpus_clear(*dp);
|
|
for (j = i; j < csn; j++) {
|
|
struct cpuset *b = csa[j];
|
|
|
|
if (apn == b->pn) {
|
|
cpus_or(*dp, *dp, b->cpus_allowed);
|
|
b->pn = -1;
|
|
}
|
|
}
|
|
nslot++;
|
|
}
|
|
}
|
|
BUG_ON(nslot != ndoms);
|
|
|
|
rebuild:
|
|
/* Have scheduler rebuild sched domains */
|
|
lock_cpu_hotplug();
|
|
partition_sched_domains(ndoms, doms);
|
|
unlock_cpu_hotplug();
|
|
|
|
done:
|
|
if (q && !IS_ERR(q))
|
|
kfifo_free(q);
|
|
kfree(csa);
|
|
/* Don't kfree(doms) -- partition_sched_domains() does that. */
|
|
}
|
|
|
|
static inline int started_after_time(struct task_struct *t1,
|
|
struct timespec *time,
|
|
struct task_struct *t2)
|
|
{
|
|
int start_diff = timespec_compare(&t1->start_time, time);
|
|
if (start_diff > 0) {
|
|
return 1;
|
|
} else if (start_diff < 0) {
|
|
return 0;
|
|
} else {
|
|
/*
|
|
* Arbitrarily, if two processes started at the same
|
|
* time, we'll say that the lower pointer value
|
|
* started first. Note that t2 may have exited by now
|
|
* so this may not be a valid pointer any longer, but
|
|
* that's fine - it still serves to distinguish
|
|
* between two tasks started (effectively)
|
|
* simultaneously.
|
|
*/
|
|
return t1 > t2;
|
|
}
|
|
}
|
|
|
|
static inline int started_after(void *p1, void *p2)
|
|
{
|
|
struct task_struct *t1 = p1;
|
|
struct task_struct *t2 = p2;
|
|
return started_after_time(t1, &t2->start_time, t2);
|
|
}
|
|
|
|
/*
|
|
* Call with manage_mutex held. May take callback_mutex during call.
|
|
*/
|
|
|
|
static int update_cpumask(struct cpuset *cs, char *buf)
|
|
{
|
|
struct cpuset trialcs;
|
|
int retval, i;
|
|
int is_load_balanced;
|
|
struct cgroup_iter it;
|
|
struct cgroup *cgrp = cs->css.cgroup;
|
|
struct task_struct *p, *dropped;
|
|
/* Never dereference latest_task, since it's not refcounted */
|
|
struct task_struct *latest_task = NULL;
|
|
struct ptr_heap heap;
|
|
struct timespec latest_time = { 0, 0 };
|
|
|
|
/* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */
|
|
if (cs == &top_cpuset)
|
|
return -EACCES;
|
|
|
|
trialcs = *cs;
|
|
|
|
/*
|
|
* An empty cpus_allowed is ok iff there are no tasks in the cpuset.
|
|
* Since cpulist_parse() fails on an empty mask, we special case
|
|
* that parsing. The validate_change() call ensures that cpusets
|
|
* with tasks have cpus.
|
|
*/
|
|
buf = strstrip(buf);
|
|
if (!*buf) {
|
|
cpus_clear(trialcs.cpus_allowed);
|
|
} else {
|
|
retval = cpulist_parse(buf, trialcs.cpus_allowed);
|
|
if (retval < 0)
|
|
return retval;
|
|
}
|
|
cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
|
|
retval = validate_change(cs, &trialcs);
|
|
if (retval < 0)
|
|
return retval;
|
|
|
|
/* Nothing to do if the cpus didn't change */
|
|
if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed))
|
|
return 0;
|
|
retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, &started_after);
|
|
if (retval)
|
|
return retval;
|
|
|
|
is_load_balanced = is_sched_load_balance(&trialcs);
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cs->cpus_allowed = trialcs.cpus_allowed;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
again:
|
|
/*
|
|
* Scan tasks in the cpuset, and update the cpumasks of any
|
|
* that need an update. Since we can't call set_cpus_allowed()
|
|
* while holding tasklist_lock, gather tasks to be processed
|
|
* in a heap structure. If the statically-sized heap fills up,
|
|
* overflow tasks that started later, and in future iterations
|
|
* only consider tasks that started after the latest task in
|
|
* the previous pass. This guarantees forward progress and
|
|
* that we don't miss any tasks
|
|
*/
|
|
heap.size = 0;
|
|
cgroup_iter_start(cgrp, &it);
|
|
while ((p = cgroup_iter_next(cgrp, &it))) {
|
|
/* Only affect tasks that don't have the right cpus_allowed */
|
|
if (cpus_equal(p->cpus_allowed, cs->cpus_allowed))
|
|
continue;
|
|
/*
|
|
* Only process tasks that started after the last task
|
|
* we processed
|
|
*/
|
|
if (!started_after_time(p, &latest_time, latest_task))
|
|
continue;
|
|
dropped = heap_insert(&heap, p);
|
|
if (dropped == NULL) {
|
|
get_task_struct(p);
|
|
} else if (dropped != p) {
|
|
get_task_struct(p);
|
|
put_task_struct(dropped);
|
|
}
|
|
}
|
|
cgroup_iter_end(cgrp, &it);
|
|
if (heap.size) {
|
|
for (i = 0; i < heap.size; i++) {
|
|
struct task_struct *p = heap.ptrs[i];
|
|
if (i == 0) {
|
|
latest_time = p->start_time;
|
|
latest_task = p;
|
|
}
|
|
set_cpus_allowed(p, cs->cpus_allowed);
|
|
put_task_struct(p);
|
|
}
|
|
/*
|
|
* If we had to process any tasks at all, scan again
|
|
* in case some of them were in the middle of forking
|
|
* children that didn't notice the new cpumask
|
|
* restriction. Not the most efficient way to do it,
|
|
* but it avoids having to take callback_mutex in the
|
|
* fork path
|
|
*/
|
|
goto again;
|
|
}
|
|
heap_free(&heap);
|
|
if (is_load_balanced)
|
|
rebuild_sched_domains();
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* cpuset_migrate_mm
|
|
*
|
|
* Migrate memory region from one set of nodes to another.
|
|
*
|
|
* Temporarilly set tasks mems_allowed to target nodes of migration,
|
|
* so that the migration code can allocate pages on these nodes.
|
|
*
|
|
* Call holding manage_mutex, so our current->cpuset won't change
|
|
* during this call, as manage_mutex holds off any attach_task()
|
|
* calls. Therefore we don't need to take task_lock around the
|
|
* call to guarantee_online_mems(), as we know no one is changing
|
|
* our tasks cpuset.
