#include "trace.h"
-/* Global flag to disable all recording to ring buffers */
-static int ring_buffers_off __read_mostly;
+/*
+ * A fast way to enable or disable all ring buffers is to
+ * call tracing_on or tracing_off. Turning off the ring buffers
+ * prevents all ring buffers from being recorded to.
+ * Turning this switch on, makes it OK to write to the
+ * ring buffer, if the ring buffer is enabled itself.
+ *
+ * There's three layers that must be on in order to write
+ * to the ring buffer.
+ *
+ * 1) This global flag must be set.
+ * 2) The ring buffer must be enabled for recording.
+ * 3) The per cpu buffer must be enabled for recording.
+ *
+ * In case of an anomaly, this global flag has a bit set that
+ * will permantly disable all ring buffers.
+ */
+
+/*
+ * Global flag to disable all recording to ring buffers
+ * This has two bits: ON, DISABLED
+ *
+ * ON DISABLED
+ * ---- ----------
+ * 0 0 : ring buffers are off
+ * 1 0 : ring buffers are on
+ * X 1 : ring buffers are permanently disabled
+ */
+
+enum {
+ RB_BUFFERS_ON_BIT = 0,
+ RB_BUFFERS_DISABLED_BIT = 1,
+};
+
+enum {
+ RB_BUFFERS_ON = 1 << RB_BUFFERS_ON_BIT,
+ RB_BUFFERS_DISABLED = 1 << RB_BUFFERS_DISABLED_BIT,
+};
+
+static long ring_buffer_flags __read_mostly = RB_BUFFERS_ON;
/**
* tracing_on - enable all tracing buffers
*/
void tracing_on(void)
{
- ring_buffers_off = 0;
+ set_bit(RB_BUFFERS_ON_BIT, &ring_buffer_flags);
}
+EXPORT_SYMBOL_GPL(tracing_on);
/**
* tracing_off - turn off all tracing buffers
*/
void tracing_off(void)
{
- ring_buffers_off = 1;
+ clear_bit(RB_BUFFERS_ON_BIT, &ring_buffer_flags);
+}
+EXPORT_SYMBOL_GPL(tracing_off);
+
+/**
+ * tracing_off_permanent - permanently disable ring buffers
+ *
+ * This function, once called, will disable all ring buffers
+ * permanenty.
+ */
+void tracing_off_permanent(void)
+{
+ set_bit(RB_BUFFERS_DISABLED_BIT, &ring_buffer_flags);
}
#include "trace.h"
/* FIXME!!! */
u64 ring_buffer_time_stamp(int cpu)
{
+ u64 time;
+
+ preempt_disable_notrace();
/* shift to debug/test normalization and TIME_EXTENTS */
- return sched_clock() << DEBUG_SHIFT;
+ time = sched_clock() << DEBUG_SHIFT;
+ preempt_enable_no_resched_notrace();
+
+ return time;
}
+EXPORT_SYMBOL_GPL(ring_buffer_time_stamp);
void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)
{
/* Just stupid testing the normalize function and deltas */
*ts >>= DEBUG_SHIFT;
}
+EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
#define RB_EVNT_HDR_SIZE (sizeof(struct ring_buffer_event))
#define RB_ALIGNMENT_SHIFT 2
*/
unsigned ring_buffer_event_length(struct ring_buffer_event *event)
{
- return rb_event_length(event);
+ unsigned length = rb_event_length(event);
+ if (event->type != RINGBUF_TYPE_DATA)
+ return length;
+ length -= RB_EVNT_HDR_SIZE;
+ if (length > RB_MAX_SMALL_DATA + sizeof(event->array[0]))
+ length -= sizeof(event->array[0]);
+ return length;
}
+EXPORT_SYMBOL_GPL(ring_buffer_event_length);
/* inline for ring buffer fast paths */
static inline void *
{
return rb_event_data(event);
}
+EXPORT_SYMBOL_GPL(ring_buffer_event_data);
#define for_each_buffer_cpu(buffer, cpu) \
- for_each_cpu_mask(cpu, buffer->cpumask)
+ for_each_cpu(cpu, buffer->cpumask)
#define TS_SHIFT 27
#define TS_MASK ((1ULL << TS_SHIFT) - 1)
#define TS_DELTA_TEST (~TS_MASK)
-/*
- * This hack stolen from mm/slob.c.
- * We can store per page timing information in the page frame of the page.
- * Thanks to Peter Zijlstra for suggesting this idea.
- */
-struct buffer_page {
+struct buffer_data_page {
u64 time_stamp; /* page time stamp */
- local_t write; /* index for next write */
local_t commit; /* write commited index */
+ unsigned char data[]; /* data of buffer page */
+};
+
+struct buffer_page {
+ local_t write; /* index for next write */
unsigned read; /* index for next read */
struct list_head list; /* list of free pages */
- void *page; /* Actual data page */
+ struct buffer_data_page *page; /* Actual data page */
};
+static void rb_init_page(struct buffer_data_page *bpage)
+{
+ local_set(&bpage->commit, 0);
+}
+
/*
* Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
* this issue out.
return 0;
}
-#define BUF_PAGE_SIZE PAGE_SIZE
+#define BUF_PAGE_SIZE (PAGE_SIZE - offsetof(struct buffer_data_page, data))
/*
* head_page == tail_page && head == tail then buffer is empty.
};
struct ring_buffer {
- unsigned long size;
unsigned pages;
unsigned flags;
int cpus;
- cpumask_t cpumask;
+ cpumask_var_t cpumask;
atomic_t record_disabled;
struct mutex mutex;
static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
{
struct list_head *head = &cpu_buffer->pages;
- struct buffer_page *page, *tmp;
+ struct buffer_page *bpage, *tmp;
if (RB_WARN_ON(cpu_buffer, head->next->prev != head))
return -1;
if (RB_WARN_ON(cpu_buffer, head->prev->next != head))
return -1;
- list_for_each_entry_safe(page, tmp, head, list) {
+ list_for_each_entry_safe(bpage, tmp, head, list) {
if (RB_WARN_ON(cpu_buffer,
- page->list.next->prev != &page->list))
+ bpage->list.next->prev != &bpage->list))
return -1;
if (RB_WARN_ON(cpu_buffer,
- page->list.prev->next != &page->list))
+ bpage->list.prev->next != &bpage->list))
return -1;
}
unsigned nr_pages)
{
struct list_head *head = &cpu_buffer->pages;
- struct buffer_page *page, *tmp;
+ struct buffer_page *bpage, *tmp;
unsigned long addr;
LIST_HEAD(pages);
unsigned i;
for (i = 0; i < nr_pages; i++) {
- page = kzalloc_node(ALIGN(sizeof(*page), cache_line_size()),
+ bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
GFP_KERNEL, cpu_to_node(cpu_buffer->cpu));
- if (!page)
+ if (!bpage)
goto free_pages;
- list_add(&page->list, &pages);
+ list_add(&bpage->list, &pages);
addr = __get_free_page(GFP_KERNEL);
if (!addr)
goto free_pages;
- page->page = (void *)addr;
+ bpage->page = (void *)addr;
+ rb_init_page(bpage->page);
}
list_splice(&pages, head);
return 0;
free_pages:
- list_for_each_entry_safe(page, tmp, &pages, list) {
- list_del_init(&page->list);
- free_buffer_page(page);
+ list_for_each_entry_safe(bpage, tmp, &pages, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
}
return -ENOMEM;
}
rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
- struct buffer_page *page;
+ struct buffer_page *bpage;
unsigned long addr;
int ret;
cpu_buffer->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
INIT_LIST_HEAD(&cpu_buffer->pages);
- page = kzalloc_node(ALIGN(sizeof(*page), cache_line_size()),
+ bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
GFP_KERNEL, cpu_to_node(cpu));
- if (!page)
+ if (!bpage)
goto fail_free_buffer;
- cpu_buffer->reader_page = page;
+ cpu_buffer->reader_page = bpage;
addr = __get_free_page(GFP_KERNEL);
if (!addr)
goto fail_free_reader;
- page->page = (void *)addr;
+ bpage->page = (void *)addr;
+ rb_init_page(bpage->page);
INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
{
struct list_head *head = &cpu_buffer->pages;
- struct buffer_page *page, *tmp;
+ struct buffer_page *bpage, *tmp;
list_del_init(&cpu_buffer->reader_page->list);
free_buffer_page(cpu_buffer->reader_page);
- list_for_each_entry_safe(page, tmp, head, list) {
- list_del_init(&page->list);
- free_buffer_page(page);
+ list_for_each_entry_safe(bpage, tmp, head, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
}
kfree(cpu_buffer);
}
/**
* ring_buffer_alloc - allocate a new ring_buffer
- * @size: the size in bytes that is needed.
+ * @size: the size in bytes per cpu that is needed.
* @flags: attributes to set for the ring buffer.
*
* Currently the only flag that is available is the RB_FL_OVERWRITE
if (!buffer)
return NULL;
+ if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
+ goto fail_free_buffer;
+
buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
buffer->flags = flags;
if (buffer->pages == 1)
buffer->pages++;
- buffer->cpumask = cpu_possible_map;
+ cpumask_copy(buffer->cpumask, cpu_possible_mask);
buffer->cpus = nr_cpu_ids;
bsize = sizeof(void *) * nr_cpu_ids;
buffer->buffers = kzalloc(ALIGN(bsize, cache_line_size()),
GFP_KERNEL);
if (!buffer->buffers)
- goto fail_free_buffer;
+ goto fail_free_cpumask;
for_each_buffer_cpu(buffer, cpu) {
buffer->buffers[cpu] =
}
kfree(buffer->buffers);
+ fail_free_cpumask:
+ free_cpumask_var(buffer->cpumask);
+
fail_free_buffer:
kfree(buffer);
return NULL;
}
+EXPORT_SYMBOL_GPL(ring_buffer_alloc);
/**
* ring_buffer_free - free a ring buffer.
for_each_buffer_cpu(buffer, cpu)
rb_free_cpu_buffer(buffer->buffers[cpu]);
+ free_cpumask_var(buffer->cpumask);
+
kfree(buffer);
}
+EXPORT_SYMBOL_GPL(ring_buffer_free);
static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
static void
rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
{
- struct buffer_page *page;
+ struct buffer_page *bpage;
struct list_head *p;
unsigned i;
if (RB_WARN_ON(cpu_buffer, list_empty(&cpu_buffer->pages)))
return;
p = cpu_buffer->pages.next;
- page = list_entry(p, struct buffer_page, list);
- list_del_init(&page->list);
- free_buffer_page(page);
+ bpage = list_entry(p, struct buffer_page, list);
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
}
if (RB_WARN_ON(cpu_buffer, list_empty(&cpu_buffer->pages)))
return;
rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
struct list_head *pages, unsigned nr_pages)
{
- struct buffer_page *page;
+ struct buffer_page *bpage;
struct list_head *p;
unsigned i;
if (RB_WARN_ON(cpu_buffer, list_empty(pages)))
return;
p = pages->next;
- page = list_entry(p, struct buffer_page, list);
- list_del_init(&page->list);
- list_add_tail(&page->list, &cpu_buffer->pages);
+ bpage = list_entry(p, struct buffer_page, list);
+ list_del_init(&bpage->list);
+ list_add_tail(&bpage->list, &cpu_buffer->pages);
}
rb_reset_cpu(cpu_buffer);
{
struct ring_buffer_per_cpu *cpu_buffer;
unsigned nr_pages, rm_pages, new_pages;
- struct buffer_page *page, *tmp;
+ struct buffer_page *bpage, *tmp;
unsigned long buffer_size;
unsigned long addr;
LIST_HEAD(pages);
int i, cpu;
+ /*
+ * Always succeed at resizing a non-existent buffer:
+ */
+ if (!buffer)
+ return size;
+
size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
size *= BUF_PAGE_SIZE;
buffer_size = buffer->pages * BUF_PAGE_SIZE;
for_each_buffer_cpu(buffer, cpu) {
for (i = 0; i < new_pages; i++) {
- page = kzalloc_node(ALIGN(sizeof(*page),
+ bpage = kzalloc_node(ALIGN(sizeof(*bpage),
cache_line_size()),
GFP_KERNEL, cpu_to_node(cpu));
- if (!page)
+ if (!bpage)
goto free_pages;
- list_add(&page->list, &pages);
+ list_add(&bpage->list, &pages);
addr = __get_free_page(GFP_KERNEL);
if (!addr)
goto free_pages;
- page->page = (void *)addr;
+ bpage->page = (void *)addr;
+ rb_init_page(bpage->page);
}
}
return size;
free_pages:
- list_for_each_entry_safe(page, tmp, &pages, list) {
- list_del_init(&page->list);
- free_buffer_page(page);
+ list_for_each_entry_safe(bpage, tmp, &pages, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
}
+ mutex_unlock(&buffer->mutex);
return -ENOMEM;
}
+EXPORT_SYMBOL_GPL(ring_buffer_resize);
static inline int rb_null_event(struct ring_buffer_event *event)
{
return event->type == RINGBUF_TYPE_PADDING;
}
-static inline void *__rb_page_index(struct buffer_page *page, unsigned index)
+static inline void *
+__rb_data_page_index(struct buffer_data_page *bpage, unsigned index)
+{
+ return bpage->data + index;
+}
+
+static inline void *__rb_page_index(struct buffer_page *bpage, unsigned index)
{
- return page->page + index;
+ return bpage->page->data + index;
}
static inline struct ring_buffer_event *
static inline unsigned rb_page_commit(struct buffer_page *bpage)
{
- return local_read(&bpage->commit);
+ return local_read(&bpage->page->commit);
}
/* Size is determined by what has been commited */
}
static inline void rb_inc_page(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page **page)
+ struct buffer_page **bpage)
{
- struct list_head *p = (*page)->list.next;
+ struct list_head *p = (*bpage)->list.next;
if (p == &cpu_buffer->pages)
p = p->next;
- *page = list_entry(p, struct buffer_page, list);
+ *bpage = list_entry(p, struct buffer_page, list);
}
static inline unsigned
if (RB_WARN_ON(cpu_buffer,
cpu_buffer->commit_page == cpu_buffer->tail_page))
return;
- cpu_buffer->commit_page->commit =
+ cpu_buffer->commit_page->page->commit =
cpu_buffer->commit_page->write;
rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
- cpu_buffer->write_stamp = cpu_buffer->commit_page->time_stamp;
+ cpu_buffer->write_stamp =
+ cpu_buffer->commit_page->page->time_stamp;
}
/* Now set the commit to the event's index */
- local_set(&cpu_buffer->commit_page->commit, index);
+ local_set(&cpu_buffer->commit_page->page->commit, index);
}
static inline void
* back to us). This allows us to do a simple loop to
* assign the commit to the tail.
*/
+ again:
while (cpu_buffer->commit_page != cpu_buffer->tail_page) {
- cpu_buffer->commit_page->commit =
+ cpu_buffer->commit_page->page->commit =
cpu_buffer->commit_page->write;
rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
- cpu_buffer->write_stamp = cpu_buffer->commit_page->time_stamp;
+ cpu_buffer->write_stamp =
+ cpu_buffer->commit_page->page->time_stamp;
/* add barrier to keep gcc from optimizing too much */
barrier();
}
while (rb_commit_index(cpu_buffer) !=
rb_page_write(cpu_buffer->commit_page)) {
- cpu_buffer->commit_page->commit =
+ cpu_buffer->commit_page->page->commit =
cpu_buffer->commit_page->write;
barrier();
}
+
+ /* again, keep gcc from optimizing */
+ barrier();
+
+ /*
+ * If an interrupt came in just after the first while loop
+ * and pushed the tail page forward, we will be left with
+ * a dangling commit that will never go forward.
+ */
+ if (unlikely(cpu_buffer->commit_page != cpu_buffer->tail_page))
+ goto again;
}
static void rb_reset_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
{
- cpu_buffer->read_stamp = cpu_buffer->reader_page->time_stamp;
+ cpu_buffer->read_stamp = cpu_buffer->reader_page->page->time_stamp;
cpu_buffer->reader_page->read = 0;
}
else
rb_inc_page(cpu_buffer, &iter->head_page);
- iter->read_stamp = iter->head_page->time_stamp;
+ iter->read_stamp = iter->head_page->page->time_stamp;
iter->head = 0;
}
__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
unsigned type, unsigned long length, u64 *ts)
{
- struct buffer_page *tail_page, *head_page, *reader_page;
+ struct buffer_page *tail_page, *head_page, *reader_page, *commit_page;
unsigned long tail, write;
struct ring_buffer *buffer = cpu_buffer->buffer;
struct ring_buffer_event *event;
unsigned long flags;
+ commit_page = cpu_buffer->commit_page;
+ /* we just need to protect against interrupts */
+ barrier();
tail_page = cpu_buffer->tail_page;
write = local_add_return(length, &tail_page->write);
tail = write - length;
* it all the way around the buffer, bail, and warn
* about it.
*/
- if (unlikely(next_page == cpu_buffer->commit_page)) {
+ if (unlikely(next_page == commit_page)) {
WARN_ON_ONCE(1);
goto out_unlock;
}
if (next_page == head_page) {
- if (!(buffer->flags & RB_FL_OVERWRITE)) {
- /* reset write */
- if (tail <= BUF_PAGE_SIZE)
- local_set(&tail_page->write, tail);
+ if (!(buffer->flags & RB_FL_OVERWRITE))
goto out_unlock;
- }
/* tail_page has not moved yet? */
if (tail_page == cpu_buffer->tail_page) {
*/
if (tail_page == cpu_buffer->tail_page) {
local_set(&next_page->write, 0);
- local_set(&next_page->commit, 0);
+ local_set(&next_page->page->commit, 0);
cpu_buffer->tail_page = next_page;
/* reread the time stamp */
*ts = ring_buffer_time_stamp(cpu_buffer->cpu);
- cpu_buffer->tail_page->time_stamp = *ts;
+ cpu_buffer->tail_page->page->time_stamp = *ts;
}
/*
* this page's time stamp.
*/
if (!tail && rb_is_commit(cpu_buffer, event))
- cpu_buffer->commit_page->time_stamp = *ts;
+ cpu_buffer->commit_page->page->time_stamp = *ts;
return event;
out_unlock:
+ /* reset write */
+ if (tail <= BUF_PAGE_SIZE)
+ local_set(&tail_page->write, tail);
+
__raw_spin_unlock(&cpu_buffer->lock);
local_irq_restore(flags);
return NULL;
event->time_delta = *delta & TS_MASK;
event->array[0] = *delta >> TS_SHIFT;
} else {
- cpu_buffer->commit_page->time_stamp = *ts;
+ cpu_buffer->commit_page->page->time_stamp = *ts;
event->time_delta = 0;
event->array[0] = 0;
}
struct ring_buffer_event *event;
int cpu, resched;
- if (ring_buffers_off)
+ if (ring_buffer_flags != RB_BUFFERS_ON)
return NULL;
if (atomic_read(&buffer->record_disabled))
cpu = raw_smp_processor_id();
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
goto out;
cpu_buffer = buffer->buffers[cpu];
ftrace_preempt_enable(resched);
return NULL;
}
+EXPORT_SYMBOL_GPL(ring_buffer_lock_reserve);
static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
struct ring_buffer_event *event)
return 0;
}
+EXPORT_SYMBOL_GPL(ring_buffer_unlock_commit);
/**
* ring_buffer_write - write data to the buffer without reserving
int ret = -EBUSY;
int cpu, resched;
- if (ring_buffers_off)
+ if (ring_buffer_flags != RB_BUFFERS_ON)
return -EBUSY;
if (atomic_read(&buffer->record_disabled))
cpu = raw_smp_processor_id();
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
goto out;
cpu_buffer = buffer->buffers[cpu];
return ret;
}
+EXPORT_SYMBOL_GPL(ring_buffer_write);
static inline int rb_per_cpu_empty(struct ring_buffer_per_cpu *cpu_buffer)
{
{
atomic_inc(&buffer->record_disabled);
}
+EXPORT_SYMBOL_GPL(ring_buffer_record_disable);
/**
* ring_buffer_record_enable - enable writes to the buffer
{
atomic_dec(&buffer->record_disabled);
}
+EXPORT_SYMBOL_GPL(ring_buffer_record_enable);
/**
* ring_buffer_record_disable_cpu - stop all writes into the cpu_buffer
{
struct ring_buffer_per_cpu *cpu_buffer;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return;
cpu_buffer = buffer->buffers[cpu];
atomic_inc(&cpu_buffer->record_disabled);
}
+EXPORT_SYMBOL_GPL(ring_buffer_record_disable_cpu);
/**
* ring_buffer_record_enable_cpu - enable writes to the buffer
{
struct ring_buffer_per_cpu *cpu_buffer;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return;
cpu_buffer = buffer->buffers[cpu];
atomic_dec(&cpu_buffer->record_disabled);
}
+EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
/**
* ring_buffer_entries_cpu - get the number of entries in a cpu buffer
{
struct ring_buffer_per_cpu *cpu_buffer;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 0;
cpu_buffer = buffer->buffers[cpu];
return cpu_buffer->entries;
}
+EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu);
/**
* ring_buffer_overrun_cpu - get the number of overruns in a cpu_buffer
{
struct ring_buffer_per_cpu *cpu_buffer;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 0;
cpu_buffer = buffer->buffers[cpu];
return cpu_buffer->overrun;
}
+EXPORT_SYMBOL_GPL(ring_buffer_overrun_cpu);
/**
* ring_buffer_entries - get the number of entries in a buffer
return entries;
}
+EXPORT_SYMBOL_GPL(ring_buffer_entries);
/**
* ring_buffer_overrun_cpu - get the number of overruns in buffer
return overruns;
}
+EXPORT_SYMBOL_GPL(ring_buffer_overruns);
static void rb_iter_reset(struct ring_buffer_iter *iter)
{
if (iter->head)
iter->read_stamp = cpu_buffer->read_stamp;
else
- iter->read_stamp = iter->head_page->time_stamp;
+ iter->read_stamp = iter->head_page->page->time_stamp;
}
/**
rb_iter_reset(iter);
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_reset);
/**
* ring_buffer_iter_empty - check if an iterator has no more to read
return iter->head_page == cpu_buffer->commit_page &&
iter->head == rb_commit_index(cpu_buffer);
}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_empty);
static void
rb_update_read_stamp(struct ring_buffer_per_cpu *cpu_buffer,
cpu_buffer->reader_page->list.prev = reader->list.prev;
local_set(&cpu_buffer->reader_page->write, 0);
- local_set(&cpu_buffer->reader_page->commit, 0);
+ local_set(&cpu_buffer->reader_page->page->commit, 0);
/* Make the reader page now replace the head */
reader->list.prev->next = &cpu_buffer->reader_page->list;
struct buffer_page *reader;
int nr_loops = 0;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return NULL;
cpu_buffer = buffer->buffers[cpu];
return NULL;
}
+EXPORT_SYMBOL_GPL(ring_buffer_peek);
static struct ring_buffer_event *
rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
return NULL;
}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_peek);
/**
* ring_buffer_peek - peek at the next event to be read
struct ring_buffer_event *event;
unsigned long flags;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return NULL;
spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
return event;
}
+EXPORT_SYMBOL_GPL(ring_buffer_consume);
/**
* ring_buffer_read_start - start a non consuming read of the buffer
struct ring_buffer_iter *iter;
unsigned long flags;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return NULL;
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
return iter;
}
+EXPORT_SYMBOL_GPL(ring_buffer_read_start);
/**
* ring_buffer_finish - finish reading the iterator of the buffer
atomic_dec(&cpu_buffer->record_disabled);
kfree(iter);
}
+EXPORT_SYMBOL_GPL(ring_buffer_read_finish);
/**
* ring_buffer_read - read the next item in the ring buffer by the iterator
return event;
}
+EXPORT_SYMBOL_GPL(ring_buffer_read);
/**
* ring_buffer_size - return the size of the ring buffer (in bytes)
{
return BUF_PAGE_SIZE * buffer->pages;
}
+EXPORT_SYMBOL_GPL(ring_buffer_size);
static void
rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
cpu_buffer->head_page
= list_entry(cpu_buffer->pages.next, struct buffer_page, list);
local_set(&cpu_buffer->head_page->write, 0);
- local_set(&cpu_buffer->head_page->commit, 0);
+ local_set(&cpu_buffer->head_page->page->commit, 0);
cpu_buffer->head_page->read = 0;
INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
local_set(&cpu_buffer->reader_page->write, 0);
- local_set(&cpu_buffer->reader_page->commit, 0);
+ local_set(&cpu_buffer->reader_page->page->commit, 0);
cpu_buffer->reader_page->read = 0;
cpu_buffer->overrun = 0;
struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
unsigned long flags;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return;
spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
}
+EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu);
/**
* ring_buffer_reset - reset a ring buffer
for_each_buffer_cpu(buffer, cpu)
ring_buffer_reset_cpu(buffer, cpu);
}
+EXPORT_SYMBOL_GPL(ring_buffer_reset);
/**
* rind_buffer_empty - is the ring buffer empty?
}
return 1;
}
+EXPORT_SYMBOL_GPL(ring_buffer_empty);
/**
* ring_buffer_empty_cpu - is a cpu buffer of a ring buffer empty?
{
struct ring_buffer_per_cpu *cpu_buffer;
- if (!cpu_isset(cpu, buffer->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 1;
cpu_buffer = buffer->buffers[cpu];
return rb_per_cpu_empty(cpu_buffer);
}
+EXPORT_SYMBOL_GPL(ring_buffer_empty_cpu);
/**
* ring_buffer_swap_cpu - swap a CPU buffer between two ring buffers
struct ring_buffer_per_cpu *cpu_buffer_a;
struct ring_buffer_per_cpu *cpu_buffer_b;
- if (!cpu_isset(cpu, buffer_a->cpumask) ||
- !cpu_isset(cpu, buffer_b->cpumask))
+ if (!cpumask_test_cpu(cpu, buffer_a->cpumask) ||
+ !cpumask_test_cpu(cpu, buffer_b->cpumask))
return -EINVAL;
/* At least make sure the two buffers are somewhat the same */
- if (buffer_a->size != buffer_b->size ||
- buffer_a->pages != buffer_b->pages)
+ if (buffer_a->pages != buffer_b->pages)
return -EINVAL;
cpu_buffer_a = buffer_a->buffers[cpu];
return 0;
}
+EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
+
+static void rb_remove_entries(struct ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_data_page *bpage)
+{
+ struct ring_buffer_event *event;
+ unsigned long head;
+
+ __raw_spin_lock(&cpu_buffer->lock);
+ for (head = 0; head < local_read(&bpage->commit);
+ head += rb_event_length(event)) {
+
+ event = __rb_data_page_index(bpage, head);
+ if (RB_WARN_ON(cpu_buffer, rb_null_event(event)))
+ return;
+ /* Only count data entries */
+ if (event->type != RINGBUF_TYPE_DATA)
+ continue;
+ cpu_buffer->entries--;
+ }
+ __raw_spin_unlock(&cpu_buffer->lock);
+}
+
+/**
+ * ring_buffer_alloc_read_page - allocate a page to read from buffer
+ * @buffer: the buffer to allocate for.
+ *
+ * This function is used in conjunction with ring_buffer_read_page.
+ * When reading a full page from the ring buffer, these functions
+ * can be used to speed up the process. The calling function should
+ * allocate a few pages first with this function. Then when it
+ * needs to get pages from the ring buffer, it passes the result
+ * of this function into ring_buffer_read_page, which will swap
+ * the page that was allocated, with the read page of the buffer.
+ *
+ * Returns:
+ * The page allocated, or NULL on error.
+ */
+void *ring_buffer_alloc_read_page(struct ring_buffer *buffer)
+{
+ unsigned long addr;
+ struct buffer_data_page *bpage;
+
+ addr = __get_free_page(GFP_KERNEL);
+ if (!addr)
+ return NULL;
+
+ bpage = (void *)addr;
+
+ return bpage;
+}
+
+/**
+ * ring_buffer_free_read_page - free an allocated read page
+ * @buffer: the buffer the page was allocate for
+ * @data: the page to free
+ *
+ * Free a page allocated from ring_buffer_alloc_read_page.
+ */
+void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
+{
+ free_page((unsigned long)data);
+}
+
+/**
+ * ring_buffer_read_page - extract a page from the ring buffer
+ * @buffer: buffer to extract from
+ * @data_page: the page to use allocated from ring_buffer_alloc_read_page
+ * @cpu: the cpu of the buffer to extract
+ * @full: should the extraction only happen when the page is full.
