/**
* cgroup_scan_tasks - iterate though all the tasks in a cgroup
- * @scan: struct cgroup_scanner containing arguments for the scan
+ * @cgrp: the cgroup to iterate tasks of
+ * @test: optional test callback
+ * @process: process callback
+ * @data: data passed to @test and @process
+ * @heap: optional pre-allocated heap used for task iteration
*
- * Arguments include pointers to callback functions test_task() and
- * process_task().
- * Iterate through all the tasks in a cgroup, calling test_task() for each,
- * and if it returns true, call process_task() for it also.
- * The test_task pointer may be NULL, meaning always true (select all tasks).
- * Effectively duplicates cgroup_task_iter_{start,next,end}()
- * but does not lock css_set_lock for the call to process_task().
- * The struct cgroup_scanner may be embedded in any structure of the caller's
- * creation.
- * It is guaranteed that process_task() will act on every task that
- * is a member of the cgroup for the duration of this call. This
- * function may or may not call process_task() for tasks that exit
- * or move to a different cgroup during the call, or are forked or
- * move into the cgroup during the call.
+ * Iterate through all the tasks in a cgroup, calling @test for each, and
+ * if it returns %true, call @process for it also.
*
- * Note that test_task() may be called with locks held, and may in some
- * situations be called multiple times for the same task, so it should
- * be cheap.
- * If the heap pointer in the struct cgroup_scanner is non-NULL, a heap has been
- * pre-allocated and will be used for heap operations (and its "gt" member will
- * be overwritten), else a temporary heap will be used (allocation of which
- * may cause this function to fail).
+ * @test may be NULL, meaning always true (select all tasks), which
+ * effectively duplicates cgroup_task_iter_{start,next,end}() but does not
+ * lock css_set_lock for the call to @process.
+ *
+ * It is guaranteed that @process will act on every task that is a member
+ * of @cgrp for the duration of this call. This function may or may not
+ * call @process for tasks that exit or move to a different cgroup during
+ * the call, or are forked or move into the cgroup during the call.
+ *
+ * Note that @test may be called with locks held, and may in some
+ * situations be called multiple times for the same task, so it should be
+ * cheap.
+ *
+ * If @heap is non-NULL, a heap has been pre-allocated and will be used for
+ * heap operations (and its "gt" member will be overwritten), else a
+ * temporary heap will be used (allocation of which may cause this function
+ * to fail).
*/
-int cgroup_scan_tasks(struct cgroup_scanner *scan)
+int cgroup_scan_tasks(struct cgroup *cgrp,
+ bool (*test)(struct task_struct *, void *),
+ void (*process)(struct task_struct *, void *),
+ void *data, struct ptr_heap *heap)
{
int retval, i;
struct cgroup_task_iter it;
/* Never dereference latest_task, since it's not refcounted */
struct task_struct *latest_task = NULL;
struct ptr_heap tmp_heap;
- struct ptr_heap *heap;
struct timespec latest_time = { 0, 0 };
- if (scan->heap) {
+ if (heap) {
/* The caller supplied our heap and pre-allocated its memory */
- heap = scan->heap;
heap->gt = &started_after;
} else {
/* We need to allocate our own heap memory */
again:
/*
- * Scan tasks in the cgroup, using the scanner's "test_task" callback
- * to determine which are of interest, and using the scanner's
- * "process_task" callback to process any of them that need an update.
- * Since we don't want to hold any locks during the task updates,
- * gather tasks to be processed in a heap structure.
- * The heap is sorted by descending task start time.
- * If the statically-sized heap fills up, we overflow tasks that
- * started later, and in future iterations only consider tasks that
- * started after the latest task in the previous pass. This
+ * Scan tasks in the cgroup, using the @test callback to determine
+ * which are of interest, and invoking @process callback on the
+ * ones which need an update. Since we don't want to hold any
+ * locks during the task updates, gather tasks to be processed in a
+ * heap structure. The heap is sorted by descending task start
+ * time. If the statically-sized heap fills up, we overflow tasks
+ * that started later, and in future iterations only consider tasks
+ * that started after the latest task in the previous pass. This
* guarantees forward progress and that we don't miss any tasks.
*/
heap->size = 0;
- cgroup_task_iter_start(scan->cgrp, &it);
+ cgroup_task_iter_start(cgrp, &it);
while ((p = cgroup_task_iter_next(&it))) {
/*
* Only affect tasks that qualify per the caller's callback,
* if he provided one
*/
- if (scan->test_task && !scan->test_task(p, scan))
+ if (test && !test(p, data))
continue;
/*
* Only process tasks that started after the last task
latest_task = q;
}
/* Process the task per the caller's callback */
- scan->process_task(q, scan);
+ process(q, data);
put_task_struct(q);
}
/*
return 0;
}
-static void cgroup_transfer_one_task(struct task_struct *task,
- struct cgroup_scanner *scan)
+static void cgroup_transfer_one_task(struct task_struct *task, void *data)
{
- struct cgroup *new_cgroup = scan->data;
+ struct cgroup *new_cgroup = data;
mutex_lock(&cgroup_mutex);
cgroup_attach_task(new_cgroup, task, false);
*/
int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
{
- struct cgroup_scanner scan;
-
- scan.cgrp = from;
- scan.test_task = NULL; /* select all tasks in cgroup */
- scan.process_task = cgroup_transfer_one_task;
- scan.heap = NULL;
- scan.data = to;
-
- return cgroup_scan_tasks(&scan);
+ return cgroup_scan_tasks(from, NULL, cgroup_transfer_one_task, to, NULL);
}
/*
/**
* cpuset_change_cpumask - make a task's cpus_allowed the same as its cpuset's
* @tsk: task to test
- * @scan: struct cgroup_scanner containing the cgroup of the task
+ * @data: cpuset to @tsk belongs to
*
* Called by cgroup_scan_tasks() for each task in a cgroup whose
* cpus_allowed mask needs to be changed.
