perf ui: Improve handling sigwinch a bit

No need to unblock it at each ui__getch() and also allow other users to
check if a resize is needed, or force an refresh of terminal dimensions.

The 'force' one shouldn't be needed, but its in a slow path, so leave it
like that for now, I'll revisit this another day.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-aujchu6yx3bfy64non1rky0w@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/ui/browser.c

@@ -4,6 +4,7 @@
 #include "libslang.h"
 #include <newt.h>
 #include "ui.h"
+#include "util.h"
 #include <linux/compiler.h>
 #include <linux/list.h>
 #include <linux/rbtree.h>
@@ -291,53 +292,10 @@ void ui_browser__update_nr_entries(struct ui_browser *browser, u32 nr_entries)
 	browser->seek(browser, browser->top_idx, SEEK_SET);
 }
 
-static int ui__getch(int delay_secs)
-{
-	struct timeval timeout, *ptimeout = delay_secs ? &timeout : NULL;
-	fd_set read_set;
-	int err, key;
-
-	FD_ZERO(&read_set);
-	FD_SET(0, &read_set);
-
-	if (delay_secs) {
-		timeout.tv_sec = delay_secs;
-		timeout.tv_usec = 0;
-	}
-
-        err = select(1, &read_set, NULL, NULL, ptimeout);
-
-	if (err == 0)
-		return K_TIMER;
-
-	if (err == -1) {
-		if (errno == EINTR)
-			return K_RESIZE;
-		return K_ERROR;
-	}
-
-	key = SLang_getkey();
-	if (key != K_ESC)
-		return key;
-
-	FD_ZERO(&read_set);
-	FD_SET(0, &read_set);
-	timeout.tv_sec = 0;
-	timeout.tv_usec = 20;
-        err = select(1, &read_set, NULL, NULL, &timeout);
-	if (err == 0)
-		return K_ESC;
-
-	SLang_ungetkey(key);
-	return SLkp_getkey();
-}
-
 int ui_browser__run(struct ui_browser *self, int delay_secs)
 {
 	int err, key;
 
-	pthread__unblock_sigwinch();
-
 	while (1) {
 		off_t offset;
 
@@ -351,10 +309,7 @@ int ui_browser__run(struct ui_browser *self, int delay_secs)
 		key = ui__getch(delay_secs);
 
 		if (key == K_RESIZE) {
-			pthread_mutex_lock(&ui__lock);
-			SLtt_get_screen_size();
-			SLsmg_reinit_smg();
-			pthread_mutex_unlock(&ui__lock);
+			ui__refresh_dimensions(false);
 			ui_browser__refresh_dimensions(self);
 			__ui_browser__show_title(self, self->title);
 			ui_helpline__puts(self->helpline);

tools/perf/util/ui/progress.c

@@ -14,6 +14,7 @@ void ui_progress__update(u64 curr, u64 total, const char *title)
 	if (use_browser <= 0)
 		return;
 
+	ui__refresh_dimensions(true);
 	pthread_mutex_lock(&ui__lock);
 	y = SLtt_Screen_Rows / 2 - 2;
 	SLsmg_set_color(0);

tools/perf/util/ui/setup.c

@@ -7,10 +7,85 @@
 #include "browser.h"
 #include "helpline.h"
 #include "ui.h"
+#include "util.h"
 #include "libslang.h"
+#include "keysyms.h"
 
 pthread_mutex_t ui__lock = PTHREAD_MUTEX_INITIALIZER;
 
+static volatile int ui__need_resize;
+
+void ui__refresh_dimensions(bool force)
+{
+	if (force || ui__need_resize) {
+		ui__need_resize = 0;
+		pthread_mutex_lock(&ui__lock);
+		SLtt_get_screen_size();
+		SLsmg_reinit_smg();
+		pthread_mutex_unlock(&ui__lock);
+	}
+}
+
+static void ui__sigwinch(int sig __used)
+{
+	ui__need_resize = 1;
+}
+
+static void ui__setup_sigwinch(void)
+{
+	static bool done;
+
+	if (done)
+		return;
+
+	done = true;
+	pthread__unblock_sigwinch();
+	signal(SIGWINCH, ui__sigwinch);
+}
+
+int ui__getch(int delay_secs)
+{
+	struct timeval timeout, *ptimeout = delay_secs ? &timeout : NULL;
+	fd_set read_set;
+	int err, key;
+
+	ui__setup_sigwinch();
+
+	FD_ZERO(&read_set);
+	FD_SET(0, &read_set);
+
+	if (delay_secs) {
+		timeout.tv_sec = delay_secs;
+		timeout.tv_usec = 0;
+	}
+
+        err = select(1, &read_set, NULL, NULL, ptimeout);
+
+	if (err == 0)
+		return K_TIMER;
+
+	if (err == -1) {
+		if (errno == EINTR)
+			return K_RESIZE;
+		return K_ERROR;
+	}
+
+	key = SLang_getkey();
+	if (key != K_ESC)
+		return key;
+
+	FD_ZERO(&read_set);
+	FD_SET(0, &read_set);
+	timeout.tv_sec = 0;
+	timeout.tv_usec = 20;
+        err = select(1, &read_set, NULL, NULL, &timeout);
+	if (err == 0)
+		return K_ESC;
+
+	SLang_ungetkey(key);
+	return SLkp_getkey();
+}
+
 static void newt_suspend(void *d __used)
 {
 	newtSuspend();

tools/perf/util/ui/ui.h

@@ -2,7 +2,10 @@
 #define _PERF_UI_H_ 1
 
 #include <pthread.h>
+#include <stdbool.h>
 
 extern pthread_mutex_t ui__lock;
 
+void ui__refresh_dimensions(bool force);
+
 #endif /* _PERF_UI_H_ */

tools/perf/util/ui/util.h

@@ -3,6 +3,7 @@
 
 #include <stdbool.h>
 
+int ui__getch(int delay_secs);
 int ui__popup_menu(int argc, char * const argv[]);
 int ui__help_window(const char *text);
 bool ui__dialog_yesno(const char *msg);