sched, cpuset: customize sched domains, core

[rebased for sched-devel/latest]

 - Add a new cpuset file, having levels:
     sched_relax_domain_level

 - Modify partition_sched_domains() and build_sched_domains()
   to take attributes parameter passed from cpuset.

 - Fill newidle_idx for node domains which currently unused but
   might be required if sched_relax_domain_level become higher.

 - We can change the default level by boot option 'relax_domain_level='.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

7 files changed, 161 insertions, 11 deletions

diff --git a/include/asm-ia64/topology.h b/include/asm-ia64/topology.h
index f929dde85343..f2f72ef2a897 100644
--- a/include/asm-ia64/topology.h
+++ b/include/asm-ia64/topology.h
@@ -93,7 +93,7 @@ void build_cpu_to_node_map(void);
         .cache_nice_tries       = 2,                    \
         .busy_idx               = 3,                    \
         .idle_idx               = 2,                    \
-        .newidle_idx            = 0, /* unused */       \
+        .newidle_idx            = 2,                    \
         .wake_idx               = 1,                    \
         .forkexec_idx           = 1,                    \
         .flags                  = SD_LOAD_BALANCE       \
diff --git a/include/asm-sh/topology.h b/include/asm-sh/topology.h
index f402a3b1cfa4..34cdb28e8f44 100644
--- a/include/asm-sh/topology.h
+++ b/include/asm-sh/topology.h
@@ -16,7 +16,7 @@
         .cache_nice_tries       = 2,                    \
         .busy_idx               = 3,                    \
         .idle_idx               = 2,                    \
-        .newidle_idx            = 0,                    \
+        .newidle_idx            = 2,                    \
         .wake_idx               = 1,                    \
         .forkexec_idx           = 1,                    \
         .flags                  = SD_LOAD_BALANCE       \
diff --git a/include/asm-x86/topology.h b/include/asm-x86/topology.h
index 9ef74c5d5ad6..22073268b481 100644
--- a/include/asm-x86/topology.h
+++ b/include/asm-x86/topology.h
@@ -147,7 +147,7 @@ extern unsigned long node_remap_size[];
 
 # define SD_CACHE_NICE_TRIES    2
 # define SD_IDLE_IDX            2
-# define SD_NEWIDLE_IDX         0
+# define SD_NEWIDLE_IDX         2
 # define SD_FORKEXEC_IDX        1
 
 #endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ada24022d230..11f47249cdd2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -704,6 +704,7 @@ enum cpu_idle_type {
 #define SD_POWERSAVINGS_BALANCE 256     /* Balance for power savings */
 #define SD_SHARE_PKG_RESOURCES  512     /* Domain members share cpu pkg resources */
 #define SD_SERIALIZE            1024    /* Only a single load balancing instance */
+#define SD_WAKE_IDLE_FAR        2048    /* Gain latency sacrificing cache hit */
 
 #define BALANCE_FOR_MC_POWER    \
         (sched_smt_power_savings ? SD_POWERSAVINGS_BALANCE : 0)
@@ -733,6 +734,24 @@ struct sched_group {
         u32 reciprocal_cpu_power;
 };
 
+enum sched_domain_level {
+        SD_LV_NONE = 0,
+        SD_LV_SIBLING,
+        SD_LV_MC,
+        SD_LV_CPU,
+        SD_LV_NODE,
+        SD_LV_ALLNODES,
+        SD_LV_MAX
+};
+
+struct sched_domain_attr {
+        int relax_domain_level;
+};
+
+#define SD_ATTR_INIT    (struct sched_domain_attr) {    \
+        .relax_domain_level = -1,                       \
+}
+
 struct sched_domain {
         /* These fields must be setup */
         struct sched_domain *parent;    /* top domain must be null terminated */
@@ -750,6 +769,7 @@ struct sched_domain {
         unsigned int wake_idx;
         unsigned int forkexec_idx;
         int flags;                      /* See SD_* */
+        enum sched_domain_level level;
 