|
|
*
|
|
* Hold callback_mutex around the two modifications of our tasks
|
|
* mems_allowed to synchronize with cpuset_mems_allowed().
|
|
*
|
|
* While the mm_struct we are migrating is typically from some
|
|
* other task, the task_struct mems_allowed that we are hacking
|
|
* is for our current task, which must allocate new pages for that
|
|
* migrating memory region.
|
|
*
|
|
* We call cpuset_update_task_memory_state() before hacking
|
|
* our tasks mems_allowed, so that we are assured of being in
|
|
* sync with our tasks cpuset, and in particular, callbacks to
|
|
* cpuset_update_task_memory_state() from nested page allocations
|
|
* won't see any mismatch of our cpuset and task mems_generation
|
|
* values, so won't overwrite our hacked tasks mems_allowed
|
|
* nodemask.
|
|
*/
|
|
|
|
static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
|
|
const nodemask_t *to)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
cpuset_update_task_memory_state();
|
|
|
|
mutex_lock(&callback_mutex);
|
|
tsk->mems_allowed = *to;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
|
|
|
|
mutex_lock(&callback_mutex);
|
|
guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed);
|
|
mutex_unlock(&callback_mutex);
|
|
}
|
|
|
|
/*
|
|
* Handle user request to change the 'mems' memory placement
|
|
* of a cpuset. Needs to validate the request, update the
|
|
* cpusets mems_allowed and mems_generation, and for each
|
|
* task in the cpuset, rebind any vma mempolicies and if
|
|
* the cpuset is marked 'memory_migrate', migrate the tasks
|
|
* pages to the new memory.
|
|
*
|
|
* Call with manage_mutex held. May take callback_mutex during call.
|
|
* Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
|
|
* lock each such tasks mm->mmap_sem, scan its vma's and rebind
|
|
* their mempolicies to the cpusets new mems_allowed.
|
|
*/
|
|
|
|
static void *cpuset_being_rebound;
|
|
|
|
static int update_nodemask(struct cpuset *cs, char *buf)
|
|
{
|
|
struct cpuset trialcs;
|
|
nodemask_t oldmem;
|
|
struct task_struct *p;
|
|
struct mm_struct **mmarray;
|
|
int i, n, ntasks;
|
|
int migrate;
|
|
int fudge;
|
|
int retval;
|
|
struct cgroup_iter it;
|
|
|
|
/*
|
|
* top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];
|
|
* it's read-only
|
|
*/
|
|
if (cs == &top_cpuset)
|
|
return -EACCES;
|
|
|
|
trialcs = *cs;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
buf = strstrip(buf);
|
|
if (!*buf) {
|
|
nodes_clear(trialcs.mems_allowed);
|
|
} else {
|
|
retval = nodelist_parse(buf, trialcs.mems_allowed);
|
|
if (retval < 0)
|
|
goto done;
|
|
}
|
|
nodes_and(trialcs.mems_allowed, trialcs.mems_allowed,
|
|
node_states[N_HIGH_MEMORY]);
|
|
oldmem = cs->mems_allowed;
|
|
if (nodes_equal(oldmem, trialcs.mems_allowed)) {
|
|
retval = 0; /* Too easy - nothing to do */
|
|
goto done;
|
|
}
|
|
retval = validate_change(cs, &trialcs);
|
|
if (retval < 0)
|
|
goto done;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cs->mems_allowed = trialcs.mems_allowed;
|
|
cs->mems_generation = cpuset_mems_generation++;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
cpuset_being_rebound = cs; /* causes mpol_copy() rebind */
|
|
|
|
fudge = 10; /* spare mmarray[] slots */
|
|
fudge += cpus_weight(cs->cpus_allowed); /* imagine one fork-bomb/cpu */
|
|
retval = -ENOMEM;
|
|
|
|
/*
|
|
* Allocate mmarray[] to hold mm reference for each task
|
|
* in cpuset cs. Can't kmalloc GFP_KERNEL while holding
|
|
* tasklist_lock. We could use GFP_ATOMIC, but with a
|
|
* few more lines of code, we can retry until we get a big
|
|
* enough mmarray[] w/o using GFP_ATOMIC.
|
|
*/
|
|
while (1) {
|
|
ntasks = cgroup_task_count(cs->css.cgroup); /* guess */
|
|
ntasks += fudge;
|
|
mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
|
|
if (!mmarray)
|
|
goto done;
|
|
read_lock(&tasklist_lock); /* block fork */
|
|
if (cgroup_task_count(cs->css.cgroup) <= ntasks)
|
|
break; /* got enough */
|
|
read_unlock(&tasklist_lock); /* try again */
|
|
kfree(mmarray);
|
|
}
|
|
|
|
n = 0;
|
|
|
|
/* Load up mmarray[] with mm reference for each task in cpuset. */
|
|
cgroup_iter_start(cs->css.cgroup, &it);
|
|
while ((p = cgroup_iter_next(cs->css.cgroup, &it))) {
|
|
struct mm_struct *mm;
|
|
|
|
if (n >= ntasks) {
|
|
printk(KERN_WARNING
|
|
"Cpuset mempolicy rebind incomplete.\n");
|
|
break;
|
|
}
|
|
mm = get_task_mm(p);
|
|
if (!mm)
|
|
continue;
|
|
mmarray[n++] = mm;
|
|
}
|
|
cgroup_iter_end(cs->css.cgroup, &it);
|
|
read_unlock(&tasklist_lock);
|
|
|
|
/*
|
|
* Now that we've dropped the tasklist spinlock, we can
|
|
* rebind the vma mempolicies of each mm in mmarray[] to their
|
|
* new cpuset, and release that mm. The mpol_rebind_mm()
|
|
* call takes mmap_sem, which we couldn't take while holding
|
|
* tasklist_lock. Forks can happen again now - the mpol_copy()
|
|
* cpuset_being_rebound check will catch such forks, and rebind
|
|
* their vma mempolicies too. Because we still hold the global
|
|
* cpuset manage_mutex, we know that no other rebind effort will
|
|
* be contending for the global variable cpuset_being_rebound.
|
|
* It's ok if we rebind the same mm twice; mpol_rebind_mm()
|
|
* is idempotent. Also migrate pages in each mm to new nodes.
|
|
*/
|
|
migrate = is_memory_migrate(cs);
|
|
for (i = 0; i < n; i++) {
|
|
struct mm_struct *mm = mmarray[i];
|
|
|
|
mpol_rebind_mm(mm, &cs->mems_allowed);
|
|
if (migrate)
|
|
cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed);
|
|
mmput(mm);
|
|
}
|
|
|
|
/* We're done rebinding vma's to this cpusets new mems_allowed. */
|
|
kfree(mmarray);
|
|
cpuset_being_rebound = NULL;
|
|
retval = 0;
|
|
done:
|
|
return retval;
|
|
}
|
|
|
|
int current_cpuset_is_being_rebound(void)
|
|
{
|
|
return task_cs(current) == cpuset_being_rebound;
|
|
}
|
|
|
|
/*
|
|
* Call with manage_mutex held.
