ftrace: make work with new ring buffer

This patch ports ftrace over to the new ring buffer.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

11 files changed, 288 insertions, 798 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6ada059832a6..ef80793858b8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -33,25 +33,22 @@
 #include <linux/writeback.h>
 
 #include <linux/stacktrace.h>
+#include <linux/ring_buffer.h>
 
 #include "trace.h"
 
+#define TRACE_BUFFER_FLAGS      (RB_FL_OVERWRITE)
+
 unsigned long __read_mostly     tracing_max_latency = (cycle_t)ULONG_MAX;
 unsigned long __read_mostly     tracing_thresh;
 
-static unsigned long __read_mostly      tracing_nr_buffers;
 static cpumask_t __read_mostly          tracing_buffer_mask;
 
 #define for_each_tracing_cpu(cpu)       \
         for_each_cpu_mask(cpu, tracing_buffer_mask)
 
-static int trace_alloc_page(void);
-static int trace_free_page(void);
-
 static int tracing_disabled = 1;
 
-static unsigned long tracing_pages_allocated;
-
 long
 ns2usecs(cycle_t nsec)
 {
@@ -62,7 +59,9 @@ ns2usecs(cycle_t nsec)
 
 cycle_t ftrace_now(int cpu)
 {
-        return cpu_clock(cpu);
+        u64 ts = ring_buffer_time_stamp(cpu);
+        ring_buffer_normalize_time_stamp(cpu, &ts);
+        return ts;
 }
 
 /*
@@ -102,18 +101,18 @@ static int			tracer_enabled = 1;
 int                             ftrace_function_enabled;
 
 /*
- * trace_nr_entries is the number of entries that is allocated
- * for a buffer. Note, the number of entries is always rounded
- * to ENTRIES_PER_PAGE.
+ * trace_buf_size is the size in bytes that is allocated
+ * for a buffer. Note, the number of bytes is always rounded
+ * to page size.
  *
  * This number is purposely set to a low number of 16384.
  * If the dump on oops happens, it will be much appreciated
  * to not have to wait for all that output. Anyway this can be
  * boot time and run time configurable.
  */
-#define TRACE_ENTRIES_DEFAULT   16384UL
+#define TRACE_BUF_SIZE_DEFAULT  1441792UL /* 16384 * 88 (sizeof(entry)) */
 
-static unsigned long            trace_nr_entries = TRACE_ENTRIES_DEFAULT;
+static unsigned long            trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
 
 /* trace_types holds a link list of available tracers. */
 static struct tracer            *trace_types __read_mostly;
@@ -158,23 +157,21 @@ void trace_wake_up(void)
                 wake_up(&trace_wait);
 }
 
-#define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry))
-
-static int __init set_nr_entries(char *str)
+static int __init set_buf_size(char *str)
 {
-        unsigned long nr_entries;
+        unsigned long buf_size;
         int ret;
 
         if (!str)
                 return 0;
-        ret = strict_strtoul(str, 0, &nr_entries);
+        ret = strict_strtoul(str, 0, &buf_size);
         /* nr_entries can not be zero */
-        if (ret < 0 || nr_entries == 0)
+        if (ret < 0 || buf_size == 0)
                 return 0;
-        trace_nr_entries = nr_entries;
+        trace_buf_size = buf_size;
         return 1;
 }
-__setup("trace_entries=", set_nr_entries);
+__setup("trace_buf_size=", set_buf_size);
 
 unsigned long nsecs_to_usecs(unsigned long nsecs)
 {
@@ -243,54 +240,6 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
         tracing_record_cmdline(current);
 }
 
-#define CHECK_COND(cond)                        \
-        if (unlikely(cond)) {                   \
-                tracing_disabled = 1;           \
-                WARN_ON(1);                     \
-                return -1;                      \
-        }
-
-/**
- * check_pages - integrity check of trace buffers
- *
- * As a safty measure we check to make sure the data pages have not
- * been corrupted.
- */
-int check_pages(struct trace_array_cpu *data)
-{
-        struct page *page, *tmp;
-
-        CHECK_COND(data->trace_pages.next->prev != &data->trace_pages);
-        CHECK_COND(data->trace_pages.prev->next != &data->trace_pages);
-
-        list_for_each_entry_safe(page, tmp, &data->trace_pages, lru) {
-                CHECK_COND(page->lru.next->prev != &page->lru);
-                CHECK_COND(page->lru.prev->next != &page->lru);
-        }
-
-        return 0;
-}
-
-/**
- * head_page - page address of the first page in per_cpu buffer.
- *
- * head_page returns the page address of the first page in
- * a per_cpu buffer. This also preforms various consistency
- * checks to make sure the buffer has not been corrupted.
- */
-void *head_page(struct trace_array_cpu *data)
-{
-        struct page *page;
-
-        if (list_empty(&data->trace_pages))
-                return NULL;
-
-        page = list_entry(data->trace_pages.next, struct page, lru);
-        BUG_ON(&page->lru == &data->trace_pages);
-
-        return page_address(page);
-}
-
 /**
  * trace_seq_printf - sequence printing of trace information
  * @s: trace sequence descriptor
@@ -437,34 +386,6 @@ trace_print_seq(struct seq_file *m, struct trace_seq *s)
         trace_seq_reset(s);
 }
 
-/*
- * flip the trace buffers between two trace descriptors.
- * This usually is the buffers between the global_trace and
- * the max_tr to record a snapshot of a current trace.
- *
- * The ftrace_max_lock must be held.
- */
-static void
-flip_trace(struct trace_array_cpu *tr1, struct trace_array_cpu *tr2)
-{
-        struct list_head flip_pages;
-
-        INIT_LIST_HEAD(&flip_pages);
-
-        memcpy(&tr1->trace_head_idx, &tr2->trace_head_idx,
-                sizeof(struct trace_array_cpu) -
-                offsetof(struct trace_array_cpu, trace_head_idx));
-
-        check_pages(tr1);
-        check_pages(tr2);
-        list_splice_init(&tr1->trace_pages, &flip_pages);
-        list_splice_init(&tr2->trace_pages, &tr1->trace_pages);
-        list_splice_init(&flip_pages, &tr2->trace_pages);
-        BUG_ON(!list_empty(&flip_pages));
-        check_pages(tr1);
-        check_pages(tr2);
-}
-
 /**
  * update_max_tr - snapshot all trace buffers from global_trace to max_tr
  * @tr: tracer
@@ -477,17 +398,15 @@ flip_trace(struct trace_array_cpu *tr1, struct trace_array_cpu *tr2)
 void
 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
-        struct trace_array_cpu *data;
-        int i;
+        struct ring_buffer *buf = tr->buffer;
 
         WARN_ON_ONCE(!irqs_disabled());
         __raw_spin_lock(&ftrace_max_lock);
-        /* clear out all the previous traces */
-        for_each_tracing_cpu(i) {
-                data = tr->data[i];
-                flip_trace(max_tr.data[i], data);
-                tracing_reset(data);
-        }
+
+        tr->buffer = max_tr.buffer;
+        max_tr.buffer = buf;
+
+        ring_buffer_reset(tr->buffer);
 
         __update_max_tr(tr, tsk, cpu);
         __raw_spin_unlock(&ftrace_max_lock);
@@ -504,16 +423,15 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 void
 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
-        struct trace_array_cpu *data = tr->data[cpu];
-        int i;
+        int ret;
 
         WARN_ON_ONCE(!irqs_disabled());
         __raw_spin_lock(&ftrace_max_lock);
-        for_each_tracing_cpu(i)
-                tracing_reset(max_tr.data[i]);
 
-        flip_trace(max_tr.data[cpu], data);
-        tracing_reset(data);
+        ring_buffer_reset(max_tr.buffer);
+        ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
+
+        WARN_ON_ONCE(ret);
 
