![Josef Sipek](/assets/img/avatar_default.png)
Signed-off-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2627 lines
76 KiB
C
2627 lines
76 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) 2004-2006 Silicon Graphics, 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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*
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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/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/smp_lock.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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#define CPUSET_SUPER_MAGIC 0x27e0eb
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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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/* 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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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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/*
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* Count is atomic so can incr (fork) or decr (exit) without a lock.
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*/
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atomic_t count; /* count tasks using this cpuset */
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/*
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* We link our 'sibling' struct into our parents 'children'.
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* Our children link their 'sibling' into our 'children'.
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*/
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struct list_head sibling; /* my parents children */
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struct list_head children; /* my children */
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struct cpuset *parent; /* my parent */
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struct dentry *dentry; /* cpuset fs entry */
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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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};
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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_REMOVED,
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CS_NOTIFY_ON_RELEASE,
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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_removed(const struct cpuset *cs)
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{
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return test_bit(CS_REMOVED, &cs->flags);
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}
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static inline int notify_on_release(const struct cpuset *cs)
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{
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return test_bit(CS_NOTIFY_ON_RELEASE, &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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.count = ATOMIC_INIT(0),
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.sibling = LIST_HEAD_INIT(top_cpuset.sibling),
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.children = LIST_HEAD_INIT(top_cpuset.children),
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};
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static struct vfsmount *cpuset_mount;
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static struct super_block *cpuset_sb;
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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(manage_mutex);
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static DEFINE_MUTEX(callback_mutex);
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/*
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* A couple of forward declarations required, due to cyclic reference loop:
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* cpuset_mkdir -> cpuset_create -> cpuset_populate_dir -> cpuset_add_file
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* -> cpuset_create_file -> cpuset_dir_inode_operations -> cpuset_mkdir.
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*/
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static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode);
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static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry);
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static struct backing_dev_info cpuset_backing_dev_info = {
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.ra_pages = 0, /* No readahead */
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.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
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};
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static struct inode *cpuset_new_inode(mode_t mode)
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{
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struct inode *inode = new_inode(cpuset_sb);
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if (inode) {
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inode->i_mode = mode;
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inode->i_uid = current->fsuid;
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inode->i_gid = current->fsgid;
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inode->i_blocks = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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inode->i_mapping->backing_dev_info = &cpuset_backing_dev_info;
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}
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return inode;
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}
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static void cpuset_diput(struct dentry *dentry, struct inode *inode)
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{
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/* is dentry a directory ? if so, kfree() associated cpuset */
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if (S_ISDIR(inode->i_mode)) {
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struct cpuset *cs = dentry->d_fsdata;
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BUG_ON(!(is_removed(cs)));
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kfree(cs);
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}
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iput(inode);
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}
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static struct dentry_operations cpuset_dops = {
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.d_iput = cpuset_diput,
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};
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static struct dentry *cpuset_get_dentry(struct dentry *parent, const char *name)
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{
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struct dentry *d = lookup_one_len(name, parent, strlen(name));
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if (!IS_ERR(d))
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d->d_op = &cpuset_dops;
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return d;
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}
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static void remove_dir(struct dentry *d)
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{
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struct dentry *parent = dget(d->d_parent);
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d_delete(d);
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simple_rmdir(parent->d_inode, d);
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dput(parent);
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}
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/*
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* NOTE : the dentry must have been dget()'ed
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*/
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static void cpuset_d_remove_dir(struct dentry *dentry)
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{
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struct list_head *node;
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spin_lock(&dcache_lock);
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node = dentry->d_subdirs.next;
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while (node != &dentry->d_subdirs) {
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struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
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list_del_init(node);
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if (d->d_inode) {
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d = dget_locked(d);
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spin_unlock(&dcache_lock);
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d_delete(d);
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simple_unlink(dentry->d_inode, d);
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dput(d);
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spin_lock(&dcache_lock);
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}
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node = dentry->d_subdirs.next;
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}
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list_del_init(&dentry->d_u.d_child);
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spin_unlock(&dcache_lock);
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remove_dir(dentry);
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}
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static struct super_operations cpuset_ops = {
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.statfs = simple_statfs,
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.drop_inode = generic_delete_inode,
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};
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static int cpuset_fill_super(struct super_block *sb, void *unused_data,
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int unused_silent)
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{
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struct inode *inode;
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struct dentry *root;
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sb->s_blocksize = PAGE_CACHE_SIZE;
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sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
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sb->s_magic = CPUSET_SUPER_MAGIC;
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sb->s_op = &cpuset_ops;
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cpuset_sb = sb;
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inode = cpuset_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR);
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if (inode) {
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inode->i_op = &simple_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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/* directories start off with i_nlink == 2 (for "." entry) */
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inc_nlink(inode);
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} else {
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return -ENOMEM;
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}
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root = d_alloc_root(inode);
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if (!root) {
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iput(inode);
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return -ENOMEM;
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}
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sb->s_root = root;
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return 0;
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}
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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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return get_sb_single(fs_type, flags, data, cpuset_fill_super, mnt);
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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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.kill_sb = kill_litter_super,
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};
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/* struct cftype:
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*
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* The files in the cpuset filesystem mostly have a very simple read/write
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* handling, some common function will take care of it. Nevertheless some cases
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* (read tasks) are special and therefore I define this structure for every
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* kind of file.
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*
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*
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* When reading/writing to a file:
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* - the cpuset to use in file->f_path.dentry->d_parent->d_fsdata
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* - the 'cftype' of the file is file->f_path.dentry->d_fsdata
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*/
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struct cftype {
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char *name;
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int private;
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int (*open) (struct inode *inode, struct file *file);
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ssize_t (*read) (struct file *file, char __user *buf, size_t nbytes,
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loff_t *ppos);
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int (*write) (struct file *file, const char __user *buf, size_t nbytes,
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loff_t *ppos);
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int (*release) (struct inode *inode, struct file *file);
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};
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static inline struct cpuset *__d_cs(struct dentry *dentry)
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{
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return dentry->d_fsdata;
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}
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static inline struct cftype *__d_cft(struct dentry *dentry)
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{
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return dentry->d_fsdata;
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}
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/*
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* Call with manage_mutex held. Writes path of cpuset into buf.
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* Returns 0 on success, -errno on error.
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*/
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static int cpuset_path(const struct cpuset *cs, char *buf, int buflen)
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{
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char *start;
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start = buf + buflen;
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*--start = '\0';
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for (;;) {
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int len = cs->dentry->d_name.len;
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if ((start -= len) < buf)
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return -ENAMETOOLONG;
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memcpy(start, cs->dentry->d_name.name, len);
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cs = cs->parent;
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if (!cs)
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break;
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if (!cs->parent)
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continue;
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if (--start < buf)
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return -ENAMETOOLONG;
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*start = '/';
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}
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memmove(buf, start, buf + buflen - start);
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return 0;
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}
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/*
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* Notify userspace when a cpuset is released, by running
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* /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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* Most likely, this user command will try to rmdir this cpuset.
