struct cpuset *parent; /* my parent */
- /*
- * Copy of global cpuset_mems_generation as of the most
- * recent time this cpuset changed its mems_allowed.
- */
- int mems_generation;
-
struct fmeter fmeter; /* memory_pressure filter */
/* partition number for rebuild_sched_domains() */
return test_bit(CS_SPREAD_SLAB, &cs->flags);
}
-/*
- * Increment this integer everytime any cpuset changes its
- * mems_allowed value. Users of cpusets can track this generation
- * number, and avoid having to lock and reload mems_allowed unless
- * the cpuset they're using changes generation.
- *
- * A single, global generation is needed because cpuset_attach_task() could
- * reattach a task to a different cpuset, which must not have its
- * generation numbers aliased with those of that tasks previous cpuset.
- *
- * Generations are needed for mems_allowed because one task cannot
- * modify another's memory placement. So we must enable every task,
- * on every visit to __alloc_pages(), to efficiently check whether
- * its current->cpuset->mems_allowed has changed, requiring an update
- * of its current->mems_allowed.
- *
- * Since writes to cpuset_mems_generation are guarded by the cgroup lock
- * there is no need to mark it atomic.
- */
-static int cpuset_mems_generation;
-
static struct cpuset top_cpuset = {
.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
};
* If a task is only holding callback_mutex, then it has read-only
* access to cpusets.
*
- * The task_struct fields mems_allowed and mems_generation may only
- * be accessed in the context of that task, so require no locks.
+ * Now, the task_struct fields mems_allowed and mempolicy may be changed
+ * by other task, we use alloc_lock in the task_struct fields to protect
+ * them.
*
* The cpuset_common_file_read() handlers only hold callback_mutex across
* small pieces of code, such as when reading out possibly multi-word
tsk->flags &= ~PF_SPREAD_SLAB;
}
-/**
- * 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 cgroup_mutex held. Thanks in part to
- * 'the_top_cpuset_hack', the task's cpuset pointer will never
- * be NULL. This routine also might acquire callback_mutex 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 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;
-
- rcu_read_lock();
- my_cpusets_mem_gen = task_cs(tsk)->mems_generation;
- rcu_read_unlock();
-
- if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
- mutex_lock(&callback_mutex);
- task_lock(tsk);
- cs = task_cs(tsk); /* Maybe changed when task not locked */
- guarantee_online_mems(cs, &tsk->mems_allowed);
- tsk->cpuset_mems_generation = cs->mems_generation;
- 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?
*
* 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,
{
struct task_struct *tsk = current;
- cpuset_update_task_memory_state();
-
- mutex_lock(&callback_mutex);
tsk->mems_allowed = *to;
- mutex_unlock(&callback_mutex);
do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
- mutex_lock(&callback_mutex);
guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed);
- mutex_unlock(&callback_mutex);
}
/*
- * Rebind task's vmas to cpuset's new mems_allowed, and migrate pages to new
- * nodes if memory_migrate flag is set. Called with cgroup_mutex held.
+ * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
+ * @tsk: the task to change
+ * @newmems: new nodes that the task will be set
+ *
+ * In order to avoid seeing no nodes if the old and new nodes are disjoint,
+ * we structure updates as setting all new allowed nodes, then clearing newly
+ * disallowed ones.
+ *
+ * Called with task's alloc_lock held
+ */
+static void cpuset_change_task_nodemask(struct task_struct *tsk,
+ nodemask_t *newmems)
+{
+ nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
+ mpol_rebind_task(tsk, &tsk->mems_allowed);
+ mpol_rebind_task(tsk, newmems);
+ tsk->mems_allowed = *newmems;
+}
+
+/*
+ * Update task's mems_allowed and rebind its mempolicy and vmas' mempolicy
+ * of it to cpuset's new mems_allowed, and migrate pages to new nodes if
+ * memory_migrate flag is set. Called with cgroup_mutex held.
*/
static void cpuset_change_nodemask(struct task_struct *p,
struct cgroup_scanner *scan)
struct cpuset *cs;
int migrate;
const nodemask_t *oldmem = scan->data;
+ nodemask_t newmems;
+
+ cs = cgroup_cs(scan->cg);
+ guarantee_online_mems(cs, &newmems);
+
+ task_lock(p);
+ cpuset_change_task_nodemask(p, &newmems);
+ task_unlock(p);
mm = get_task_mm(p);
if (!mm)
return;
- cs = cgroup_cs(scan->cg);
migrate = is_memory_migrate(cs);
mpol_rebind_mm(mm, &cs->mems_allowed);
/*
* 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.
+ * cpusets mems_allowed, and for each task in the cpuset,
+ * update mems_allowed and rebind task's mempolicy and any vma
+ * mempolicies and if the cpuset is marked 'memory_migrate',
+ * migrate the tasks pages to the new memory.
*
* Call with cgroup_mutex held. May take callback_mutex during call.
* Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
mutex_lock(&callback_mutex);
cs->mems_allowed = trialcs->mems_allowed;
- cs->mems_generation = cpuset_mems_generation++;
mutex_unlock(&callback_mutex);
update_tasks_nodemask(cs, &oldmem, &heap);
if (cs == &top_cpuset) {
cpumask_copy(cpus_attach, cpu_possible_mask);
+ to = node_possible_map;
} else {
- mutex_lock(&callback_mutex);
guarantee_online_cpus(cs, cpus_attach);
- mutex_unlock(&callback_mutex);
+ guarantee_online_mems(cs, &to);
}
err = set_cpus_allowed_ptr(tsk, cpus_attach);
if (err)
return;
+ task_lock(tsk);
+ cpuset_change_task_nodemask(tsk, &to);
+ task_unlock(tsk);
cpuset_update_task_spread_flag(cs, tsk);
from = oldcs->mems_allowed;
struct cpuset *parent;
if (!cont->parent) {
- /* This is early initialization for the top cgroup */
- top_cpuset.mems_generation = cpuset_mems_generation++;
return &top_cpuset.css;
}
parent = cgroup_cs(cont->parent);
return ERR_PTR(-ENOMEM);
}
- cpuset_update_task_memory_state();
cs->flags = 0;
if (is_spread_page(parent))
set_bit(CS_SPREAD_PAGE, &cs->flags);
set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
cpumask_clear(cs->cpus_allowed);
nodes_clear(cs->mems_allowed);
- cs->mems_generation = cpuset_mems_generation++;
fmeter_init(&cs->fmeter);
cs->relax_domain_level = -1;
{
struct cpuset *cs = cgroup_cs(cont);
- cpuset_update_task_memory_state();
-
if (is_sched_load_balance(cs))
update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
.early_init = 1,
};
-/*
- * cpuset_init_early - just enough so that the calls to
- * cpuset_update_task_memory_state() in early init code
- * are harmless.
- */
-
-int __init cpuset_init_early(void)
-{
- alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_NOWAIT);
-
- top_cpuset.mems_generation = cpuset_mems_generation++;
- return 0;
-}
-
-
/**
* cpuset_init - initialize cpusets at system boot
*
{
int err = 0;
+ if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL))
+ BUG();
+
cpumask_setall(top_cpuset.cpus_allowed);
nodes_setall(top_cpuset.mems_allowed);
fmeter_init(&top_cpuset.fmeter);
- top_cpuset.mems_generation = cpuset_mems_generation++;
set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
top_cpuset.relax_domain_level = -1;
return 0;
}
-/* Create a new policy */
+/*
+ * mpol_set_nodemask is called after mpol_new() to set up the nodemask, if
+ * any, for the new policy. mpol_new() has already validated the nodes
+ * parameter with respect to the policy mode and flags. But, we need to
+ * handle an empty nodemask with MPOL_PREFERRED here.
+ *
+ * Must be called holding task's alloc_lock to protect task's mems_allowed
+ * and mempolicy. May also be called holding the mmap_semaphore for write.
+ */
+static int mpol_set_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
+{
+ nodemask_t cpuset_context_nmask;
+ int ret;
+
+ /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */
+ if (pol == NULL)
+ return 0;
+
+ VM_BUG_ON(!nodes);
+ if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes))
+ nodes = NULL; /* explicit local allocation */
+ else {
+ if (pol->flags & MPOL_F_RELATIVE_NODES)
+ mpol_relative_nodemask(&cpuset_context_nmask, nodes,
+ &cpuset_current_mems_allowed);
+ else
+ nodes_and(cpuset_context_nmask, *nodes,
+ cpuset_current_mems_allowed);
+ if (mpol_store_user_nodemask(pol))
+ pol->w.user_nodemask = *nodes;
+ else
+ pol->w.cpuset_mems_allowed =
+ cpuset_current_mems_allowed;
+ }
+
+ ret = mpol_ops[pol->mode].create(pol,
+ nodes ? &cpuset_context_nmask : NULL);
+ return ret;
+}
+
+/*
+ * This function just creates a new policy, does some check and simple
+ * initialization. You must invoke mpol_set_nodemask() to set nodes.