|
|
*/
|
|
|
|
static int update_memory_pressure_enabled(struct cpuset *cs, char *buf)
|
|
{
|
|
if (simple_strtoul(buf, NULL, 10) != 0)
|
|
cpuset_memory_pressure_enabled = 1;
|
|
else
|
|
cpuset_memory_pressure_enabled = 0;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* update_flag - read a 0 or a 1 in a file and update associated flag
|
|
* bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE,
|
|
* CS_SCHED_LOAD_BALANCE,
|
|
* CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE,
|
|
* CS_SPREAD_PAGE, CS_SPREAD_SLAB)
|
|
* cs: the cpuset to update
|
|
* buf: the buffer where we read the 0 or 1
|
|
*
|
|
* Call with manage_mutex held.
|
|
*/
|
|
|
|
static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf)
|
|
{
|
|
int turning_on;
|
|
struct cpuset trialcs;
|
|
int err;
|
|
int cpus_nonempty, balance_flag_changed;
|
|
|
|
turning_on = (simple_strtoul(buf, NULL, 10) != 0);
|
|
|
|
trialcs = *cs;
|
|
if (turning_on)
|
|
set_bit(bit, &trialcs.flags);
|
|
else
|
|
clear_bit(bit, &trialcs.flags);
|
|
|
|
err = validate_change(cs, &trialcs);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
cpus_nonempty = !cpus_empty(trialcs.cpus_allowed);
|
|
balance_flag_changed = (is_sched_load_balance(cs) !=
|
|
is_sched_load_balance(&trialcs));
|
|
|
|
mutex_lock(&callback_mutex);
|
|
cs->flags = trialcs.flags;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
if (cpus_nonempty && balance_flag_changed)
|
|
rebuild_sched_domains();
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Frequency meter - How fast is some event occurring?
|
|
*
|
|
* These routines manage a digitally filtered, constant time based,
|
|
* event frequency meter. There are four routines:
|
|
* fmeter_init() - initialize a frequency meter.
|
|
* fmeter_markevent() - called each time the event happens.
|
|
* fmeter_getrate() - returns the recent rate of such events.
|
|
* fmeter_update() - internal routine used to update fmeter.
|
|
*
|
|
* A common data structure is passed to each of these routines,
|
|
* which is used to keep track of the state required to manage the
|
|
* frequency meter and its digital filter.
|
|
*
|
|
* The filter works on the number of events marked per unit time.
|
|
* The filter is single-pole low-pass recursive (IIR). The time unit
|
|
* is 1 second. Arithmetic is done using 32-bit integers scaled to
|
|
* simulate 3 decimal digits of precision (multiplied by 1000).
|
|
*
|
|
* With an FM_COEF of 933, and a time base of 1 second, the filter
|
|
* has a half-life of 10 seconds, meaning that if the events quit
|
|
* happening, then the rate returned from the fmeter_getrate()
|
|
* will be cut in half each 10 seconds, until it converges to zero.
|
|
*
|
|
* It is not worth doing a real infinitely recursive filter. If more
|
|
* than FM_MAXTICKS ticks have elapsed since the last filter event,
|
|
* just compute FM_MAXTICKS ticks worth, by which point the level
|
|
* will be stable.
|
|
*
|
|
* Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
|
|
* arithmetic overflow in the fmeter_update() routine.
|
|
*
|
|
* Given the simple 32 bit integer arithmetic used, this meter works
|
|
* best for reporting rates between one per millisecond (msec) and
|
|
* one per 32 (approx) seconds. At constant rates faster than one
|
|
* per msec it maxes out at values just under 1,000,000. At constant
|
|
* rates between one per msec, and one per second it will stabilize
|
|
* to a value N*1000, where N is the rate of events per second.
|
|
* At constant rates between one per second and one per 32 seconds,
|
|
* it will be choppy, moving up on the seconds that have an event,
|
|
* and then decaying until the next event. At rates slower than
|
|
* about one in 32 seconds, it decays all the way back to zero between
|
|
* each event.
|
|
*/
|
|
|
|
#define FM_COEF 933 /* coefficient for half-life of 10 secs */
|
|
#define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */
|
|
#define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */
|
|
#define FM_SCALE 1000 /* faux fixed point scale */
|
|
|
|
/* Initialize a frequency meter */
|
|
static void fmeter_init(struct fmeter *fmp)
|
|
{
|
|
fmp->cnt = 0;
|
|
fmp->val = 0;
|
|
fmp->time = 0;
|
|
spin_lock_init(&fmp->lock);
|
|
}
|
|
|
|
/* Internal meter update - process cnt events and update value */
|
|
static void fmeter_update(struct fmeter *fmp)
|
|
{
|
|
time_t now = get_seconds();
|
|
time_t ticks = now - fmp->time;
|
|
|
|
if (ticks == 0)
|
|
return;
|
|
|
|
ticks = min(FM_MAXTICKS, ticks);
|
|
while (ticks-- > 0)
|
|
fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
|
|
fmp->time = now;
|
|
|
|
fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
|
|
fmp->cnt = 0;
|
|
}
|
|
|
|
/* Process any previous ticks, then bump cnt by one (times scale). */
|
|
static void fmeter_markevent(struct fmeter *fmp)
|
|
{
|
|
spin_lock(&fmp->lock);
|
|
fmeter_update(fmp);
|
|
fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
|
|
spin_unlock(&fmp->lock);
|
|
}
|
|
|
|
/* Process any previous ticks, then return current value. */
|
|
static int fmeter_getrate(struct fmeter *fmp)
|
|
{
|
|
int val;
|
|
|
|
spin_lock(&fmp->lock);
|
|
fmeter_update(fmp);
|
|
val = fmp->val;
|
|
spin_unlock(&fmp->lock);
|
|
return val;
|
|
}
|
|
|
|
static int cpuset_can_attach(struct cgroup_subsys *ss,
|
|
struct cgroup *cont, struct task_struct *tsk)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cont);
|
|
|
|
if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
|
|
return -ENOSPC;
|
|
|
|
return security_task_setscheduler(tsk, 0, NULL);
|
|
}
|
|
|
|
static void cpuset_attach(struct cgroup_subsys *ss,
