perf ui: Serialize screen updates

The ui operations so far were used by just one thread, but 'perf top
--tui' now has two threads updating the screen, so we need to use a
mutex to avoid garbling the screen.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 22 insertions, 1 deletions

diff --git a/tools/perf/util/ui/browser.c b/tools/perf/util/ui/browser.c
index 8bc010edca25..60d6c815e1db 100644
--- a/tools/perf/util/ui/browser.c
+++ b/tools/perf/util/ui/browser.c
@@ -1,4 +1,5 @@
 #include "libslang.h"
+#include "ui.h"
 #include <linux/compiler.h>
 #include <linux/list.h>
 #include <linux/rbtree.h>
@@ -178,6 +179,7 @@ int ui_browser__show(struct ui_browser *self, const char *title,
         if (self->sb == NULL)
                 return -1;
 
+        pthread_mutex_lock(&ui__lock);
         SLsmg_gotorc(0, 0);
         ui_browser__set_color(self, NEWT_COLORSET_ROOT);
         slsmg_write_nstring(title, self->width);
@@ -188,25 +190,30 @@ int ui_browser__show(struct ui_browser *self, const char *title,
         va_start(ap, helpline);
         ui_helpline__vpush(helpline, ap);
         va_end(ap);
+        pthread_mutex_unlock(&ui__lock);
         return 0;
 }
 
 void ui_browser__hide(struct ui_browser *self)
 {
+        pthread_mutex_lock(&ui__lock);
         newtFormDestroy(self->form);
         self->form = NULL;
         ui_helpline__pop();
+        pthread_mutex_unlock(&ui__lock);
 }
 
 int ui_browser__refresh(struct ui_browser *self)
 {
         int row;
 
+        pthread_mutex_lock(&ui__lock);
         newtScrollbarSet(self->sb, self->index, self->nr_entries - 1);
         row = self->refresh(self);
         ui_browser__set_color(self, HE_COLORSET_NORMAL);
         SLsmg_fill_region(self->y + row, self->x,
                           self->height - row, self->width, ' ');
+        pthread_mutex_unlock(&ui__lock);
 
         return 0;
 }
diff --git a/tools/perf/util/ui/helpline.c b/tools/perf/util/ui/helpline.c
index 8d79daa4458a..f36d2ff509ed 100644
--- a/tools/perf/util/ui/helpline.c
+++ b/tools/perf/util/ui/helpline.c
@@ -5,6 +5,7 @@
 
 #include "../debug.h"
 #include "helpline.h"
+#include "ui.h"
 
 void ui_helpline__pop(void)
 {
@@ -55,7 +56,8 @@ int ui_helpline__show_help(const char *format, va_list ap)
         int ret;
         static int backlog;
 
-        ret = vsnprintf(ui_helpline__last_msg + backlog,
+        pthread_mutex_lock(&ui__lock);
+        ret = vsnprintf(ui_helpline__last_msg + backlog,
                         sizeof(ui_helpline__last_msg) - backlog, format, ap);
         backlog += ret;
 
@@ -64,6 +66,7 @@ int ui_helpline__show_help(const char *format, va_list ap)
                 newtRefresh();
                 backlog = 0;
         }
+        pthread_mutex_unlock(&ui__lock);
 
         return ret;
 }
diff --git a/tools/perf/util/ui/setup.c b/tools/perf/util/ui/setup.c
index fbf1a145492f..ee46d671db59 100644
--- a/tools/perf/util/ui/setup.c
+++ b/tools/perf/util/ui/setup.c
@@ -6,6 +6,9 @@
 #include "../debug.h"
 #include "browser.h"
 #include "helpline.h"
+#include "ui.h"
+
+pthread_mutex_t ui__lock = PTHREAD_MUTEX_INITIALIZER;
 
 static void newt_suspend(void *d __used)
 {
diff --git a/tools/perf/util/ui/ui.h b/tools/perf/util/ui/ui.h
new file mode 100644
index 000000000000..d264e059c829
--- /dev/null
+++ b/tools/perf/util/ui/ui.h
@@ -0,0 +1,8 @@
+#ifndef _PERF_UI_H_
+#define _PERF_UI_H_ 1
+
+#include <pthread.h>
+
+extern pthread_mutex_t ui__lock;
+
+#endif /* _PERF_UI_H_ */