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*
|
|
* This races with the possibility that some other task will be
|
|
* attached to this cpuset before it is removed, or that some other
|
|
* user task will 'mkdir' a child cpuset of this cpuset. That's ok.
|
|
* The presumed 'rmdir' will fail quietly if this cpuset is no longer
|
|
* unused, and this cpuset will be reprieved from its death sentence,
|
|
* to continue to serve a useful existence. Next time it's released,
|
|
* we will get notified again, if it still has 'notify_on_release' set.
|
|
*
|
|
* The final arg to call_usermodehelper() is 0, which means don't
|
|
* wait. The separate /sbin/cpuset_release_agent task is forked by
|
|
* call_usermodehelper(), then control in this thread returns here,
|
|
* without waiting for the release agent task. We don't bother to
|
|
* wait because the caller of this routine has no use for the exit
|
|
* status of the /sbin/cpuset_release_agent task, so no sense holding
|
|
* our caller up for that.
|
|
*
|
|
* When we had only one cpuset mutex, we had to call this
|
|
* without holding it, to avoid deadlock when call_usermodehelper()
|
|
* allocated memory. With two locks, we could now call this while
|
|
* holding manage_mutex, but we still don't, so as to minimize
|
|
* the time manage_mutex is held.
|
|
*/
|
|
|
|
static void cpuset_release_agent(const char *pathbuf)
|
|
{
|
|
char *argv[3], *envp[3];
|
|
int i;
|
|
|
|
if (!pathbuf)
|
|
return;
|
|
|
|
i = 0;
|
|
argv[i++] = "/sbin/cpuset_release_agent";
|
|
argv[i++] = (char *)pathbuf;
|
|
argv[i] = NULL;
|
|
|
|
i = 0;
|
|
/* minimal command environment */
|
|
envp[i++] = "HOME=/";
|
|
envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
|
|
envp[i] = NULL;
|
|
|
|
call_usermodehelper(argv[0], argv, envp, 0);
|
|
kfree(pathbuf);
|
|
}
|
|
|
|
/*
|
|
* Either cs->count of using tasks transitioned to zero, or the
|
|
* cs->children list of child cpusets just became empty. If this
|
|
* cs is notify_on_release() and now both the user count is zero and
|
|
* the list of children is empty, prepare cpuset path in a kmalloc'd
|
|
* buffer, to be returned via ppathbuf, so that the caller can invoke
|
|
* cpuset_release_agent() with it later on, once manage_mutex is dropped.
|
|
* Call here with manage_mutex held.
|
|
*
|
|
* This check_for_release() routine is responsible for kmalloc'ing
|
|
* pathbuf. The above cpuset_release_agent() is responsible for
|
|
* kfree'ing pathbuf. The caller of these routines is responsible
|
|
* for providing a pathbuf pointer, initialized to NULL, then
|
|
* calling check_for_release() with manage_mutex held and the address
|
|
* of the pathbuf pointer, then dropping manage_mutex, then calling
|
|
* cpuset_release_agent() with pathbuf, as set by check_for_release().
|
|
*/
|
|
|
|
static void check_for_release(struct cpuset *cs, char **ppathbuf)
|
|
{
|
|
if (notify_on_release(cs) && atomic_read(&cs->count) == 0 &&
|
|
list_empty(&cs->children)) {
|
|
char *buf;
|
|
|
|
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
|
|
if (!buf)
|
|
return;
|
|
if (cpuset_path(cs, buf, PAGE_SIZE) < 0)
|
|
kfree(buf);
|
|
else
|
|
*ppathbuf = buf;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return in *pmask the portion of a cpusets's cpus_allowed that
|
|
* are online. If none are online, walk up the cpuset hierarchy
|
|
* until we find one that does have some online cpus. If we get
|
|
* all the way to the top and still haven't found any online cpus,
|
|
* return cpu_online_map. Or if passed a NULL cs from an exit'ing
|
|
* task, return cpu_online_map.
|
|
*
|
|
* One way or another, we guarantee to return some non-empty subset
|
|
* of cpu_online_map.
|
|
*
|
|
* Call with callback_mutex held.
|
|
*/
|
|
|
|
static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask)
|
|
{
|
|
while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map))
|
|
cs = cs->parent;
|
|
if (cs)
|
|
cpus_and(*pmask, cs->cpus_allowed, cpu_online_map);
|
|
else
|
|
*pmask = cpu_online_map;
|
|
BUG_ON(!cpus_intersects(*pmask, cpu_online_map));
|
|
}
|
|
|
|
/*
|
|
* Return in *pmask the portion of a cpusets's mems_allowed that
|
|
* are online. If none are online, walk up the cpuset hierarchy
|
|
* until we find one that does have some online mems. If we get
|
|
* all the way to the top and still haven't found any online mems,
|
|
* return node_online_map.
|
|
*
|
|
* One way or another, we guarantee to return some non-empty subset
|
|
* of node_online_map.
|
|
*
|
|
* Call with callback_mutex held.
|
|
*/
|
|
|
|
static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
|
|
{
|
|
while (cs && !nodes_intersects(cs->mems_allowed, node_online_map))
|
|
cs = cs->parent;
|
|
if (cs)
|
|
nodes_and(*pmask, cs->mems_allowed, node_online_map);
|
|
else
|
|
*pmask = node_online_map;
|
|
BUG_ON(!nodes_intersects(*pmask, node_online_map));
|
|
}
|
|
|
|
/**
|
|
* cpuset_update_task_memory_state - update task memory placement
|
|
*
|
|
* If the current tasks cpusets mems_allowed changed behind our
|
|
* backs, update current->mems_allowed, mems_generation and task NUMA
|
|
* mempolicy to the new value.
|
|
*
|
|
* Task mempolicy is updated by rebinding it relative to the
|
|
* current->cpuset if a task has its memory placement changed.
|
|
* Do not call this routine if in_interrupt().
|
|
*
|
|
* Call without callback_mutex or task_lock() held. May be
|
|
* called with or without manage_mutex held. Thanks in part to
|
|
* 'the_top_cpuset_hack', the tasks cpuset pointer will never
|
|
* be NULL. This routine also might acquire callback_mutex and
|
|
* current->mm->mmap_sem during call.
|
|
*
|
|
* Reading current->cpuset->mems_generation doesn't need task_lock
|
|
* to guard the current->cpuset derefence, because it is guarded
|
|
* from concurrent freeing of current->cpuset by attach_task(),
|
|
* using RCU.
|
|
*
|
|
* The rcu_dereference() is technically probably not needed,
|
|
* as I don't actually mind if I see a new cpuset pointer but
|
|
* an old value of mems_generation. However this really only
|
|
* matters on alpha systems using cpusets heavily. If I dropped
|
|
* that rcu_dereference(), it would save them a memory barrier.
|
|
* For all other arch's, rcu_dereference is a no-op anyway, and for
|
|
* alpha systems not using cpusets, another planned optimization,
|
|
* avoiding the rcu critical section for tasks in the root cpuset
|
|
* which is statically allocated, so can't vanish, will make this
|
|
* irrelevant. Better to use RCU as intended, than to engage in
|
|
* some cute trick to save a memory barrier that is impossible to
|
|
* test, for alpha systems using cpusets heavily, which might not
|
|
* even exist.
|
|
*
|
|
* This routine is needed to update the per-task mems_allowed data,
|
|
* within the tasks context, when it is trying to allocate memory
|
|
* (in various mm/mempolicy.c routines) and notices that some other
|
|
* task has been modifying its cpuset.