|
|
struct cgroup *cont, struct cgroup *oldcont,
|
|
struct task_struct *tsk)
|
|
{
|
|
cpumask_t cpus;
|
|
nodemask_t from, to;
|
|
struct mm_struct *mm;
|
|
struct cpuset *cs = cgroup_cs(cont);
|
|
struct cpuset *oldcs = cgroup_cs(oldcont);
|
|
|
|
mutex_lock(&callback_mutex);
|
|
guarantee_online_cpus(cs, &cpus);
|
|
set_cpus_allowed(tsk, cpus);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
from = oldcs->mems_allowed;
|
|
to = cs->mems_allowed;
|
|
mm = get_task_mm(tsk);
|
|
if (mm) {
|
|
mpol_rebind_mm(mm, &to);
|
|
if (is_memory_migrate(cs))
|
|
cpuset_migrate_mm(mm, &from, &to);
|
|
mmput(mm);
|
|
}
|
|
|
|
}
|
|
|
|
/* 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_SCHED_LOAD_BALANCE,
|
|
FILE_MEMORY_PRESSURE_ENABLED,
|
|
FILE_MEMORY_PRESSURE,
|
|
FILE_SPREAD_PAGE,
|
|
FILE_SPREAD_SLAB,
|
|
} cpuset_filetype_t;
|
|
|
|
static ssize_t cpuset_common_file_write(struct cgroup *cont,
|
|
struct cftype *cft,
|
|
struct file *file,
|
|
const char __user *userbuf,
|
|
size_t nbytes, loff_t *unused_ppos)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cont);
|
|
cpuset_filetype_t type = cft->private;
|
|
char *buffer;
|
|
int retval = 0;
|
|
|
|
/* Crude upper limit on largest legitimate cpulist user might write. */
|
|
if (nbytes > 100U + 6 * max(NR_CPUS, MAX_NUMNODES))
|
|
return -E2BIG;
|
|
|
|
/* +1 for nul-terminator */
|
|
if ((buffer = kmalloc(nbytes + 1, GFP_KERNEL)) == 0)
|
|
return -ENOMEM;
|
|
|
|
if (copy_from_user(buffer, userbuf, nbytes)) {
|
|
retval = -EFAULT;
|
|
goto out1;
|
|
}
|
|
buffer[nbytes] = 0; /* nul-terminate */
|
|
|
|
cgroup_lock();
|
|
|
|
if (cgroup_is_removed(cont)) {
|
|
retval = -ENODEV;
|
|
goto out2;
|
|
}
|
|
|
|
switch (type) {
|
|
case FILE_CPULIST:
|
|
retval = update_cpumask(cs, buffer);
|
|
break;
|
|
case FILE_MEMLIST:
|
|
retval = update_nodemask(cs, buffer);
|
|
break;
|
|
case FILE_CPU_EXCLUSIVE:
|
|
retval = update_flag(CS_CPU_EXCLUSIVE, cs, buffer);
|
|
break;
|
|
case FILE_MEM_EXCLUSIVE:
|
|
retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer);
|
|
break;
|
|
case FILE_SCHED_LOAD_BALANCE:
|
|
retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, buffer);
|
|
break;
|
|
case FILE_MEMORY_MIGRATE:
|
|
retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer);
|
|
break;
|
|
case FILE_MEMORY_PRESSURE_ENABLED:
|
|
retval = update_memory_pressure_enabled(cs, buffer);
|
|
break;
|
|
case FILE_MEMORY_PRESSURE:
|
|
retval = -EACCES;
|
|
break;
|
|
case FILE_SPREAD_PAGE:
|
|
retval = update_flag(CS_SPREAD_PAGE, cs, buffer);
|
|
cs->mems_generation = cpuset_mems_generation++;
|
|
break;
|
|
case FILE_SPREAD_SLAB:
|
|
retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
|
|
cs->mems_generation = cpuset_mems_generation++;
|
|
break;
|
|
default:
|
|
retval = -EINVAL;
|
|
goto out2;
|
|
}
|
|
|
|
if (retval == 0)
|
|
retval = nbytes;
|
|
out2:
|
|
cgroup_unlock();
|
|
out1:
|
|
kfree(buffer);
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* These ascii lists should be read in a single call, by using a user
|
|
* buffer large enough to hold the entire map. If read in smaller
|
|
* chunks, there is no guarantee of atomicity. Since the display format
|
|
* used, list of ranges of sequential numbers, is variable length,
|
|
* and since these maps can change value dynamically, one could read
|
|
* gibberish by doing partial reads while a list was changing.
|
|
* A single large read to a buffer that crosses a page boundary is
|
|
* ok, because the result being copied to user land is not recomputed
|
|
* across a page fault.
|
|
*/
|
|
|
|
static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
|
|
{
|
|
cpumask_t mask;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
mask = cs->cpus_allowed;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
return cpulist_scnprintf(page, PAGE_SIZE, mask);
|
|
}
|
|
|
|
static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
|
|
{
|
|
nodemask_t mask;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
mask = cs->mems_allowed;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
return nodelist_scnprintf(page, PAGE_SIZE, mask);
|
|
}
|
|
|
|
static ssize_t cpuset_common_file_read(struct cgroup *cont,
|
|
struct cftype *cft,
|
|
struct file *file,
|
|
char __user *buf,
|
|
size_t nbytes, loff_t *ppos)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cont);
|
|
cpuset_filetype_t type = cft->private;
|
|
char *page;
|
|
ssize_t retval = 0;
|
|
char *s;
|
|
|
|
if (!(page = (char *)__get_free_page(GFP_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;
|
|
case FILE_CPU_EXCLUSIVE:
|
|
*s++ = is_cpu_exclusive(cs) ? '1' : '0';
|
|
break;
|
|
case FILE_MEM_EXCLUSIVE:
|
|
*s++ = is_mem_exclusive(cs) ? '1' : '0';
|
|
break;
|
|
case FILE_SCHED_LOAD_BALANCE:
|
|
*s++ = is_sched_load_balance(cs) ? '1' : '0';
|
|
break;
|
|
case FILE_MEMORY_MIGRATE:
|
|
*s++ = is_memory_migrate(cs) ? '1' : '0';
|
|
break;
|
|
case FILE_MEMORY_PRESSURE_ENABLED:
|
|
*s++ = cpuset_memory_pressure_enabled ? '1' : '0';
|
|
break;
|
|
case FILE_MEMORY_PRESSURE:
|
|
s += sprintf(s, "%d", fmeter_getrate(&cs->fmeter));
|
|
break;
|
|
case FILE_SPREAD_PAGE:
|
|
*s++ = is_spread_page(cs) ? '1' : '0';
|
|
break;
|
|
case FILE_SPREAD_SLAB:
|
|
*s++ = is_spread_slab(cs) ? '1' : '0';
|
|
break;
|
|
default:
|
|
retval = -EINVAL;
|
|
goto out;
|
|
}
|
|
*s++ = '\n';
|
|
|
|
retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
|
|
out:
|
|
free_page((unsigned long)page);
|
|
return retval;
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
* for the common functions, 'private' gives the type of file
|
|
*/
|
|
|
|
static struct cftype cft_cpus = {
