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authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-21 19:43:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-21 19:43:57 -0700
commitbf67f3a5c456a18f2e8d062f7e88506ef2cd9837 (patch)
tree2a2324b2572162059307db82f9238eeb25673a77 /kernel
parent226da0dbc84ed97f448523e2a4cb91c27fa68ed9 (diff)
parent203dacbdca977bedaba61ad2fca75d934060a5d5 (diff)
downloadlinux-bf67f3a5c456a18f2e8d062f7e88506ef2cd9837.tar.gz
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull smp hotplug cleanups from Thomas Gleixner: "This series is merily a cleanup of code copied around in arch/* and not changing any of the real cpu hotplug horrors yet. I wish I'd had something more substantial for 3.5, but I underestimated the lurking horror..." Fix up trivial conflicts in arch/{arm,sparc,x86}/Kconfig and arch/sparc/include/asm/thread_info_32.h * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits) um: Remove leftover declaration of alloc_task_struct_node() task_allocator: Use config switches instead of magic defines sparc: Use common threadinfo allocator score: Use common threadinfo allocator sh-use-common-threadinfo-allocator mn10300: Use common threadinfo allocator powerpc: Use common threadinfo allocator mips: Use common threadinfo allocator hexagon: Use common threadinfo allocator m32r: Use common threadinfo allocator frv: Use common threadinfo allocator cris: Use common threadinfo allocator x86: Use common threadinfo allocator c6x: Use common threadinfo allocator fork: Provide kmemcache based thread_info allocator tile: Use common threadinfo allocator fork: Provide weak arch_release_[task_struct|thread_info] functions fork: Move thread info gfp flags to header fork: Remove the weak insanity sh: Remove cpu_idle_wait() ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Makefile1
-rw-r--r--kernel/cpu.c13
-rw-r--r--kernel/fork.c69
-rw-r--r--kernel/sched/Makefile2
-rw-r--r--kernel/sched/core.c2
-rw-r--r--kernel/smp.c27
-rw-r--r--kernel/smpboot.c62
-rw-r--r--kernel/smpboot.h18
8 files changed, 171 insertions, 23 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index cb41b9547c9..6c07f30fa9b 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
obj-$(CONFIG_SMP) += smp.o
+obj-$(CONFIG_SMP) += smpboot.o
ifneq ($(CONFIG_SMP),y)
obj-y += up.o
endif
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 2060c6e5702..0e6353cf147 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -17,6 +17,8 @@
#include <linux/gfp.h>
#include <linux/suspend.h>
+#include "smpboot.h"
+
#ifdef CONFIG_SMP
/* Serializes the updates to cpu_online_mask, cpu_present_mask */
static DEFINE_MUTEX(cpu_add_remove_lock);
@@ -295,11 +297,19 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
int ret, nr_calls = 0;
void *hcpu = (void *)(long)cpu;
unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
+ struct task_struct *idle;
if (cpu_online(cpu) || !cpu_present(cpu))
return -EINVAL;
cpu_hotplug_begin();
+
+ idle = idle_thread_get(cpu);
+ if (IS_ERR(idle)) {
+ ret = PTR_ERR(idle);
+ goto out;
+ }
+
ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
if (ret) {
nr_calls--;
@@ -309,7 +319,7 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
}
/* Arch-specific enabling code. */
- ret = __cpu_up(cpu);
+ ret = __cpu_up(cpu, idle);
if (ret != 0)
goto out_notify;
BUG_ON(!cpu_online(cpu));
@@ -320,6 +330,7 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
out_notify:
if (ret != 0)
__cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
+out:
cpu_hotplug_done();
return ret;
diff --git a/kernel/fork.c b/kernel/fork.c
index 687a15d5624..9f9b296fa6d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -112,32 +112,67 @@ int nr_processes(void)
return total;
}
-#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
-# define alloc_task_struct_node(node) \
- kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node)
-# define free_task_struct(tsk) \
- kmem_cache_free(task_struct_cachep, (tsk))
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
static struct kmem_cache *task_struct_cachep;
+
+static inline struct task_struct *alloc_task_struct_node(int node)
+{
+ return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
+}
+
+void __weak arch_release_task_struct(struct task_struct *tsk) { }
+
+static inline void free_task_struct(struct task_struct *tsk)
+{
+ arch_release_task_struct(tsk);
+ kmem_cache_free(task_struct_cachep, tsk);
+}
#endif
-#ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR
+#ifndef CONFIG_ARCH_THREAD_INFO_ALLOCATOR
+void __weak arch_release_thread_info(struct thread_info *ti) { }
+
+/*
+ * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
+ * kmemcache based allocator.
+ */
+# if THREAD_SIZE >= PAGE_SIZE
static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
int node)
{
-#ifdef CONFIG_DEBUG_STACK_USAGE
- gfp_t mask = GFP_KERNEL | __GFP_ZERO;
-#else
- gfp_t mask = GFP_KERNEL;
-#endif
- struct page *page = alloc_pages_node(node, mask, THREAD_SIZE_ORDER);
+ struct page *page = alloc_pages_node(node, THREADINFO_GFP,
+ THREAD_SIZE_ORDER);
return page ? page_address(page) : NULL;
}
static inline void free_thread_info(struct thread_info *ti)
{
+ arch_release_thread_info(ti);
free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
}
+# else
+static struct kmem_cache *thread_info_cache;
+
+static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
+ int node)
+{
+ return kmem_cache_alloc_node(thread_info_cache, THREADINFO_GFP, node);
+}
+
+static void free_thread_info(struct thread_info *ti)
+{
+ arch_release_thread_info(ti);
+ kmem_cache_free(thread_info_cache, ti);
+}
+
+void thread_info_cache_init(void)
+{
+ thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
+ THREAD_SIZE, 0, NULL);
+ BUG_ON(thread_info_cache == NULL);
+}
+# endif
#endif
/* SLAB cache for signal_struct structures (tsk->signal) */
@@ -204,17 +239,11 @@ void __put_task_struct(struct task_struct *tsk)
}
EXPORT_SYMBOL_GPL(__put_task_struct);
-/*
- * macro override instead of weak attribute alias, to workaround
- * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions.