|
|
*/
|
|
|
|
void cpuset_update_task_memory_state(void)
|
|
{
|
|
int my_cpusets_mem_gen;
|
|
struct task_struct *tsk = current;
|
|
struct cpuset *cs;
|
|
|
|
if (tsk->cpuset == &top_cpuset) {
|
|
/* Don't need rcu for top_cpuset. It's never freed. */
|
|
my_cpusets_mem_gen = top_cpuset.mems_generation;
|
|
} else {
|
|
rcu_read_lock();
|
|
cs = rcu_dereference(tsk->cpuset);
|
|
my_cpusets_mem_gen = cs->mems_generation;
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
|
|
mutex_lock(&callback_mutex);
|
|
task_lock(tsk);
|
|
cs = tsk->cpuset; /* Maybe changed when task not locked */
|
|
guarantee_online_mems(cs, &tsk->mems_allowed);
|
|
tsk->cpuset_mems_generation = cs->mems_generation;
|
|
if (is_spread_page(cs))
|
|
tsk->flags |= PF_SPREAD_PAGE;
|
|
else
|
|
tsk->flags &= ~PF_SPREAD_PAGE;
|
|
if (is_spread_slab(cs))
|
|
tsk->flags |= PF_SPREAD_SLAB;
|
|
else
|
|
tsk->flags &= ~PF_SPREAD_SLAB;
|
|
task_unlock(tsk);
|
|
mutex_unlock(&callback_mutex);
|
|
mpol_rebind_task(tsk, &tsk->mems_allowed);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
|
|
*
|
|
* One cpuset is a subset of another if all its allowed CPUs and
|
|
* Memory Nodes are a subset of the other, and its exclusive flags
|
|
* are only set if the other's are set. Call holding manage_mutex.
|
|
*/
|
|
|
|
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 cpuset *c, *par;
|
|
|
|
/* Each of our child cpusets must be a subset of us */
|
|
list_for_each_entry(c, &cur->children, sibling) {
|
|
if (!is_cpuset_subset(c, trial))
|
|
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(c, &par->children, sibling) {
|
|
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;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* For a given cpuset cur, partition the system as follows
|
|
* a. All cpus in the parent cpuset's cpus_allowed that are not part of any
|
|
* exclusive child cpusets
|
|
* b. All cpus in the current cpuset's cpus_allowed that are not part of any
|
|
* exclusive child cpusets
|
|
* Build these two partitions by calling partition_sched_domains
|
|
*
|
|
* Call with manage_mutex held. May nest a call to the
|
|
* lock_cpu_hotplug()/unlock_cpu_hotplug() pair.
|
|
* Must not be called holding callback_mutex, because we must
|
|
* not call lock_cpu_hotplug() while holding callback_mutex.
|
|
*/
|
|
|
|
static void update_cpu_domains(struct cpuset *cur)
|
|
{
|
|
struct cpuset *c, *par = cur->parent;
|
|
cpumask_t pspan, cspan;
|
|
|
|
if (par == NULL || cpus_empty(cur->cpus_allowed))
|
|
return;
|
|
|
|
/*
|
|
* Get all cpus from parent's cpus_allowed not part of exclusive
|
|
* children
|
|
*/
|
|
pspan = par->cpus_allowed;
|
|
list_for_each_entry(c, &par->children, sibling) {
|
|
if (is_cpu_exclusive(c))
|
|
cpus_andnot(pspan, pspan, c->cpus_allowed);
|
|
}
|
|
if (!is_cpu_exclusive(cur)) {
|
|
cpus_or(pspan, pspan, cur->cpus_allowed);
|
|
if (cpus_equal(pspan, cur->cpus_allowed))
|
|
return;
|
|
cspan = CPU_MASK_NONE;
|
|
} else {
|
|
if (cpus_empty(pspan))
|
|
return;
|
|
cspan = cur->cpus_allowed;
|
|
/*
|
|
* Get all cpus from current cpuset's cpus_allowed not part
|
|
* of exclusive children
|
|
*/
|
|
list_for_each_entry(c, &cur->children, sibling) {
|
|
if (is_cpu_exclusive(c))
|
|
cpus_andnot(cspan, cspan, c->cpus_allowed);
|
|
}
|
|
}
|
|
|
|
lock_cpu_hotplug();
|
|
partition_sched_domains(&pspan, &cspan);
|
|
unlock_cpu_hotplug();
|
|
}
|
|
|
|
/*
|
|
* 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, cpus_unchanged;
|
|
|
|
/* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */
|
|
if (cs == &top_cpuset)
|
|
return -EACCES;
|
|
|
|
trialcs = *cs;
|
|
retval = cpulist_parse(buf, trialcs.cpus_allowed);
|
|
if (retval < 0)
|
|
return retval;
|
|
cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
|
|
if (cpus_empty(trialcs.cpus_allowed))
|
|
return -ENOSPC;
|
|
retval = validate_change(cs, &trialcs);
|
|
if (retval < 0)
|
|
return retval;
|
|
cpus_unchanged = cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed);
|
|
mutex_lock(&callback_mutex);
|
|
cs->cpus_allowed = trialcs.cpus_allowed;
|
|
mutex_unlock(&callback_mutex);
|
|
if (is_cpu_exclusive(cs) && !cpus_unchanged)
|
|
update_cpu_domains(cs);
|
|
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(tsk->cpuset, &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 int update_nodemask(struct cpuset *cs, char *buf)
|
|
{
|
|
struct cpuset trialcs;
|
|
nodemask_t oldmem;
|
|
struct task_struct *g, *p;
|
|
struct mm_struct **mmarray;
|
|
int i, n, ntasks;
|
|
int migrate;
|
|
int fudge;
|
|
int retval;
|
|
|
|
/* top_cpuset.mems_allowed tracks node_online_map; it's read-only */
|
|
if (cs == &top_cpuset)
|
|
return -EACCES;
|
|
|
|
trialcs = *cs;
|
|
retval = nodelist_parse(buf, trialcs.mems_allowed);
|
|
if (retval < 0)
|
|
goto done;
|
|
nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map);
|
|
oldmem = cs->mems_allowed;
|
|
if (nodes_equal(oldmem, trialcs.mems_allowed)) {
|
|
retval = 0; /* Too easy - nothing to do */
|
|
goto done;
|
|
}
|
|
if (nodes_empty(trialcs.mems_allowed)) {
|
|
retval = -ENOSPC;
|
|
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);
|
|
|
|
set_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 = atomic_read(&cs->count); /* guess */
|
|
ntasks += fudge;
|
|
mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
|
|
if (!mmarray)
|
|
goto done;
|
|
write_lock_irq(&tasklist_lock); /* block fork */
|
|
if (atomic_read(&cs->count) <= ntasks)
|
|
break; /* got enough */
|
|
write_unlock_irq(&tasklist_lock); /* try again */
|
|
kfree(mmarray);
|
|
}
|
|
|
|
n = 0;
|
|
|
|
/* Load up mmarray[] with mm reference for each task in cpuset. */
|
|
do_each_thread(g, p) {
|
|
struct mm_struct *mm;
|
|
|
|
if (n >= ntasks) {
|
|
printk(KERN_WARNING
|
|
"Cpuset mempolicy rebind incomplete.\n");
|
|
continue;
|
|
}
|
|
if (p->cpuset != cs)
|
|
continue;
|
|
mm = get_task_mm(p);
|
|
if (!mm)
|
|
continue;
|
|
mmarray[n++] = mm;
|
|
} while_each_thread(g, p);
|
|
write_unlock_irq(&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);
|
|
set_cpuset_being_rebound(NULL);
|
|
retval = 0;
|
|
done:
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* 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_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, cpu_exclusive_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;
|
|
cpu_exclusive_changed =
|
|
(is_cpu_exclusive(cs) != is_cpu_exclusive(&trialcs));
|
|
mutex_lock(&callback_mutex);
|
|
cs->flags = trialcs.flags;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
if (cpu_exclusive_changed)
|
|
update_cpu_domains(cs);
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* Attack task specified by pid in 'pidbuf' to cpuset 'cs', possibly
|
|
* writing the path of the old cpuset in 'ppathbuf' if it needs to be
|
|
* notified on release.
|
|
*
|
|
* Call holding manage_mutex. May take callback_mutex and task_lock of
|
|
* the task 'pid' during call.
|
|
*/
|
|
|
|
static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf)
|
|
{
|
|
pid_t pid;
|
|
struct task_struct *tsk;
|
|
struct cpuset *oldcs;
|
|
cpumask_t cpus;
|
|
nodemask_t from, to;
|
|
struct mm_struct *mm;
|
|
int retval;
|
|
|
|
if (sscanf(pidbuf, "%d", &pid) != 1)
|
|
return -EIO;
|
|
if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
|
|
return -ENOSPC;
|
|
|
|
if (pid) {
|
|
read_lock(&tasklist_lock);
|
|
|
|
tsk = find_task_by_pid(pid);
|
|
if (!tsk || tsk->flags & PF_EXITING) {
|
|
read_unlock(&tasklist_lock);
|
|
return -ESRCH;
|
|
}
|
|
|
|
get_task_struct(tsk);
|
|
read_unlock(&tasklist_lock);
|
|
|
|
if ((current->euid) && (current->euid != tsk->uid)
|
|
&& (current->euid != tsk->suid)) {
|
|
put_task_struct(tsk);
|
|
return -EACCES;
|
|
}
|
|
} else {
|
|
tsk = current;
|
|
get_task_struct(tsk);
|
|
}
|
|
|
|
retval = security_task_setscheduler(tsk, 0, NULL);
|
|
if (retval) {
|
|
put_task_struct(tsk);
|
|
return retval;
|
|
}
|
|
|
|
mutex_lock(&callback_mutex);
|
|
|
|
task_lock(tsk);
|
|
oldcs = tsk->cpuset;
|
|
/*
|
|
* After getting 'oldcs' cpuset ptr, be sure still not exiting.
|
|
* If 'oldcs' might be the top_cpuset due to the_top_cpuset_hack
|
|
* then fail this attach_task(), to avoid breaking top_cpuset.count.
|
|
*/
|
|
if (tsk->flags & PF_EXITING) {
|
|
task_unlock(tsk);
|
|
mutex_unlock(&callback_mutex);
|
|
put_task_struct(tsk);
|
|
return -ESRCH;
|
|
}
|
|
atomic_inc(&cs->count);
|
|
rcu_assign_pointer(tsk->cpuset, cs);
|
|
task_unlock(tsk);
|
|
|
|
guarantee_online_cpus(cs, &cpus);
|
|
set_cpus_allowed(tsk, cpus);
|
|
|
|
from = oldcs->mems_allowed;
|
|
to = cs->mems_allowed;
|
|
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
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);
|
|
}
|
|
|
|
put_task_struct(tsk);
|
|
synchronize_rcu();
|
|
if (atomic_dec_and_test(&oldcs->count))
|
|
check_for_release(oldcs, ppathbuf);
|
|
return 0;
|
|
}
|
|
|
|
/* The various types of files and directories in a cpuset file system */
|
|
|
|
typedef enum {
|
|
FILE_ROOT,
|
|
FILE_DIR,
|
|
FILE_MEMORY_MIGRATE,
|
|
FILE_CPULIST,
|
|
FILE_MEMLIST,
|
|
FILE_CPU_EXCLUSIVE,
|
|
FILE_MEM_EXCLUSIVE,
|
|
FILE_NOTIFY_ON_RELEASE,
|
|
FILE_MEMORY_PRESSURE_ENABLED,
|
|
FILE_MEMORY_PRESSURE,
|
|
FILE_SPREAD_PAGE,
|
|
FILE_SPREAD_SLAB,
|
|
FILE_TASKLIST,
|
|
} cpuset_filetype_t;
|
|
|
|
static ssize_t cpuset_common_file_write(struct file *file,
|
|
const char __user *userbuf,
|
|
size_t nbytes, loff_t *unused_ppos)
|
|
{
|
|
struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
|
|
struct cftype *cft = __d_cft(file->f_path.dentry);
|
|
cpuset_filetype_t type = cft->private;
|
|
char *buffer;
|
|
char *pathbuf = NULL;
|
|
int retval = 0;
|
|
|
|
/* Crude upper limit on largest legitimate cpulist user might write. */
|
|
if (nbytes > 100 + 6 * max(NR_CPUS, MAX_NUMNODES))
|
|
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 */
|
|
|
|
mutex_lock(&manage_mutex);
|
|
|
|
if (is_removed(cs)) {
|
|
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_NOTIFY_ON_RELEASE:
|
|
retval = update_flag(CS_NOTIFY_ON_RELEASE, 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;
|
|
case FILE_TASKLIST:
|
|
retval = attach_task(cs, buffer, &pathbuf);
|
|
break;
|
|
default:
|
|
retval = -EINVAL;
|
|
goto out2;
|
|
}
|
|
|
|
if (retval == 0)
|
|
retval = nbytes;
|
|
out2:
|
|
mutex_unlock(&manage_mutex);
|
|
cpuset_release_agent(pathbuf);
|
|
out1:
|
|
kfree(buffer);
|
|
return retval;
|
|
}
|
|
|
|
static ssize_t cpuset_file_write(struct file *file, const char __user *buf,
|
|
size_t nbytes, loff_t *ppos)
|
|
{
|
|
ssize_t retval = 0;
|
|
struct cftype *cft = __d_cft(file->f_path.dentry);
|
|
if (!cft)
|
|
return -ENODEV;
|
|
|
|
/* special function ? */
|
|
if (cft->write)
|
|
retval = cft->write(file, buf, nbytes, ppos);
|
|
else
|
|
retval = cpuset_common_file_write(file, buf, nbytes, ppos);
|
|
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* These ascii lists should be read in a single call, by using a user
|
|
* buffer large enough to hold the entire map. If read in smaller
|
|
* 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 file *file, char __user *buf,
|
|
size_t nbytes, loff_t *ppos)
|
|
{
|
|
struct cftype *cft = __d_cft(file->f_path.dentry);
|
|
struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
|
|
cpuset_filetype_t type = cft->private;
|
|
char *page;
|
|
ssize_t retval = 0;
|
|
char *s;
|
|
|
|
if (!(page = (char *)__get_free_page(GFP_KERNEL)))
|
|
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_NOTIFY_ON_RELEASE:
|
|
*s++ = notify_on_release(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;
|
|
}
|
|
|
|
static ssize_t cpuset_file_read(struct file *file, char __user *buf, size_t nbytes,
|
|
loff_t *ppos)
|
|
{
|
|
ssize_t retval = 0;
|
|
struct cftype *cft = __d_cft(file->f_path.dentry);
|
|
if (!cft)
|
|
return -ENODEV;
|
|
|
|
/* special function ? */
|
|
if (cft->read)
|
|
retval = cft->read(file, buf, nbytes, ppos);
|
|
else
|
|
retval = cpuset_common_file_read(file, buf, nbytes, ppos);
|
|
|
|
return retval;
|
|
}
|
|
|
|
static int cpuset_file_open(struct inode *inode, struct file *file)
|
|
{
|
|
int err;
|
|
struct cftype *cft;
|
|
|
|
err = generic_file_open(inode, file);
|
|
if (err)
|
|
return err;
|
|
|
|
cft = __d_cft(file->f_path.dentry);
|
|
if (!cft)
|
|
return -ENODEV;
|
|
if (cft->open)
|
|
err = cft->open(inode, file);
|
|
else
|
|
err = 0;
|
|
|
|
return err;
|
|
}
|
|
|
|
static int cpuset_file_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct cftype *cft = __d_cft(file->f_path.dentry);
|
|
if (cft->release)
|
|
return cft->release(inode, file);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* cpuset_rename - Only allow simple rename of directories in place.
