AutoPage Migration - add auto_migration enable per cpuset control
This patch implements a per cpuset "auto_migration" control.
Default is disabled.
Earlier versions of this patch used a task flag for this purpose
to avoid extra cache misses in the fault path and such. There
are currently no task flags available, so this version uses
a flag in another variable in another cache line :(.
Because AUTO_MIGRATE requires CPUSETS, unconditionally select
same in mm/Kconfig.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
include/linux/cpuset.h | 16 ++++++++++++++++
include/linux/sched.h | 18 ++++++++++++++++++
kernel/cpuset.c | 31 ++++++++++++++++++++++++++++++-
mm/Kconfig | 1 +
4 files changed, 65 insertions(+), 1 deletion(-)
Index: linux-2.6.36-mmotm-101103-1217/include/linux/sched.h
===================================================================
--- linux-2.6.36-mmotm-101103-1217.orig/include/linux/sched.h
+++ linux-2.6.36-mmotm-101103-1217/include/linux/sched.h
@@ -1458,6 +1458,7 @@ struct task_struct {
short shared_huge_policy_enabled:1;
short shared_file_policy_enabled:1;
short migrate_on_fault_enabled:1;
+ short auto_migrate_enabled:1;
#endif
atomic_t fs_excl; /* holding fs exclusive resources */
struct rcu_head rcu;
@@ -1926,6 +1927,23 @@ static inline int migrate_on_fault_enabl
}
#endif
+#ifdef CONFIG_AUTO_MIGRATION
+static inline void set_auto_migrate_enabled(struct task_struct *tsk,
+ int val)
+{
+ tsk->auto_migrate_enabled = !!val;
+}
+static inline int auto_migrate_enabled(struct task_struct *tsk)
+{
+ return tsk->auto_migrate_enabled;
+}
+#else
+static inline void set_auto_migrate_enabled(struct task_struct *tsk,
+ int val)
+{
+}
+#endif
+
#ifdef CONFIG_HOTPLUG_CPU
extern void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p);
extern void idle_task_exit(void);
Index: linux-2.6.36-mmotm-101103-1217/kernel/cpuset.c
===================================================================
--- linux-2.6.36-mmotm-101103-1217.orig/kernel/cpuset.c
+++ linux-2.6.36-mmotm-101103-1217/kernel/cpuset.c
@@ -135,6 +135,7 @@ typedef enum {
CS_SHARED_HUGE_POLICY,
CS_SHARED_FILE_POLICY,
CS_MIGRATE_ON_FAULT,
+ CS_AUTO_MIGRATE,
} cpuset_flagbits_t;
/* convenient tests for these bits */
@@ -188,6 +189,11 @@ static inline int is_migrate_on_fault(co
return test_bit(CS_MIGRATE_ON_FAULT, &cs->flags);
}
+static inline int is_auto_migrate(const struct cpuset *cs)
+{
+ return test_bit(CS_AUTO_MIGRATE, &cs->flags);
+}
+
static struct cpuset top_cpuset = {
.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
};
@@ -352,6 +358,10 @@ static void cpuset_update_task_cpuset_fl
set_migrate_on_fault_enabled(tsk, 1);
else
set_migrate_on_fault_enabled(tsk, 0);
+ if (is_auto_migrate(cs))
+ set_auto_migrate_enabled(tsk, 1);
+ else
+ set_auto_migrate_enabled(tsk, 0);
}
@@ -1294,7 +1304,8 @@ static int update_flag(cpuset_flagbits_t
|| (is_spread_page(cs) != is_spread_page(trialcs))
|| (is_shared_huge_policy(cs) != is_shared_huge_policy(trialcs))
|| (is_shared_file_policy(cs) != is_shared_file_policy(trialcs))
- || (is_migrate_on_fault(cs) != is_migrate_on_fault(trialcs)));
+ || (is_migrate_on_fault(cs) != is_migrate_on_fault(trialcs))