         __update_max_tr(tr, tsk, cpu);
         __raw_spin_unlock(&ftrace_max_lock);
@@ -550,7 +468,6 @@ int register_tracer(struct tracer *type)
 #ifdef CONFIG_FTRACE_STARTUP_TEST
         if (type->selftest) {
                 struct tracer *saved_tracer = current_trace;
-                struct trace_array_cpu *data;
                 struct trace_array *tr = &global_trace;
                 int saved_ctrl = tr->ctrl;
                 int i;
@@ -562,10 +479,7 @@ int register_tracer(struct tracer *type)
                  * If we fail, we do not register this tracer.
                  */
                 for_each_tracing_cpu(i) {
-                        data = tr->data[i];
-                        if (!head_page(data))
-                                continue;
-                        tracing_reset(data);
+                        tracing_reset(tr, i);
                 }
                 current_trace = type;
                 tr->ctrl = 0;
@@ -581,10 +495,7 @@ int register_tracer(struct tracer *type)
                 }
                 /* Only reset on passing, to avoid touching corrupted buffers */
                 for_each_tracing_cpu(i) {
-                        data = tr->data[i];
-                        if (!head_page(data))
-                                continue;
-                        tracing_reset(data);
+                        tracing_reset(tr, i);
                 }
                 printk(KERN_CONT "PASSED\n");
         }
@@ -630,13 +541,9 @@ void unregister_tracer(struct tracer *type)
         mutex_unlock(&trace_types_lock);
 }
 
-void tracing_reset(struct trace_array_cpu *data)
+void tracing_reset(struct trace_array *tr, int cpu)
 {
-        data->trace_idx = 0;
-        data->overrun = 0;
-        data->trace_head = data->trace_tail = head_page(data);
-        data->trace_head_idx = 0;
-        data->trace_tail_idx = 0;
+        ring_buffer_reset_cpu(tr->buffer, cpu);
 }
 
 #define SAVED_CMDLINES 128
@@ -722,70 +629,6 @@ void tracing_record_cmdline(struct task_struct *tsk)
         trace_save_cmdline(tsk);
 }
 
-static inline struct list_head *
-trace_next_list(struct trace_array_cpu *data, struct list_head *next)
-{
-        /*
-         * Roundrobin - but skip the head (which is not a real page):
-         */
-        next = next->next;
-        if (unlikely(next == &data->trace_pages))
-                next = next->next;
-        BUG_ON(next == &data->trace_pages);
-
-        return next;
-}
-
-static inline void *
-trace_next_page(struct trace_array_cpu *data, void *addr)
-{
-        struct list_head *next;
-        struct page *page;
-
-        page = virt_to_page(addr);
-
-        next = trace_next_list(data, &page->lru);
-        page = list_entry(next, struct page, lru);
-
-        return page_address(page);
-}
-
-struct trace_entry *
-tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data)
-{
-        unsigned long idx, idx_next;
-        struct trace_entry *entry;
-
-        data->trace_idx++;
-        idx = data->trace_head_idx;
-        idx_next = idx + 1;
-
-        BUG_ON(idx * TRACE_ENTRY_SIZE >= PAGE_SIZE);
-
-        entry = data->trace_head + idx * TRACE_ENTRY_SIZE;
-
-        if (unlikely(idx_next >= ENTRIES_PER_PAGE)) {
-                data->trace_head = trace_next_page(data, data->trace_head);
-                idx_next = 0;
-        }
-
-        if (data->trace_head == data->trace_tail &&
-            idx_next == data->trace_tail_idx) {
-                /* overrun */
-                data->overrun++;
-                data->trace_tail_idx++;
-                if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
-                        data->trace_tail =
-                                trace_next_page(data, data->trace_tail);
-                        data->trace_tail_idx = 0;
-                }
-        }
-
-        data->trace_head_idx = idx_next;
-
-        return entry;
-}
-
 void
 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags)
 {
@@ -796,7 +639,6 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags)
 
         entry->field.preempt_count      = pc & 0xff;
         entry->field.pid                = (tsk) ? tsk->pid : 0;
-        entry->field.t                  = ftrace_now(raw_smp_processor_id());
         entry->field.flags =
                 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
                 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
@@ -808,18 +650,20 @@ void
 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
                unsigned long ip, unsigned long parent_ip, unsigned long flags)
 {
+        struct ring_buffer_event *event;
         struct trace_entry *entry;
         unsigned long irq_flags;
 
-        raw_local_irq_save(irq_flags);
-        __raw_spin_lock(&data->lock);
-        entry                           = tracing_get_trace_entry(tr, data);
+        event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                         &irq_flags);
+        if (!event)
+                return;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, flags);
         entry->type                     = TRACE_FN;
         entry->field.fn.ip              = ip;
         entry->field.fn.parent_ip       = parent_ip;
-        __raw_spin_unlock(&data->lock);
-        raw_local_irq_restore(irq_flags);
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 }
 
 void
@@ -835,13 +679,19 @@ void __trace_stack(struct trace_array *tr,
                    unsigned long flags,
                    int skip)
 {
+        struct ring_buffer_event *event;
         struct trace_entry *entry;
         struct stack_trace trace;
+        unsigned long irq_flags;
 
         if (!(trace_flags & TRACE_ITER_STACKTRACE))
                 return;
 
-        entry                   = tracing_get_trace_entry(tr, data);
+        event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                         &irq_flags);
+        if (!event)
+                return;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, flags);
         entry->type             = TRACE_STACK;
 
@@ -853,28 +703,31 @@ void __trace_stack(struct trace_array *tr,
         trace.entries           = entry->field.stack.caller;
 
         save_stack_trace(&trace);
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 }
 
 void
 __trace_special(void *__tr, void *__data,
                 unsigned long arg1, unsigned long arg2, unsigned long arg3)
 {
+        struct ring_buffer_event *event;
         struct trace_array_cpu *data = __data;
         struct trace_array *tr = __tr;
         struct trace_entry *entry;
         unsigned long irq_flags;
 
-        raw_local_irq_save(irq_flags);
-        __raw_spin_lock(&data->lock);
-        entry                           = tracing_get_trace_entry(tr, data);
+        event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                         &irq_flags);
+        if (!event)
+                return;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, 0);
         entry->type                     = TRACE_SPECIAL;
         entry->field.special.arg1       = arg1;
         entry->field.special.arg2       = arg2;
         entry->field.special.arg3       = arg3;
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
         __trace_stack(tr, data, irq_flags, 4);
-        __raw_spin_unlock(&data->lock);
-        raw_local_irq_restore(irq_flags);
 
         trace_wake_up();
 }
@@ -886,12 +739,15 @@ tracing_sched_switch_trace(struct trace_array *tr,
                            struct task_struct *next,
                            unsigned long flags)
 {
+        struct ring_buffer_event *event;
         struct trace_entry *entry;
         unsigned long irq_flags;
 
-        raw_local_irq_save(irq_flags);
-        __raw_spin_lock(&data->lock);
-        entry                           = tracing_get_trace_entry(tr, data);
+        event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                           &irq_flags);
+        if (!event)
+                return;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, flags);
         entry->type                     = TRACE_CTX;
         entry->field.ctx.prev_pid       = prev->pid;
@@ -901,9 +757,8 @@ tracing_sched_switch_trace(struct trace_array *tr,
         entry->field.ctx.next_prio      = next->prio;
         entry->field.ctx.next_state     = next->state;
         entry->field.ctx.next_cpu       = task_cpu(next);
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
         __trace_stack(tr, data, flags, 5);
-        __raw_spin_unlock(&data->lock);
-        raw_local_irq_restore(irq_flags);
 }
 
 void
@@ -913,12 +768,15 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
                            struct task_struct *curr,
                            unsigned long flags)
 {
+        struct ring_buffer_event *event;
         struct trace_entry *entry;
         unsigned long irq_flags;
 
