Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 563 insertions, 0 deletions

diff --git a/kernel/profile.c b/kernel/profile.c
new file mode 100644
index 00000000000..a38fa70075f
--- /dev/null
+++ b/kernel/profile.c
@@ -0,0 +1,563 @@
+/*
+ *  linux/kernel/profile.c
+ *  Simple profiling. Manages a direct-mapped profile hit count buffer,
+ *  with configurable resolution, support for restricting the cpus on
+ *  which profiling is done, and switching between cpu time and
+ *  schedule() calls via kernel command line parameters passed at boot.
+ *
+ *  Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
+ *	Red Hat, July 2004
+ *  Consolidation of architecture support code for profiling,
+ *	William Irwin, Oracle, July 2004
+ *  Amortized hit count accounting via per-cpu open-addressed hashtables
+ *	to resolve timer interrupt livelocks, William Irwin, Oracle, 2004
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/profile.h>
+#include <linux/bootmem.h>
+#include <linux/notifier.h>
+#include <linux/mm.h>
+#include <linux/cpumask.h>
+#include <linux/cpu.h>
+#include <linux/profile.h>
+#include <linux/highmem.h>
+#include <asm/sections.h>
+#include <asm/semaphore.h>
+
+struct profile_hit {
+	u32 pc, hits;
+};
+#define PROFILE_GRPSHIFT	3
+#define PROFILE_GRPSZ		(1 << PROFILE_GRPSHIFT)
+#define NR_PROFILE_HIT		(PAGE_SIZE/sizeof(struct profile_hit))
+#define NR_PROFILE_GRP		(NR_PROFILE_HIT/PROFILE_GRPSZ)
+
+/* Oprofile timer tick hook */
+int (*timer_hook)(struct pt_regs *);
+
+static atomic_t *prof_buffer;
+static unsigned long prof_len, prof_shift;
+static int prof_on;
+static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
+#ifdef CONFIG_SMP
+static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
+static DEFINE_PER_CPU(int, cpu_profile_flip);
+static DECLARE_MUTEX(profile_flip_mutex);
+#endif /* CONFIG_SMP */
+
+static int __init profile_setup(char * str)
+{
+	int par;
+
+	if (!strncmp(str, "schedule", 8)) {
+		prof_on = SCHED_PROFILING;
+		printk(KERN_INFO "kernel schedule profiling enabled\n");
+		if (str[7] == ',')
+			str += 8;
+	}
+	if (get_option(&str,&par)) {
+		prof_shift = par;
+		prof_on = CPU_PROFILING;
+		printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
+			prof_shift);
+	}
+	return 1;
+}
+__setup("profile=", profile_setup);
+
+
+void __init profile_init(void)
+{
+	if (!prof_on) 
+		return;
+ 
+	/* only text is profiled */
+	prof_len = (_etext - _stext) >> prof_shift;
+	prof_buffer = alloc_bootmem(prof_len*sizeof(atomic_t));
+}
+
+/* Profile event notifications */
+ 
+#ifdef CONFIG_PROFILING
+ 
+static DECLARE_RWSEM(profile_rwsem);
+static DEFINE_RWLOCK(handoff_lock);
+static struct notifier_block * task_exit_notifier;
+static struct notifier_block * task_free_notifier;
+static struct notifier_block * munmap_notifier;
+ 
+void profile_task_exit(struct task_struct * task)
+{
+	down_read(&profile_rwsem);
+	notifier_call_chain(&task_exit_notifier, 0, task);
+	up_read(&profile_rwsem);
+}
+ 
+int profile_handoff_task(struct task_struct * task)
+{
+	int ret;
+	read_lock(&handoff_lock);
+	ret = notifier_call_chain(&task_free_notifier, 0, task);
+	read_unlock(&handoff_lock);
+	return (ret == NOTIFY_OK) ? 1 : 0;
+}
+
+void profile_munmap(unsigned long addr)
+{
+	down_read(&profile_rwsem);
+	notifier_call_chain(&munmap_notifier, 0, (void *)addr);
+	up_read(&profile_rwsem);
+}
+
+int task_handoff_register(struct notifier_block * n)
+{
+	int err = -EINVAL;
+
