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authorLinus Torvalds <torvalds@linux-foundation.org>2010-03-18 16:52:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-18 16:52:46 -0700
commitf82c37e7bb4c4d9b6a476c642d5c2d2efbd6f240 (patch)
tree09fc553c2fb6f527962048d139159dc139e04afc /kernel/trace/trace_event_perf.c
parentc6b9e73f2fee8bb86058f296de808b326473456b (diff)
parentdcd5c1662db59a6b82942f47fb6ac9dd63f6d3dd (diff)
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (35 commits) perf: Fix unexported generic perf_arch_fetch_caller_regs perf record: Don't try to find buildids in a zero sized file perf: export perf_trace_regs and perf_arch_fetch_caller_regs perf, x86: Fix hw_perf_enable() event assignment perf, ppc: Fix compile error due to new cpu notifiers perf: Make the install relative to DESTDIR if specified kprobes: Calculate the index correctly when freeing the out-of-line execution slot perf tools: Fix sparse CPU numbering related bugs perf_event: Fix oops triggered by cpu offline/online perf: Drop the obsolete profile naming for trace events perf: Take a hot regs snapshot for trace events perf: Introduce new perf_fetch_caller_regs() for hot regs snapshot perf/x86-64: Use frame pointer to walk on irq and process stacks lockdep: Move lock events under lockdep recursion protection perf report: Print the map table just after samples for which no map was found perf report: Add multiple event support perf session: Change perf_session post processing functions to take histogram tree perf session: Add storage for seperating event types in report perf session: Change add_hist_entry to take the tree root instead of session perf record: Add ID and to recorded event data when recording multiple events ...
Diffstat (limited to 'kernel/trace/trace_event_perf.c')
-rw-r--r--kernel/trace/trace_event_perf.c168
1 files changed, 168 insertions, 0 deletions
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
new file mode 100644
index 00000000000..81f691eb3a3
--- /dev/null
+++ b/kernel/trace/trace_event_perf.c
@@ -0,0 +1,168 @@
+/*
+ * trace event based perf event profiling/tracing
+ *
+ * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra <pzijlstr@redhat.com>
+ * Copyright (C) 2009-2010 Frederic Weisbecker <fweisbec@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kprobes.h>
+#include "trace.h"
+
+DEFINE_PER_CPU(struct pt_regs, perf_trace_regs);
+EXPORT_PER_CPU_SYMBOL_GPL(perf_trace_regs);
+
+EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs);
+
+static char *perf_trace_buf;
+static char *perf_trace_buf_nmi;
+
+typedef typeof(char [PERF_MAX_TRACE_SIZE]) perf_trace_t ;
+
+/* Count the events in use (per event id, not per instance) */
+static int total_ref_count;
+
+static int perf_trace_event_enable(struct ftrace_event_call *event)
+{
+ char *buf;
+ int ret = -ENOMEM;
+
+ if (event->perf_refcount++ > 0)
+ return 0;
+
+ if (!total_ref_count) {
+ buf = (char *)alloc_percpu(perf_trace_t);
+ if (!buf)
+ goto fail_buf;
+
+ rcu_assign_pointer(perf_trace_buf, buf);
+
+ buf = (char *)alloc_percpu(perf_trace_t);
+ if (!buf)
+ goto fail_buf_nmi;
+
+ rcu_assign_pointer(perf_trace_buf_nmi, buf);
+ }
+
+ ret = event->perf_event_enable(event);
+ if (!ret) {
+ total_ref_count++;
+ return 0;
+ }
+
+fail_buf_nmi:
+ if (!total_ref_count) {
+ free_percpu(perf_trace_buf_nmi);
+ free_percpu(perf_trace_buf);
+ perf_trace_buf_nmi = NULL;
+ perf_trace_buf = NULL;
+ }
+fail_buf:
+ event->perf_refcount--;
+
+ return ret;
+}
+
+int perf_trace_enable(int event_id)
+{
+ struct ftrace_event_call *event;
+ int ret = -EINVAL;
+
+ mutex_lock(&event_mutex);
+ list_for_each_entry(event, &ftrace_events, list) {
+ if (event->id == event_id && event->perf_event_enable &&
+ try_module_get(event->mod)) {
+ ret = perf_trace_event_enable(event);
+ break;
+ }
+ }
+ mutex_unlock(&event_mutex);
+
+ return ret;
+}
+
+static void perf_trace_event_disable(struct ftrace_event_call *event)
+{
+ char *buf, *nmi_buf;
+
+ if (--event->perf_refcount > 0)
+ return;
+
+ event->perf_event_disable(event);
+
+ if (!--total_ref_count) {
+ buf = perf_trace_buf;
+ rcu_assign_pointer(perf_trace_buf, NULL);
+
+ nmi_buf = perf_trace_buf_nmi;
+ rcu_assign_pointer(perf_trace_buf_nmi, NULL);
+
+ /*
+ * Ensure every events in profiling have finished before
+ * releasing the buffers
+ */
+ synchronize_sched();
+
+ free_percpu(buf);
+ free_percpu(nmi_buf);
+ }
+}
+
+void perf_trace_disable(int event_id)
+{
+ struct ftrace_event_call *event;
+
+ mutex_lock(&event_mutex);
+ list_for_each_entry(event, &ftrace_events, list) {
+ if (event->id == event_id) {
+ perf_trace_event_disable(event);
+ module_put(event->mod);
+ break;
+ }
+ }
+ mutex_unlock(&event_mutex);
+}
+
+__kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
+ int *rctxp, unsigned long *irq_flags)
+{
+ struct trace_entry *entry;
+ char *trace_buf, *raw_data;
+ int pc, cpu;
+
+ pc = preempt_count();
+
+ /* Protect the per cpu buffer, begin the rcu read side */
+ local_irq_save(*irq_flags);
+
+ *rctxp = perf_swevent_get_recursion_context();
+ if (*rctxp < 0)
+ goto err_recursion;
+
+ cpu = smp_processor_id();
+
+ if (in_nmi())
+ trace_buf = rcu_dereference_sched(perf_trace_buf_nmi);
+ else
+ trace_buf = rcu_dereference_sched(perf_trace_buf);
+
+ if (!trace_buf)
+ goto err;
+
+ raw_data = per_cpu_ptr(trace_buf, cpu);
+
+ /* zero the dead bytes from align to not leak stack to user */
+ *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+
+ entry = (struct trace_entry *)raw_data;
+ tracing_generic_entry_update(entry, *irq_flags, pc);
+ entry->type = type;
+
+ return raw_data;
+err:
+ perf_swevent_put_recursion_context(*rctxp);
+err_recursion:
+ local_irq_restore(*irq_flags);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(perf_trace_buf_prepare);