- */
-#ifndef arch_task_cache_init
-#define arch_task_cache_init()
-#endif
+void __init __weak arch_task_cache_init(void) { }
void __init fork_init(unsigned long mempages)
{
-#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
#ifndef ARCH_MIN_TASKALIGN
#define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
#endif
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 9a7dd35102a..173ea52f3af 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -16,5 +16,3 @@ obj-$(CONFIG_SMP) += cpupri.o
obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o
obj-$(CONFIG_SCHEDSTATS) += stats.o
obj-$(CONFIG_SCHED_DEBUG) += debug.o
-
-
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index eb4131b8ad6..ea8a4769fea 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -83,6 +83,7 @@
#include "sched.h"
#include "../workqueue_sched.h"
+#include "../smpboot.h"
#define CREATE_TRACE_POINTS
#include <trace/events/sched.h>
@@ -7062,6 +7063,7 @@ void __init sched_init(void)
/* May be allocated at isolcpus cmdline parse time */
if (cpu_isolated_map == NULL)
zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+ idle_thread_set_boot_cpu();
#endif
init_sched_fair_class();
diff --git a/kernel/smp.c b/kernel/smp.c
index 2f8b10ecf75..d0ae5b24875 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -13,6 +13,8 @@
#include <linux/smp.h>
#include <linux/cpu.h>
+#include "smpboot.h"
+
#ifdef CONFIG_USE_GENERIC_SMP_HELPERS
static struct {
struct list_head queue;
@@ -669,6 +671,8 @@ void __init smp_init(void)
{
unsigned int cpu;
+ idle_threads_init();
+
/* FIXME: This should be done in userspace --RR */
for_each_present_cpu(cpu) {
if (num_online_cpus() >= setup_max_cpus)
@@ -791,3 +795,26 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
}
}
EXPORT_SYMBOL(on_each_cpu_cond);
+
+static void do_nothing(void *unused)
+{
+}
+
+/**
+ * kick_all_cpus_sync - Force all cpus out of idle
+ *
+ * Used to synchronize the update of pm_idle function pointer. It's
+ * called after the pointer is updated and returns after the dummy
+ * callback function has been executed on all cpus. The execution of
+ * the function can only happen on the remote cpus after they have
+ * left the idle function which had been called via pm_idle function
+ * pointer. So it's guaranteed that nothing uses the previous pointer
+ * anymore.
+ */
+void kick_all_cpus_sync(void)
+{
+ /* Make sure the change is visible before we kick the cpus */
+ smp_mb();
+ smp_call_function(do_nothing, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
new file mode 100644
index 00000000000..e1a797e028a
--- /dev/null
+++ b/kernel/smpboot.c
@@ -0,0 +1,62 @@
+/*
+ * Common SMP CPU bringup/teardown functions
+ */
+#include <linux/err.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/percpu.h>
+
+#include "smpboot.h"
+
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+/*
+ * For the hotplug case we keep the task structs around and reuse
+ * them.
+ */
+static DEFINE_PER_CPU(struct task_struct *, idle_threads);
+
+struct task_struct * __cpuinit idle_thread_get(unsigned int cpu)
+{
+ struct task_struct *tsk = per_cpu(idle_threads, cpu);
+
+ if (!tsk)
+ return ERR_PTR(-ENOMEM);
+ init_idle(tsk, cpu);
+ return tsk;
+}
+
+void __init idle_thread_set_boot_cpu(void)
+{
+ per_cpu(idle_threads, smp_processor_id()) = current;
+}
+
+static inline void idle_init(unsigned int cpu)
+{
+ struct task_struct *tsk = per_cpu(idle_threads, cpu);
+
+ if (!tsk) {
+ tsk = fork_idle(cpu);
+ if (IS_ERR(tsk))
+ pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
+ else
+ per_cpu(idle_threads, cpu) = tsk;
+ }
+}
+
+/**
+ * idle_thread_init - Initialize the idle thread for a cpu
+ * @cpu: The cpu for which the idle thread should be initialized
+ *
+ * Creates the thread if it does not exist.
+ */
+void __init idle_threads_init(void)
+{
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu) {
+ if (cpu != smp_processor_id())
+ idle_init(cpu);
+ }
+}
+#endif
diff --git a/kernel/smpboot.h b/kernel/smpboot.h
new file mode 100644
index 00000000000..80c0acfb847
--- /dev/null
+++ b/kernel/smpboot.h
@@ -0,0 +1,18 @@
+#ifndef SMPBOOT_H
+#define SMPBOOT_H
+
+struct task_struct;
+
+int smpboot_prepare(unsigned int cpu);
+
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+struct task_struct *idle_thread_get(unsigned int cpu);
+void idle_thread_set_boot_cpu(void);
+void idle_threads_init(void);
+#else
+static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
+static inline void idle_thread_set_boot_cpu(void) { }
+static inline void idle_threads_init(void) { }
+#endif
+
+#endif