Migrate-on-fault - add migrate on fault per cpuset control
Add a migrate_on_fault control file to cpusets. Default is
disabled ['0']. When set '1', enables migrate-on-fault for
tasks in the cpuset once they notice the flag: for already
running tasks, this means after they update their cpuset memory
state.
To avoid adding #ifdefs to kernel/cpuset.c [at Paul Jackson's
request], most of the migrate-on-fault support is unconditionally
included in cpuset.c. However, the control file will only be
created if migrate-on-fault is configured.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
include/linux/cpuset.h | 16 ++++++++++++++++
include/linux/sched.h | 19 +++++++++++++++++++
kernel/cpuset.c | 34 +++++++++++++++++++++++++++++++++-
mm/Kconfig | 1 +
4 files changed, 69 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
@@ -1457,6 +1457,7 @@ struct task_struct {
short il_next;
short shared_huge_policy_enabled:1;
short shared_file_policy_enabled:1;
+ short migrate_on_fault_enabled:1;
#endif
atomic_t fs_excl; /* holding fs exclusive resources */
struct rcu_head rcu;
@@ -1905,6 +1906,24 @@ static int shared_file_policy_enabled(st
{
return 0;
}
+#endif
+
+#ifdef CONFIG_MIGRATE_ON_FAULT
+static inline void set_migrate_on_fault_enabled(struct task_struct *tsk,
+ int val)
+{
+ tsk->migrate_on_fault_enabled = !!val;
+}
+static inline int migrate_on_fault_enabled(struct task_struct *tsk)
+{
+ return tsk->migrate_on_fault_enabled;
+}
+#else
+static void set_shared_file_policy_enabled(struct task_struct *tsk, int val) { }
+static inline int migrate_on_fault_enabled(struct task_struct *tsk)
+{
+ return 0;
+}
#endif
#ifdef CONFIG_HOTPLUG_CPU
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
@@ -134,6 +134,7 @@ typedef enum {
CS_SPREAD_SLAB,
CS_SHARED_HUGE_POLICY,
CS_SHARED_FILE_POLICY,
+ CS_MIGRATE_ON_FAULT,
} cpuset_flagbits_t;
/* convenient tests for these bits */
@@ -182,6 +183,11 @@ static inline int is_shared_file_policy(
return test_bit(CS_SHARED_FILE_POLICY, &cs->flags);
}
+static inline int is_migrate_on_fault(const struct cpuset *cs)
+{
+ return test_bit(CS_MIGRATE_ON_FAULT, &cs->flags);
+}
+
static struct cpuset top_cpuset = {
.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
};
@@ -341,6 +347,12 @@ static void cpuset_update_task_cpuset_fl
set_shared_file_policy_enabled(tsk, 1);
else
set_shared_file_policy_enabled(tsk, 0);
+
+ if (is_migrate_on_fault(cs))
+ set_migrate_on_fault_enabled(tsk, 1);
+ else
+ set_migrate_on_fault_enabled(tsk, 0);
+
}
/*
@@ -1281,7 +1293,8 @@ static int update_flag(cpuset_flagbits_t
cpuset_flags_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
|| (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_shared_file_policy(cs) != is_shared_file_policy(trialcs))
+ || (is_migrate_on_fault(cs) != is_migrate_on_fault(trialcs)));
mutex_lock(&callback_mutex);
cs->flags = trialcs->flags;
@@ -1519,6 +1532,7 @@ typedef enum {
FILE_SPREAD_SLAB,
FILE_SHARED_HUGE_POLICY,
FILE_SHARED_FILE_POLICY,
+ FILE_MIGRATE_ON_FAULT,
} cpuset_filetype_t;
static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
@@ -1564,6 +1578,9 @@ static int cpuset_write_u64(struct cgrou
case FILE_SHARED_FILE_POLICY:
retval = update_flag(CS_SHARED_FILE_POLICY, cs, val);
break;
+ case FILE_MIGRATE_ON_FAULT:
+ retval = update_flag(CS_MIGRATE_ON_FAULT, cs, val);
+ break;
default:
retval = -EINVAL;
break;
@@ -1732,6 +1749,8 @@ static u64 cpuset_read_u64(struct cgroup
return is_shared_huge_policy(cs);
case FILE_SHARED_FILE_POLICY:
return is_shared_file_policy(cs);
+ case FILE_MIGRATE_ON_FAULT:
+ return is_migrate_on_fault(cs);
default:
BUG();
}
@@ -1863,6 +1882,13 @@ static struct cftype cft_shared_file_pol
.private = FILE_SHARED_FILE_POLICY,
};
+static struct cftype cft_migrate_on_fault = {
+ .name = "migrate_on_fault",
+ .read_u64 = cpuset_read_u64,
+ .write_u64 = cpuset_write_u64,
+ .private = FILE_MIGRATE_ON_FAULT,
+};
+
static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
{
int err;
@@ -1879,6 +1905,10 @@ static int cpuset_populate(struct cgroup
err = add_shared_xxx_policy_file(cont, ss, &cft_shared_file_policy);
if (err < 0)
return err;
+ err = add_migrate_on_fault_file(cont, ss,
+ &cft_migrate_on_fault);
+ if (err < 0)
+ return err;
/* memory_pressure_enabled is in root cpuset only */
if (!cont->parent)
err = cgroup_add_file(cont, ss,
@@ -1957,6 +1987,8 @@ static struct cgroup_subsys_state *cpuse
set_bit(CS_SHARED_HUGE_POLICY, &cs->flags);
if (is_shared_file_policy(parent))
set_bit(CS_SHARED_FILE_POLICY, &cs->flags);
+ if (is_migrate_on_fault(parent))
+ set_bit(CS_MIGRATE_ON_FAULT, &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
@@ -204,6 +204,7 @@ config MIGRATE_ON_FAULT
bool "Migrate unmapped page on fault"
depends on MIGRATION
depends on SWAP
+ select CPUSETS
help
Allows "misplaced" pages found in a page cache at fault time to be
migrated to the node specified by the applicable policy when the
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
@@ -148,6 +148,22 @@ static inline int add_shared_xxx_policy_
}
#endif
+#ifdef CONFIG_MIGRATE_ON_FAULT
+static inline int add_migrate_on_fault_file(struct cgroup *cg,
+ struct cgroup_subsys *ss,
+ struct cftype *cft)
+{
+ return cgroup_add_file(cg, ss, cft);
+}
+#else
+static inline int add_migrate_on_fault_file(struct cgroup *cont,
+ 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);
--
To unsubscribe from this list: send the line "unsubscribe linux-numa" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