-        raw_local_irq_save(irq_flags);
-        __raw_spin_lock(&data->lock);
-        entry                   = tracing_get_trace_entry(tr, data);
+        event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                           &irq_flags);
+        if (!event)
+                return;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, flags);
         entry->type             = TRACE_WAKE;
         entry->field.ctx.prev_pid       = curr->pid;
@@ -928,9 +786,8 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
         entry->field.ctx.next_prio      = wakee->prio;
         entry->field.ctx.next_state     = wakee->state;
         entry->field.ctx.next_cpu       = task_cpu(wakee);
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
         __trace_stack(tr, data, flags, 6);
-        __raw_spin_unlock(&data->lock);
-        raw_local_irq_restore(irq_flags);
 
         trace_wake_up();
 }
@@ -1011,183 +868,77 @@ enum trace_file_type {
         TRACE_FILE_LAT_FMT      = 1,
 };
 
-/* Return the current entry.  */
-static struct trace_entry *
-trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
-                struct trace_iterator *iter, int cpu)
-{
-        struct page *page;
-        struct trace_entry *array;
-
-        if (iter->next_idx[cpu] >= tr->entries ||
-            iter->next_idx[cpu] >= data->trace_idx ||
-            (data->trace_head == data->trace_tail &&
-             data->trace_head_idx == data->trace_tail_idx))
-                return NULL;
-
-        if (!iter->next_page[cpu]) {
-                /* Initialize the iterator for this cpu trace buffer */
-                WARN_ON(!data->trace_tail);
-                page = virt_to_page(data->trace_tail);
-                iter->next_page[cpu] = &page->lru;
-                iter->next_page_idx[cpu] = data->trace_tail_idx;
-        }
-
-        page = list_entry(iter->next_page[cpu], struct page, lru);
-        BUG_ON(&data->trace_pages == &page->lru);
-
-        array = page_address(page);
-
-        WARN_ON(iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE);
-        return &array[iter->next_page_idx[cpu]];
-}
-
-/* Increment the index counter of an iterator by one */
-static void __trace_iterator_increment(struct trace_iterator *iter, int cpu)
-{
-        iter->next_idx[cpu]++;
-        iter->next_page_idx[cpu]++;
-
-        if (iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE) {
-                struct trace_array_cpu *data = iter->tr->data[cpu];
-
-                iter->next_page_idx[cpu] = 0;
-                iter->next_page[cpu] =
-                        trace_next_list(data, iter->next_page[cpu]);
-        }
-}
-
 static void trace_iterator_increment(struct trace_iterator *iter, int cpu)
 {
         iter->idx++;
-        __trace_iterator_increment(iter, cpu);
+        ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
 }
 
 static struct trace_entry *
-trace_entry_next(struct trace_array *tr, struct trace_array_cpu *data,
-                 struct trace_iterator *iter, int cpu)
+peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
 {
-        struct list_head *next_page;
-        struct trace_entry *ent;
-        int idx, next_idx, next_page_idx;
-
-        ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
-
-        if (likely(!ent || ent->type != TRACE_CONT))
-                return ent;
-
-        /* save the iterator details */
-        idx             = iter->idx;
-        next_idx        = iter->next_idx[cpu];
-        next_page_idx   = iter->next_page_idx[cpu];
-        next_page       = iter->next_page[cpu];
-
-        /* find a real entry */
-        do {
-                __trace_iterator_increment(iter, cpu);
-                ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
-        } while (ent && ent->type != TRACE_CONT);
-
-        /* reset the iterator */
-        iter->idx                       = idx;
-        iter->next_idx[cpu]             = next_idx;
-        iter->next_page_idx[cpu]        = next_page_idx;
-        iter->next_page[cpu]            = next_page;
+        struct ring_buffer_event *event;
+        struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
 
-        return ent;
+        event = ring_buffer_iter_peek(buf_iter, ts);
+        return event ? ring_buffer_event_data(event) : NULL;
 }
-
 static struct trace_entry *
-__find_next_entry(struct trace_iterator *iter, int *ent_cpu, int inc)
+__find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
 {
-        struct trace_array *tr = iter->tr;
+        struct ring_buffer *buffer = iter->tr->buffer;
         struct trace_entry *ent, *next = NULL;
+        u64 next_ts = 0, ts;
         int next_cpu = -1;
         int cpu;
 
         for_each_tracing_cpu(cpu) {
-                if (!head_page(tr->data[cpu]))
-                        continue;
 
-                ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
+                if (ring_buffer_empty_cpu(buffer, cpu))
+                        continue;
 
-                if (ent && ent->type == TRACE_CONT) {
-                        struct trace_array_cpu *data = tr->data[cpu];
-
-                        if (!inc)
-                                ent = trace_entry_next(tr, data, iter, cpu);
-                        else {
-                                while (ent && ent->type == TRACE_CONT) {
-                                        __trace_iterator_increment(iter, cpu);
-                                        ent = trace_entry_idx(tr, tr->data[cpu],
-                                                              iter, cpu);
-                                }
-                        }
-                }
+                ent = peek_next_entry(iter, cpu, &ts);
 
                 /*
                  * Pick the entry with the smallest timestamp:
                  */
-                if (ent && (!next || ent->field.t < next->field.t)) {
+                if (ent && (!next || ts < next_ts)) {
                         next = ent;
                         next_cpu = cpu;
+                        next_ts = ts;
                 }
         }
 
         if (ent_cpu)
                 *ent_cpu = next_cpu;
 
+        if (ent_ts)
+                *ent_ts = next_ts;
+
         return next;
 }
 
 /* Find the next real entry, without updating the iterator itself */
 static struct trace_entry *
-find_next_entry(struct trace_iterator *iter, int *ent_cpu)
+find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
 {
-        return __find_next_entry(iter, ent_cpu, 0);
+        return __find_next_entry(iter, ent_cpu, ent_ts);
 }
 
 /* Find the next real entry, and increment the iterator to the next entry */
 static void *find_next_entry_inc(struct trace_iterator *iter)
 {
-        struct trace_entry *next;
-        int next_cpu = -1;
-
-        next = __find_next_entry(iter, &next_cpu, 1);
-
-        iter->prev_ent = iter->ent;
-        iter->prev_cpu = iter->cpu;
+        iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
 
-        iter->ent = next;
-        iter->cpu = next_cpu;
-
-        if (next)
+        if (iter->ent)
                 trace_iterator_increment(iter, iter->cpu);
 
-        return next ? iter : NULL;
+        return iter->ent ? iter : NULL;
 }
 
 static void trace_consume(struct trace_iterator *iter)
 {
-        struct trace_array_cpu *data = iter->tr->data[iter->cpu];
-        struct trace_entry *ent;
-
- again:
-        data->trace_tail_idx++;
-        if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
-                data->trace_tail = trace_next_page(data, data->trace_tail);
-                data->trace_tail_idx = 0;
-        }
-
-        /* Check if we empty it, then reset the index */
-        if (data->trace_head == data->trace_tail &&
-            data->trace_head_idx == data->trace_tail_idx)
-                data->trace_idx = 0;
-
-        ent = trace_entry_idx(iter->tr, iter->tr->data[iter->cpu],
-                              iter, iter->cpu);
-        if (ent && ent->type == TRACE_CONT)
-                goto again;
+        ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
 }
 
 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
@@ -1220,7 +971,7 @@ static void *s_start(struct seq_file *m, loff_t *pos)
         struct trace_iterator *iter = m->private;
         void *p = NULL;
         loff_t l = 0;
-        int i;
+        int cpu;
 
         mutex_lock(&trace_types_lock);
 
@@ -1239,12 +990,9 @@ static void *s_start(struct seq_file *m, loff_t *pos)
                 iter->ent = NULL;
                 iter->cpu = 0;
                 iter->idx = -1;
-                iter->prev_ent = NULL;
-                iter->prev_cpu = -1;
 
-                for_each_tracing_cpu(i) {
-                        iter->next_idx[i] = 0;
-                        iter->next_page[i] = NULL;
+                for_each_tracing_cpu(cpu) {
+                        ring_buffer_iter_reset(iter->buffer_iter[cpu]);
                 }
 