+	write_lock(&handoff_lock);
+	err = notifier_chain_register(&task_free_notifier, n);
+	write_unlock(&handoff_lock);
+	return err;
+}
+
+int task_handoff_unregister(struct notifier_block * n)
+{
+	int err = -EINVAL;
+
+	write_lock(&handoff_lock);
+	err = notifier_chain_unregister(&task_free_notifier, n);
+	write_unlock(&handoff_lock);
+	return err;
+}
+
+int profile_event_register(enum profile_type type, struct notifier_block * n)
+{
+	int err = -EINVAL;
+ 
+	down_write(&profile_rwsem);
+ 
+	switch (type) {
+		case PROFILE_TASK_EXIT:
+			err = notifier_chain_register(&task_exit_notifier, n);
+			break;
+		case PROFILE_MUNMAP:
+			err = notifier_chain_register(&munmap_notifier, n);
+			break;
+	}
+ 
+	up_write(&profile_rwsem);
+ 
+	return err;
+}
+
+ 
+int profile_event_unregister(enum profile_type type, struct notifier_block * n)
+{
+	int err = -EINVAL;
+ 
+	down_write(&profile_rwsem);
+ 
+	switch (type) {
+		case PROFILE_TASK_EXIT:
+			err = notifier_chain_unregister(&task_exit_notifier, n);
+			break;
+		case PROFILE_MUNMAP:
+			err = notifier_chain_unregister(&munmap_notifier, n);
+			break;
+	}
+
+	up_write(&profile_rwsem);
+	return err;
+}
+
+int register_timer_hook(int (*hook)(struct pt_regs *))
+{
+	if (timer_hook)
+		return -EBUSY;
+	timer_hook = hook;
+	return 0;
+}
+
+void unregister_timer_hook(int (*hook)(struct pt_regs *))
+{
+	WARN_ON(hook != timer_hook);
+	timer_hook = NULL;
+	/* make sure all CPUs see the NULL hook */
+	synchronize_kernel();
+}
+
+EXPORT_SYMBOL_GPL(register_timer_hook);
+EXPORT_SYMBOL_GPL(unregister_timer_hook);
+EXPORT_SYMBOL_GPL(task_handoff_register);
+EXPORT_SYMBOL_GPL(task_handoff_unregister);
+
+#endif /* CONFIG_PROFILING */
+
+EXPORT_SYMBOL_GPL(profile_event_register);
+EXPORT_SYMBOL_GPL(profile_event_unregister);
+
+#ifdef CONFIG_SMP
+/*
+ * Each cpu has a pair of open-addressed hashtables for pending
+ * profile hits. read_profile() IPI's all cpus to request them
+ * to flip buffers and flushes their contents to prof_buffer itself.
+ * Flip requests are serialized by the profile_flip_mutex. The sole
+ * use of having a second hashtable is for avoiding cacheline
+ * contention that would otherwise happen during flushes of pending
+ * profile hits required for the accuracy of reported profile hits
+ * and so resurrect the interrupt livelock issue.
+ *
+ * The open-addressed hashtables are indexed by profile buffer slot
+ * and hold the number of pending hits to that profile buffer slot on
+ * a cpu in an entry. When the hashtable overflows, all pending hits
+ * are accounted to their corresponding profile buffer slots with
+ * atomic_add() and the hashtable emptied. As numerous pending hits
+ * may be accounted to a profile buffer slot in a hashtable entry,
+ * this amortizes a number of atomic profile buffer increments likely
+ * to be far larger than the number of entries in the hashtable,
+ * particularly given that the number of distinct profile buffer
+ * positions to which hits are accounted during short intervals (e.g.
+ * several seconds) is usually very small. Exclusion from buffer
+ * flipping is provided by interrupt disablement (note that for
+ * SCHED_PROFILING profile_hit() may be called from process context).
+ * The hash function is meant to be lightweight as opposed to strong,
+ * and was vaguely inspired by ppc64 firmware-supported inverted
+ * pagetable hash functions, but uses a full hashtable full of finite
+ * collision chains, not just pairs of them.