         /* Runtime fields. */
         unsigned long last_balance;     /* init to jiffies. units in jiffies */
@@ -789,7 +809,8 @@ struct sched_domain {
 #endif
 };
 
-extern void partition_sched_domains(int ndoms_new, cpumask_t *doms_new);
+extern void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
+                                    struct sched_domain_attr *dattr_new);
 extern int arch_reinit_sched_domains(void);
 
 #endif  /* CONFIG_SMP */
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index b0c870b2ac30..8b35fbd8292f 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -98,6 +98,9 @@ struct cpuset {
         /* partition number for rebuild_sched_domains() */
         int pn;
 
+        /* for custom sched domain */
+        int relax_domain_level;
+
         /* used for walking a cpuset heirarchy */
         struct list_head stack_list;
 };
@@ -478,6 +481,16 @@ static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
         return cpus_intersects(a->cpus_allowed, b->cpus_allowed);
 }
 
+static void
+update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
+{
+        if (!dattr)
+                return;
+        if (dattr->relax_domain_level < c->relax_domain_level)
+                dattr->relax_domain_level = c->relax_domain_level;
+        return;
+}
+
 /*
  * rebuild_sched_domains()
  *
@@ -553,12 +566,14 @@ static void rebuild_sched_domains(void)
         int csn;                /* how many cpuset ptrs in csa so far */
         int i, j, k;            /* indices for partition finding loops */
         cpumask_t *doms;        /* resulting partition; i.e. sched domains */
+        struct sched_domain_attr *dattr;  /* attributes for custom domains */
         int ndoms;              /* number of sched domains in result */
         int nslot;              /* next empty doms[] cpumask_t slot */
 
         q = NULL;
         csa = NULL;
         doms = NULL;
+        dattr = NULL;
 
         /* Special case for the 99% of systems with one, full, sched domain */
         if (is_sched_load_balance(&top_cpuset)) {
@@ -566,6 +581,11 @@ static void rebuild_sched_domains(void)
                 doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
                 if (!doms)
                         goto rebuild;
+                dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
+                if (dattr) {
+                        *dattr = SD_ATTR_INIT;
+                        update_domain_attr(dattr, &top_cpuset);
+                }
                 *doms = top_cpuset.cpus_allowed;
                 goto rebuild;
         }
@@ -622,6 +642,7 @@ restart:
         doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
         if (!doms)
                 goto rebuild;
+        dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL);
 
         for (nslot = 0, i = 0; i < csn; i++) {
                 struct cpuset *a = csa[i];
@@ -644,12 +665,15 @@ restart:
                         }
 
                         cpus_clear(*dp);
+                        if (dattr)
+                                *(dattr + nslot) = SD_ATTR_INIT;
                         for (j = i; j < csn; j++) {
                                 struct cpuset *b = csa[j];
 
                                 if (apn == b->pn) {
                                         cpus_or(*dp, *dp, b->cpus_allowed);
                                         b->pn = -1;
+                                        update_domain_attr(dattr, b);
                                 }
                         }
                         nslot++;
@@ -660,7 +684,7 @@ restart:
 rebuild:
         /* Have scheduler rebuild sched domains */
         get_online_cpus();
-        partition_sched_domains(ndoms, doms);
+        partition_sched_domains(ndoms, doms, dattr);
         put_online_cpus();
 
 done:
@@ -668,6 +692,7 @@ done:
                 kfifo_free(q);
         kfree(csa);
         /* Don't kfree(doms) -- partition_sched_domains() does that. */
+        /* Don't kfree(dattr) -- partition_sched_domains() does that. */
 }
 
 static inline int started_after_time(struct task_struct *t1,
@@ -1011,6 +1036,21 @@ static int update_memory_pressure_enabled(struct cpuset *cs, char *buf)
         return 0;
 }
 
+static int update_relax_domain_level(struct cpuset *cs, char *buf)
+{
+        int val = simple_strtol(buf, NULL, 10);
+
+        if (val < 0)
+                val = -1;
+
+        if (val != cs->relax_domain_level) {
+                cs->relax_domain_level = val;
+                rebuild_sched_domains();
+        }
+
+        return 0;
+}
+
 /*
  * update_flag - read a 0 or a 1 in a file and update associated flag
  * bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE,
@@ -1202,6 +1242,7 @@ typedef enum {
         FILE_CPU_EXCLUSIVE,
         FILE_MEM_EXCLUSIVE,
         FILE_SCHED_LOAD_BALANCE,
+        FILE_SCHED_RELAX_DOMAIN_LEVEL,
         FILE_MEMORY_PRESSURE_ENABLED,
         FILE_MEMORY_PRESSURE,
         FILE_SPREAD_PAGE,
@@ -1256,6 +1297,9 @@ static ssize_t cpuset_common_file_write(struct cgroup *cont,
         case FILE_SCHED_LOAD_BALANCE:
                 retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, buffer);
                 break;
+        case FILE_SCHED_RELAX_DOMAIN_LEVEL:
+                retval = update_relax_domain_level(cs, buffer);
+                break;
         case FILE_MEMORY_MIGRATE:
                 retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer);
                 break;
@@ -1354,6 +1398,9 @@ static ssize_t cpuset_common_file_read(struct cgroup *cont,
         case FILE_SCHED_LOAD_BALANCE:
                 *s++ = is_sched_load_balance(cs) ? '1' : '0';
                 break;
+        case FILE_SCHED_RELAX_DOMAIN_LEVEL:
+                s += sprintf(s, "%d", cs->relax_domain_level);
+                break;
         case FILE_MEMORY_MIGRATE:
                 *s++ = is_memory_migrate(cs) ? '1' : '0';
                 break;
@@ -1424,6 +1471,13 @@ static struct cftype cft_sched_load_balance = {
         .private = FILE_SCHED_LOAD_BALANCE,
 };
 
+static struct cftype cft_sched_relax_domain_level = {
+        .name = "sched_relax_domain_level",
+        .read = cpuset_common_file_read,
+        .write = cpuset_common_file_write,
+        .private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
+};
+
 static struct cftype cft_memory_migrate = {
         .name = "memory_migrate",
         .read = cpuset_common_file_read,
@@ -1475,6 +1529,9 @@ static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
                 return err;
         if ((err = cgroup_add_file(cont, ss, &cft_sched_load_balance)) < 0)
                 return err;
+        if ((err = cgroup_add_file(cont, ss,
+                                        &cft_sched_relax_domain_level)) < 0)
+                return err;
         if ((err = cgroup_add_file(cont, ss, &cft_memory_pressure)) < 0)
                 return err;
         if ((err = cgroup_add_file(cont, ss, &cft_spread_page)) < 0)
@@ -1559,6 +1616,7 @@ static struct cgroup_subsys_state *cpuset_create(
         nodes_clear(cs->mems_allowed);
         cs->mems_generation = cpuset_mems_generation++;
         fmeter_init(&cs->fmeter);
+        cs->relax_domain_level = -1;
 
         cs->parent = parent;
         number_of_cpusets++;
@@ -1631,6 +1689,7 @@ int __init cpuset_init(void)
         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;
 
         err = register_filesystem(&cpuset_fs_type);
         if (err < 0)
diff --git a/kernel/sched.c b/kernel/sched.c
index 475e3fcab738..62d7481caca5 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6771,6 +6771,7 @@ static noinline void sd_init_##type(struct sched_domain *sd)	\
 {                                                               \
         memset(sd, 0, sizeof(*sd));                             \
         *sd = SD_##type##_INIT;                                 \
+        sd->level = SD_LV_##type;                               \
 }
 
 SD_INIT_FUNC(CPU)
@@ -6819,11 +6820,42 @@ struct allmasks {
 #define SCHED_CPUMASK_VAR(v, a)         cpumask_t *v = (cpumask_t *) \
                         ((unsigned long)(a) + offsetof(struct allmasks, v))
 
+static int default_relax_domain_level = -1;
+
+static int __init setup_relax_domain_level(char *str)
+{
+        default_relax_domain_level = simple_strtoul(str, NULL, 0);
+        return 1;
+}
+__setup("relax_domain_level=", setup_relax_domain_level);
+
+static void set_domain_attribute(struct sched_domain *sd,
+                                 struct sched_domain_attr *attr)
+{
+        int request;
+
+        if (!attr || attr->relax_domain_level < 0) {
+                if (default_relax_domain_level < 0)
+                        return;
+                else
+                        request = default_relax_domain_level;
+        } else
+                request = attr->relax_domain_level;
+        if (request < sd->level) {
+                /* turn off idle balance on this domain */
+                sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
+        } else {
+                /* turn on idle balance on this domain */
+                sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
+        }
+}
+
 /*
  * Build sched domains for a given set of cpus and attach the sched domains
  * to the individual cpus
  */
-static int build_sched_domains(const cpumask_t *cpu_map)
+static int __build_sched_domains(const cpumask_t *cpu_map,
+                                 struct sched_domain_attr *attr)
 {
         int i;
         struct root_domain *rd;
@@ -6887,6 +6919,7 @@ static int build_sched_domains(const cpumask_t *cpu_map)
                                 SD_NODES_PER_DOMAIN*cpus_weight(*nodemask)) {
                         sd = &per_cpu(allnodes_domains, i);
                         SD_INIT(sd, ALLNODES);
+                        set_domain_attribute(sd, attr);
                         sd->span = *cpu_map;
                         cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
                         p = sd;
@@ -6896,6 +6929,7 @@ static int build_sched_domains(const cpumask_t *cpu_map)
 
                 sd = &per_cpu(node_domains, i);
                 SD_INIT(sd, NODE);
+                set_domain_attribute(sd, attr);
                 sched_domain_node_span(cpu_to_node(i), &sd->span);
                 sd->parent = p;
                 if (p)
@@ -6906,6 +6940,7 @@ static int build_sched_domains(const cpumask_t *cpu_map)
                 p = sd;
                 sd = &per_cpu(phys_domains, i);
                 SD_INIT(sd, CPU);
+                set_domain_attribute(sd, attr);
                 sd->span = *nodemask;
                 sd->parent = p;
                 if (p)
@@ -6916,6 +6951,7 @@ static int build_sched_domains(const cpumask_t *cpu_map)
                 p = sd;
                 sd = &per_cpu(core_domains, i);
                 SD_INIT(sd, MC);
+                set_domain_attribute(sd, attr);
                 sd->span = cpu_coregroup_map(i);
                 cpus_and(sd->span, sd->span, *cpu_map);
                 sd->parent = p;
@@ -6927,6 +6963,7 @@ static int build_sched_domains(const cpumask_t *cpu_map)
                 p = sd;
                 sd = &per_cpu(cpu_domains, i);
                 SD_INIT(sd, SIBLING);
+                set_domain_attribute(sd, attr);
                 sd->span = per_cpu(cpu_sibling_map, i);
                 cpus_and(sd->span, sd->span, *cpu_map);
                 sd->parent = p;
@@ -7124,8 +7161,15 @@ error:
 #endif
 }
 
+static int build_sched_domains(const cpumask_t *cpu_map)
+{
+        return __build_sched_domains(cpu_map, NULL);
+}
+
 static cpumask_t *doms_cur;     /* current sched domains */
 static int ndoms_cur;           /* number of sched domains in 'doms_cur' */
+static struct sched_domain_attr *dattr_cur;     /* attribues of custom domains
+                                                   in 'doms_cur' */
 
 /*
  * Special case: If a kmalloc of a doms_cur partition (array of
@@ -7153,6 +7197,7 @@ static int arch_init_sched_domains(const cpumask_t *cpu_map)
         if (!doms_cur)
                 doms_cur = &fallback_doms;
         cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map);
+        dattr_cur = NULL;
         err = build_sched_domains(doms_cur);
         register_sched_domain_sysctl();
 
@@ -7182,6 +7227,22 @@ static void detach_destroy_domains(const cpumask_t *cpu_map)
         arch_destroy_sched_domains(cpu_map, &tmpmask);
 }
 
+/* handle null as "default" */
+static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
+                        struct sched_domain_attr *new, int idx_new)
+{
+        struct sched_domain_attr tmp;
+
+        /* fast path */
+        if (!new && !cur)
+                return 1;
+
+        tmp = SD_ATTR_INIT;
+        return !memcmp(cur ? (cur + idx_cur) : &tmp,
+                        new ? (new + idx_new) : &tmp,
+                        sizeof(struct sched_domain_attr));
+}
+
 /*
  * Partition sched domains as specified by the 'ndoms_new'
  * cpumasks in the array doms_new[] of cpumasks. This compares
@@ -7203,7 +7264,8 @@ static void detach_destroy_domains(const cpumask_t *cpu_map)
  *
  * Call with hotplug lock held
  */
-void partition_sched_domains(int ndoms_new, cpumask_t *doms_new)
+void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
+                             struct sched_domain_attr *dattr_new)
 {
         int i, j;
 
@@ -7216,12 +7278,14 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new)
                 ndoms_new = 1;
                 doms_new = &fallback_doms;
                 cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
+                dattr_new = NULL;
         }
 
         /* Destroy deleted domains */
         for (i = 0; i < ndoms_cur; i++) {
                 for (j = 0; j < ndoms_new; j++) {
-                        if (cpus_equal(doms_cur[i], doms_new[j]))
+                        if (cpus_equal(doms_cur[i], doms_new[j])
+                            && dattrs_equal(dattr_cur, i, dattr_new, j))
                                 goto match1;
                 }
                 /* no match - a current sched domain not in new doms_new[] */
@@ -7233,11 +7297,13 @@ match1:
         /* Build new domains */
         for (i = 0; i < ndoms_new; i++) {
                 for (j = 0; j < ndoms_cur; j++) {
-                        if (cpus_equal(doms_new[i], doms_cur[j]))
+                        if (cpus_equal(doms_new[i], doms_cur[j])
+                            && dattrs_equal(dattr_new, i, dattr_cur, j))
                                 goto match2;
                 }
                 /* no match - add a new doms_new */
-                build_sched_domains(doms_new + i);
+                __build_sched_domains(doms_new + i,
+                                        dattr_new ? dattr_new + i : NULL);
 match2:
                 ;
         }
@@ -7245,7 +7311,9 @@ match2:
         /* Remember the new sched domains */
         if (doms_cur != &fallback_doms)
                 kfree(doms_cur);
+        kfree(dattr_cur);       /* kfree(NULL) is safe */
         doms_cur = doms_new;
+        dattr_cur = dattr_new;
         ndoms_cur = ndoms_new;
 
         register_sched_domain_sysctl();
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index de4250c53a19..b43748efaa7f 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -940,7 +940,9 @@ static int wake_idle(int cpu, struct task_struct *p)
                 return cpu;
 
         for_each_domain(cpu, sd) {
-                if (sd->flags & SD_WAKE_IDLE) {
+                if ((sd->flags & SD_WAKE_IDLE)
+                    || ((sd->flags & SD_WAKE_IDLE_FAR)
+                        && !task_hot(p, task_rq(p)->clock, sd))) {
                         cpus_and(tmp, sd->span, p->cpus_allowed);
                         for_each_cpu_mask(i, tmp) {
                                 if (idle_cpu(i)) {