                 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
@@ -1365,23 +1113,16 @@ print_trace_header(struct seq_file *m, struct trace_iterator *iter)
         struct trace_array *tr = iter->tr;
         struct trace_array_cpu *data = tr->data[tr->cpu];
         struct tracer *type = current_trace;
-        unsigned long total   = 0;
-        unsigned long entries = 0;
-        int cpu;
+        unsigned long total;
+        unsigned long entries;
         const char *name = "preemption";
 
         if (type)
                 name = type->name;
 
-        for_each_tracing_cpu(cpu) {
-                if (head_page(tr->data[cpu])) {
-                        total += tr->data[cpu]->trace_idx;
-                        if (tr->data[cpu]->trace_idx > tr->entries)
-                                entries += tr->entries;
-                        else
-                                entries += tr->data[cpu]->trace_idx;
-                }
-        }
+        entries = ring_buffer_entries(iter->tr->buffer);
+        total = entries +
+                ring_buffer_overruns(iter->tr->buffer);
 
         seq_printf(m, "%s latency trace v1.1.5 on %s\n",
                    name, UTS_RELEASE);
@@ -1468,7 +1209,7 @@ lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
 unsigned long preempt_mark_thresh = 100;
 
 static void
-lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
+lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
                     unsigned long rel_usecs)
 {
         trace_seq_printf(s, " %4lldus", abs_usecs);
@@ -1488,12 +1229,10 @@ static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
  */
 void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
 {
-        struct trace_array *tr = iter->tr;
-        struct trace_array_cpu *data = tr->data[iter->cpu];
         struct trace_entry *ent;
         bool ok = true;
 
-        ent = trace_entry_idx(tr, data, iter, iter->cpu);
+        ent = peek_next_entry(iter, iter->cpu, NULL);
         if (!ent || ent->type != TRACE_CONT) {
                 trace_seq_putc(s, '\n');
                 return;
@@ -1502,8 +1241,8 @@ void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
         do {
                 if (ok)
                         ok = (trace_seq_printf(s, "%s", ent->cont.buf) > 0);
-                __trace_iterator_increment(iter, iter->cpu);
-                ent = trace_entry_idx(tr, data, iter, iter->cpu);
+                ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
+                ent = peek_next_entry(iter, iter->cpu, NULL);
         } while (ent && ent->type == TRACE_CONT);
 
         if (!ok)
@@ -1515,25 +1254,26 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
 {
         struct trace_seq *s = &iter->seq;
         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
-        struct trace_entry *next_entry = find_next_entry(iter, NULL);
+        struct trace_entry *next_entry;
         unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
         struct trace_entry *entry = iter->ent;
         struct trace_field *field = &entry->field;
         unsigned long abs_usecs;
         unsigned long rel_usecs;
+        u64 next_ts;
         char *comm;
         int S, T;
         int i;
         unsigned state;
 
-        if (!next_entry)
-                next_entry = entry;
-
         if (entry->type == TRACE_CONT)
                 return 1;
 
-        rel_usecs = ns2usecs(next_entry->field.t - entry->field.t);
-        abs_usecs = ns2usecs(entry->field.t - iter->tr->time_start);
+        next_entry = find_next_entry(iter, NULL, &next_ts);
+        if (!next_entry)
+                next_ts = iter->ts;
+        rel_usecs = ns2usecs(next_ts - iter->ts);
+        abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
 
         if (verbose) {
                 comm = trace_find_cmdline(field->pid);
@@ -1542,7 +1282,7 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
                                  comm,
                                  field->pid, cpu, field->flags,
                                  field->preempt_count, trace_idx,
-                                 ns2usecs(field->t),
+                                 ns2usecs(iter->ts),
                                  abs_usecs/1000,
                                  abs_usecs % 1000, rel_usecs/1000,
                                  rel_usecs % 1000);
@@ -1627,7 +1367,7 @@ static int print_trace_fmt(struct trace_iterator *iter)
 
         comm = trace_find_cmdline(iter->ent->field.pid);
 
-        t = ns2usecs(field->t);
+        t = ns2usecs(iter->ts);
         usec_rem = do_div(t, 1000000ULL);
         secs = (unsigned long)t;
 
@@ -1732,7 +1472,7 @@ static int print_raw_fmt(struct trace_iterator *iter)
         field = &entry->field;
 
         ret = trace_seq_printf(s, "%d %d %llu ",
-                field->pid, iter->cpu, field->t);
+                field->pid, iter->cpu, iter->ts);
         if (!ret)
                 return 0;
 
@@ -1811,7 +1551,7 @@ static int print_hex_fmt(struct trace_iterator *iter)
 
         SEQ_PUT_HEX_FIELD_RET(s, field->pid);
         SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
-        SEQ_PUT_HEX_FIELD_RET(s, field->t);
+        SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
 
         switch (entry->type) {
         case TRACE_FN:
@@ -1861,7 +1601,7 @@ static int print_bin_fmt(struct trace_iterator *iter)
 
         SEQ_PUT_FIELD_RET(s, field->pid);
         SEQ_PUT_FIELD_RET(s, field->cpu);
-        SEQ_PUT_FIELD_RET(s, field->t);
+        SEQ_PUT_FIELD_RET(s, iter->ts);
 
         switch (entry->type) {
         case TRACE_FN:
@@ -1888,15 +1628,10 @@ static int print_bin_fmt(struct trace_iterator *iter)
 
 static int trace_empty(struct trace_iterator *iter)
 {
-        struct trace_array_cpu *data;
         int cpu;
 
         for_each_tracing_cpu(cpu) {
-                data = iter->tr->data[cpu];
-
-                if (head_page(data) && data->trace_idx &&
-                    (data->trace_tail != data->trace_head ||
-                     data->trace_tail_idx != data->trace_head_idx))
+                if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
                         return 0;
         }
         return 1;
@@ -1961,6 +1696,8 @@ static struct trace_iterator *
 __tracing_open(struct inode *inode, struct file *file, int *ret)
 {
         struct trace_iterator *iter;
+        struct seq_file *m;
+        int cpu;
 
         if (tracing_disabled) {
                 *ret = -ENODEV;
@@ -1981,28 +1718,43 @@ __tracing_open(struct inode *inode, struct file *file, int *ret)
         iter->trace = current_trace;
         iter->pos = -1;
 
+        for_each_tracing_cpu(cpu) {
+                iter->buffer_iter[cpu] =
+                        ring_buffer_read_start(iter->tr->buffer, cpu);
+                if (!iter->buffer_iter[cpu])
+                        goto fail_buffer;
+        }
+
         /* TODO stop tracer */
         *ret = seq_open(file, &tracer_seq_ops);
-        if (!*ret) {
-                struct seq_file *m = file->private_data;
-                m->private = iter;
+        if (*ret)
+                goto fail_buffer;
 
-                /* stop the trace while dumping */
-                if (iter->tr->ctrl) {
-                        tracer_enabled = 0;
-                        ftrace_function_enabled = 0;
-                }
+        m = file->private_data;
+        m->private = iter;
 
-                if (iter->trace && iter->trace->open)
-                        iter->trace->open(iter);
-        } else {
-                kfree(iter);
-                iter = NULL;
+        /* stop the trace while dumping */
+        if (iter->tr->ctrl) {
+                tracer_enabled = 0;
+                ftrace_function_enabled = 0;
         }
+
+        if (iter->trace && iter->trace->open)
+                        iter->trace->open(iter);
+
         mutex_unlock(&trace_types_lock);
 
  out:
         return iter;
+
+ fail_buffer:
+        for_each_tracing_cpu(cpu) {
+                if (iter->buffer_iter[cpu])
+                        ring_buffer_read_finish(iter->buffer_iter[cpu]);
+        }
+        mutex_unlock(&trace_types_lock);
+
+        return ERR_PTR(-ENOMEM);
 }
 
 int tracing_open_generic(struct inode *inode, struct file *filp)
@@ -2018,8 +1770,14 @@ int tracing_release(struct inode *inode, struct file *file)
 {
         struct seq_file *m = (struct seq_file *)file->private_data;
         struct trace_iterator *iter = m->private;
+        int cpu;
 
         mutex_lock(&trace_types_lock);
+        for_each_tracing_cpu(cpu) {
+                if (iter->buffer_iter[cpu])
+                        ring_buffer_read_finish(iter->buffer_iter[cpu]);
+        }
+
         if (iter->trace && iter->trace->close)
                 iter->trace->close(iter);
 