|
|
*/
|
|
static int cpuset_rename(struct inode *old_dir, struct dentry *old_dentry,
|
|
struct inode *new_dir, struct dentry *new_dentry)
|
|
{
|
|
if (!S_ISDIR(old_dentry->d_inode->i_mode))
|
|
return -ENOTDIR;
|
|
if (new_dentry->d_inode)
|
|
return -EEXIST;
|
|
if (old_dir != new_dir)
|
|
return -EIO;
|
|
return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
|
|
}
|
|
|
|
static const struct file_operations cpuset_file_operations = {
|
|
.read = cpuset_file_read,
|
|
.write = cpuset_file_write,
|
|
.llseek = generic_file_llseek,
|
|
.open = cpuset_file_open,
|
|
.release = cpuset_file_release,
|
|
};
|
|
|
|
static struct inode_operations cpuset_dir_inode_operations = {
|
|
.lookup = simple_lookup,
|
|
.mkdir = cpuset_mkdir,
|
|
.rmdir = cpuset_rmdir,
|
|
.rename = cpuset_rename,
|
|
};
|
|
|
|
static int cpuset_create_file(struct dentry *dentry, int mode)
|
|
{
|
|
struct inode *inode;
|
|
|
|
if (!dentry)
|
|
return -ENOENT;
|
|
if (dentry->d_inode)
|
|
return -EEXIST;
|
|
|
|
inode = cpuset_new_inode(mode);
|
|
if (!inode)
|
|
return -ENOMEM;
|
|
|
|
if (S_ISDIR(mode)) {
|
|
inode->i_op = &cpuset_dir_inode_operations;
|
|
inode->i_fop = &simple_dir_operations;
|
|
|
|
/* start off with i_nlink == 2 (for "." entry) */
|
|
inc_nlink(inode);
|
|
} else if (S_ISREG(mode)) {
|
|
inode->i_size = 0;
|
|
inode->i_fop = &cpuset_file_operations;
|
|
}
|
|
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry); /* Extra count - pin the dentry in core */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* cpuset_create_dir - create a directory for an object.
|
|
* cs: the cpuset we create the directory for.
|
|
* It must have a valid ->parent field
|
|
* And we are going to fill its ->dentry field.
|
|
* name: The name to give to the cpuset directory. Will be copied.
|
|
* mode: mode to set on new directory.
|
|
*/
|
|
|
|
static int cpuset_create_dir(struct cpuset *cs, const char *name, int mode)
|
|
{
|
|
struct dentry *dentry = NULL;
|
|
struct dentry *parent;
|
|
int error = 0;
|
|
|
|
parent = cs->parent->dentry;
|
|
dentry = cpuset_get_dentry(parent, name);
|
|
if (IS_ERR(dentry))
|
|
return PTR_ERR(dentry);
|
|
error = cpuset_create_file(dentry, S_IFDIR | mode);
|
|
if (!error) {
|
|
dentry->d_fsdata = cs;
|
|
inc_nlink(parent->d_inode);
|
|
cs->dentry = dentry;
|
|
}
|
|
dput(dentry);
|
|
|
|
return error;
|
|
}
|
|
|
|
static int cpuset_add_file(struct dentry *dir, const struct cftype *cft)
|
|
{
|
|
struct dentry *dentry;
|
|
int error;
|
|
|
|
mutex_lock(&dir->d_inode->i_mutex);
|
|
dentry = cpuset_get_dentry(dir, cft->name);
|
|
if (!IS_ERR(dentry)) {
|
|
error = cpuset_create_file(dentry, 0644 | S_IFREG);
|
|
if (!error)
|
|
dentry->d_fsdata = (void *)cft;
|
|
dput(dentry);
|
|
} else
|
|
error = PTR_ERR(dentry);
|
|
mutex_unlock(&dir->d_inode->i_mutex);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Stuff for reading the 'tasks' file.
|
|
*
|
|
* Reading this file can return large amounts of data if a cpuset has
|
|
* *lots* of attached tasks. So it may need several calls to read(),
|
|
* but we cannot guarantee that the information we produce is correct
|
|
* unless we produce it entirely atomically.
|
|
*
|
|
* Upon tasks file open(), a struct ctr_struct is allocated, that
|
|
* will have a pointer to an array (also allocated here). The struct
|
|
* ctr_struct * is stored in file->private_data. Its resources will
|
|
* be freed by release() when the file is closed. The array is used
|
|
* to sprintf the PIDs and then used by read().
|
|
*/
|
|
|
|
/* cpusets_tasks_read array */
|
|
|
|
struct ctr_struct {
|
|
char *buf;
|
|
int bufsz;
|
|
};
|
|
|
|
/*
|
|
* Load into 'pidarray' up to 'npids' of the tasks using cpuset 'cs'.
|
|
* Return actual number of pids loaded. No need to task_lock(p)
|
|
* when reading out p->cpuset, as we don't really care if it changes
|
|
* on the next cycle, and we are not going to try to dereference it.
|
|
*/
|
|
static int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs)
|
|
{
|
|
int n = 0;
|
|
struct task_struct *g, *p;
|
|
|
|
read_lock(&tasklist_lock);
|
|
|
|
do_each_thread(g, p) {
|
|
if (p->cpuset == cs) {
|
|
pidarray[n++] = p->pid;
|
|
if (unlikely(n == npids))
|
|
goto array_full;
|
|
}
|
|
} while_each_thread(g, p);
|
|
|
|
array_full:
|
|
read_unlock(&tasklist_lock);
|
|
return n;
|
|
}
|
|
|
|
static int cmppid(const void *a, const void *b)
|
|
{
|
|
return *(pid_t *)a - *(pid_t *)b;
|
|
}
|
|
|
|
/*
|
|
* Convert array 'a' of 'npids' pid_t's to a string of newline separated
|
|
* decimal pids in 'buf'. Don't write more than 'sz' chars, but return
|
|
* count 'cnt' of how many chars would be written if buf were large enough.
