perf, trace: Optimize tracepoints by using per-tracepoint-per-cpu hlist to track events

Avoid the swevent hash-table by using per-tracepoint
hlists.

Also, avoid conditionals on the fast path by ordering
with probe unregister so that we should never get on
the callback path without the data being there.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100521090710.473188012@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 4 deletions

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index a657cefbb137..eb769f270291 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -438,6 +438,7 @@ static void perf_syscall_enter(struct pt_regs *regs, long id)
 {
         struct syscall_metadata *sys_data;
         struct syscall_trace_enter *rec;
+        struct hlist_head *head;
         int syscall_nr;
         int rctx;
         int size;
@@ -467,8 +468,9 @@ static void perf_syscall_enter(struct pt_regs *regs, long id)
         rec->nr = syscall_nr;
         syscall_get_arguments(current, regs, 0, sys_data->nb_args,
                                (unsigned long *)&rec->args);
-        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs,
-                        sys_data->enter_event->perf_data);
+
+        head = per_cpu_ptr(sys_data->enter_event->perf_events, smp_processor_id());
+        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
 }
 
 int perf_sysenter_enable(struct ftrace_event_call *call)
@@ -510,6 +512,7 @@ static void perf_syscall_exit(struct pt_regs *regs, long ret)
 {
         struct syscall_metadata *sys_data;
         struct syscall_trace_exit *rec;
+        struct hlist_head *head;
         int syscall_nr;
         int rctx;
         int size;
@@ -542,8 +545,8 @@ static void perf_syscall_exit(struct pt_regs *regs, long ret)
         rec->nr = syscall_nr;
         rec->ret = syscall_get_return_value(current, regs);
 
-        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs,
-                        sys_data->exit_event->perf_data);
+        head = per_cpu_ptr(sys_data->exit_event->perf_events, smp_processor_id());
+        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
 }
 
 int perf_sysexit_enable(struct ftrace_event_call *call)