@@ -2526,6 +2284,7 @@ static atomic_t tracing_reader;
 static int tracing_open_pipe(struct inode *inode, struct file *filp)
 {
         struct trace_iterator *iter;
+        int cpu;
 
         if (tracing_disabled)
                 return -ENODEV;
@@ -2546,17 +2305,38 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
         iter->trace = current_trace;
         filp->private_data = iter;
 
+        for_each_tracing_cpu(cpu) {
+                iter->buffer_iter[cpu] =
+                        ring_buffer_read_start(iter->tr->buffer, cpu);
+                if (!iter->buffer_iter[cpu])
+                        goto fail_buffer;
+        }
+
         if (iter->trace->pipe_open)
                 iter->trace->pipe_open(iter);
         mutex_unlock(&trace_types_lock);
 
         return 0;
+
+ fail_buffer:
+        for_each_tracing_cpu(cpu) {
+                if (iter->buffer_iter[cpu])
+                        ring_buffer_read_finish(iter->buffer_iter[cpu]);
+        }
+        mutex_unlock(&trace_types_lock);
+
+        return -ENOMEM;
 }
 
 static int tracing_release_pipe(struct inode *inode, struct file *file)
 {
         struct trace_iterator *iter = file->private_data;
+        int cpu;
 
+        for_each_tracing_cpu(cpu) {
+                if (iter->buffer_iter[cpu])
+                        ring_buffer_read_finish(iter->buffer_iter[cpu]);
+        }
         kfree(iter);
         atomic_dec(&tracing_reader);
 
@@ -2592,13 +2372,10 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
                   size_t cnt, loff_t *ppos)
 {
         struct trace_iterator *iter = filp->private_data;
-        struct trace_array_cpu *data;
-        static cpumask_t mask;
         unsigned long flags;
 #ifdef CONFIG_FTRACE
         int ftrace_save;
 #endif
-        int cpu;
         ssize_t sret;
 
         /* return any leftover data */
@@ -2687,32 +2464,13 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
          * and then release the locks again.
          */
 
-        cpus_clear(mask);
-        local_irq_save(flags);
+        local_irq_disable();
 #ifdef CONFIG_FTRACE
         ftrace_save = ftrace_enabled;
         ftrace_enabled = 0;
 #endif
         smp_wmb();
-        for_each_tracing_cpu(cpu) {
-                data = iter->tr->data[cpu];
-
-                if (!head_page(data) || !data->trace_idx)
-                        continue;
-
-                atomic_inc(&data->disabled);
-                cpu_set(cpu, mask);
-        }
-
-        for_each_cpu_mask(cpu, mask) {
-                data = iter->tr->data[cpu];
-                __raw_spin_lock(&data->lock);
-
-                if (data->overrun > iter->last_overrun[cpu])
-                        iter->overrun[cpu] +=
-                                data->overrun - iter->last_overrun[cpu];
-                iter->last_overrun[cpu] = data->overrun;
-        }
+        ring_buffer_lock(iter->tr->buffer, &flags);
 
         while (find_next_entry_inc(iter) != NULL) {
                 int ret;
@@ -2731,19 +2489,11 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
                         break;
         }
 
-        for_each_cpu_mask(cpu, mask) {
-                data = iter->tr->data[cpu];
-                __raw_spin_unlock(&data->lock);
-        }
-
-        for_each_cpu_mask(cpu, mask) {
-                data = iter->tr->data[cpu];
-                atomic_dec(&data->disabled);
-        }
+        ring_buffer_unlock(iter->tr->buffer, flags);
 #ifdef CONFIG_FTRACE
         ftrace_enabled = ftrace_save;
 #endif
-        local_irq_restore(flags);
+        local_irq_enable();
 
         /* Now copy what we have to the user */
         sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
@@ -2776,7 +2526,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
 {
         unsigned long val;
         char buf[64];
-        int i, ret;
+        int ret;
         struct trace_array *tr = filp->private_data;
 
         if (cnt >= sizeof(buf))
@@ -2804,52 +2554,31 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
                 goto out;
         }
 
-        if (val > global_trace.entries) {
-                long pages_requested;
-                unsigned long freeable_pages;
-
-                /* make sure we have enough memory before mapping */
-                pages_requested =
-                        (val + (ENTRIES_PER_PAGE-1)) / ENTRIES_PER_PAGE;
-
-                /* account for each buffer (and max_tr) */
-                pages_requested *= tracing_nr_buffers * 2;
-
-                /* Check for overflow */
-                if (pages_requested < 0) {
-                        cnt = -ENOMEM;
-                        goto out;
-                }
-
-                freeable_pages = determine_dirtyable_memory();
-
-                /* we only allow to request 1/4 of useable memory */
-                if (pages_requested >
-                    ((freeable_pages + tracing_pages_allocated) / 4)) {
-                        cnt = -ENOMEM;
+        if (val != global_trace.entries) {
+                ret = ring_buffer_resize(global_trace.buffer, val);
+                if (ret < 0) {
+                        cnt = ret;
                         goto out;
                 }
 
-                while (global_trace.entries < val) {
-                        if (trace_alloc_page()) {
-                                cnt = -ENOMEM;
-                                goto out;
+                ret = ring_buffer_resize(max_tr.buffer, val);
+                if (ret < 0) {
+                        int r;
+                        cnt = ret;
+                        r = ring_buffer_resize(global_trace.buffer,
+                                               global_trace.entries);
+                        if (r < 0) {
+                                /* AARGH! We are left with different
+                                 * size max buffer!!!! */
+                                WARN_ON(1);
+                                tracing_disabled = 1;
                         }
-                        /* double check that we don't go over the known pages */
-                        if (tracing_pages_allocated > pages_requested)
-                                break;
+                        goto out;
                 }
 
-        } else {
-                /* include the number of entries in val (inc of page entries) */
-                while (global_trace.entries > val + (ENTRIES_PER_PAGE - 1))
-                        trace_free_page();
+                global_trace.entries = val;
         }
 
-        /* check integrity */
-        for_each_tracing_cpu(i)
-                check_pages(global_trace.data[i]);
-
         filp->f_pos += cnt;
 
         /* If check pages failed, return ENOMEM */
@@ -3086,10 +2815,11 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
         static DEFINE_SPINLOCK(trace_buf_lock);
         static char trace_buf[TRACE_BUF_SIZE];
 
+        struct ring_buffer_event *event;
         struct trace_array *tr = &global_trace;
         struct trace_array_cpu *data;
         struct trace_entry *entry;
-        unsigned long flags;
+        unsigned long flags, irq_flags;
         long disabled;
         int cpu, len = 0, write, written = 0;
 
@@ -3110,8 +2840,11 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
         len = min(len, TRACE_BUF_SIZE-1);
         trace_buf[len] = 0;
 
-        __raw_spin_lock(&data->lock);
-        entry                           = tracing_get_trace_entry(tr, data);
+        event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                         &irq_flags);
+        if (!event)
+                goto out_unlock;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, flags);
         entry->type                     = TRACE_PRINT;
         entry->field.print.ip           = ip;
@@ -3121,21 +2854,27 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
         memcpy(&entry->field.print.buf, trace_buf, write);
         entry->field.print.buf[write] = 0;
         written = write;
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 
         if (written != len)
                 entry->field.flags |= TRACE_FLAG_CONT;
 
         while (written != len) {
-                entry = tracing_get_trace_entry(tr, data);
+                event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                                 &irq_flags);
+                if (!event)
+                        goto out_unlock;
+                entry   = ring_buffer_event_data(event);
 
                 entry->type = TRACE_CONT;
                 write = min(len - written, (int)(TRACE_CONT_BUF_SIZE-1));
                 memcpy(&entry->cont.buf, trace_buf+written, write);
                 entry->cont.buf[write] = 0;
                 written += write;
+                ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
         }
-        __raw_spin_unlock(&data->lock);
 