|
|
.name = "cpus",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_CPULIST,
|
|
};
|
|
|
|
static struct cftype cft_mems = {
|
|
.name = "mems",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_MEMLIST,
|
|
};
|
|
|
|
static struct cftype cft_cpu_exclusive = {
|
|
.name = "cpu_exclusive",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_CPU_EXCLUSIVE,
|
|
};
|
|
|
|
static struct cftype cft_mem_exclusive = {
|
|
.name = "mem_exclusive",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_MEM_EXCLUSIVE,
|
|
};
|
|
|
|
static struct cftype cft_sched_load_balance = {
|
|
.name = "sched_load_balance",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_SCHED_LOAD_BALANCE,
|
|
};
|
|
|
|
static struct cftype cft_memory_migrate = {
|
|
.name = "memory_migrate",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_MEMORY_MIGRATE,
|
|
};
|
|
|
|
static struct cftype cft_memory_pressure_enabled = {
|
|
.name = "memory_pressure_enabled",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_MEMORY_PRESSURE_ENABLED,
|
|
};
|
|
|
|
static struct cftype cft_memory_pressure = {
|
|
.name = "memory_pressure",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_MEMORY_PRESSURE,
|
|
};
|
|
|
|
static struct cftype cft_spread_page = {
|
|
.name = "memory_spread_page",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_SPREAD_PAGE,
|
|
};
|
|
|
|
static struct cftype cft_spread_slab = {
|
|
.name = "memory_spread_slab",
|
|
.read = cpuset_common_file_read,
|
|
.write = cpuset_common_file_write,
|
|
.private = FILE_SPREAD_SLAB,
|
|
};
|
|
|
|
static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
|
|
{
|
|
int err;
|
|
|
|
if ((err = cgroup_add_file(cont, ss, &cft_cpus)) < 0)
|
|
return err;
|
|
if ((err = cgroup_add_file(cont, ss, &cft_mems)) < 0)
|
|
return err;
|
|
if ((err = cgroup_add_file(cont, ss, &cft_cpu_exclusive)) < 0)
|
|
return err;
|
|
if ((err = cgroup_add_file(cont, ss, &cft_mem_exclusive)) < 0)
|
|
return err;
|
|
if ((err = cgroup_add_file(cont, ss, &cft_memory_migrate)) < 0)
|
|
return err;
|
|
if ((err = cgroup_add_file(cont, ss, &cft_sched_load_balance)) < 0)
|
|
return err;
|
|
if ((err = cgroup_add_file(cont, ss, &cft_memory_pressure)) < 0)
|
|
return err;
|
|
if ((err = cgroup_add_file(cont, ss, &cft_spread_page)) < 0)
|
|
return err;
|
|
if ((err = cgroup_add_file(cont, ss, &cft_spread_slab)) < 0)
|
|
return err;
|
|
/* memory_pressure_enabled is in root cpuset only */
|
|
if (err == 0 && !cont->parent)
|
|
err = cgroup_add_file(cont, ss,
|
|
&cft_memory_pressure_enabled);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* post_clone() is called at the end of cgroup_clone().
|
|
* 'cgroup' was just created automatically as a result of
|
|
* a cgroup_clone(), and the current task is about to
|
|
* be moved into 'cgroup'.
|
|
*
|
|
* Currently we refuse to set up the cgroup - thereby
|
|
* refusing the task to be entered, and as a result refusing
|
|
* the sys_unshare() or clone() which initiated it - if any
|
|
* sibling cpusets have exclusive cpus or mem.
|
|
*
|
|
* If this becomes a problem for some users who wish to
|
|
* allow that scenario, then cpuset_post_clone() could be
|
|
* changed to grant parent->cpus_allowed-sibling_cpus_exclusive
|
|
* (and likewise for mems) to the new cgroup.
|
|
*/
|
|
static void cpuset_post_clone(struct cgroup_subsys *ss,
|
|
struct cgroup *cgroup)
|
|
{
|
|
struct cgroup *parent, *child;
|
|
struct cpuset *cs, *parent_cs;
|
|
|
|
parent = cgroup->parent;
|
|
list_for_each_entry(child, &parent->children, sibling) {
|
|
cs = cgroup_cs(child);
|
|
if (is_mem_exclusive(cs) || is_cpu_exclusive(cs))
|
|
return;
|
|
}
|
|
cs = cgroup_cs(cgroup);
|
|
parent_cs = cgroup_cs(parent);
|
|
|
|
cs->mems_allowed = parent_cs->mems_allowed;
|
|
cs->cpus_allowed = parent_cs->cpus_allowed;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* cpuset_create - create a cpuset
|
|
* parent: cpuset that will be parent of the new cpuset.
|
|
* name: name of the new cpuset. Will be strcpy'ed.
|
|
* mode: mode to set on new inode
|
|
*
|
|
* Must be called with the mutex on the parent inode held
|
|
*/
|
|
|
|
static struct cgroup_subsys_state *cpuset_create(
|
|
struct cgroup_subsys *ss,
|
|
struct cgroup *cont)
|
|
{
|
|
struct cpuset *cs;
|
|
struct cpuset *parent;
|
|
|
|
if (!cont->parent) {
|
|
/* This is early initialization for the top cgroup */
|
|
top_cpuset.mems_generation = cpuset_mems_generation++;
|
|
return &top_cpuset.css;
|
|
}
|
|
parent = cgroup_cs(cont->parent);
|
|
cs = kmalloc(sizeof(*cs), GFP_KERNEL);
|
|
if (!cs)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
cpuset_update_task_memory_state();
|
|
cs->flags = 0;
|
|
if (is_spread_page(parent))
|
|
set_bit(CS_SPREAD_PAGE, &cs->flags);
|
|
if (is_spread_slab(parent))
|
|
set_bit(CS_SPREAD_SLAB, &cs->flags);
|
|
set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
|
|
cs->cpus_allowed = CPU_MASK_NONE;
|
|
cs->mems_allowed = NODE_MASK_NONE;
|
|
cs->mems_generation = cpuset_mems_generation++;
|
|
fmeter_init(&cs->fmeter);
|
|
|
|
cs->parent = parent;
|
|
number_of_cpusets++;
|
|
return &cs->css ;
|
|
}
|
|
|
|
/*
|
|
* Locking note on the strange update_flag() call below:
|
|
*
|
|
* If the cpuset being removed has its flag 'sched_load_balance'
|
|
* enabled, then simulate turning sched_load_balance off, which
|
|
* will call rebuild_sched_domains(). The lock_cpu_hotplug()
|
|
* call in rebuild_sched_domains() must not be made while holding
|
|
* callback_mutex. Elsewhere the kernel nests callback_mutex inside
|
|
* lock_cpu_hotplug() calls. So the reverse nesting would risk an
|
|
* ABBA deadlock.