+ *
+ * -- wli
+ */
+static void __profile_flip_buffers(void *unused)
+{
+	int cpu = smp_processor_id();
+
+	per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
+}
+
+static void profile_flip_buffers(void)
+{
+	int i, j, cpu;
+
+	down(&profile_flip_mutex);
+	j = per_cpu(cpu_profile_flip, get_cpu());
+	put_cpu();
+	on_each_cpu(__profile_flip_buffers, NULL, 0, 1);
+	for_each_online_cpu(cpu) {
+		struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
+		for (i = 0; i < NR_PROFILE_HIT; ++i) {
+			if (!hits[i].hits) {
+				if (hits[i].pc)
+					hits[i].pc = 0;
+				continue;
+			}
+			atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
+			hits[i].hits = hits[i].pc = 0;
+		}
+	}
+	up(&profile_flip_mutex);
+}
+
+static void profile_discard_flip_buffers(void)
+{
+	int i, cpu;
+
+	down(&profile_flip_mutex);
+	i = per_cpu(cpu_profile_flip, get_cpu());
+	put_cpu();
+	on_each_cpu(__profile_flip_buffers, NULL, 0, 1);
+	for_each_online_cpu(cpu) {
+		struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
+		memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
+	}
+	up(&profile_flip_mutex);
+}
+
+void profile_hit(int type, void *__pc)
+{
+	unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
+	int i, j, cpu;
+	struct profile_hit *hits;
+
+	if (prof_on != type || !prof_buffer)
+		return;
+	pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
+	i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
+	secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
+	cpu = get_cpu();
+	hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
+	if (!hits) {
+		put_cpu();
+		return;
+	}
+	local_irq_save(flags);
+	do {
+		for (j = 0; j < PROFILE_GRPSZ; ++j) {
+			if (hits[i + j].pc == pc) {
+				hits[i + j].hits++;
+				goto out;
+			} else if (!hits[i + j].hits) {
+				hits[i + j].pc = pc;
+				hits[i + j].hits = 1;
+				goto out;
+			}
+		}
+		i = (i + secondary) & (NR_PROFILE_HIT - 1);
+	} while (i != primary);
+	atomic_inc(&prof_buffer[pc]);
+	for (i = 0; i < NR_PROFILE_HIT; ++i) {
+		atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
+		hits[i].pc = hits[i].hits = 0;
+	}
+out:
+	local_irq_restore(flags);
+	put_cpu();
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int __devinit profile_cpu_callback(struct notifier_block *info,
+					unsigned long action, void *__cpu)
+{
+	int node, cpu = (unsigned long)__cpu;
+	struct page *page;
+
+	switch (action) {
+	case CPU_UP_PREPARE:
+		node = cpu_to_node(cpu);
+		per_cpu(cpu_profile_flip, cpu) = 0;
+		if (!per_cpu(cpu_profile_hits, cpu)[1]) {
+			page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+			if (!page)
+				return NOTIFY_BAD;
+			per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);
+		}
+		if (!per_cpu(cpu_profile_hits, cpu)[0]) {
+			page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+			if (!page)
+				goto out_free;
+			per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);
+		}
+		break;
+	out_free:
+		page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
+		per_cpu(cpu_profile_hits, cpu)[1] = NULL;
+		__free_page(page);
+		return NOTIFY_BAD;
+	case CPU_ONLINE:
+		cpu_set(cpu, prof_cpu_mask);
+		break;
+	case CPU_UP_CANCELED:
+	case CPU_DEAD:
+		cpu_clear(cpu, prof_cpu_mask);
+		if (per_cpu(cpu_profile_hits, cpu)[0]) {
+			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
+			per_cpu(cpu_profile_hits, cpu)[0] = NULL;
+			__free_page(page);
+		}
+		if (per_cpu(cpu_profile_hits, cpu)[1]) {
+			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
+			per_cpu(cpu_profile_hits, cpu)[1] = NULL;
+			__free_page(page);
+		}
+		break;
+	}
+	return NOTIFY_OK;
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+#else /* !CONFIG_SMP */
+#define profile_flip_buffers()		do { } while (0)
+#define profile_discard_flip_buffers()	do { } while (0)
+
+void profile_hit(int type, void *__pc)
+{
+	unsigned long pc;
+
+	if (prof_on != type || !prof_buffer)
+		return;
+	pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
+	atomic_inc(&prof_buffer[min(pc, prof_len - 1)]);
+}
+#endif /* !CONFIG_SMP */
+
+void profile_tick(int type, struct pt_regs *regs)
+{
+	if (type == CPU_PROFILING && timer_hook)
+		timer_hook(regs);
+	if (!user_mode(regs) && cpu_isset(smp_processor_id(), prof_cpu_mask))
+		profile_hit(type, (void *)profile_pc(regs));
+}
+
+#ifdef CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+#include <asm/uaccess.h>
+#include <asm/ptrace.h>
+
+static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
+			int count, int *eof, void *data)
+{
+	int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
+	if (count - len < 2)
+		return -EINVAL;
+	len += sprintf(page + len, "\n");
+	return len;
+}
+
+static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffer,
+					unsigned long count, void *data)
+{
+	cpumask_t *mask = (cpumask_t *)data;
+	unsigned long full_count = count, err;
+	cpumask_t new_value;
+
+	err = cpumask_parse(buffer, count, new_value);
+	if (err)
+		return err;
+
+	*mask = new_value;
+	return full_count;
+}
+
+void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir)
+{
+	struct proc_dir_entry *entry;
+
+	/* create /proc/irq/prof_cpu_mask */
+	if (!(entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir)))
+		return;
+	entry->nlink = 1;
+	entry->data = (void *)&prof_cpu_mask;
+	entry->read_proc = prof_cpu_mask_read_proc;
+	entry->write_proc = prof_cpu_mask_write_proc;
+}
+
+/*
+ * This function accesses profiling information. The returned data is
+ * binary: the sampling step and the actual contents of the profile
+ * buffer. Use of the program readprofile is recommended in order to
+ * get meaningful info out of these data.