+ out_unlock:
         spin_unlock(&trace_buf_lock);
 
  out:
@@ -3227,12 +2966,10 @@ void ftrace_dump(void)
         static DEFINE_SPINLOCK(ftrace_dump_lock);
         /* use static because iter can be a bit big for the stack */
         static struct trace_iterator iter;
-        struct trace_array_cpu *data;
         static cpumask_t mask;
         static int dump_ran;
-        unsigned long flags;
+        unsigned long flags, irq_flags;
         int cnt = 0;
-        int cpu;
 
         /* only one dump */
         spin_lock_irqsave(&ftrace_dump_lock, flags);
@@ -3258,25 +2995,7 @@ void ftrace_dump(void)
 
         cpus_clear(mask);
 
-        for_each_tracing_cpu(cpu) {
-                data = iter.tr->data[cpu];
-
-                if (!head_page(data) || !data->trace_idx)
-                        continue;
-
-                atomic_inc(&data->disabled);
-                cpu_set(cpu, mask);
-        }
-
-        for_each_cpu_mask(cpu, mask) {
-                data = iter.tr->data[cpu];
-                __raw_spin_lock(&data->lock);
-
-                if (data->overrun > iter.last_overrun[cpu])
-                        iter.overrun[cpu] +=
-                                data->overrun - iter.last_overrun[cpu];
-                iter.last_overrun[cpu] = data->overrun;
-        }
+        ring_buffer_lock(iter.tr->buffer, &irq_flags);
 
         while (!trace_empty(&iter)) {
 
@@ -3305,205 +3024,47 @@ void ftrace_dump(void)
         else
                 printk(KERN_TRACE "---------------------------------\n");
 
-        for_each_cpu_mask(cpu, mask) {
-                data = iter.tr->data[cpu];
-                __raw_spin_unlock(&data->lock);
-        }
-
-        for_each_cpu_mask(cpu, mask) {
-                data = iter.tr->data[cpu];
-                atomic_dec(&data->disabled);
-        }
-
+        ring_buffer_unlock(iter.tr->buffer, irq_flags);
 
  out:
         spin_unlock_irqrestore(&ftrace_dump_lock, flags);
 }
 
-static int trace_alloc_page(void)
+__init static int tracer_alloc_buffers(void)
 {
         struct trace_array_cpu *data;
-        struct page *page, *tmp;
-        LIST_HEAD(pages);
-        void *array;
-        unsigned pages_allocated = 0;
         int i;
 
-        /* first allocate a page for each CPU */
-        for_each_tracing_cpu(i) {
-                array = (void *)__get_free_page(GFP_KERNEL);
-                if (array == NULL) {
-                        printk(KERN_ERR "tracer: failed to allocate page"
-                               "for trace buffer!\n");
-                        goto free_pages;
-                }
-
-                pages_allocated++;
-                page = virt_to_page(array);
-                list_add(&page->lru, &pages);
+        /* TODO: make the number of buffers hot pluggable with CPUS */
+        tracing_buffer_mask = cpu_possible_map;
 
-/* Only allocate if we are actually using the max trace */
-#ifdef CONFIG_TRACER_MAX_TRACE
-                array = (void *)__get_free_page(GFP_KERNEL);
-                if (array == NULL) {
-                        printk(KERN_ERR "tracer: failed to allocate page"
-                               "for trace buffer!\n");
-                        goto free_pages;
-                }
-                pages_allocated++;
-                page = virt_to_page(array);
-                list_add(&page->lru, &pages);
-#endif
+        global_trace.buffer = ring_buffer_alloc(trace_buf_size,
+                                                   TRACE_BUFFER_FLAGS);
+        if (!global_trace.buffer) {
+                printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
+                WARN_ON(1);
+                return 0;
         }
-
-        /* Now that we successfully allocate a page per CPU, add them */
-        for_each_tracing_cpu(i) {
-                data = global_trace.data[i];
-                page = list_entry(pages.next, struct page, lru);
-                list_del_init(&page->lru);
-                list_add_tail(&page->lru, &data->trace_pages);
-                ClearPageLRU(page);
+        global_trace.entries = ring_buffer_size(global_trace.buffer);
 
 #ifdef CONFIG_TRACER_MAX_TRACE
-                data = max_tr.data[i];
-                page = list_entry(pages.next, struct page, lru);
-                list_del_init(&page->lru);
-                list_add_tail(&page->lru, &data->trace_pages);
-                SetPageLRU(page);
-#endif
-        }
-        tracing_pages_allocated += pages_allocated;
-        global_trace.entries += ENTRIES_PER_PAGE;
-
-        return 0;
-
- free_pages:
-        list_for_each_entry_safe(page, tmp, &pages, lru) {
-                list_del_init(&page->lru);
-                __free_page(page);
+        max_tr.buffer = ring_buffer_alloc(trace_buf_size,
+                                             TRACE_BUFFER_FLAGS);
+        if (!max_tr.buffer) {
+                printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
+                WARN_ON(1);
+                ring_buffer_free(global_trace.buffer);
+                return 0;
         }
-        return -ENOMEM;
-}
-
-static int trace_free_page(void)
-{
-        struct trace_array_cpu *data;
-        struct page *page;
-        struct list_head *p;
-        int i;
-        int ret = 0;
-
-        /* free one page from each buffer */
-        for_each_tracing_cpu(i) {
-                data = global_trace.data[i];
-                p = data->trace_pages.next;
-                if (p == &data->trace_pages) {
-                        /* should never happen */
-                        WARN_ON(1);
-                        tracing_disabled = 1;
-                        ret = -1;
-                        break;
-                }
-                page = list_entry(p, struct page, lru);
-                ClearPageLRU(page);
-                list_del(&page->lru);
-                tracing_pages_allocated--;
-                tracing_pages_allocated--;
-                __free_page(page);
-
-                tracing_reset(data);
-
-#ifdef CONFIG_TRACER_MAX_TRACE
-                data = max_tr.data[i];
-                p = data->trace_pages.next;
-                if (p == &data->trace_pages) {
-                        /* should never happen */
-                        WARN_ON(1);
-                        tracing_disabled = 1;
-                        ret = -1;
-                        break;
-                }
-                page = list_entry(p, struct page, lru);
-                ClearPageLRU(page);
-                list_del(&page->lru);
-                __free_page(page);
-
-                tracing_reset(data);
+        max_tr.entries = ring_buffer_size(max_tr.buffer);
+        WARN_ON(max_tr.entries != global_trace.entries);
 #endif
-        }
-        global_trace.entries -= ENTRIES_PER_PAGE;
-
-        return ret;
-}
-
-__init static int tracer_alloc_buffers(void)
-{
-        struct trace_array_cpu *data;
-        void *array;
-        struct page *page;
-        int pages = 0;
-        int ret = -ENOMEM;
-        int i;
-
-        /* TODO: make the number of buffers hot pluggable with CPUS */
-        tracing_nr_buffers = num_possible_cpus();
-        tracing_buffer_mask = cpu_possible_map;
 