|
|
*/
|
|
|
|
static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
|
|
{
|
|
struct cpuset *cs = cgroup_cs(cont);
|
|
|
|
cpuset_update_task_memory_state();
|
|
|
|
if (is_sched_load_balance(cs))
|
|
update_flag(CS_SCHED_LOAD_BALANCE, cs, "0");
|
|
|
|
number_of_cpusets--;
|
|
kfree(cs);
|
|
}
|
|
|
|
struct cgroup_subsys cpuset_subsys = {
|
|
.name = "cpuset",
|
|
.create = cpuset_create,
|
|
.destroy = cpuset_destroy,
|
|
.can_attach = cpuset_can_attach,
|
|
.attach = cpuset_attach,
|
|
.populate = cpuset_populate,
|
|
.post_clone = cpuset_post_clone,
|
|
.subsys_id = cpuset_subsys_id,
|
|
.early_init = 1,
|
|
};
|
|
|
|
/*
|
|
* cpuset_init_early - just enough so that the calls to
|
|
* cpuset_update_task_memory_state() in early init code
|
|
* are harmless.
|
|
*/
|
|
|
|
int __init cpuset_init_early(void)
|
|
{
|
|
top_cpuset.mems_generation = cpuset_mems_generation++;
|
|
return 0;
|
|
}
|
|
|
|
|
|
/**
|
|
* cpuset_init - initialize cpusets at system boot
|
|
*
|
|
* Description: Initialize top_cpuset and the cpuset internal file system,
|
|
**/
|
|
|
|
int __init cpuset_init(void)
|
|
{
|
|
int err = 0;
|
|
|
|
top_cpuset.cpus_allowed = CPU_MASK_ALL;
|
|
top_cpuset.mems_allowed = NODE_MASK_ALL;
|
|
|
|
fmeter_init(&top_cpuset.fmeter);
|
|
top_cpuset.mems_generation = cpuset_mems_generation++;
|
|
set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
|
|
|
|
err = register_filesystem(&cpuset_fs_type);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
number_of_cpusets = 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
|
|
* or memory nodes, we need to walk over the cpuset hierarchy,
|
|
* removing that CPU or node from all cpusets. If this removes the
|
|
* last CPU or node from a cpuset, then the guarantee_online_cpus()
|
|
* or guarantee_online_mems() code will use that emptied cpusets
|
|
* parent online CPUs or nodes. Cpusets that were already empty of
|
|
* CPUs or nodes are left empty.
|
|
*
|
|
* This routine is intentionally inefficient in a couple of regards.
|
|
* It will check all cpusets in a subtree even if the top cpuset of
|
|
* the subtree has no offline CPUs or nodes. It checks both CPUs and
|
|
* nodes, even though the caller could have been coded to know that
|
|
* only one of CPUs or nodes needed to be checked on a given call.
|
|
* This was done to minimize text size rather than cpu cycles.
|
|
*
|
|
* Call with both manage_mutex and callback_mutex held.
|
|
*
|
|
* Recursive, on depth of cpuset subtree.
|
|
*/
|
|
|
|
static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur)
|
|
{
|
|
struct cgroup *cont;
|
|
struct cpuset *c;
|
|
|
|
/* Each of our child cpusets mems must be online */
|
|
list_for_each_entry(cont, &cur->css.cgroup->children, sibling) {
|
|
c = cgroup_cs(cont);
|
|
guarantee_online_cpus_mems_in_subtree(c);
|
|
if (!cpus_empty(c->cpus_allowed))
|
|
guarantee_online_cpus(c, &c->cpus_allowed);
|
|
if (!nodes_empty(c->mems_allowed))
|
|
guarantee_online_mems(c, &c->mems_allowed);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
|
|
* cpu_online_map and node_states[N_HIGH_MEMORY]. Force the top cpuset to
|
|
* track what's online after any CPU or memory node hotplug or unplug
|
|
* event.
|
|
*
|
|
* To ensure that we don't remove a CPU or node from the top cpuset
|
|
* that is currently in use by a child cpuset (which would violate
|
|
* the rule that cpusets must be subsets of their parent), we first
|
|
* call the recursive routine guarantee_online_cpus_mems_in_subtree().
|
|
*
|
|
* Since there are two callers of this routine, one for CPU hotplug
|
|
* events and one for memory node hotplug events, we could have coded
|
|
* two separate routines here. We code it as a single common routine
|
|
* in order to minimize text size.
|
|
*/
|
|
|
|
static void common_cpu_mem_hotplug_unplug(void)
|
|
{
|
|
cgroup_lock();
|
|
mutex_lock(&callback_mutex);
|
|
|
|
guarantee_online_cpus_mems_in_subtree(&top_cpuset);
|
|
top_cpuset.cpus_allowed = cpu_online_map;
|
|
top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
|
|
|
|
mutex_unlock(&callback_mutex);
|
|
cgroup_unlock();
|
|
}
|
|
|
|
/*
|
|
* The top_cpuset tracks what CPUs and Memory Nodes are online,
|
|
* period. This is necessary in order to make cpusets transparent
|
|
* (of no affect) on systems that are actively using CPU hotplug
|
|
* but making no active use of cpusets.
|
|
*
|
|
* This routine ensures that top_cpuset.cpus_allowed tracks
|
|
* cpu_online_map on each CPU hotplug (cpuhp) event.
|
|
*/
|
|
|
|
static int cpuset_handle_cpuhp(struct notifier_block *unused_nb,
|
|
unsigned long phase, void *unused_cpu)
|
|
{
|
|
if (phase == CPU_DYING || phase == CPU_DYING_FROZEN)
|
|
return NOTIFY_DONE;
|
|
|
|
common_cpu_mem_hotplug_unplug();
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_MEMORY_HOTPLUG
|
|
/*
|
|
* Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY].
|
|
* Call this routine anytime after you change
|
|
* node_states[N_HIGH_MEMORY].
|
|
* See also the previous routine cpuset_handle_cpuhp().
|
|
*/
|
|
|
|
void cpuset_track_online_nodes(void)
|
|
{
|
|
common_cpu_mem_hotplug_unplug();
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* cpuset_init_smp - initialize cpus_allowed
|
|
*
|
|
* Description: Finish top cpuset after cpu, node maps are initialized
|
|
**/
|
|
|
|
void __init cpuset_init_smp(void)
|
|
{
|
|
top_cpuset.cpus_allowed = cpu_online_map;
|
|
top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
|
|
|
|
hotcpu_notifier(cpuset_handle_cpuhp, 0);
|
|
}
|
|
|
|
/**
|
|
|
|
* cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
|
|
* @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
|
|
*
|
|
* Description: Returns the cpumask_t cpus_allowed of the cpuset
|
|
* attached to the specified @tsk. Guaranteed to return some non-empty
|
|
* subset of cpu_online_map, even if this means going outside the
|
|
* tasks cpuset.