+ */
+static ssize_t
+read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	unsigned long p = *ppos;
+	ssize_t read;
+	char * pnt;
+	unsigned int sample_step = 1 << prof_shift;
+
+	profile_flip_buffers();
+	if (p >= (prof_len+1)*sizeof(unsigned int))
+		return 0;
+	if (count > (prof_len+1)*sizeof(unsigned int) - p)
+		count = (prof_len+1)*sizeof(unsigned int) - p;
+	read = 0;
+
+	while (p < sizeof(unsigned int) && count > 0) {
+		put_user(*((char *)(&sample_step)+p),buf);
+		buf++; p++; count--; read++;
+	}
+	pnt = (char *)prof_buffer + p - sizeof(atomic_t);
+	if (copy_to_user(buf,(void *)pnt,count))
+		return -EFAULT;
+	read += count;
+	*ppos += read;
+	return read;
+}
+
+/*
+ * Writing to /proc/profile resets the counters
+ *
+ * Writing a 'profiling multiplier' value into it also re-sets the profiling
+ * interrupt frequency, on architectures that support this.
+ */
+static ssize_t write_profile(struct file *file, const char __user *buf,
+			     size_t count, loff_t *ppos)
+{
+#ifdef CONFIG_SMP
+	extern int setup_profiling_timer (unsigned int multiplier);
+
+	if (count == sizeof(int)) {
+		unsigned int multiplier;
+
+		if (copy_from_user(&multiplier, buf, sizeof(int)))
+			return -EFAULT;
+
+		if (setup_profiling_timer(multiplier))
+			return -EINVAL;
+	}
+#endif
+	profile_discard_flip_buffers();
+	memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
+	return count;
+}
+
+static struct file_operations proc_profile_operations = {
+	.read		= read_profile,
+	.write		= write_profile,
+};
+
+#ifdef CONFIG_SMP
+static void __init profile_nop(void *unused)
+{
+}
+
+static int __init create_hash_tables(void)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		int node = cpu_to_node(cpu);
+		struct page *page;
+
+		page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+		if (!page)
+			goto out_cleanup;
+		per_cpu(cpu_profile_hits, cpu)[1]
+				= (struct profile_hit *)page_address(page);
+		page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+		if (!page)
+			goto out_cleanup;
+		per_cpu(cpu_profile_hits, cpu)[0]
+				= (struct profile_hit *)page_address(page);
+	}
+	return 0;
+out_cleanup:
+	prof_on = 0;
+	mb();
+	on_each_cpu(profile_nop, NULL, 0, 1);
+	for_each_online_cpu(cpu) {
+		struct page *page;
+
+		if (per_cpu(cpu_profile_hits, cpu)[0]) {
+			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
+			per_cpu(cpu_profile_hits, cpu)[0] = NULL;
+			__free_page(page);
+		}
+		if (per_cpu(cpu_profile_hits, cpu)[1]) {
+			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
+			per_cpu(cpu_profile_hits, cpu)[1] = NULL;
+			__free_page(page);
+		}
+	}
+	return -1;
+}
+#else
+#define create_hash_tables()			({ 0; })
+#endif
+
+static int __init create_proc_profile(void)
+{
+	struct proc_dir_entry *entry;
+
+	if (!prof_on)
+		return 0;
+	if (create_hash_tables())
+		return -1;
+	if (!(entry = create_proc_entry("profile", S_IWUSR | S_IRUGO, NULL)))
+		return 0;
+	entry->proc_fops = &proc_profile_operations;
+	entry->size = (1+prof_len) * sizeof(atomic_t);
+	hotcpu_notifier(profile_cpu_callback, 0);
+	return 0;
+}
+module_init(create_proc_profile);
+#endif /* CONFIG_PROC_FS */