         /* Allocate the first page for all buffers */
         for_each_tracing_cpu(i) {
                 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
                 max_tr.data[i] = &per_cpu(max_data, i);
-
-                array = (void *)__get_free_page(GFP_KERNEL);
-                if (array == NULL) {
-                        printk(KERN_ERR "tracer: failed to allocate page"
-                               "for trace buffer!\n");
-                        goto free_buffers;
-                }
-
-                /* set the array to the list */
-                INIT_LIST_HEAD(&data->trace_pages);
-                page = virt_to_page(array);
-                list_add(&page->lru, &data->trace_pages);
-                /* use the LRU flag to differentiate the two buffers */
-                ClearPageLRU(page);
-
-                data->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
-                max_tr.data[i]->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
-
-/* Only allocate if we are actually using the max trace */
-#ifdef CONFIG_TRACER_MAX_TRACE
-                array = (void *)__get_free_page(GFP_KERNEL);
-                if (array == NULL) {
-                        printk(KERN_ERR "tracer: failed to allocate page"
-                               "for trace buffer!\n");
-                        goto free_buffers;
-                }
-
-                INIT_LIST_HEAD(&max_tr.data[i]->trace_pages);
-                page = virt_to_page(array);
-                list_add(&page->lru, &max_tr.data[i]->trace_pages);
-                SetPageLRU(page);
-#endif
-        }
-
-        /*
-         * Since we allocate by orders of pages, we may be able to
-         * round up a bit.
-         */
-        global_trace.entries = ENTRIES_PER_PAGE;
-        pages++;
-
-        while (global_trace.entries < trace_nr_entries) {
-                if (trace_alloc_page())
-                        break;
-                pages++;
         }
-        max_tr.entries = global_trace.entries;
-
-        pr_info("tracer: %d pages allocated for %ld entries of %ld bytes\n",
-                pages, trace_nr_entries, (long)TRACE_ENTRY_SIZE);
-        pr_info("   actual entries %ld\n", global_trace.entries);
 
         trace_init_cmdlines();
 
@@ -3519,38 +3080,13 @@ __init static int tracer_alloc_buffers(void)
         /* All seems OK, enable tracing */
         global_trace.ctrl = tracer_enabled;
         tracing_disabled = 0;
+
         atomic_notifier_chain_register(&panic_notifier_list,
                                        &trace_panic_notifier);
 
         register_die_notifier(&trace_die_notifier);
 
         return 0;
-
- free_buffers:
-        for (i-- ; i >= 0; i--) {
-                struct page *page, *tmp;
-                struct trace_array_cpu *data = global_trace.data[i];
-
-                if (data) {
-                        list_for_each_entry_safe(page, tmp,
-                                                 &data->trace_pages, lru) {
-                                list_del_init(&page->lru);
-                                __free_page(page);
-                        }
-                }
-
-#ifdef CONFIG_TRACER_MAX_TRACE
-                data = max_tr.data[i];
-                if (data) {
-                        list_for_each_entry_safe(page, tmp,
-                                                 &data->trace_pages, lru) {
-                                list_del_init(&page->lru);
-                                __free_page(page);
-                        }
-                }
-#endif
-        }
-        return ret;
 }
 early_initcall(tracer_alloc_buffers);
 fs_initcall(tracer_init_debugfs);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index b28bf8812efc..f6965f775b43 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -5,6 +5,7 @@
 #include <asm/atomic.h>
 #include <linux/sched.h>
 #include <linux/clocksource.h>
+#include <linux/ring_buffer.h>
 #include <linux/mmiotrace.h>
 #include <linux/ftrace.h>
 
@@ -102,7 +103,6 @@ struct trace_field {
         char                    flags;
         char                    preempt_count;
         int                     pid;
-        cycle_t                 t;
         union {
                 struct ftrace_entry             fn;
                 struct ctx_switch_entry         ctx;
@@ -139,16 +139,9 @@ struct trace_entry {
  * the trace, etc.)
  */
 struct trace_array_cpu {
-        struct list_head        trace_pages;
         atomic_t                disabled;
-        raw_spinlock_t          lock;
-        struct lock_class_key   lock_key;
 
         /* these fields get copied into max-trace: */
-        unsigned                trace_head_idx;
-        unsigned                trace_tail_idx;
-        void                    *trace_head; /* producer */
-        void                    *trace_tail; /* consumer */
         unsigned long           trace_idx;
         unsigned long           overrun;
         unsigned long           saved_latency;
@@ -172,6 +165,7 @@ struct trace_iterator;
  * They have on/off state as well:
  */
 struct trace_array {
+        struct ring_buffer      *buffer;
         unsigned long           entries;
         long                    ctrl;
         int                     cpu;
@@ -219,27 +213,21 @@ struct trace_iterator {
         struct trace_array      *tr;
         struct tracer           *trace;
         void                    *private;
-        long                    last_overrun[NR_CPUS];
-        long                    overrun[NR_CPUS];
+        struct ring_buffer_iter *buffer_iter[NR_CPUS];
 
         /* The below is zeroed out in pipe_read */
         struct trace_seq        seq;
         struct trace_entry      *ent;
         int                     cpu;
-
-        struct trace_entry      *prev_ent;
-        int                     prev_cpu;
+        u64                     ts;
 
         unsigned long           iter_flags;
         loff_t                  pos;
-        unsigned long           next_idx[NR_CPUS];
-        struct list_head        *next_page[NR_CPUS];
-        unsigned                next_page_idx[NR_CPUS];
         long                    idx;
 };
 
 void trace_wake_up(void);
-void tracing_reset(struct trace_array_cpu *data);
+void tracing_reset(struct trace_array *tr, int cpu);
 int tracing_open_generic(struct inode *inode, struct file *filp);
 struct dentry *tracing_init_dentry(void);
 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index d5c9e2e4a9c4..3657eec6b87d 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -34,7 +34,7 @@ static void boot_trace_init(struct trace_array *tr)
         trace_boot_enabled = 0;
 
         for_each_cpu_mask(cpu, cpu_possible_map)
-                tracing_reset(tr->data[cpu]);
+                tracing_reset(tr, cpu);
 }
 
 static void boot_trace_ctrl_update(struct trace_array *tr)
@@ -74,6 +74,7 @@ struct tracer boot_tracer __read_mostly =
 
 void trace_boot(struct boot_trace *it)
 {
+        struct ring_buffer_event *event;
         struct trace_entry *entry;
         struct trace_array_cpu *data;
         unsigned long irq_flags;
@@ -85,17 +86,18 @@ void trace_boot(struct boot_trace *it)
         preempt_disable();
         data = tr->data[smp_processor_id()];
 
-        raw_local_irq_save(irq_flags);
-        __raw_spin_lock(&data->lock);
-
-        entry = tracing_get_trace_entry(tr, data);
+        event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                         &irq_flags);
+        if (!event)
+                goto out;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, 0);
         entry->type = TRACE_BOOT;
         entry->field.initcall = *it;
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 
-        __raw_spin_unlock(&data->lock);
-        raw_local_irq_restore(irq_flags);
         trace_wake_up();
 
+ out:
         preempt_enable();
 }
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 312144897970..e90eb0c2c56c 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -23,7 +23,7 @@ static void function_reset(struct trace_array *tr)
         tr->time_start = ftrace_now(tr->cpu);
 
         for_each_online_cpu(cpu)
-                tracing_reset(tr->data[cpu]);
+                tracing_reset(tr, cpu);
 }
 
 static void start_function_trace(struct trace_array *tr)
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index ece6cfb649fa..37ad49407f27 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -173,7 +173,7 @@ out_unlock:
 out:
         data->critical_sequence = max_sequence;
         data->preempt_timestamp = ftrace_now(cpu);
-        tracing_reset(data);
+        tracing_reset(tr, cpu);
         trace_function(tr, data, CALLER_ADDR0, parent_ip, flags);
 }
 
@@ -203,7 +203,7 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip)
         data->critical_sequence = max_sequence;
         data->preempt_timestamp = ftrace_now(cpu);
         data->critical_start = parent_ip ? : ip;
-        tracing_reset(data);
+        tracing_reset(tr, cpu);
 
         local_save_flags(flags);
 
@@ -234,7 +234,7 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 
         data = tr->data[cpu];
 
-        if (unlikely(!data) || unlikely(!head_page(data)) ||
+        if (unlikely(!data) ||
             !data->critical_start || atomic_read(&data->disabled))
                 return;
 