|
|
*/
|
|
static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids)
|
|
{
|
|
int cnt = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < npids; i++)
|
|
cnt += snprintf(buf + cnt, max(sz - cnt, 0), "%d\n", a[i]);
|
|
return cnt;
|
|
}
|
|
|
|
/*
|
|
* Handle an open on 'tasks' file. Prepare a buffer listing the
|
|
* process id's of tasks currently attached to the cpuset being opened.
|
|
*
|
|
* Does not require any specific cpuset mutexes, and does not take any.
|
|
*/
|
|
static int cpuset_tasks_open(struct inode *unused, struct file *file)
|
|
{
|
|
struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
|
|
struct ctr_struct *ctr;
|
|
pid_t *pidarray;
|
|
int npids;
|
|
char c;
|
|
|
|
if (!(file->f_mode & FMODE_READ))
|
|
return 0;
|
|
|
|
ctr = kmalloc(sizeof(*ctr), GFP_KERNEL);
|
|
if (!ctr)
|
|
goto err0;
|
|
|
|
/*
|
|
* If cpuset gets more users after we read count, we won't have
|
|
* enough space - tough. This race is indistinguishable to the
|
|
* caller from the case that the additional cpuset users didn't
|
|
* show up until sometime later on.
|
|
*/
|
|
npids = atomic_read(&cs->count);
|
|
pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
|
|
if (!pidarray)
|
|
goto err1;
|
|
|
|
npids = pid_array_load(pidarray, npids, cs);
|
|
sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
|
|
|
|
/* Call pid_array_to_buf() twice, first just to get bufsz */
|
|
ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1;
|
|
ctr->buf = kmalloc(ctr->bufsz, GFP_KERNEL);
|
|
if (!ctr->buf)
|
|
goto err2;
|
|
ctr->bufsz = pid_array_to_buf(ctr->buf, ctr->bufsz, pidarray, npids);
|
|
|
|
kfree(pidarray);
|
|
file->private_data = ctr;
|
|
return 0;
|
|
|
|
err2:
|
|
kfree(pidarray);
|
|
err1:
|
|
kfree(ctr);
|
|
err0:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static ssize_t cpuset_tasks_read(struct file *file, char __user *buf,
|
|
size_t nbytes, loff_t *ppos)
|
|
{
|
|
struct ctr_struct *ctr = file->private_data;
|
|
|
|
if (*ppos + nbytes > ctr->bufsz)
|
|
nbytes = ctr->bufsz - *ppos;
|
|
if (copy_to_user(buf, ctr->buf + *ppos, nbytes))
|
|
return -EFAULT;
|
|
*ppos += nbytes;
|
|
return nbytes;
|
|
}
|
|
|
|
static int cpuset_tasks_release(struct inode *unused_inode, struct file *file)
|
|
{
|
|
struct ctr_struct *ctr;
|
|
|
|
if (file->f_mode & FMODE_READ) {
|
|
ctr = file->private_data;
|
|
kfree(ctr->buf);
|
|
kfree(ctr);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* for the common functions, 'private' gives the type of file
|
|
*/
|
|
|
|
static struct cftype cft_tasks = {
|
|
.name = "tasks",
|
|
.open = cpuset_tasks_open,
|
|
.read = cpuset_tasks_read,
|
|
.release = cpuset_tasks_release,
|
|
.private = FILE_TASKLIST,
|
|
};
|
|
|
|
static struct cftype cft_cpus = {
|
|
.name = "cpus",
|
|
.private = FILE_CPULIST,
|
|
};
|
|
|
|
static struct cftype cft_mems = {
|
|
.name = "mems",
|
|
.private = FILE_MEMLIST,
|
|
};
|
|
|
|
static struct cftype cft_cpu_exclusive = {
|
|
.name = "cpu_exclusive",
|
|
.private = FILE_CPU_EXCLUSIVE,
|
|
};
|
|
|
|
static struct cftype cft_mem_exclusive = {
|
|
.name = "mem_exclusive",
|
|
.private = FILE_MEM_EXCLUSIVE,
|
|
};
|
|
|
|
static struct cftype cft_notify_on_release = {
|
|
.name = "notify_on_release",
|
|
.private = FILE_NOTIFY_ON_RELEASE,
|
|
};
|
|
|
|
static struct cftype cft_memory_migrate = {
|
|
.name = "memory_migrate",
|
|
.private = FILE_MEMORY_MIGRATE,
|
|
};
|
|
|
|
static struct cftype cft_memory_pressure_enabled = {
|
|
.name = "memory_pressure_enabled",
|
|
.private = FILE_MEMORY_PRESSURE_ENABLED,
|
|
};
|
|
|
|
static struct cftype cft_memory_pressure = {
|
|
.name = "memory_pressure",
|
|
.private = FILE_MEMORY_PRESSURE,
|
|
};
|
|
|
|
static struct cftype cft_spread_page = {
|
|
.name = "memory_spread_page",
|
|
.private = FILE_SPREAD_PAGE,
|
|
};
|
|
|
|
static struct cftype cft_spread_slab = {
|
|
.name = "memory_spread_slab",
|
|
.private = FILE_SPREAD_SLAB,
|
|
};
|
|
|
|
static int cpuset_populate_dir(struct dentry *cs_dentry)
|
|
{
|
|
int err;
|
|
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_cpus)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_mems)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_cpu_exclusive)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_mem_exclusive)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_notify_on_release)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_memory_migrate)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_memory_pressure)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_spread_page)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_spread_slab)) < 0)
|
|
return err;
|
|
if ((err = cpuset_add_file(cs_dentry, &cft_tasks)) < 0)
|
|
return err;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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 long cpuset_create(struct cpuset *parent, const char *name, int mode)
|
|
{
|
|
struct cpuset *cs;
|
|
int err;
|
|
|
|
cs = kmalloc(sizeof(*cs), GFP_KERNEL);
|
|
if (!cs)
|
|
return -ENOMEM;
|
|
|
|
mutex_lock(&manage_mutex);
|
|
cpuset_update_task_memory_state();
|
|
cs->flags = 0;
|
|
if (notify_on_release(parent))
|
|
set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
|
|
if (is_spread_page(parent))
|
|
set_bit(CS_SPREAD_PAGE, &cs->flags);
|
|
if (is_spread_slab(parent))
|
|
set_bit(CS_SPREAD_SLAB, &cs->flags);
|
|
cs->cpus_allowed = CPU_MASK_NONE;
|
|
cs->mems_allowed = NODE_MASK_NONE;
|
|
atomic_set(&cs->count, 0);
|
|
INIT_LIST_HEAD(&cs->sibling);
|
|
INIT_LIST_HEAD(&cs->children);
|
|
cs->mems_generation = cpuset_mems_generation++;
|
|
fmeter_init(&cs->fmeter);
|
|
|
|
cs->parent = parent;
|
|
|
|
mutex_lock(&callback_mutex);
|
|
list_add(&cs->sibling, &cs->parent->children);
|
|
number_of_cpusets++;
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
err = cpuset_create_dir(cs, name, mode);
|
|
if (err < 0)
|
|
goto err;
|
|
|
|
/*
|
|
* Release manage_mutex before cpuset_populate_dir() because it
|
|
* will down() this new directory's i_mutex and if we race with
|
|
* another mkdir, we might deadlock.