+ || (is_auto_migrate(cs) != is_auto_migrate(trialcs)));
mutex_lock(&callback_mutex);
cs->flags = trialcs->flags;
@@ -1533,6 +1544,7 @@ typedef enum {
FILE_SHARED_HUGE_POLICY,
FILE_SHARED_FILE_POLICY,
FILE_MIGRATE_ON_FAULT,
+ FILE_AUTO_MIGRATE,
} cpuset_filetype_t;
static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
@@ -1580,6 +1592,9 @@ static int cpuset_write_u64(struct cgrou
break;
case FILE_MIGRATE_ON_FAULT:
retval = update_flag(CS_MIGRATE_ON_FAULT, cs, val);
+ break;
+ case FILE_AUTO_MIGRATE:
+ retval = update_flag(CS_AUTO_MIGRATE, cs, val);
break;
default:
retval = -EINVAL;
@@ -1751,6 +1766,8 @@ static u64 cpuset_read_u64(struct cgroup
return is_shared_file_policy(cs);
case FILE_MIGRATE_ON_FAULT:
return is_migrate_on_fault(cs);
+ case FILE_AUTO_MIGRATE:
+ return is_auto_migrate(cs);
default:
BUG();
}
@@ -1889,6 +1906,13 @@ static struct cftype cft_migrate_on_faul
.private = FILE_MIGRATE_ON_FAULT,
};
+static struct cftype cft_auto_migration = {
+ .name = "auto_migration",
+ .read_u64 = cpuset_read_u64,
+ .write_u64 = cpuset_write_u64,
+ .private = FILE_AUTO_MIGRATE,
+};
+
static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
{
int err;
@@ -1909,6 +1933,9 @@ static int cpuset_populate(struct cgroup
&cft_migrate_on_fault);
if (err < 0)
return err;
+ err = add_auto_migration_file(cont, ss, &cft_auto_migration);
+ if (err < 0)
+ return err;
/* memory_pressure_enabled is in root cpuset only */
if (!cont->parent)
err = cgroup_add_file(cont, ss,
@@ -1989,6 +2016,8 @@ static struct cgroup_subsys_state *cpuse
set_bit(CS_SHARED_FILE_POLICY, &cs->flags);
if (is_migrate_on_fault(parent))
set_bit(CS_MIGRATE_ON_FAULT, &cs->flags);
+ if (is_auto_migrate(parent))
+ set_bit(CS_AUTO_MIGRATE, &cs->flags);
set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
cpumask_clear(cs->cpus_allowed);
nodes_clear(cs->mems_allowed);
Index: linux-2.6.36-mmotm-101103-1217/mm/Kconfig
===================================================================
--- linux-2.6.36-mmotm-101103-1217.orig/mm/Kconfig
+++ linux-2.6.36-mmotm-101103-1217/mm/Kconfig
@@ -214,6 +214,7 @@ config MIGRATE_ON_FAULT
config AUTO_MIGRATION
bool "Auto-migrate task memory"
depends on MIGRATION
+ select CPUSETS
help
Allows tasks' private memory to follow that task itself across
inter-node migrations.
Index: linux-2.6.36-mmotm-101103-1217/include/linux/cpuset.h
===================================================================
--- linux-2.6.36-mmotm-101103-1217.orig/include/linux/cpuset.h
+++ linux-2.6.36-mmotm-101103-1217/include/linux/cpuset.h
@@ -164,6 +164,22 @@ static inline int add_migrate_on_fault_f
}
#endif
+#ifdef CONFIG_AUTO_MIGRATION
+static inline int add_auto_migration_file(struct cgroup *cg,
+ struct cgroup_subsys *ss,
+ struct cftype *cft)
+{
+ return cgroup_add_file(cg, ss, cft);
+}
+#else
+static inline int add_auto_migration_file(struct cgroup *cg,
+ struct cgroup_subsys *ss,
+ struct cftype *cft)
+{
+ return 0;
+}
+#endif
+
extern void __init cpuset_init_shared_huge_policy(int dflt);
extern void __init cpuset_init_shared_file_policy(int dflt);
--
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