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index a108c326f36e..bdbf09d8413c 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -27,7 +27,7 @@ static void mmio_reset_data(struct trace_array *tr)
         tr->time_start = ftrace_now(tr->cpu);
 
         for_each_online_cpu(cpu)
-                tracing_reset(tr->data[cpu]);
+                tracing_reset(tr, cpu);
 }
 
 static void mmio_trace_init(struct trace_array *tr)
@@ -130,10 +130,14 @@ static unsigned long count_overruns(struct trace_iterator *iter)
 {
         int cpu;
         unsigned long cnt = 0;
+/* FIXME: */
+#if 0
         for_each_online_cpu(cpu) {
                 cnt += iter->overrun[cpu];
                 iter->overrun[cpu] = 0;
         }
+#endif
+        (void)cpu;
         return cnt;
 }
 
@@ -176,7 +180,7 @@ static int mmio_print_rw(struct trace_iterator *iter)
         struct trace_entry *entry = iter->ent;
         struct mmiotrace_rw *rw = &entry->field.mmiorw;
         struct trace_seq *s     = &iter->seq;
-        unsigned long long t    = ns2usecs(entry->field.t);
+        unsigned long long t    = ns2usecs(iter->ts);
         unsigned long usec_rem  = do_div(t, 1000000ULL);
         unsigned secs           = (unsigned long)t;
         int ret = 1;
@@ -218,7 +222,7 @@ static int mmio_print_map(struct trace_iterator *iter)
         struct trace_entry *entry = iter->ent;
         struct mmiotrace_map *m = &entry->field.mmiomap;
         struct trace_seq *s     = &iter->seq;
-        unsigned long long t    = ns2usecs(entry->field.t);
+        unsigned long long t    = ns2usecs(iter->ts);
         unsigned long usec_rem  = do_div(t, 1000000ULL);
         unsigned secs           = (unsigned long)t;
         int ret = 1;
@@ -250,7 +254,7 @@ static int mmio_print_mark(struct trace_iterator *iter)
         struct trace_entry *entry = iter->ent;
         const char *msg         = entry->field.print.buf;
         struct trace_seq *s     = &iter->seq;
-        unsigned long long t    = ns2usecs(entry->field.t);
+        unsigned long long t    = ns2usecs(iter->ts);
         unsigned long usec_rem  = do_div(t, 1000000ULL);
         unsigned secs           = (unsigned long)t;
         int ret;
@@ -303,19 +307,19 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
                                 struct trace_array_cpu *data,
                                 struct mmiotrace_rw *rw)
 {
+        struct ring_buffer_event *event;
         struct trace_entry *entry;
         unsigned long irq_flags;
 
-        raw_local_irq_save(irq_flags);
-        __raw_spin_lock(&data->lock);
-
-        entry                           = tracing_get_trace_entry(tr, data);
+        event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                           &irq_flags);
+        if (!event)
+                return;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, 0);
         entry->type                     = TRACE_MMIO_RW;
         entry->field.mmiorw             = *rw;
-
-        __raw_spin_unlock(&data->lock);
-        raw_local_irq_restore(irq_flags);
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 
         trace_wake_up();
 }
@@ -331,19 +335,19 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
                                 struct trace_array_cpu *data,
                                 struct mmiotrace_map *map)
 {
+        struct ring_buffer_event *event;
         struct trace_entry *entry;
         unsigned long irq_flags;
 
-        raw_local_irq_save(irq_flags);
-        __raw_spin_lock(&data->lock);
-
-        entry                           = tracing_get_trace_entry(tr, data);
+        event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                           &irq_flags);
+        if (!event)
+                return;
+        entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(entry, 0);
         entry->type                     = TRACE_MMIO_MAP;
         entry->field.mmiomap            = *map;
-
-        __raw_spin_unlock(&data->lock);
-        raw_local_irq_restore(irq_flags);
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 
         trace_wake_up();
 }
diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c
index 16c9ba060bab..4592b4862515 100644
--- a/kernel/trace/trace_nop.c
+++ b/kernel/trace/trace_nop.c
@@ -30,7 +30,7 @@ static void nop_trace_init(struct trace_array *tr)
         ctx_trace = tr;
 
         for_each_online_cpu(cpu)
-                tracing_reset(tr->data[cpu]);
+                tracing_reset(tr, cpu);
 
         if (tr->ctrl)
                 start_nop_trace(tr);
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 789e927abc9c..e0b06db0f7af 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -81,7 +81,7 @@ static void sched_switch_reset(struct trace_array *tr)
         tr->time_start = ftrace_now(tr->cpu);
 
         for_each_online_cpu(cpu)
-                tracing_reset(tr->data[cpu]);
+                tracing_reset(tr, cpu);
 }
 
 static int tracing_sched_register(void)
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 08206b4e29c4..01e75e0639b7 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -191,7 +191,7 @@ static void __wakeup_reset(struct trace_array *tr)
 
         for_each_possible_cpu(cpu) {
                 data = tr->data[cpu];
-                tracing_reset(data);
+                tracing_reset(tr, cpu);
         }
 
         wakeup_cpu = -1;
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 5ebd4b135498..09cf230d7eca 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -18,58 +18,20 @@ static inline int trace_valid_entry(struct trace_entry *entry)
         return 0;
 }
 
-static int
-trace_test_buffer_cpu(struct trace_array *tr, struct trace_array_cpu *data)
+static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
 {
-        struct trace_entry *entries;
-        struct page *page;
-        int idx = 0;
-        int i;
+        struct ring_buffer_event *event;
+        struct trace_entry *entry;
 
-        BUG_ON(list_empty(&data->trace_pages));
-        page = list_entry(data->trace_pages.next, struct page, lru);
-        entries = page_address(page);
+        while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
+                entry = ring_buffer_event_data(event);
 
-        check_pages(data);
-        if (head_page(data) != entries)
-                goto failed;
-
-        /*
-         * The starting trace buffer always has valid elements,
-         * if any element exists.
-         */
-        entries = head_page(data);
-
-        for (i = 0; i < tr->entries; i++) {
-
-                if (i < data->trace_idx && !trace_valid_entry(&entries[idx])) {
+                if (!trace_valid_entry(entry)) {
                         printk(KERN_CONT ".. invalid entry %d ",
-                                entries[idx].type);
+                                entry->type);
                         goto failed;
                 }
-
-                idx++;
-                if (idx >= ENTRIES_PER_PAGE) {
-                        page = virt_to_page(entries);
-                        if (page->lru.next == &data->trace_pages) {
-                                if (i != tr->entries - 1) {
-                                        printk(KERN_CONT ".. entries buffer mismatch");
-                                        goto failed;
-                                }
-                        } else {
-                                page = list_entry(page->lru.next, struct page, lru);
-                                entries = page_address(page);
-                        }
-                        idx = 0;
-                }
-        }
-
-        page = virt_to_page(entries);
-        if (page->lru.next != &data->trace_pages) {
-                printk(KERN_CONT ".. too many entries");
-                goto failed;
         }
-
         return 0;
 
  failed:
@@ -91,13 +53,11 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
         /* Don't allow flipping of max traces now */
         raw_local_irq_save(flags);
         __raw_spin_lock(&ftrace_max_lock);
-        for_each_possible_cpu(cpu) {
-                if (!head_page(tr->data[cpu]))
-                        continue;
 
-                cnt += tr->data[cpu]->trace_idx;
+        cnt = ring_buffer_entries(tr->buffer);
 
-                ret = trace_test_buffer_cpu(tr, tr->data[cpu]);
+        for_each_possible_cpu(cpu) {
+                ret = trace_test_buffer_cpu(tr, cpu);
                 if (ret)
                         break;
         }
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index db58fb66a135..9587d3bcba55 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -241,7 +241,7 @@ static void stack_reset(struct trace_array *tr)
         tr->time_start = ftrace_now(tr->cpu);
 
         for_each_online_cpu(cpu)
-                tracing_reset(tr->data[cpu]);
+                tracing_reset(tr, cpu);
 }
 
 static void start_stack_trace(struct trace_array *tr)