|
|
*/
|
|
mutex_unlock(&manage_mutex);
|
|
|
|
err = cpuset_populate_dir(cs->dentry);
|
|
/* If err < 0, we have a half-filled directory - oh well ;) */
|
|
return 0;
|
|
err:
|
|
list_del(&cs->sibling);
|
|
mutex_unlock(&manage_mutex);
|
|
kfree(cs);
|
|
return err;
|
|
}
|
|
|
|
static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode)
|
|
{
|
|
struct cpuset *c_parent = dentry->d_parent->d_fsdata;
|
|
|
|
/* the vfs holds inode->i_mutex already */
|
|
return cpuset_create(c_parent, dentry->d_name.name, mode | S_IFDIR);
|
|
}
|
|
|
|
/*
|
|
* Locking note on the strange update_flag() call below:
|
|
*
|
|
* If the cpuset being removed is marked cpu_exclusive, then simulate
|
|
* turning cpu_exclusive off, which will call update_cpu_domains().
|
|
* The lock_cpu_hotplug() call in update_cpu_domains() must not be
|
|
* made while holding callback_mutex. Elsewhere the kernel nests
|
|
* callback_mutex inside lock_cpu_hotplug() calls. So the reverse
|
|
* nesting would risk an ABBA deadlock.
|
|
*/
|
|
|
|
static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry)
|
|
{
|
|
struct cpuset *cs = dentry->d_fsdata;
|
|
struct dentry *d;
|
|
struct cpuset *parent;
|
|
char *pathbuf = NULL;
|
|
|
|
/* the vfs holds both inode->i_mutex already */
|
|
|
|
mutex_lock(&manage_mutex);
|
|
cpuset_update_task_memory_state();
|
|
if (atomic_read(&cs->count) > 0) {
|
|
mutex_unlock(&manage_mutex);
|
|
return -EBUSY;
|
|
}
|
|
if (!list_empty(&cs->children)) {
|
|
mutex_unlock(&manage_mutex);
|
|
return -EBUSY;
|
|
}
|
|
if (is_cpu_exclusive(cs)) {
|
|
int retval = update_flag(CS_CPU_EXCLUSIVE, cs, "0");
|
|
if (retval < 0) {
|
|
mutex_unlock(&manage_mutex);
|
|
return retval;
|
|
}
|
|
}
|
|
parent = cs->parent;
|
|
mutex_lock(&callback_mutex);
|
|
set_bit(CS_REMOVED, &cs->flags);
|
|
list_del(&cs->sibling); /* delete my sibling from parent->children */
|
|
spin_lock(&cs->dentry->d_lock);
|
|
d = dget(cs->dentry);
|
|
cs->dentry = NULL;
|
|
spin_unlock(&d->d_lock);
|
|
cpuset_d_remove_dir(d);
|
|
dput(d);
|
|
number_of_cpusets--;
|
|
mutex_unlock(&callback_mutex);
|
|
if (list_empty(&parent->children))
|
|
check_for_release(parent, &pathbuf);
|
|
mutex_unlock(&manage_mutex);
|
|
cpuset_release_agent(pathbuf);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
tsk->cpuset = &top_cpuset;
|
|
tsk->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)
|
|
{
|
|
struct dentry *root;
|
|
int err;
|
|
|
|
top_cpuset.cpus_allowed = CPU_MASK_ALL;
|
|
top_cpuset.mems_allowed = NODE_MASK_ALL;
|
|
|
|
fmeter_init(&top_cpuset.fmeter);
|
|
top_cpuset.mems_generation = cpuset_mems_generation++;
|
|
|
|
init_task.cpuset = &top_cpuset;
|
|
|
|
err = register_filesystem(&cpuset_fs_type);
|
|
if (err < 0)
|
|
goto out;
|
|
cpuset_mount = kern_mount(&cpuset_fs_type);
|
|
if (IS_ERR(cpuset_mount)) {
|
|
printk(KERN_ERR "cpuset: could not mount!\n");
|
|
err = PTR_ERR(cpuset_mount);
|
|
cpuset_mount = NULL;
|
|
goto out;
|
|
}
|
|
root = cpuset_mount->mnt_sb->s_root;
|
|
root->d_fsdata = &top_cpuset;
|
|
inc_nlink(root->d_inode);
|
|
top_cpuset.dentry = root;
|
|
root->d_inode->i_op = &cpuset_dir_inode_operations;
|
|
number_of_cpusets = 1;
|
|
err = cpuset_populate_dir(root);
|
|
/* memory_pressure_enabled is in root cpuset only */
|
|
if (err == 0)
|
|
err = cpuset_add_file(root, &cft_memory_pressure_enabled);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* 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 cpuset *c;
|
|
|
|
/* Each of our child cpusets mems must be online */
|
|
list_for_each_entry(c, &cur->children, sibling) {
|
|
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_online_map. Force the top cpuset to track
|
|
* whats 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)
|
|
{
|
|
mutex_lock(&manage_mutex);
|
|
mutex_lock(&callback_mutex);
|
|
|
|
guarantee_online_cpus_mems_in_subtree(&top_cpuset);
|
|
top_cpuset.cpus_allowed = cpu_online_map;
|
|
top_cpuset.mems_allowed = node_online_map;
|
|
|
|
mutex_unlock(&callback_mutex);
|
|
mutex_unlock(&manage_mutex);
|
|
}
|
|
|
|
/*
|
|
* 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 *nb,
|
|
unsigned long phase, void *cpu)
|
|
{
|
|
common_cpu_mem_hotplug_unplug();
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_MEMORY_HOTPLUG
|
|
/*
|
|
* Keep top_cpuset.mems_allowed tracking node_online_map.
|
|
* Call this routine anytime after you change node_online_map.
|
|
* 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_online_map;
|
|
|
|
hotcpu_notifier(cpuset_handle_cpuhp, 0);
|
|
}
|
|
|
|
/**
|
|
* cpuset_fork - attach newly forked task to its parents cpuset.
|
|
* @tsk: pointer to task_struct of forking parent process.
|
|
*
|
|
* Description: A task inherits its parent's cpuset at fork().
|
|
*
|
|
* A pointer to the shared cpuset was automatically copied in fork.c
|
|
* by dup_task_struct(). However, we ignore that copy, since it was
|
|
* not made under the protection of task_lock(), so might no longer be
|
|
* a valid cpuset pointer. attach_task() might have already changed
|
|
* current->cpuset, allowing the previously referenced cpuset to
|
|
* be removed and freed. Instead, we task_lock(current) and copy
|
|
* its present value of current->cpuset for our freshly forked child.
|
|
*
|
|
* At the point that cpuset_fork() is called, 'current' is the parent
|
|
* task, and the passed argument 'child' points to the child task.
|
|
**/
|
|
|
|
void cpuset_fork(struct task_struct *child)
|
|
{
|
|
task_lock(current);
|
|
child->cpuset = current->cpuset;
|
|
atomic_inc(&child->cpuset->count);
|
|
task_unlock(current);
|
|
}
|
|
|
|
/**
|
|
* cpuset_exit - detach cpuset from exiting task
|
|
* @tsk: pointer to task_struct of exiting process
|
|
*
|
|
* Description: Detach cpuset from @tsk and release it.
|
|
*
|
|
* Note that cpusets marked notify_on_release force every task in
|
|
* them to take the global manage_mutex mutex when exiting.
|
|
* This could impact scaling on very large systems. Be reluctant to
|
|
* use notify_on_release cpusets where very high task exit scaling
|
|
* is required on large systems.
|
|
*
|
|
* Don't even think about derefencing 'cs' after the cpuset use count
|
|
* goes to zero, except inside a critical section guarded by manage_mutex
|
|
* or callback_mutex. Otherwise a zero cpuset use count is a license to
|
|
* any other task to nuke the cpuset immediately, via cpuset_rmdir().
|
|
*
|
|
* This routine has to take manage_mutex, not callback_mutex, because
|
|
* it is holding that mutex while calling check_for_release(),
|
|
* which calls kmalloc(), so can't be called holding callback_mutex().
|
|
*
|
|
* We don't need to task_lock() this reference to tsk->cpuset,
|
|
* because tsk is already marked PF_EXITING, so attach_task() won't
|
|
* mess with it, or task is a failed fork, never visible to attach_task.
|
|
*
|
|
* the_top_cpuset_hack:
|
|
*
|
|
* Set the exiting tasks cpuset to the root cpuset (top_cpuset).
|
|
*
|
|
* Don't leave a task unable to allocate memory, as that is an
|
|
* accident waiting to happen should someone add a callout in
|
|
* do_exit() after the cpuset_exit() call that might allocate.
|
|
* If a task tries to allocate memory with an invalid cpuset,
|
|
* it will oops in cpuset_update_task_memory_state().
|
|
*
|
|
* We call cpuset_exit() while the task is still competent to
|
|
* handle notify_on_release(), then leave the task attached to
|
|
* the root cpuset (top_cpuset) for the remainder of its exit.
|
|
*
|
|
* To do this properly, we would increment the reference count on
|
|
* top_cpuset, and near the very end of the kernel/exit.c do_exit()
|
|
* code we would add a second cpuset function call, to drop that
|
|
* reference. This would just create an unnecessary hot spot on
|
|
* the top_cpuset reference count, to no avail.
|
|
*
|
|
* Normally, holding a reference to a cpuset without bumping its
|
|
* count is unsafe. The cpuset could go away, or someone could
|
|
* attach us to a different cpuset, decrementing the count on
|
|
* the first cpuset that we never incremented. But in this case,
|
|
* top_cpuset isn't going away, and either task has PF_EXITING set,
|
|
* which wards off any attach_task() attempts, or task is a failed
|
|
* fork, never visible to attach_task.
|
|
*
|
|
* Another way to do this would be to set the cpuset pointer
|
|
* to NULL here, and check in cpuset_update_task_memory_state()
|
|
* for a NULL pointer. This hack avoids that NULL check, for no
|
|
* cost (other than this way too long comment ;).
|
|
**/
|
|
|
|
void cpuset_exit(struct task_struct *tsk)
|
|
{
|
|
struct cpuset *cs;
|
|
|
|
cs = tsk->cpuset;
|
|
tsk->cpuset = &top_cpuset; /* the_top_cpuset_hack - see above */
|
|
|
|
if (notify_on_release(cs)) {
|
|
char *pathbuf = NULL;
|
|
|
|
mutex_lock(&manage_mutex);
|
|
if (atomic_dec_and_test(&cs->count))
|
|
check_for_release(cs, &pathbuf);
|
|
mutex_unlock(&manage_mutex);
|
|
cpuset_release_agent(pathbuf);
|
|
} else {
|
|
atomic_dec(&cs->count);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
|
|
* @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
|
|
*
|
|
* 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);
|
|
task_lock(tsk);
|
|
guarantee_online_cpus(tsk->cpuset, &mask);
|
|
task_unlock(tsk);
|
|
mutex_unlock(&callback_mutex);
|
|
|
|
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_online_map, 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(tsk->cpuset, &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 - Can we allocate memory on zone z's memory node?
|
|
* @z: is this zone on an allowed node?
|
|
* @gfp_mask: memory allocation flags (we use __GFP_HARDWALL)
|
|
*
|
|
* If we're in interrupt, 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.
|
|
* Otherwise, no.
|
|
*
|
|
* GFP_USER allocations are marked with the __GFP_HARDWALL bit,
|
|
* and do not allow allocations outside the current tasks cpuset.
|
|
* GFP_KERNEL allocations are not so marked, so can escape to the
|
|
* nearest 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
|
|
* 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() 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(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;
|
|
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(current->cpuset);
|
|
task_unlock(current);
|
|
|
|
allowed = node_isset(node, cs->mems_allowed);
|
|
mutex_unlock(&callback_mutex);
|
|
return allowed;
|
|
}
|
|
|
|
/**
|
|
* 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;
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return node;
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|
}
|
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EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
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|
|
|
/**
|
|
* cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors?
|
|
* @p: pointer to task_struct of some other task.
|
|
*
|
|
* Description: Return true if the nearest mem_exclusive ancestor
|
|
* cpusets of tasks @p and current overlap. Used by oom killer to
|
|
* determine if task @p's memory usage might impact the memory
|
|
* available to the current task.
|
|
*
|
|
* Call while holding callback_mutex.
|
|
**/
|
|
|
|
int cpuset_excl_nodes_overlap(const struct task_struct *p)
|
|
{
|
|
const struct cpuset *cs1, *cs2; /* my and p's cpuset ancestors */
|
|
int overlap = 1; /* do cpusets overlap? */
|
|
|
|
task_lock(current);
|
|
if (current->flags & PF_EXITING) {
|
|
task_unlock(current);
|
|
goto done;
|
|
}
|
|
cs1 = nearest_exclusive_ancestor(current->cpuset);
|
|
task_unlock(current);
|
|
|
|
task_lock((struct task_struct *)p);
|
|
if (p->flags & PF_EXITING) {
|
|
task_unlock((struct task_struct *)p);
|
|
goto done;
|
|
}
|
|
cs2 = nearest_exclusive_ancestor(p->cpuset);
|
|
task_unlock((struct task_struct *)p);
|
|
|
|
overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed);
|
|
done:
|
|
return overlap;
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
struct cpuset *cs;
|
|
|
|
task_lock(current);
|
|
cs = current->cpuset;
|
|
fmeter_markevent(&cs->fmeter);
|
|
task_unlock(current);
|
|
}
|
|
|
|
/*
|
|
* 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 *v)
|
|
{
|
|
struct pid *pid;
|
|
struct task_struct *tsk;
|
|
char *buf;
|
|
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;
|
|
mutex_lock(&manage_mutex);
|
|
|
|
retval = cpuset_path(tsk->cpuset, buf, PAGE_SIZE);
|
|
if (retval < 0)
|
|
goto out_unlock;
|
|
seq_puts(m, buf);
|
|
seq_putc(m, '\n');
|
|
out_unlock:
|
|
mutex_unlock(&manage_mutex);
|
|
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,
|
|
};
|
|
|
|
/* 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;
|
|
}
|