cpumask: reduce stack usage in SD_x_INIT initializers

  * Remove empty cpumask_t (and all non-zero/non-null) variables
    in SD_*_INIT macros.  Use memset(0) to clear.  Also, don't
    inline the initializer functions to save on stack space in
    build_sched_domains().

  * Merge change to include/linux/topology.h that uses the new
    node_to_cpumask_ptr function in the nr_cpus_node macro into
    this patch.

Depends on:
	[mm-patch]: asm-generic-add-node_to_cpumask_ptr-macro.patch
	[sched-devel]: sched: add new set_cpus_allowed_ptr function

Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 8 insertions, 38 deletions

diff --git a/include/linux/topology.h b/include/linux/topology.h
index bd14f8b30f09..4bb7074a2c3a 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -38,16 +38,15 @@
 #endif
 
 #ifndef nr_cpus_node
-#define nr_cpus_node(node)                                                      \
-        ({                                                                      \
-                cpumask_t __tmp__;                                              \
-                __tmp__ = node_to_cpumask(node);                                \
-                cpus_weight(__tmp__);                                           \
+#define nr_cpus_node(node)                              \
+        ({                                              \
+                node_to_cpumask_ptr(__tmp__, node);     \
+                cpus_weight(*__tmp__);                  \
         })
 #endif
 
-#define for_each_node_with_cpus(node)                                           \
-        for_each_online_node(node)                                              \
+#define for_each_node_with_cpus(node)                   \
+        for_each_online_node(node)                      \
                 if (nr_cpus_node(node))
 
 void arch_update_cpu_topology(void);
@@ -80,7 +79,9 @@ void arch_update_cpu_topology(void);
  * by defining their own arch-specific initializer in include/asm/topology.h.
  * A definition there will automagically override these default initializers
  * and allow arch-specific performance tuning of sched_domains.
+ * (Only non-zero and non-null fields need be specified.)
  */
+
 #ifdef CONFIG_SCHED_SMT
 /* MCD - Do we really need this?  It is always on if CONFIG_SCHED_SMT is,
  * so can't we drop this in favor of CONFIG_SCHED_SMT?
@@ -89,20 +90,10 @@ void arch_update_cpu_topology(void);
 /* Common values for SMT siblings */
 #ifndef SD_SIBLING_INIT
 #define SD_SIBLING_INIT (struct sched_domain) {         \
-        .span                   = CPU_MASK_NONE,        \
-        .parent                 = NULL,                 \
-        .child                  = NULL,                 \
-        .groups                 = NULL,                 \
         .min_interval           = 1,                    \
         .max_interval           = 2,                    \
         .busy_factor            = 64,                   \
         .imbalance_pct          = 110,                  \
-        .cache_nice_tries       = 0,                    \
-        .busy_idx               = 0,                    \
-        .idle_idx               = 0,                    \
-        .newidle_idx            = 0,                    \
-        .wake_idx               = 0,                    \
-        .forkexec_idx           = 0,                    \
         .flags                  = SD_LOAD_BALANCE       \
                                 | SD_BALANCE_NEWIDLE    \
                                 | SD_BALANCE_FORK       \
@@ -112,7 +103,6 @@ void arch_update_cpu_topology(void);
                                 | SD_SHARE_CPUPOWER,    \
         .last_balance           = jiffies,              \
         .balance_interval       = 1,                    \
-        .nr_balance_failed      = 0,                    \
 }
 #endif
 #endif /* CONFIG_SCHED_SMT */
@@ -121,18 +111,12 @@ void arch_update_cpu_topology(void);
 /* Common values for MC siblings. for now mostly derived from SD_CPU_INIT */
 #ifndef SD_MC_INIT
 #define SD_MC_INIT (struct sched_domain) {              \
-        .span                   = CPU_MASK_NONE,        \
-        .parent                 = NULL,                 \
-        .child                  = NULL,                 \
-        .groups                 = NULL,                 \
         .min_interval           = 1,                    \
         .max_interval           = 4,                    \
         .busy_factor            = 64,                   \
         .imbalance_pct          = 125,                  \
         .cache_nice_tries       = 1,                    \
         .busy_idx               = 2,                    \
-        .idle_idx               = 0,                    \
-        .newidle_idx            = 0,                    \
         .wake_idx               = 1,                    \
         .forkexec_idx           = 1,                    \
         .flags                  = SD_LOAD_BALANCE       \
@@ -144,7 +128,6 @@ void arch_update_cpu_topology(void);
                                 | BALANCE_FOR_MC_POWER, \
         .last_balance           = jiffies,              \
         .balance_interval       = 1,                    \
-        .nr_balance_failed      = 0,                    \
 }
 #endif
 #endif /* CONFIG_SCHED_MC */
@@ -152,10 +135,6 @@ void arch_update_cpu_topology(void);
 /* Common values for CPUs */
 #ifndef SD_CPU_INIT
 #define SD_CPU_INIT (struct sched_domain) {             \
-        .span                   = CPU_MASK_NONE,        \
-        .parent                 = NULL,                 \
-        .child                  = NULL,                 \
-        .groups                 = NULL,                 \
         .min_interval           = 1,                    \
         .max_interval           = 4,                    \
         .busy_factor            = 64,                   \
@@ -174,16 +153,11 @@ void arch_update_cpu_topology(void);
                                 | BALANCE_FOR_PKG_POWER,\
         .last_balance           = jiffies,              \
         .balance_interval       = 1,                    \
-        .nr_balance_failed      = 0,                    \
 }
 #endif
 
 /* sched_domains SD_ALLNODES_INIT for NUMA machines */
 #define SD_ALLNODES_INIT (struct sched_domain) {        \
-        .span                   = CPU_MASK_NONE,        \
-        .parent                 = NULL,                 \
-        .child                  = NULL,                 \
-        .groups                 = NULL,                 \
         .min_interval           = 64,                   \
         .max_interval           = 64*num_online_cpus(), \
         .busy_factor            = 128,                  \
@@ -191,14 +165,10 @@ void arch_update_cpu_topology(void);
         .cache_nice_tries       = 1,                    \
         .busy_idx               = 3,                    \
         .idle_idx               = 3,                    \
-        .newidle_idx            = 0, /* unused */       \
-        .wake_idx               = 0, /* unused */       \
-        .forkexec_idx           = 0, /* unused */       \
         .flags                  = SD_LOAD_BALANCE       \
                                 | SD_SERIALIZE, \
         .last_balance           = jiffies,              \
         .balance_interval       = 64,                   \
-        .nr_balance_failed      = 0,                    \
 }
 
 #ifdef CONFIG_NUMA