* We don't need to re-check for the cgroup/cpuset membership, since we're
* holding cpuset_mutex at this point.
*/
-static void cpuset_change_cpumask(struct task_struct *tsk,
- struct cgroup_scanner *scan)
+static void cpuset_change_cpumask(struct task_struct *tsk, void *data)
{
- struct cpuset *cpus_cs;
+ struct cpuset *cs = data;
+ struct cpuset *cpus_cs = effective_cpumask_cpuset(cs);
- cpus_cs = effective_cpumask_cpuset(cgroup_cs(scan->cgrp));
set_cpus_allowed_ptr(tsk, cpus_cs->cpus_allowed);
}
*/
static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap)
{
- struct cgroup_scanner scan;
-
- scan.cgrp = cs->css.cgroup;
- scan.test_task = NULL;
- scan.process_task = cpuset_change_cpumask;
- scan.heap = heap;
- cgroup_scan_tasks(&scan);
+ cgroup_scan_tasks(cs->css.cgroup, NULL, cpuset_change_cpumask, cs,
+ heap);
}
/*
task_unlock(tsk);
}
+struct cpuset_change_nodemask_arg {
+ struct cpuset *cs;
+ nodemask_t *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 cpuset_mutex held.
*/
-static void cpuset_change_nodemask(struct task_struct *p,
- struct cgroup_scanner *scan)
+static void cpuset_change_nodemask(struct task_struct *p, void *data)
{
- struct cpuset *cs = cgroup_cs(scan->cgrp);
+ struct cpuset_change_nodemask_arg *arg = data;
+ struct cpuset *cs = arg->cs;
struct mm_struct *mm;
int migrate;
- nodemask_t *newmems = scan->data;
- cpuset_change_task_nodemask(p, newmems);
+ cpuset_change_task_nodemask(p, arg->newmems);
mm = get_task_mm(p);
if (!mm)
mpol_rebind_mm(mm, &cs->mems_allowed);
if (migrate)
- cpuset_migrate_mm(mm, &cs->old_mems_allowed, newmems);
+ cpuset_migrate_mm(mm, &cs->old_mems_allowed, arg->newmems);
mmput(mm);
}
static void update_tasks_nodemask(struct cpuset *cs, struct ptr_heap *heap)
{
static nodemask_t newmems; /* protected by cpuset_mutex */
- struct cgroup_scanner scan;
struct cpuset *mems_cs = effective_nodemask_cpuset(cs);
+ struct cpuset_change_nodemask_arg arg = { .cs = cs,
+ .newmems = &newmems };
cpuset_being_rebound = cs; /* causes mpol_dup() rebind */
guarantee_online_mems(mems_cs, &newmems);
- scan.cgrp = cs->css.cgroup;
- scan.test_task = NULL;
- scan.process_task = cpuset_change_nodemask;
- scan.heap = heap;
- scan.data = &newmems;
-
/*
* The mpol_rebind_mm() call takes mmap_sem, which we couldn't
* take while holding tasklist_lock. Forks can happen - the
* It's ok if we rebind the same mm twice; mpol_rebind_mm()
* is idempotent. Also migrate pages in each mm to new nodes.
*/
- cgroup_scan_tasks(&scan);
+ cgroup_scan_tasks(cs->css.cgroup, NULL, cpuset_change_nodemask, &arg,
+ heap);
/*
* All the tasks' nodemasks have been updated, update
/*
* cpuset_change_flag - make a task's spread flags the same as its cpuset's
* @tsk: task to be updated
- * @scan: struct cgroup_scanner containing the cgroup of the task
+ * @data: cpuset to @tsk belongs to
*
* Called by cgroup_scan_tasks() for each task in a cgroup.
*
* We don't need to re-check for the cgroup/cpuset membership, since we're
* holding cpuset_mutex at this point.
*/
-static void cpuset_change_flag(struct task_struct *tsk,
- struct cgroup_scanner *scan)
+static void cpuset_change_flag(struct task_struct *tsk, void *data)
{
- cpuset_update_task_spread_flag(cgroup_cs(scan->cgrp), tsk);
+ struct cpuset *cs = data;
+
+ cpuset_update_task_spread_flag(cs, tsk);
}
/*
*/
static void update_tasks_flags(struct cpuset *cs, struct ptr_heap *heap)
{
- struct cgroup_scanner scan;
-
- scan.cgrp = cs->css.cgroup;
- scan.test_task = NULL;
- scan.process_task = cpuset_change_flag;
- scan.heap = heap;
- cgroup_scan_tasks(&scan);
+ cgroup_scan_tasks(cs->css.cgroup, NULL, cpuset_change_flag, cs, heap);
}
/*
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff