#include <linux/cpu.h>
#include <linux/oom.h>
+#include <asm/local64.h>
#include <asm/local.h>
/*
unsigned char data[] RB_ALIGN_DATA; /* data of buffer page */
};
+struct buffer_data_read_page {
+ unsigned order; /* order of the page */
+ struct buffer_data_page *data; /* actual data, stored in this page */
+};
+
/*
* Note, the buffer_page list must be first. The buffer pages
* are allocated in cache lines, which means that each buffer
unsigned read; /* index for next read */
local_t entries; /* entries on this page */
unsigned long real_end; /* real end of data */
+ unsigned order; /* order of the page */
struct buffer_data_page *page; /* Actual data page */
};
static void free_buffer_page(struct buffer_page *bpage)
{
- free_page((unsigned long)bpage->page);
+ free_pages((unsigned long)bpage->page, bpage->order);
kfree(bpage);
}
return !!(delta & TS_DELTA_TEST);
}
-#define BUF_PAGE_SIZE (PAGE_SIZE - BUF_PAGE_HDR_SIZE)
-
-/* Max payload is BUF_PAGE_SIZE - header (8bytes) */
-#define BUF_MAX_DATA_SIZE (BUF_PAGE_SIZE - (sizeof(u32) * 2))
-
-int ring_buffer_print_page_header(struct trace_seq *s)
-{
- struct buffer_data_page field;
-
- trace_seq_printf(s, "\tfield: u64 timestamp;\t"
- "offset:0;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)sizeof(field.time_stamp),
- (unsigned int)is_signed_type(u64));
-
- trace_seq_printf(s, "\tfield: local_t commit;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), commit),
- (unsigned int)sizeof(field.commit),
- (unsigned int)is_signed_type(long));
-
- trace_seq_printf(s, "\tfield: int overwrite;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), commit),
- 1,
- (unsigned int)is_signed_type(long));
-
- trace_seq_printf(s, "\tfield: char data;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), data),
- (unsigned int)BUF_PAGE_SIZE,
- (unsigned int)is_signed_type(char));
-
- return !trace_seq_has_overflowed(s);
-}
-
struct rb_irq_work {
struct irq_work work;
wait_queue_head_t waiters;
RB_CTX_MAX
};
-#if BITS_PER_LONG == 32
-#define RB_TIME_32
-#endif
-
-/* To test on 64 bit machines */
-//#define RB_TIME_32
-
-#ifdef RB_TIME_32
-
-struct rb_time_struct {
- local_t cnt;
- local_t top;
- local_t bottom;
- local_t msb;
-};
-#else
-#include <asm/local64.h>
struct rb_time_struct {
local64_t time;
};
-#endif
typedef struct rb_time_struct rb_time_t;
#define MAX_NEST 5
struct rb_irq_work irq_work;
bool time_stamp_abs;
+
+ unsigned int subbuf_size;
+ unsigned int subbuf_order;
+ unsigned int max_data_size;
};
struct ring_buffer_iter {
u64 read_stamp;
u64 page_stamp;
struct ring_buffer_event *event;
+ size_t event_size;
int missed_events;
};
-#ifdef RB_TIME_32
-
-/*
- * On 32 bit machines, local64_t is very expensive. As the ring
- * buffer doesn't need all the features of a true 64 bit atomic,
- * on 32 bit, it uses these functions (64 still uses local64_t).
- *
- * For the ring buffer, 64 bit required operations for the time is
- * the following:
- *
- * - Reads may fail if it interrupted a modification of the time stamp.
- * It will succeed if it did not interrupt another write even if
- * the read itself is interrupted by a write.
- * It returns whether it was successful or not.
- *
- * - Writes always succeed and will overwrite other writes and writes
- * that were done by events interrupting the current write.
- *
- * - A write followed by a read of the same time stamp will always succeed,
- * but may not contain the same value.
- *
- * - A cmpxchg will fail if it interrupted another write or cmpxchg.
- * Other than that, it acts like a normal cmpxchg.
- *
- * The 60 bit time stamp is broken up by 30 bits in a top and bottom half
- * (bottom being the least significant 30 bits of the 60 bit time stamp).
- *
- * The two most significant bits of each half holds a 2 bit counter (0-3).
- * Each update will increment this counter by one.
- * When reading the top and bottom, if the two counter bits match then the
- * top and bottom together make a valid 60 bit number.
- */
-#define RB_TIME_SHIFT 30
-#define RB_TIME_VAL_MASK ((1 << RB_TIME_SHIFT) - 1)
-#define RB_TIME_MSB_SHIFT 60
-
-static inline int rb_time_cnt(unsigned long val)
+int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s)
{
- return (val >> RB_TIME_SHIFT) & 3;
-}
-
-static inline u64 rb_time_val(unsigned long top, unsigned long bottom)
-{
- u64 val;
-
- val = top & RB_TIME_VAL_MASK;
- val <<= RB_TIME_SHIFT;
- val |= bottom & RB_TIME_VAL_MASK;
-
- return val;
-}
-
-static inline bool __rb_time_read(rb_time_t *t, u64 *ret, unsigned long *cnt)
-{
- unsigned long top, bottom, msb;
- unsigned long c;
-
- /*
- * If the read is interrupted by a write, then the cnt will
- * be different. Loop until both top and bottom have been read
- * without interruption.
- */
- do {
- c = local_read(&t->cnt);
- top = local_read(&t->top);
- bottom = local_read(&t->bottom);
- msb = local_read(&t->msb);
- } while (c != local_read(&t->cnt));
-
- *cnt = rb_time_cnt(top);
-
- /* If top, msb or bottom counts don't match, this interrupted a write */
- if (*cnt != rb_time_cnt(msb) || *cnt != rb_time_cnt(bottom))
- return false;
-
- /* The shift to msb will lose its cnt bits */
- *ret = rb_time_val(top, bottom) | ((u64)msb << RB_TIME_MSB_SHIFT);
- return true;
-}
-
-static bool rb_time_read(rb_time_t *t, u64 *ret)
-{
- unsigned long cnt;
-
- return __rb_time_read(t, ret, &cnt);
-}
-
-static inline unsigned long rb_time_val_cnt(unsigned long val, unsigned long cnt)
-{
- return (val & RB_TIME_VAL_MASK) | ((cnt & 3) << RB_TIME_SHIFT);
-}
-
-static inline void rb_time_split(u64 val, unsigned long *top, unsigned long *bottom,
- unsigned long *msb)
-{
- *top = (unsigned long)((val >> RB_TIME_SHIFT) & RB_TIME_VAL_MASK);
- *bottom = (unsigned long)(val & RB_TIME_VAL_MASK);
- *msb = (unsigned long)(val >> RB_TIME_MSB_SHIFT);
-}
+ struct buffer_data_page field;
-static inline void rb_time_val_set(local_t *t, unsigned long val, unsigned long cnt)
-{
- val = rb_time_val_cnt(val, cnt);
- local_set(t, val);
-}
+ trace_seq_printf(s, "\tfield: u64 timestamp;\t"
+ "offset:0;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)sizeof(field.time_stamp),
+ (unsigned int)is_signed_type(u64));
-static void rb_time_set(rb_time_t *t, u64 val)
-{
- unsigned long cnt, top, bottom, msb;
+ trace_seq_printf(s, "\tfield: local_t commit;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), commit),
+ (unsigned int)sizeof(field.commit),
+ (unsigned int)is_signed_type(long));
- rb_time_split(val, &top, &bottom, &msb);
+ trace_seq_printf(s, "\tfield: int overwrite;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), commit),
+ 1,
+ (unsigned int)is_signed_type(long));
- /* Writes always succeed with a valid number even if it gets interrupted. */
- do {
- cnt = local_inc_return(&t->cnt);
- rb_time_val_set(&t->top, top, cnt);
- rb_time_val_set(&t->bottom, bottom, cnt);
- rb_time_val_set(&t->msb, val >> RB_TIME_MSB_SHIFT, cnt);
- } while (cnt != local_read(&t->cnt));
-}
+ trace_seq_printf(s, "\tfield: char data;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), data),
+ (unsigned int)buffer->subbuf_size,
+ (unsigned int)is_signed_type(char));
-static inline bool
-rb_time_read_cmpxchg(local_t *l, unsigned long expect, unsigned long set)
-{
- return local_try_cmpxchg(l, &expect, set);
+ return !trace_seq_has_overflowed(s);
}
-#else /* 64 bits */
-
-/* local64_t always succeeds */
-
-static inline bool rb_time_read(rb_time_t *t, u64 *ret)
+static inline void rb_time_read(rb_time_t *t, u64 *ret)
{
*ret = local64_read(&t->time);
- return true;
}
static void rb_time_set(rb_time_t *t, u64 val)
{
local64_set(&t->time, val);
}
-#endif
/*
* Enable this to make sure that the event passed to
WARN_ONCE(1, "nest (%d) greater than max", nest);
fail:
- /* Can only fail on 32 bit */
- if (!rb_time_read(&cpu_buffer->write_stamp, &ts))
- /* Screw it, just read the current time */
- ts = rb_time_stamp(cpu_buffer->buffer);
+ rb_time_read(&cpu_buffer->write_stamp, &ts);
return ts;
}
full = 0;
} else {
if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return -EINVAL;
+ return EPOLLERR;
cpu_buffer = buffer->buffers[cpu];
work = &cpu_buffer->irq_work;
list_add(&bpage->list, pages);
- page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), mflags, 0);
+ page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), mflags,
+ cpu_buffer->buffer->subbuf_order);
if (!page)
goto free_pages;
bpage->page = page_address(page);
+ bpage->order = cpu_buffer->buffer->subbuf_order;
rb_init_page(bpage->page);
if (user_thread && fatal_signal_pending(current))
rb_check_bpage(cpu_buffer, bpage);
cpu_buffer->reader_page = bpage;
- page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, 0);
+
+ page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, cpu_buffer->buffer->subbuf_order);
if (!page)
goto fail_free_reader;
bpage->page = page_address(page);
if (!zalloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
goto fail_free_buffer;
- nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+ /* Default buffer page size - one system page */
+ buffer->subbuf_order = 0;
+ buffer->subbuf_size = PAGE_SIZE - BUF_PAGE_HDR_SIZE;
+
+ /* Max payload is buffer page size - header (8bytes) */
+ buffer->max_data_size = buffer->subbuf_size - (sizeof(u32) * 2);
+
+ nr_pages = DIV_ROUND_UP(size, buffer->subbuf_size);
buffer->flags = flags;
buffer->clock = trace_clock_local;
buffer->reader_lock_key = key;
* @size: the new size.
* @cpu_id: the cpu buffer to resize
*
- * Minimum size is 2 * BUF_PAGE_SIZE.
+ * Minimum size is 2 * buffer->subbuf_size.
*
* Returns 0 on success and < 0 on failure.
*/
!cpumask_test_cpu(cpu_id, buffer->cpumask))
return 0;
- nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+ nr_pages = DIV_ROUND_UP(size, buffer->subbuf_size);
/* we need a minimum of two pages */
if (nr_pages < 2)
*/
barrier();
- if ((iter->head + length) > commit || length > BUF_PAGE_SIZE)
+ if ((iter->head + length) > commit || length > iter->event_size)
/* Writer corrupted the read? */
goto reset;
}
static __always_inline unsigned
-rb_event_index(struct ring_buffer_event *event)
+rb_event_index(struct ring_buffer_per_cpu *cpu_buffer, struct ring_buffer_event *event)
{
unsigned long addr = (unsigned long)event;
- return (addr & ~PAGE_MASK) - BUF_PAGE_HDR_SIZE;
+ addr &= (PAGE_SIZE << cpu_buffer->buffer->subbuf_order) - 1;
+
+ return addr - BUF_PAGE_HDR_SIZE;
}
static void rb_inc_iter(struct ring_buffer_iter *iter)
rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
unsigned long tail, struct rb_event_info *info)
{
+ unsigned long bsize = READ_ONCE(cpu_buffer->buffer->subbuf_size);
struct buffer_page *tail_page = info->tail_page;
struct ring_buffer_event *event;
unsigned long length = info->length;
* Only the event that crossed the page boundary
* must fill the old tail_page with padding.
*/
- if (tail >= BUF_PAGE_SIZE) {
+ if (tail >= bsize) {
/*
* If the page was filled, then we still need
* to update the real_end. Reset it to zero
* and the reader will ignore it.
*/
- if (tail == BUF_PAGE_SIZE)
+ if (tail == bsize)
tail_page->real_end = 0;
local_sub(length, &tail_page->write);
* If we are less than the minimum size, we don't need to
* worry about it.
*/
- if (tail > (BUF_PAGE_SIZE - RB_EVNT_MIN_SIZE)) {
+ if (tail > (bsize - RB_EVNT_MIN_SIZE)) {
/* No room for any events */
/* Mark the rest of the page with padding */
}
/* Put in a discarded event */
- event->array[0] = (BUF_PAGE_SIZE - tail) - RB_EVNT_HDR_SIZE;
+ event->array[0] = (bsize - tail) - RB_EVNT_HDR_SIZE;
event->type_len = RINGBUF_TYPE_PADDING;
/* time delta must be non zero */
event->time_delta = 1;
/* account for padding bytes */
- local_add(BUF_PAGE_SIZE - tail, &cpu_buffer->entries_bytes);
+ local_add(bsize - tail, &cpu_buffer->entries_bytes);
/* Make sure the padding is visible before the tail_page->write update */
smp_wmb();
/* Set write to end of buffer */
- length = (tail + length) - BUF_PAGE_SIZE;
+ length = (tail + length) - bsize;
local_sub(length, &tail_page->write);
}
/* Slow path */
static struct ring_buffer_event *
-rb_add_time_stamp(struct ring_buffer_event *event, u64 delta, bool abs)
+rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
+ struct ring_buffer_event *event, u64 delta, bool abs)
{
if (abs)
event->type_len = RINGBUF_TYPE_TIME_STAMP;
event->type_len = RINGBUF_TYPE_TIME_EXTEND;
/* Not the first event on the page, or not delta? */
- if (abs || rb_event_index(event)) {
+ if (abs || rb_event_index(cpu_buffer, event)) {
event->time_delta = delta & TS_MASK;
event->array[0] = delta >> TS_SHIFT;
} else {
(unsigned long long)info->ts,
(unsigned long long)info->before,
(unsigned long long)info->after,
- (unsigned long long)(rb_time_read(&cpu_buffer->write_stamp, &write_stamp) ? write_stamp : 0),
+ (unsigned long long)({rb_time_read(&cpu_buffer->write_stamp, &write_stamp); write_stamp;}),
sched_clock_stable() ? "" :
"If you just came from a suspend/resume,\n"
"please switch to the trace global clock:\n"
if (!abs)
info->delta = 0;
}
- *event = rb_add_time_stamp(*event, info->delta, abs);
+ *event = rb_add_time_stamp(cpu_buffer, *event, info->delta, abs);
*length -= RB_LEN_TIME_EXTEND;
*delta = 0;
}
struct buffer_page *bpage;
unsigned long addr;
- new_index = rb_event_index(event);
+ new_index = rb_event_index(cpu_buffer, event);
old_index = new_index + rb_event_ts_length(event);
addr = (unsigned long)event;
- addr &= PAGE_MASK;
+ addr &= ~((PAGE_SIZE << cpu_buffer->buffer->subbuf_order) - 1);
bpage = READ_ONCE(cpu_buffer->tail_page);
#define CHECK_FULL_PAGE 1L
#ifdef CONFIG_RING_BUFFER_VALIDATE_TIME_DELTAS
+
+static const char *show_irq_str(int bits)
+{
+ const char *type[] = {
+ ".", // 0
+ "s", // 1
+ "h", // 2
+ "Hs", // 3
+ "n", // 4
+ "Ns", // 5
+ "Nh", // 6
+ "NHs", // 7
+ };
+
+ return type[bits];
+}
+
+/* Assume this is an trace event */
+static const char *show_flags(struct ring_buffer_event *event)
+{
+ struct trace_entry *entry;
+ int bits = 0;
+
+ if (rb_event_data_length(event) - RB_EVNT_HDR_SIZE < sizeof(*entry))
+ return "X";
+
+ entry = ring_buffer_event_data(event);
+
+ if (entry->flags & TRACE_FLAG_SOFTIRQ)
+ bits |= 1;
+
+ if (entry->flags & TRACE_FLAG_HARDIRQ)
+ bits |= 2;
+
+ if (entry->flags & TRACE_FLAG_NMI)
+ bits |= 4;
+
+ return show_irq_str(bits);
+}
+
+static const char *show_irq(struct ring_buffer_event *event)
+{
+ struct trace_entry *entry;
+
+ if (rb_event_data_length(event) - RB_EVNT_HDR_SIZE < sizeof(*entry))
+ return "";
+
+ entry = ring_buffer_event_data(event);
+ if (entry->flags & TRACE_FLAG_IRQS_OFF)
+ return "d";
+ return "";
+}
+
+static const char *show_interrupt_level(void)
+{
+ unsigned long pc = preempt_count();
+ unsigned char level = 0;
+
+ if (pc & SOFTIRQ_OFFSET)
+ level |= 1;
+
+ if (pc & HARDIRQ_MASK)
+ level |= 2;
+
+ if (pc & NMI_MASK)
+ level |= 4;
+
+ return show_irq_str(level);
+}
+
static void dump_buffer_page(struct buffer_data_page *bpage,
struct rb_event_info *info,
unsigned long tail)
case RINGBUF_TYPE_TIME_EXTEND:
delta = rb_event_time_stamp(event);
ts += delta;
- pr_warn(" [%lld] delta:%lld TIME EXTEND\n", ts, delta);
+ pr_warn(" 0x%x: [%lld] delta:%lld TIME EXTEND\n",
+ e, ts, delta);
break;
case RINGBUF_TYPE_TIME_STAMP:
delta = rb_event_time_stamp(event);
ts = rb_fix_abs_ts(delta, ts);
- pr_warn(" [%lld] absolute:%lld TIME STAMP\n", ts, delta);
+ pr_warn(" 0x%x: [%lld] absolute:%lld TIME STAMP\n",
+ e, ts, delta);
break;
case RINGBUF_TYPE_PADDING:
ts += event->time_delta;
- pr_warn(" [%lld] delta:%d PADDING\n", ts, event->time_delta);
+ pr_warn(" 0x%x: [%lld] delta:%d PADDING\n",
+ e, ts, event->time_delta);
break;
case RINGBUF_TYPE_DATA:
ts += event->time_delta;
- pr_warn(" [%lld] delta:%d\n", ts, event->time_delta);
+ pr_warn(" 0x%x: [%lld] delta:%d %s%s\n",
+ e, ts, event->time_delta,
+ show_flags(event), show_irq(event));
break;
default:
break;
}
}
+ pr_warn("expected end:0x%lx last event actually ended at:0x%x\n", tail, e);
}
static DEFINE_PER_CPU(atomic_t, checking);
static atomic_t ts_dump;
+#define buffer_warn_return(fmt, ...) \
+ do { \
+ /* If another report is happening, ignore this one */ \
+ if (atomic_inc_return(&ts_dump) != 1) { \
+ atomic_dec(&ts_dump); \
+ goto out; \
+ } \
+ atomic_inc(&cpu_buffer->record_disabled); \
+ pr_warn(fmt, ##__VA_ARGS__); \
+ dump_buffer_page(bpage, info, tail); \
+ atomic_dec(&ts_dump); \
+ /* There's some cases in boot up that this can happen */ \
+ if (WARN_ON_ONCE(system_state != SYSTEM_BOOTING)) \
+ /* Do not re-enable checking */ \
+ return; \
+ } while (0)
+
/*
* Check if the current event time stamp matches the deltas on
* the buffer page.
case RINGBUF_TYPE_TIME_STAMP:
delta = rb_event_time_stamp(event);
- ts = rb_fix_abs_ts(delta, ts);
+ delta = rb_fix_abs_ts(delta, ts);
+ if (delta < ts) {
+ buffer_warn_return("[CPU: %d]ABSOLUTE TIME WENT BACKWARDS: last ts: %lld absolute ts: %lld\n",
+ cpu_buffer->cpu, ts, delta);
+ }
+ ts = delta;
break;
case RINGBUF_TYPE_PADDING:
}
if ((full && ts > info->ts) ||
(!full && ts + info->delta != info->ts)) {
- /* If another report is happening, ignore this one */
- if (atomic_inc_return(&ts_dump) != 1) {
- atomic_dec(&ts_dump);
- goto out;
- }
- atomic_inc(&cpu_buffer->record_disabled);
- /* There's some cases in boot up that this can happen */
- WARN_ON_ONCE(system_state != SYSTEM_BOOTING);
- pr_warn("[CPU: %d]TIME DOES NOT MATCH expected:%lld actual:%lld delta:%lld before:%lld after:%lld%s\n",
- cpu_buffer->cpu,
- ts + info->delta, info->ts, info->delta,
- info->before, info->after,
- full ? " (full)" : "");
- dump_buffer_page(bpage, info, tail);
- atomic_dec(&ts_dump);
- /* Do not re-enable checking */
- return;
+ buffer_warn_return("[CPU: %d]TIME DOES NOT MATCH expected:%lld actual:%lld delta:%lld before:%lld after:%lld%s context:%s\n",
+ cpu_buffer->cpu,
+ ts + info->delta, info->ts, info->delta,
+ info->before, info->after,
+ full ? " (full)" : "", show_interrupt_level());
}
out:
atomic_dec(this_cpu_ptr(&checking));
struct ring_buffer_event *event;
struct buffer_page *tail_page;
unsigned long tail, write, w;
- bool a_ok;
- bool b_ok;
/* Don't let the compiler play games with cpu_buffer->tail_page */
tail_page = info->tail_page = READ_ONCE(cpu_buffer->tail_page);
/*A*/ w = local_read(&tail_page->write) & RB_WRITE_MASK;
barrier();
- b_ok = rb_time_read(&cpu_buffer->before_stamp, &info->before);
- a_ok = rb_time_read(&cpu_buffer->write_stamp, &info->after);
+ rb_time_read(&cpu_buffer->before_stamp, &info->before);
+ rb_time_read(&cpu_buffer->write_stamp, &info->after);
barrier();
info->ts = rb_time_stamp(cpu_buffer->buffer);
if (!w) {
/* Use the sub-buffer timestamp */
info->delta = 0;
- } else if (unlikely(!a_ok || !b_ok || info->before != info->after)) {
+ } else if (unlikely(info->before != info->after)) {
info->add_timestamp |= RB_ADD_STAMP_FORCE | RB_ADD_STAMP_EXTEND;
info->length += RB_LEN_TIME_EXTEND;
} else {
tail = write - info->length;
/* See if we shot pass the end of this buffer page */
- if (unlikely(write > BUF_PAGE_SIZE)) {
+ if (unlikely(write > cpu_buffer->buffer->subbuf_size)) {
check_buffer(cpu_buffer, info, CHECK_FULL_PAGE);
return rb_move_tail(cpu_buffer, tail, info);
}
/* SLOW PATH - Interrupted between A and C */
/* Save the old before_stamp */
- a_ok = rb_time_read(&cpu_buffer->before_stamp, &info->before);
- RB_WARN_ON(cpu_buffer, !a_ok);
+ rb_time_read(&cpu_buffer->before_stamp, &info->before);
/*
* Read a new timestamp and update the before_stamp to make
rb_time_set(&cpu_buffer->before_stamp, ts);
barrier();
- /*E*/ a_ok = rb_time_read(&cpu_buffer->write_stamp, &info->after);
- /* Was interrupted before here, write_stamp must be valid */
- RB_WARN_ON(cpu_buffer, !a_ok);
+ /*E*/ rb_time_read(&cpu_buffer->write_stamp, &info->after);
barrier();
/*F*/ if (write == (local_read(&tail_page->write) & RB_WRITE_MASK) &&
info->after == info->before && info->after < ts) {
if (ring_buffer_time_stamp_abs(cpu_buffer->buffer)) {
add_ts_default = RB_ADD_STAMP_ABSOLUTE;
info.length += RB_LEN_TIME_EXTEND;
- if (info.length > BUF_MAX_DATA_SIZE)
+ if (info.length > cpu_buffer->buffer->max_data_size)
goto out_fail;
} else {
add_ts_default = RB_ADD_STAMP_NONE;
if (unlikely(atomic_read(&cpu_buffer->record_disabled)))
goto out;
- if (unlikely(length > BUF_MAX_DATA_SIZE))
+ if (unlikely(length > buffer->max_data_size))
goto out;
if (unlikely(trace_recursive_lock(cpu_buffer)))
struct buffer_page *bpage = cpu_buffer->commit_page;
struct buffer_page *start;
- addr &= PAGE_MASK;
+ addr &= ~((PAGE_SIZE << cpu_buffer->buffer->subbuf_order) - 1);
/* Do the likely case first */
if (likely(bpage->page == (void *)addr)) {
if (atomic_read(&cpu_buffer->record_disabled))
goto out;
- if (length > BUF_MAX_DATA_SIZE)
+ if (length > buffer->max_data_size)
goto out;
if (unlikely(trace_recursive_lock(cpu_buffer)))
rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
{
struct buffer_page *reader = NULL;
+ unsigned long bsize = READ_ONCE(cpu_buffer->buffer->subbuf_size);
unsigned long overwrite;
unsigned long flags;
int nr_loops = 0;
#define USECS_WAIT 1000000
for (nr_loops = 0; nr_loops < USECS_WAIT; nr_loops++) {
/* If the write is past the end of page, a writer is still updating it */
- if (likely(!reader || rb_page_write(reader) <= BUF_PAGE_SIZE))
+ if (likely(!reader || rb_page_write(reader) <= bsize))
break;
udelay(1);
return NULL;
/* Holds the entire event: data and meta data */
- iter->event = kmalloc(BUF_PAGE_SIZE, flags);
+ iter->event_size = buffer->subbuf_size;
+ iter->event = kmalloc(iter->event_size, flags);
if (!iter->event) {
kfree(iter);
return NULL;
*/
unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu)
{
- /*
- * Earlier, this method returned
- * BUF_PAGE_SIZE * buffer->nr_pages
- * Since the nr_pages field is now removed, we have converted this to
- * return the per cpu buffer value.
- */
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 0;
- return BUF_PAGE_SIZE * buffer->buffers[cpu]->nr_pages;
+ return buffer->subbuf_size * buffer->buffers[cpu]->nr_pages;
}
EXPORT_SYMBOL_GPL(ring_buffer_size);
+/**
+ * ring_buffer_max_event_size - return the max data size of an event
+ * @buffer: The ring buffer.
+ *
+ * Returns the maximum size an event can be.
+ */
+unsigned long ring_buffer_max_event_size(struct trace_buffer *buffer)
+{
+ /* If abs timestamp is requested, events have a timestamp too */
+ if (ring_buffer_time_stamp_abs(buffer))
+ return buffer->max_data_size - RB_LEN_TIME_EXTEND;
+ return buffer->max_data_size;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_max_event_size);
+
static void rb_clear_buffer_page(struct buffer_page *page)
{
local_set(&page->write, 0);
if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages)
goto out;
+ if (buffer_a->subbuf_order != buffer_b->subbuf_order)
+ goto out;
+
ret = -EAGAIN;
if (atomic_read(&buffer_a->record_disabled))
* Returns:
* The page allocated, or ERR_PTR
*/
-void *ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu)
+struct buffer_data_read_page *
+ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
- struct buffer_data_page *bpage = NULL;
+ struct buffer_data_read_page *bpage = NULL;
unsigned long flags;
struct page *page;
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return ERR_PTR(-ENODEV);
+ bpage = kzalloc(sizeof(*bpage), GFP_KERNEL);
+ if (!bpage)
+ return ERR_PTR(-ENOMEM);
+
+ bpage->order = buffer->subbuf_order;
cpu_buffer = buffer->buffers[cpu];
local_irq_save(flags);
arch_spin_lock(&cpu_buffer->lock);
if (cpu_buffer->free_page) {
- bpage = cpu_buffer->free_page;
+ bpage->data = cpu_buffer->free_page;
cpu_buffer->free_page = NULL;
}
arch_spin_unlock(&cpu_buffer->lock);
local_irq_restore(flags);
- if (bpage)
+ if (bpage->data)
goto out;
- page = alloc_pages_node(cpu_to_node(cpu),
- GFP_KERNEL | __GFP_NORETRY, 0);
- if (!page)
+ page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_NORETRY,
+ cpu_buffer->buffer->subbuf_order);
+ if (!page) {
+ kfree(bpage);
return ERR_PTR(-ENOMEM);
+ }
- bpage = page_address(page);
+ bpage->data = page_address(page);
out:
- rb_init_page(bpage);
+ rb_init_page(bpage->data);
return bpage;
}
* ring_buffer_free_read_page - free an allocated read page
* @buffer: the buffer the page was allocate for
* @cpu: the cpu buffer the page came from
- * @data: the page to free
+ * @data_page: the page to free
*
* Free a page allocated from ring_buffer_alloc_read_page.
