[PATCH 12/12] cpu/node mask: reduce stack usage using MASK_NONE, MASK_ALL

From: Mike Travis
Date: Tue Mar 25 2008 - 21:42:30 EST

Replace usages of CPU_MASK_NONE, CPU_MASK_ALL, NODE_MASK_NONE,
NODE_MASK_ALL to reduce stack requirements for large NR_CPUS
and MAXNODES counts. In some cases, the cpumask variable was
initialized but then overwritten with another value. This is
the case for changes like this:

- cpumask_t oldmask = CPU_MASK_ALL;
+ cpumask_t oldmask;


Based on:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86.git

# x86
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>

Signed-off-by: Mike Travis <travis@xxxxxxx>
---
arch/x86/kernel/cpu/cpufreq/powernow-k8.c | 6 +++---
arch/x86/kernel/cpu/mcheck/mce_amd_64.c | 4 ++--
arch/x86/kernel/genapic_flat_64.c | 4 +++-
arch/x86/kernel/io_apic_64.c | 2 +-
include/linux/cpumask.h | 6 ++++++
init/main.c | 7 ++++++-
kernel/cpu.c | 2 +-
kernel/cpuset.c | 10 +++++-----
kernel/irq/chip.c | 2 +-
kernel/kmod.c | 2 +-
kernel/kthread.c | 4 ++--
kernel/rcutorture.c | 3 ++-
kernel/sched.c | 8 ++++----
mm/allocpercpu.c | 3 ++-
14 files changed, 39 insertions(+), 24 deletions(-)

--- linux.trees.git.orig/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
+++ linux.trees.git/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
@@ -478,7 +478,7 @@ static int core_voltage_post_transition(

static int check_supported_cpu(unsigned int cpu)
{
- cpumask_t oldmask = CPU_MASK_ALL;
+ cpumask_t oldmask;
u32 eax, ebx, ecx, edx;
unsigned int rc = 0;

@@ -1015,7 +1015,7 @@ static int transition_frequency_pstate(s
/* Driver entry point to switch to the target frequency */
static int powernowk8_target(struct cpufreq_policy *pol, unsigned targfreq, unsigned relation)
{
- cpumask_t oldmask = CPU_MASK_ALL;
+ cpumask_t oldmask;
struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);
u32 checkfid;
u32 checkvid;
@@ -1104,7 +1104,7 @@ static int powernowk8_verify(struct cpuf
static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
{
struct powernow_k8_data *data;
- cpumask_t oldmask = CPU_MASK_ALL;
+ cpumask_t oldmask;
int rc;

if (!cpu_online(pol->cpu))
--- linux.trees.git.orig/arch/x86/kernel/cpu/mcheck/mce_amd_64.c
+++ linux.trees.git/arch/x86/kernel/cpu/mcheck/mce_amd_64.c
@@ -255,7 +255,7 @@ static void affinity_set(unsigned int cp
cpumask_t *newmask)
{
*oldmask = current->cpus_allowed;
- *newmask = CPU_MASK_NONE;
+ cpus_clear(*newmask);
cpu_set(cpu, *newmask);
set_cpus_allowed(current, newmask);
}
@@ -468,7 +468,7 @@ static __cpuinit int threshold_create_ba
{
int i, err = 0;
struct threshold_bank *b = NULL;
- cpumask_t oldmask = CPU_MASK_NONE, newmask;
+ cpumask_t oldmask, newmask;
char name[32];

sprintf(name, "threshold_bank%i", bank);
--- linux.trees.git.orig/arch/x86/kernel/genapic_flat_64.c
+++ linux.trees.git/arch/x86/kernel/genapic_flat_64.c
@@ -138,7 +138,9 @@ static cpumask_t physflat_target_cpus(vo

static cpumask_t physflat_vector_allocation_domain(int cpu)
{
- cpumask_t domain = CPU_MASK_NONE;
+ cpumask_t domain;
+
+ cpus_clear(domain);
cpu_set(cpu, domain);
return domain;
}
--- linux.trees.git.orig/arch/x86/kernel/io_apic_64.c
+++ linux.trees.git/arch/x86/kernel/io_apic_64.c
@@ -770,7 +770,7 @@ static void __clear_irq_vector(int irq)
per_cpu(vector_irq, cpu)[vector] = -1;

cfg->vector = 0;
- cfg->domain = CPU_MASK_NONE;
+ cpus_clear(cfg->domain);
}

void __setup_vector_irq(int cpu)
--- linux.trees.git.orig/include/linux/cpumask.h
+++ linux.trees.git/include/linux/cpumask.h
@@ -244,6 +244,8 @@ int __next_cpu(int n, const cpumask_t *s
}))
static inline void setup_cpumask_of_cpu(int num) {}