|
|
**/
|
|
|
|
cpumask_t cpuset_cpus_allowed(struct task_struct *tsk)
|
|
{
|
|
cpumask_t mask;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
mask = cpuset_cpus_allowed_locked(tsk);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
return mask;
|
|
}
|
|
|
|
/**
|
|
* cpuset_cpus_allowed_locked - return cpus_allowed mask from a tasks cpuset.
|
|
* Must be called with callback_mutex held.
|
|
**/
|
|
cpumask_t cpuset_cpus_allowed_locked(struct task_struct *tsk)
|
|
{
|
|
cpumask_t mask;
|
|
|
|
task_lock(tsk);
|
|
guarantee_online_cpus(task_cs(tsk), &mask);
|
|
task_unlock(tsk);
|
|
|
|
return mask;
|
|
}
|
|
|
|
void cpuset_init_current_mems_allowed(void)
|
|
{
|
|
current->mems_allowed = NODE_MASK_ALL;
|
|
}
|
|
|
|
/**
|
|
* cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
|
|
* @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
|
|
*
|
|
* Description: Returns the nodemask_t mems_allowed of the cpuset
|
|
* attached to the specified @tsk. Guaranteed to return some non-empty
|
|
* subset of node_states[N_HIGH_MEMORY], even if this means going outside the
|
|
* tasks cpuset.
|
|
**/
|
|
|
|
nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
|
|
{
|
|
nodemask_t mask;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
task_lock(tsk);
|
|
guarantee_online_mems(task_cs(tsk), &mask);
|
|
task_unlock(tsk);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
return mask;
|
|
}
|
|
|
|
/**
|
|
* cpuset_zonelist_valid_mems_allowed - check zonelist vs. curremt mems_allowed
|
|
* @zl: the zonelist to be checked
|
|
*
|
|
* Are any of the nodes on zonelist zl allowed in current->mems_allowed?
|
|
*/
|
|
int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; zl->zones[i]; i++) {
|
|
int nid = zone_to_nid(zl->zones[i]);
|
|
|
|
if (node_isset(nid, current->mems_allowed))
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* nearest_exclusive_ancestor() - Returns the nearest mem_exclusive
|
|
* ancestor to the specified cpuset. Call holding callback_mutex.
|
|
* If no ancestor is mem_exclusive (an unusual configuration), then
|
|
* returns the root cpuset.
|
|
*/
|
|
static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs)
|
|
{
|
|
while (!is_mem_exclusive(cs) && cs->parent)
|
|
cs = cs->parent;
|
|
return cs;
|
|
}
|
|
|
|
/**
|
|
* cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node?
|
|
* @z: is this zone on an allowed node?
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* If we're in interrupt, yes, we can always allocate. If
|
|
* __GFP_THISNODE is set, yes, we can always allocate. If zone
|
|
* z's node is in our tasks mems_allowed, yes. If it's not a
|
|
* __GFP_HARDWALL request and this zone's nodes is in the nearest
|
|
* mem_exclusive cpuset ancestor to this tasks cpuset, yes.
|
|
* If the task has been OOM killed and has access to memory reserves
|
|
* as specified by the TIF_MEMDIE flag, yes.
|
|
* Otherwise, no.
|
|
*
|
|
* If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall()
|
|
* reduces to cpuset_zone_allowed_hardwall(). Otherwise,
|
|
* cpuset_zone_allowed_softwall() might sleep, and might allow a zone
|
|
* from an enclosing cpuset.
|
|
*
|
|
* cpuset_zone_allowed_hardwall() only handles the simpler case of
|
|
* hardwall cpusets, and never sleeps.
|
|
*
|
|
* The __GFP_THISNODE placement logic is really handled elsewhere,
|
|
* by forcibly using a zonelist starting at a specified node, and by
|
|
* (in get_page_from_freelist()) refusing to consider the zones for
|
|
* any node on the zonelist except the first. By the time any such
|
|
* calls get to this routine, we should just shut up and say 'yes'.
|
|
*
|
|
* GFP_USER allocations are marked with the __GFP_HARDWALL bit,
|
|
* and do not allow allocations outside the current tasks cpuset
|
|
* unless the task has been OOM killed as is marked TIF_MEMDIE.
|
|
* GFP_KERNEL allocations are not so marked, so can escape to the
|
|
* nearest enclosing mem_exclusive ancestor cpuset.
|
|
*
|
|
* Scanning up parent cpusets requires callback_mutex. The
|
|
* __alloc_pages() routine only calls here with __GFP_HARDWALL bit
|
|
* _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
|
|
* current tasks mems_allowed came up empty on the first pass over
|
|
* the zonelist. So only GFP_KERNEL allocations, if all nodes in the
|
|
* cpuset are short of memory, might require taking the callback_mutex
|
|
* mutex.
|
|
*
|
|
* The first call here from mm/page_alloc:get_page_from_freelist()
|
|
* has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
|
|
* so no allocation on a node outside the cpuset is allowed (unless
|
|
* in interrupt, of course).
|
|
*
|
|
* The second pass through get_page_from_freelist() doesn't even call
|
|
* here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
|
|
* variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
|
|
* in alloc_flags. That logic and the checks below have the combined
|
|
* affect that:
|
|
* in_interrupt - any node ok (current task context irrelevant)
|
|
* GFP_ATOMIC - any node ok
|
|
* TIF_MEMDIE - any node ok
|
|
* GFP_KERNEL - any node in enclosing mem_exclusive cpuset ok
|
|
* GFP_USER - only nodes in current tasks mems allowed ok.
|
|
*
|
|
* Rule:
|
|
* Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you
|
|
* pass in the __GFP_HARDWALL flag set in gfp_flag, which disables
|
|
* the code that might scan up ancestor cpusets and sleep.
|
|
*/
|
|
|
|
int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
|
|
{
|
|
int node; /* node that zone z is on */
|
|
const struct cpuset *cs; /* current cpuset ancestors */
|
|
int allowed; /* is allocation in zone z allowed? */
|
|
|
|
if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
|
|
return 1;
|
|
node = zone_to_nid(z);
|
|
might_sleep_if(!(gfp_mask & __GFP_HARDWALL));
|
|
if (node_isset(node, current->mems_allowed))
|
|
return 1;
|
|
/*
|
|
* Allow tasks that have access to memory reserves because they have
|
|
* been OOM killed to get memory anywhere.
|
|
*/
|
|
if (unlikely(test_thread_flag(TIF_MEMDIE)))
|
|
return 1;
|
|
if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */
|
|
return 0;
|
|
|
|
if (current->flags & PF_EXITING) /* Let dying task have memory */
|
|
return 1;
|
|
|
|
/* Not hardwall and node outside mems_allowed: scan up cpusets */
|
|
mutex_lock(&callback_mutex);
|
|
|
|
task_lock(current);
|
|
cs = nearest_exclusive_ancestor(task_cs(current));
|
|
task_unlock(current);
|
|
|
|
allowed = node_isset(node, cs->mems_allowed);
|
|
mutex_unlock(&callback_mutex);
|
|
return allowed;
|
|
}
|
|
|
|
/*
|
|
* cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node?
|
|
* @z: is this zone on an allowed node?
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* If we're in interrupt, yes, we can always allocate.
|
|
* If __GFP_THISNODE is set, yes, we can always allocate. If zone
|
|
* z's node is in our tasks mems_allowed, yes. If the task has been
|
|
* OOM killed and has access to memory reserves as specified by the
|
|
* TIF_MEMDIE flag, yes. Otherwise, no.
|
|
*
|
|
* The __GFP_THISNODE placement logic is really handled elsewhere,
|
|
* by forcibly using a zonelist starting at a specified node, and by
|
|
* (in get_page_from_freelist()) refusing to consider the zones for
|
|
* any node on the zonelist except the first. By the time any such
|
|
* calls get to this routine, we should just shut up and say 'yes'.
|
|
*
|
|
* Unlike the cpuset_zone_allowed_softwall() variant, above,
|
|
* this variant requires that the zone be in the current tasks
|
|
* mems_allowed or that we're in interrupt. It does not scan up the
|
|
* cpuset hierarchy for the nearest enclosing mem_exclusive cpuset.
|
|
* It never sleeps.
|
|
*/
|
|
|
|
int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
|
|
{
|
|
int node; /* node that zone z is on */
|
|
|
|
if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
|
|
return 1;
|
|
node = zone_to_nid(z);
|
|
if (node_isset(node, current->mems_allowed))
|
|
return 1;
|
|
/*
|
|
* Allow tasks that have access to memory reserves because they have
|
|
* been OOM killed to get memory anywhere.
|
|
*/
|
|
if (unlikely(test_thread_flag(TIF_MEMDIE)))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cpuset_lock - lock out any changes to cpuset structures
|
|
*
|
|
* The out of memory (oom) code needs to mutex_lock cpusets
|
|
* from being changed while it scans the tasklist looking for a
|
|
* task in an overlapping cpuset. Expose callback_mutex via this
|
|
* cpuset_lock() routine, so the oom code can lock it, before
|
|
* locking the task list. The tasklist_lock is a spinlock, so
|
|
* must be taken inside callback_mutex.
|
|
*/
|
|
|
|
void cpuset_lock(void)
|
|
{
|
|
mutex_lock(&callback_mutex);
|
|
}
|
|
|
|
/**
|
|
* cpuset_unlock - release lock on cpuset changes
|
|
*
|
|
* Undo the lock taken in a previous cpuset_lock() call.
|
|
*/
|
|
|
|
void cpuset_unlock(void)
|
|
{
|
|
mutex_unlock(&callback_mutex);
|
|
}
|
|
|
|
/**
|
|
* cpuset_mem_spread_node() - On which node to begin search for a page
|
|
*
|
|
* If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
|
|
* tasks in a cpuset with is_spread_page or is_spread_slab set),
|
|
* and if the memory allocation used cpuset_mem_spread_node()
|
|
* to determine on which node to start looking, as it will for
|
|
* certain page cache or slab cache pages such as used for file
|
|
* system buffers and inode caches, then instead of starting on the
|
|
* local node to look for a free page, rather spread the starting
|
|
* node around the tasks mems_allowed nodes.
|
|
*
|
|
* We don't have to worry about the returned node being offline
|
|
* because "it can't happen", and even if it did, it would be ok.
|
|
*
|
|
* The routines calling guarantee_online_mems() are careful to
|
|
* only set nodes in task->mems_allowed that are online. So it
|
|
* should not be possible for the following code to return an
|
|
* offline node. But if it did, that would be ok, as this routine
|
|
* is not returning the node where the allocation must be, only
|
|
* the node where the search should start. The zonelist passed to
|
|
* __alloc_pages() will include all nodes. If the slab allocator
|
|
* is passed an offline node, it will fall back to the local node.
|
|
* See kmem_cache_alloc_node().
|
|
*/
|
|
|
|
int cpuset_mem_spread_node(void)
|
|
{
|
|
int node;
|
|
|
|
node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed);
|
|
if (node == MAX_NUMNODES)
|
|
node = first_node(current->mems_allowed);
|
|
current->cpuset_mem_spread_rotor = node;
|
|
return node;
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
|
|
|
|
/**
|
|
* cpuset_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);
|
|
}
|
|
|
|
/*
|
|
* 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 manage_mutex, keeping attach_task() from changing it
|
|
* anyway. No need to check that tsk->cpuset != NULL, thanks to
|
|
* the_top_cpuset_hack in cpuset_exit(), which sets an exiting tasks
|
|
* cpuset to top_cpuset.
|
|
*/
|
|
static int proc_cpuset_show(struct seq_file *m, void *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;
|
|
|
|
retval = -EINVAL;
|
|
cgroup_lock();
|
|
css = task_subsys_state(tsk, cpuset_subsys_id);
|
|
retval = cgroup_path(css->cgroup, buf, PAGE_SIZE);
|
|
if (retval < 0)
|
|
goto out_unlock;
|
|
seq_puts(m, buf);
|
|
seq_putc(m, '\n');
|
|
out_unlock:
|
|
cgroup_unlock();
|
|
put_task_struct(tsk);
|
|
out_free:
|
|
kfree(buf);
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
static int cpuset_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct pid *pid = PROC_I(inode)->pid;
|
|
return single_open(file, proc_cpuset_show, pid);
|
|
}
|
|
|
|
const struct file_operations proc_cpuset_operations = {
|
|
.open = cpuset_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = single_release,
|
|
};
|
|
#endif /* CONFIG_PROC_PID_CPUSET */
|
|
|
|
/* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */
|
|
char *cpuset_task_status_allowed(struct task_struct *task, char *buffer)
|
|
{
|
|
buffer += sprintf(buffer, "Cpus_allowed:\t");
|
|
buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed);
|
|
buffer += sprintf(buffer, "\n");
|
|
buffer += sprintf(buffer, "Mems_allowed:\t");
|
|
buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed);
|
|
buffer += sprintf(buffer, "\n");
|
|
return buffer;
|
|
}
|