*/
-void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, void *data)
+void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu,
+ struct buffer_data_read_page *data_page)
{
struct ring_buffer_per_cpu *cpu_buffer;
- struct buffer_data_page *bpage = data;
+ struct buffer_data_page *bpage = data_page->data;
struct page *page = virt_to_page(bpage);
unsigned long flags;
cpu_buffer = buffer->buffers[cpu];
- /* If the page is still in use someplace else, we can't reuse it */
- if (page_ref_count(page) > 1)
+ /*
+ * If the page is still in use someplace else, or order of the page
+ * is different from the subbuffer order of the buffer -
+ * we can't reuse it
+ */
+ if (page_ref_count(page) > 1 || data_page->order != buffer->subbuf_order)
goto out;
local_irq_save(flags);
local_irq_restore(flags);
out:
- free_page((unsigned long)bpage);
+ free_pages((unsigned long)bpage, data_page->order);
+ kfree(data_page);
}
EXPORT_SYMBOL_GPL(ring_buffer_free_read_page);
* rpage = ring_buffer_alloc_read_page(buffer, cpu);
* if (IS_ERR(rpage))
* return PTR_ERR(rpage);
- * ret = ring_buffer_read_page(buffer, &rpage, len, cpu, 0);
+ * ret = ring_buffer_read_page(buffer, rpage, len, cpu, 0);
* if (ret >= 0)
- * process_page(rpage, ret);
+ * process_page(ring_buffer_read_page_data(rpage), ret);
+ * ring_buffer_free_read_page(buffer, cpu, rpage);
*
* When @full is set, the function will not return true unless
* the writer is off the reader page.
* <0 if no data has been transferred.
*/
int ring_buffer_read_page(struct trace_buffer *buffer,
- void **data_page, size_t len, int cpu, int full)
+ struct buffer_data_read_page *data_page,
+ size_t len, int cpu, int full)
{
struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
struct ring_buffer_event *event;
len -= BUF_PAGE_HDR_SIZE;
- if (!data_page)
+ if (!data_page || !data_page->data)
+ goto out;
+ if (data_page->order != buffer->subbuf_order)
goto out;
- bpage = *data_page;
+ bpage = data_page->data;
if (!bpage)
goto out;
/* swap the pages */
rb_init_page(bpage);
bpage = reader->page;
- reader->page = *data_page;
+ reader->page = data_page->data;
local_set(&reader->write, 0);
local_set(&reader->entries, 0);
reader->read = 0;
- *data_page = bpage;
+ data_page->data = bpage;
/*
* Use the real_end for the data size,
/* If there is room at the end of the page to save the
* missed events, then record it there.
*/
- if (BUF_PAGE_SIZE - commit >= sizeof(missed_events)) {
+ if (buffer->subbuf_size - commit >= sizeof(missed_events)) {
memcpy(&bpage->data[commit], &missed_events,
sizeof(missed_events));
local_add(RB_MISSED_STORED, &bpage->commit);
/*
* This page may be off to user land. Zero it out here.
*/
- if (commit < BUF_PAGE_SIZE)
- memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit);
+ if (commit < buffer->subbuf_size)
+ memset(&bpage->data[commit], 0, buffer->subbuf_size - commit);
out_unlock:
raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
}
EXPORT_SYMBOL_GPL(ring_buffer_read_page);
+/**
+ * ring_buffer_read_page_data - get pointer to the data in the page.
+ * @page: the page to get the data from
+ *
+ * Returns pointer to the actual data in this page.
+ */
+void *ring_buffer_read_page_data(struct buffer_data_read_page *page)
+{
+ return page->data;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_read_page_data);
+
+/**
+ * ring_buffer_subbuf_size_get - get size of the sub buffer.
+ * @buffer: the buffer to get the sub buffer size from
+ *
+ * Returns size of the sub buffer, in bytes.
+ */
+int ring_buffer_subbuf_size_get(struct trace_buffer *buffer)
+{
+ return buffer->subbuf_size + BUF_PAGE_HDR_SIZE;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_subbuf_size_get);
+
+/**
+ * ring_buffer_subbuf_order_get - get order of system sub pages in one buffer page.
+ * @buffer: The ring_buffer to get the system sub page order from
+ *
+ * By default, one ring buffer sub page equals to one system page. This parameter
+ * is configurable, per ring buffer. The size of the ring buffer sub page can be
+ * extended, but must be an order of system page size.
+ *
+ * Returns the order of buffer sub page size, in system pages:
+ * 0 means the sub buffer size is 1 system page and so forth.
+ * In case of an error < 0 is returned.
+ */
+int ring_buffer_subbuf_order_get(struct trace_buffer *buffer)
+{
+ if (!buffer)
+ return -EINVAL;
+
+ return buffer->subbuf_order;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_subbuf_order_get);
+
+/**
+ * ring_buffer_subbuf_order_set - set the size of ring buffer sub page.
+ * @buffer: The ring_buffer to set the new page size.
+ * @order: Order of the system pages in one sub buffer page
+ *
+ * By default, one ring buffer pages equals to one system page. This API can be
+ * used to set new size of the ring buffer page. The size must be order of
+ * system page size, that's why the input parameter @order is the order of
+ * system pages that are allocated for one ring buffer page:
+ * 0 - 1 system page
+ * 1 - 2 system pages
+ * 3 - 4 system pages
+ * ...
+ *
+ * Returns 0 on success or < 0 in case of an error.
+ */
+int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
+{
+ struct ring_buffer_per_cpu *cpu_buffer;
+ struct buffer_page *bpage, *tmp;
+ int old_order, old_size;
+ int nr_pages;
+ int psize;
+ int err;
+ int cpu;
+
+ if (!buffer || order < 0)
+ return -EINVAL;
+
+ if (buffer->subbuf_order == order)
+ return 0;
+
+ psize = (1 << order) * PAGE_SIZE;
+ if (psize <= BUF_PAGE_HDR_SIZE)
+ return -EINVAL;
+
+ old_order = buffer->subbuf_order;
+ old_size = buffer->subbuf_size;
+
+ /* prevent another thread from changing buffer sizes */
+ mutex_lock(&buffer->mutex);
+ atomic_inc(&buffer->record_disabled);
+
+ /* Make sure all commits have finished */
+ synchronize_rcu();
+
+ buffer->subbuf_order = order;
+ buffer->subbuf_size = psize - BUF_PAGE_HDR_SIZE;
+
+ /* Make sure all new buffers are allocated, before deleting the old ones */
+ for_each_buffer_cpu(buffer, cpu) {
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ continue;
+
+ cpu_buffer = buffer->buffers[cpu];
+
+ /* Update the number of pages to match the new size */
+ nr_pages = old_size * buffer->buffers[cpu]->nr_pages;
+ nr_pages = DIV_ROUND_UP(nr_pages, buffer->subbuf_size);
+
+ /* we need a minimum of two pages */
+ if (nr_pages < 2)
+ nr_pages = 2;
+
+ cpu_buffer->nr_pages_to_update = nr_pages;
+
+ /* Include the reader page */
+ nr_pages++;
+
+ /* Allocate the new size buffer */
+ INIT_LIST_HEAD(&cpu_buffer->new_pages);
+ if (__rb_allocate_pages(cpu_buffer, nr_pages,
+ &cpu_buffer->new_pages)) {
+ /* not enough memory for new pages */
+ err = -ENOMEM;
+ goto error;
+ }
+ }
+
+ for_each_buffer_cpu(buffer, cpu) {
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ continue;
+
+ cpu_buffer = buffer->buffers[cpu];
+
+ /* Clear the head bit to make the link list normal to read */
+ rb_head_page_deactivate(cpu_buffer);
+
+ /* Now walk the list and free all the old sub buffers */
+ list_for_each_entry_safe(bpage, tmp, cpu_buffer->pages, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
+ }
+ /* The above loop stopped an the last page needing to be freed */
+ bpage = list_entry(cpu_buffer->pages, struct buffer_page, list);
+ free_buffer_page(bpage);
+
+ /* Free the current reader page */
+ free_buffer_page(cpu_buffer->reader_page);
+
+ /* One page was allocated for the reader page */
+ cpu_buffer->reader_page = list_entry(cpu_buffer->new_pages.next,
+ struct buffer_page, list);
+ list_del_init(&cpu_buffer->reader_page->list);
+
+ /* The cpu_buffer pages are a link list with no head */
+ cpu_buffer->pages = cpu_buffer->new_pages.next;
+ cpu_buffer->new_pages.next->prev = cpu_buffer->new_pages.prev;
+ cpu_buffer->new_pages.prev->next = cpu_buffer->new_pages.next;
+
+ /* Clear the new_pages list */
+ INIT_LIST_HEAD(&cpu_buffer->new_pages);
+
+ cpu_buffer->head_page
+ = list_entry(cpu_buffer->pages, struct buffer_page, list);
+ cpu_buffer->tail_page = cpu_buffer->commit_page = cpu_buffer->head_page;
+
+ cpu_buffer->nr_pages = cpu_buffer->nr_pages_to_update;
+ cpu_buffer->nr_pages_to_update = 0;
+
+ free_pages((unsigned long)cpu_buffer->free_page, old_order);
+ cpu_buffer->free_page = NULL;
+
+ rb_head_page_activate(cpu_buffer);
+
+ rb_check_pages(cpu_buffer);
+ }
+
+ atomic_dec(&buffer->record_disabled);
+ mutex_unlock(&buffer->mutex);
+
+ return 0;
+
+error:
+ buffer->subbuf_order = old_order;
+ buffer->subbuf_size = old_size;
+
+ atomic_dec(&buffer->record_disabled);
+ mutex_unlock(&buffer->mutex);
+
+ for_each_buffer_cpu(buffer, cpu) {
+ cpu_buffer = buffer->buffers[cpu];
+
+ if (!cpu_buffer->nr_pages_to_update)
+ continue;
+
+ list_for_each_entry_safe(bpage, tmp, &cpu_buffer->new_pages, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
+ }
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_subbuf_order_set);
+
/*
* We only allocate new buffers, never free them if the CPU goes down.
* If we were to free the buffer, then the user would lose any trace that was in
projects / thirdparty / kernel / linux.git / blobdiff