+ */
static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
nodemask_t *nodes)
{
struct mempolicy *policy;
- nodemask_t cpuset_context_nmask;
- int ret;
pr_debug("setting mode %d flags %d nodes[0] %lx\n",
mode, flags, nodes ? nodes_addr(*nodes)[0] : -1);
if (((flags & MPOL_F_STATIC_NODES) ||
(flags & MPOL_F_RELATIVE_NODES)))
return ERR_PTR(-EINVAL);
- nodes = NULL; /* flag local alloc */
}
} else if (nodes_empty(*nodes))
return ERR_PTR(-EINVAL);
policy->mode = mode;
policy->flags = flags;
- if (nodes) {
- /*
- * cpuset related setup doesn't apply to local allocation
- */
- cpuset_update_task_memory_state();
- if (flags & MPOL_F_RELATIVE_NODES)
- mpol_relative_nodemask(&cpuset_context_nmask, nodes,
- &cpuset_current_mems_allowed);
- else
- nodes_and(cpuset_context_nmask, *nodes,
- cpuset_current_mems_allowed);
- if (mpol_store_user_nodemask(policy))
- policy->w.user_nodemask = *nodes;
- else
- policy->w.cpuset_mems_allowed =
- cpuset_mems_allowed(current);
- }
-
- ret = mpol_ops[mode].create(policy,
- nodes ? &cpuset_context_nmask : NULL);
- if (ret < 0) {
- kmem_cache_free(policy_cache, policy);
- return ERR_PTR(ret);
- }
return policy;
}
/*
* Wrapper for mpol_rebind_policy() that just requires task
* pointer, and updates task mempolicy.
+ *
+ * Called with task's alloc_lock held.
*/
void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new)
static long do_set_mempolicy(unsigned short mode, unsigned short flags,
nodemask_t *nodes)
{
- struct mempolicy *new;
+ struct mempolicy *new, *old;
struct mm_struct *mm = current->mm;
+ int ret;
new = mpol_new(mode, flags, nodes);
if (IS_ERR(new))
*/
if (mm)
down_write(&mm->mmap_sem);
- mpol_put(current->mempolicy);
+ task_lock(current);
+ ret = mpol_set_nodemask(new, nodes);
+ if (ret) {
+ task_unlock(current);
+ if (mm)
+ up_write(&mm->mmap_sem);
+ mpol_put(new);
+ return ret;
+ }
+ old = current->mempolicy;
current->mempolicy = new;
mpol_set_task_struct_flag();
if (new && new->mode == MPOL_INTERLEAVE &&
nodes_weight(new->v.nodes))
current->il_next = first_node(new->v.nodes);
+ task_unlock(current);
if (mm)
up_write(&mm->mmap_sem);
+ mpol_put(old);
return 0;
}
/*
* Return nodemask for policy for get_mempolicy() query
+ *
+ * Called with task's alloc_lock held
*/
static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
{
struct vm_area_struct *vma = NULL;
struct mempolicy *pol = current->mempolicy;
- cpuset_update_task_memory_state();
if (flags &
~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
return -EINVAL;
if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
return -EINVAL;
*policy = 0; /* just so it's initialized */
+ task_lock(current);
*nmask = cpuset_current_mems_allowed;
+ task_unlock(current);
return 0;
}
}
err = 0;
- if (nmask)
+ if (nmask) {
+ task_lock(current);
get_policy_nodemask(pol, nmask);
+ task_unlock(current);
+ }
out:
mpol_cond_put(pol);
return err;
}
down_write(&mm->mmap_sem);
+ task_lock(current);
+ err = mpol_set_nodemask(new, nmask);
+ task_unlock(current);
+ if (err) {
+ up_write(&mm->mmap_sem);
+ mpol_put(new);
+ return err;
+ }
vma = check_range(mm, start, end, nmask,
flags | MPOL_MF_INVERT, &pagelist);
struct mempolicy *pol = get_vma_policy(current, vma, addr);
struct zonelist *zl;
- cpuset_update_task_memory_state();
-
if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
unsigned nid;
{
struct mempolicy *pol = current->mempolicy;
- if ((gfp & __GFP_WAIT) && !in_interrupt())
- cpuset_update_task_memory_state();
if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
pol = &default_policy;
*/
void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
{
+ int ret;
+
sp->root = RB_ROOT; /* empty tree == default mempolicy */
spin_lock_init(&sp->lock);
/* contextualize the tmpfs mount point mempolicy */
new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
- mpol_put(mpol); /* drop our ref on sb mpol */
- if (IS_ERR(new))
+ if (IS_ERR(new)) {
+ mpol_put(mpol); /* drop our ref on sb mpol */
return; /* no valid nodemask intersection */
+ }
+
+ task_lock(current);
+ ret = mpol_set_nodemask(new, &mpol->w.user_nodemask);
+ task_unlock(current);
+ mpol_put(mpol); /* drop our ref on sb mpol */
+ if (ret) {
+ mpol_put(new);
+ return;
+ }
/* Create pseudo-vma that contains just the policy */
memset(&pvma, 0, sizeof(struct vm_area_struct));
new = mpol_new(mode, mode_flags, &nodes);
if (IS_ERR(new))
err = 1;
- else if (no_context)
- new->w.user_nodemask = nodes; /* save for contextualization */
+ else {
+ int ret;
+
+ task_lock(current);
+ ret = mpol_set_nodemask(new, &nodes);
+ task_unlock(current);
+ if (ret)
+ err = 1;
+ else if (no_context) {
+ /* save for contextualization */
+ new->w.user_nodemask = nodes;
+ }
+ }
out:
/* Restore string for error message */
projects / mirror_ubuntu-disco-kernel.git / commitdiff