+ *
+ * This function will pull out a page from the ring buffer and consume it.
+ * @data_page must be the address of the variable that was returned
+ * from ring_buffer_alloc_read_page. This is because the page might be used
+ * to swap with a page in the ring buffer.
+ *
+ * for example:
+ * rpage = ring_buffer_alloc_page(buffer);
+ * if (!rpage)
+ * return error;
+ * ret = ring_buffer_read_page(buffer, &rpage, cpu, 0);
+ * if (ret)
+ * process_page(rpage);
+ *
+ * When @full is set, the function will not return true unless
+ * the writer is off the reader page.
+ *
+ * Note: it is up to the calling functions to handle sleeps and wakeups.
+ * The ring buffer can be used anywhere in the kernel and can not
+ * blindly call wake_up. The layer that uses the ring buffer must be
+ * responsible for that.
+ *
+ * Returns:
+ * 1 if data has been transferred
+ * 0 if no data has been transferred.
+ */
+int ring_buffer_read_page(struct ring_buffer *buffer,
+ void **data_page, int cpu, int full)
+{
+ struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+ struct ring_buffer_event *event;
+ struct buffer_data_page *bpage;
+ unsigned long flags;
+ int ret = 0;
+
+ if (!data_page)
+ return 0;
+
+ bpage = *data_page;
+ if (!bpage)
+ return 0;
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+
+ /*
+ * rb_buffer_peek will get the next ring buffer if
+ * the current reader page is empty.
+ */
+ event = rb_buffer_peek(buffer, cpu, NULL);
+ if (!event)
+ goto out;
+
+ /* check for data */
+ if (!local_read(&cpu_buffer->reader_page->page->commit))
+ goto out;
+ /*
+ * If the writer is already off of the read page, then simply
+ * switch the read page with the given page. Otherwise
+ * we need to copy the data from the reader to the writer.
+ */
+ if (cpu_buffer->reader_page == cpu_buffer->commit_page) {
+ unsigned int read = cpu_buffer->reader_page->read;
+
+ if (full)
+ goto out;
+ /* The writer is still on the reader page, we must copy */
+ bpage = cpu_buffer->reader_page->page;
+ memcpy(bpage->data,
+ cpu_buffer->reader_page->page->data + read,
+ local_read(&bpage->commit) - read);
+
+ /* consume what was read */
+ cpu_buffer->reader_page += read;
+
+ } else {
+ /* swap the pages */
+ rb_init_page(bpage);
+ bpage = cpu_buffer->reader_page->page;
+ cpu_buffer->reader_page->page = *data_page;
+ cpu_buffer->reader_page->read = 0;
+ *data_page = bpage;
+ }
+ ret = 1;
+
+ /* update the entry counter */
+ rb_remove_entries(cpu_buffer, bpage);
+ out:
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ return ret;
+}
static ssize_t
rb_simple_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
- int *p = filp->private_data;
+ long *p = filp->private_data;
char buf[64];
int r;
- /* !ring_buffers_off == tracing_on */
- r = sprintf(buf, "%d\n", !*p);
+ if (test_bit(RB_BUFFERS_DISABLED_BIT, p))
+ r = sprintf(buf, "permanently disabled\n");
+ else
+ r = sprintf(buf, "%d\n", test_bit(RB_BUFFERS_ON_BIT, p));
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
rb_simple_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
- int *p = filp->private_data;
+ long *p = filp->private_data;
char buf[64];
long val;
int ret;
if (ret < 0)
return ret;
- /* !ring_buffers_off == tracing_on */
- *p = !val;
+ if (val)
+ set_bit(RB_BUFFERS_ON_BIT, p);
+ else
+ clear_bit(RB_BUFFERS_ON_BIT, p);
(*ppos)++;
d_tracer = tracing_init_dentry();
entry = debugfs_create_file("tracing_on", 0644, d_tracer,
- &ring_buffers_off, &rb_simple_fops);
+ &ring_buffer_flags, &rb_simple_fops);
if (!entry)
pr_warning("Could not create debugfs 'tracing_on' entry\n");
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff