Commit 950592f7 authored by Miao Xie's avatar Miao Xie Committed by Linus Torvalds
Browse files

cpusets: update tasks' page/slab spread flags in time



Fix the bug that the kernel didn't spread page cache/slab object evenly
over all the allowed nodes when spread flags were set by updating tasks'
page/slab spread flags in time.
Signed-off-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Paul Menage <menage@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f3b39d47
......@@ -406,7 +406,6 @@ void cpuset_update_task_memory_state(void)
cs = task_cs(tsk); /* Maybe changed when task not locked */
guarantee_online_mems(cs, &tsk->mems_allowed);
tsk->cpuset_mems_generation = cs->mems_generation;
cpuset_update_task_spread_flag(cs, tsk);
task_unlock(tsk);
mutex_unlock(&callback_mutex);
mpol_rebind_task(tsk, &tsk->mems_allowed);
......@@ -1203,6 +1202,46 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
return 0;
}
/*
* cpuset_change_flag - make a task's spread flags the same as its cpuset's
* @tsk: task to be updated
* @scan: struct cgroup_scanner containing the cgroup of the task
*
* Called by cgroup_scan_tasks() for each task in a cgroup.
*
* We don't need to re-check for the cgroup/cpuset membership, since we're
* holding cgroup_lock() at this point.
*/
static void cpuset_change_flag(struct task_struct *tsk,
struct cgroup_scanner *scan)
{
cpuset_update_task_spread_flag(cgroup_cs(scan->cg), tsk);
}
/*
* update_tasks_flags - update the spread flags of tasks in the cpuset.
* @cs: the cpuset in which each task's spread flags needs to be changed
* @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
*
* Called with cgroup_mutex held
*
* The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
* calling callback functions for each.
*
* No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
* if @heap != NULL.
*/
static void update_tasks_flags(struct cpuset *cs, struct ptr_heap *heap)
{
struct cgroup_scanner scan;
scan.cg = cs->css.cgroup;
scan.test_task = NULL;
scan.process_task = cpuset_change_flag;
scan.heap = heap;
cgroup_scan_tasks(&scan);
}
/*
* update_flag - read a 0 or a 1 in a file and update associated flag
* bit: the bit to update (see cpuset_flagbits_t)
......@@ -1216,8 +1255,10 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
int turning_on)
{
struct cpuset *trialcs;
int err;
int balance_flag_changed;
int spread_flag_changed;
struct ptr_heap heap;
int err;
trialcs = alloc_trial_cpuset(cs);
if (!trialcs)
......@@ -1232,9 +1273,16 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
if (err < 0)
goto out;
err = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
if (err < 0)
goto out;
balance_flag_changed = (is_sched_load_balance(cs) !=
is_sched_load_balance(trialcs));
spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
|| (is_spread_page(cs) != is_spread_page(trialcs)));
mutex_lock(&callback_mutex);
cs->flags = trialcs->flags;
mutex_unlock(&callback_mutex);
......@@ -1242,6 +1290,9 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
async_rebuild_sched_domains();
if (spread_flag_changed)
update_tasks_flags(cs, &heap);
heap_free(&heap);
out:
free_trial_cpuset(trialcs);
return err;
......@@ -1392,6 +1443,8 @@ static void cpuset_attach(struct cgroup_subsys *ss,
if (err)
return;
cpuset_update_task_spread_flag(cs, tsk);
from = oldcs->mems_allowed;
to = cs->mems_allowed;
mm = get_task_mm(tsk);
......@@ -1453,11 +1506,9 @@ static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
break;
case FILE_SPREAD_PAGE:
retval = update_flag(CS_SPREAD_PAGE, cs, val);
cs->mems_generation = cpuset_mems_generation++;
break;
case FILE_SPREAD_SLAB:
retval = update_flag(CS_SPREAD_SLAB, cs, val);
cs->mems_generation = cpuset_mems_generation++;
break;
default:
retval = -EINVAL;
......
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