+#define CPU_MASK_ALL_PTR (&CPU_MASK_ALL)
+
#else

#define CPU_MASK_ALL \
@@ -252,6 +254,10 @@ static inline void setup_cpumask_of_cpu(
[BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
} }

+/* cpu_mask_all is in init/main.c */
+extern cpumask_t cpu_mask_all;
+#define CPU_MASK_ALL_PTR (&cpu_mask_all)
+
/* cpumask_of_cpu_map is in init/main.c */
#define cpumask_of_cpu(cpu) (cpumask_of_cpu_map[cpu])
extern cpumask_t *cpumask_of_cpu_map;
--- linux.trees.git.orig/init/main.c
+++ linux.trees.git/init/main.c
@@ -194,6 +194,11 @@ static const char *panic_later, *panic_p

extern struct obs_kernel_param __setup_start[], __setup_end[];

+#if NR_CPUS > BITS_PER_LONG
+cpumask_t cpu_mask_all = CPU_MASK_ALL;
+EXPORT_SYMBOL(cpu_mask_all);
+#endif
+
static int __init obsolete_checksetup(char *line)
{
struct obs_kernel_param *p;
@@ -845,7 +850,7 @@ static int __init kernel_init(void * unu
/*
* init can run on any cpu.
*/
- set_cpus_allowed(current, &CPU_MASK_ALL);
+ set_cpus_allowed(current, CPU_MASK_ALL_PTR);
/*
* Tell the world that we're going to be the grim
* reaper of innocent orphaned children.
--- linux.trees.git.orig/kernel/cpu.c
+++ linux.trees.git/kernel/cpu.c
@@ -232,7 +232,7 @@ static int _cpu_down(unsigned int cpu, i

/* Ensure that we are not runnable on dying cpu */
old_allowed = current->cpus_allowed;
- tmp = CPU_MASK_ALL;
+ cpus_setall(tmp);
cpu_clear(cpu, tmp);
set_cpus_allowed(current, &tmp);

--- linux.trees.git.orig/kernel/cpuset.c
+++ linux.trees.git/kernel/cpuset.c
@@ -1556,8 +1556,8 @@ static struct cgroup_subsys_state *cpuse
if (is_spread_slab(parent))
set_bit(CS_SPREAD_SLAB, &cs->flags);
set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
- cs->cpus_allowed = CPU_MASK_NONE;
- cs->mems_allowed = NODE_MASK_NONE;
+ cpus_clear(cs->cpus_allowed);
+ nodes_clear(cs->mems_allowed);
cs->mems_generation = cpuset_mems_generation++;
fmeter_init(&cs->fmeter);

@@ -1626,8 +1626,8 @@ int __init cpuset_init(void)
{
int err = 0;

- top_cpuset.cpus_allowed = CPU_MASK_ALL;
- top_cpuset.mems_allowed = NODE_MASK_ALL;
+ cpus_setall(top_cpuset.cpus_allowed);
+ nodes_setall(top_cpuset.mems_allowed);

fmeter_init(&top_cpuset.fmeter);
top_cpuset.mems_generation = cpuset_mems_generation++;
@@ -1873,7 +1873,7 @@ void cpuset_cpus_allowed_locked(struct t

void cpuset_init_current_mems_allowed(void)
{
- current->mems_allowed = NODE_MASK_ALL;
+ nodes_setall(current->mems_allowed);
}

/**
--- linux.trees.git.orig/kernel/irq/chip.c
+++ linux.trees.git/kernel/irq/chip.c
@@ -47,7 +47,7 @@ void dynamic_irq_init(unsigned int irq)
desc->irq_count = 0;
desc->irqs_unhandled = 0;
#ifdef CONFIG_SMP
- desc->affinity = CPU_MASK_ALL;
+ cpus_setall(desc->affinity);
#endif
spin_unlock_irqrestore(&desc->lock, flags);
}
--- linux.trees.git.orig/kernel/kmod.c
+++ linux.trees.git/kernel/kmod.c
@@ -165,7 +165,7 @@ static int ____call_usermodehelper(void
}

/* We can run anywhere, unlike our parent keventd(). */
- set_cpus_allowed(current, &CPU_MASK_ALL);
+ set_cpus_allowed(current, CPU_MASK_ALL_PTR);

/*
* Our parent is keventd, which runs with elevated scheduling priority.
--- linux.trees.git.orig/kernel/kthread.c
+++ linux.trees.git/kernel/kthread.c
@@ -107,7 +107,7 @@ static void create_kthread(struct kthrea
*/
sched_setscheduler(create->result, SCHED_NORMAL, &param);
set_user_nice(create->result, KTHREAD_NICE_LEVEL);
- set_cpus_allowed(create->result, &CPU_MASK_ALL);
+ set_cpus_allowed(create->result, CPU_MASK_ALL_PTR);
}
complete(&create->done);
}
@@ -232,7 +232,7 @@ int kthreadd(void *unused)
set_task_comm(tsk, "kthreadd");
ignore_signals(tsk);
set_user_nice(tsk, KTHREAD_NICE_LEVEL);
- set_cpus_allowed(tsk, &CPU_MASK_ALL);
+ set_cpus_allowed(tsk, CPU_MASK_ALL_PTR);

current->flags |= PF_NOFREEZE;

--- linux.trees.git.orig/kernel/rcutorture.c
+++ linux.trees.git/kernel/rcutorture.c
@@ -723,9 +723,10 @@ static int rcu_idle_cpu; /* Force all to
*/
static void rcu_torture_shuffle_tasks(void)
{
- cpumask_t tmp_mask = CPU_MASK_ALL;
+ cpumask_t tmp_mask;
int i;

+ cpus_setall(tmp_mask);
get_online_cpus();

/* No point in shuffling if there is only one online CPU (ex: UP) */
--- linux.trees.git.orig/kernel/sched.c
+++ linux.trees.git/kernel/sched.c
@@ -5502,7 +5502,7 @@ static void move_task_off_dead_cpu(int d
*/
static void migrate_nr_uninterruptible(struct rq *rq_src)
{
- struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL));
+ struct rq *rq_dest = cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR));
unsigned long flags;

local_irq_save(flags);
@@ -6220,7 +6220,7 @@ init_sched_build_groups(const cpumask_t
struct sched_group *first = NULL, *last = NULL;
int i;

- *covered = CPU_MASK_NONE;
+ cpus_clear(*covered);

for_each_cpu_mask(i, *span) {
struct sched_group *sg;
@@ -6230,7 +6230,7 @@ init_sched_build_groups(const cpumask_t
if (cpu_isset(i, *covered))
continue;

- sg->cpumask = CPU_MASK_NONE;
+ cpus_clear(sg->cpumask);
sg->__cpu_power = 0;

for_each_cpu_mask(j, *span) {
@@ -6790,7 +6790,7 @@ static int build_sched_domains(const cpu
int j;

*nodemask = node_to_cpumask(i);
- *covered = CPU_MASK_NONE;
+ cpus_clear(*covered);

cpus_and(*nodemask, *nodemask, *cpu_map);
if (cpus_empty(*nodemask)) {
--- linux.trees.git.orig/mm/allocpercpu.c
+++ linux.trees.git/mm/allocpercpu.c
@@ -82,9 +82,10 @@ EXPORT_SYMBOL_GPL(percpu_populate);
int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
cpumask_t *mask)
{
- cpumask_t populated = CPU_MASK_NONE;
+ cpumask_t populated;
int cpu;

+ cpus_clear(populated);
for_each_cpu_mask(cpu, *mask)
if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) {
__percpu_depopulate_mask(__pdata, &populated);

--
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