From b66647ab757c580b2532c117bd345d1bad3b2bd5 Mon Sep 17 00:00:00 2001

From: "Chang S. Bae" <chang.seok.bae@intel.com>

Date: Thu, 10 Feb 2022 14:46:01 -0800

Subject: [PATCH 04/14] Prepare to handle thermal event

Intel's new hardware supports Hardware Feedback Interface to provide CPU

performance and energy efficiency information. Every update on this is

delivered via thermal event interrupt. The thermal framework in the Linux

kernel relays these notifications to userspace via a Netlink interface.

When a CPU's performance and efficiency are zero, irqbalance needs to mask

the CPU from interrupts. Introduce a new CPU mask to indicate banned CPUs

for this.

Before supporting this event handling, define functions. Their

implementation will be on the following patches.

This event is available only on x86-64 systems. And it can be subscribed

with help of Netlink libraries. So check them before building it.

Also add a new build option so users may opt out this support. Setting this

option on other systems will result in a build failure.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>

---

 Makefile.am  |  7 +++--

 configure.ac | 22 ++++++++++++++

 cputree.c    |  6 ++++

 irqbalance.c |  4 +++

 thermal.c    | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++

 thermal.h    | 15 ++++++++++

 6 files changed, 135 insertions(+), 2 deletions(-)

 create mode 100644 thermal.c

 create mode 100644 thermal.h

diff --git a/Makefile.am b/Makefile.am

index 84e7d46..9181a34 100644

--- a/Makefile.am

+++ b/Makefile.am

@@ -27,7 +27,7 @@ EXTRA_DIST = COPYING autogen.sh misc/irqbalance.service misc/irqbalance.env

 SUBDIRS = tests

 UI_DIR = ui

-AM_CFLAGS = $(LIBCAP_NG_CFLAGS) $(GLIB2_CFLAGS) $(NUMA_CFLAGS)

+AM_CFLAGS = $(LIBCAP_NG_CFLAGS) $(GLIB2_CFLAGS) $(NUMA_CFLAGS) $(LIBNL3_CFLAGS)

 AM_CPPFLAGS = -I${top_srcdir} -W -Wall -Wshadow -Wformat -Wundef -D_GNU_SOURCE

 noinst_HEADERS = bitmap.h constants.h cpumask.h irqbalance.h non-atomic.h \

 	types.h $(UI_DIR)/helpers.h $(UI_DIR)/irqbalance-ui.h $(UI_DIR)/ui.h

@@ -39,7 +39,10 @@ endif

 irqbalance_SOURCES = activate.c bitmap.c classify.c cputree.c irqbalance.c \

 	irqlist.c numa.c placement.c procinterrupts.c

-irqbalance_LDADD = $(LIBCAP_NG_LIBS) $(GLIB2_LIBS) $(NUMA_LIBS)

+if THERMAL

+irqbalance_SOURCES += thermal.c

+endif

+irqbalance_LDADD = $(LIBCAP_NG_LIBS) $(GLIB2_LIBS) $(NUMA_LIBS) $(LIBNL3_LIBS)

 if IRQBALANCEUI

 irqbalance_ui_SOURCES = $(UI_DIR)/helpers.c $(UI_DIR)/irqbalance-ui.c \

 	$(UI_DIR)/ui.c

diff --git a/configure.ac b/configure.ac

index 32082fc..15532c1 100644

--- a/configure.ac

+++ b/configure.ac

@@ -36,6 +36,28 @@ AS_IF([test "x$has_ncursesw" = "xyes"], [

   AC_SUBST([LIBS])

 ])

+AC_CANONICAL_HOST

+

+AC_ARG_ENABLE(thermal,

+  AS_HELP_STRING([--enable-thermal], [enable thermal event support [default=auto]]),,

+  AS_IF([test x"$host_cpu" = x"x86_64"], [enable_thermal=yes], [enable_thermal=no])

+)

+

+AS_IF([test x"$enable_thermal" = x"yes" && test x"$host_cpu" != x"x86_64"],

+  AC_MSG_ERROR([no thermal events support on $host_cpu systems.]),

+)

+

+AS_IF([test x"$enable_thermal" = x"yes"],

+  [PKG_CHECK_MODULES([LIBNL3], [libnl-3.0 libnl-genl-3.0], [have_thermal=yes],

+    AC_MSG_NOTICE([no thermal event support as libnl-3.0 is unavailable.])

+  )]

+)

+

+AS_IF([test "x$have_thermal" = xyes],

+  AC_DEFINE([HAVE_THERMAL], 1, [Build irqbalance to support thermal events])

+)

+AM_CONDITIONAL([THERMAL], [test "x$have_thermal" = xyes])

+

 AC_C_CONST

 AC_C_INLINE

 AM_PROG_CC_C_O

diff --git a/cputree.c b/cputree.c

index b716a8f..c250977 100644

--- a/cputree.c

+++ b/cputree.c

@@ -38,6 +38,7 @@

 #include <glib.h>

 #include "irqbalance.h"

+#include "thermal.h"

 #ifdef HAVE_IRQBALANCEUI

 extern char *banned_cpumask_from_ui;

@@ -162,6 +163,11 @@ static void setup_banned_cpus(void)

 	cpumask_scnprintf(buffer, 4096, nohz_full);

 	log(TO_CONSOLE, LOG_INFO, "Adaptive-ticks CPUs: %s\n", buffer);

 out:

+#ifdef HAVE_THERMAL

+	cpus_or(banned_cpus, banned_cpus, thermal_banned_cpus);

+	cpumask_scnprintf(buffer, 4096, thermal_banned_cpus);

+	log(TO_CONSOLE, LOG_INFO, "Thermal-banned CPUs: %s\n", buffer);

+#endif

 	cpumask_scnprintf(buffer, 4096, banned_cpus);

 	log(TO_CONSOLE, LOG_INFO, "Banned CPUs: %s\n", buffer);

 }

diff --git a/irqbalance.c b/irqbalance.c

index e8d9ba9..c520c11 100644

--- a/irqbalance.c

+++ b/irqbalance.c

@@ -44,6 +44,7 @@

 #include <sys/socket.h>

 #endif

 #include "irqbalance.h"

+#include "thermal.h"

 volatile int keep_going = 1;

 int one_shot_mode;

@@ -703,6 +704,8 @@ int main(int argc, char** argv)

 		goto out;

 	}

 #endif

+	if (init_thermal())

+		log(TO_ALL, LOG_WARNING, "Failed to initialize thermal events.\n");

 	main_loop = g_main_loop_new(NULL, FALSE);

 	last_interval = sleep_interval;

 	g_timeout_add_seconds(sleep_interval, scan, NULL);

@@ -711,6 +714,7 @@ int main(int argc, char** argv)

 	g_main_loop_quit(main_loop);

 out:

+	deinit_thermal();

 	free_object_tree();

 	free_cl_opts();

 	free(polscript);

diff --git a/thermal.c b/thermal.c

new file mode 100644

index 0000000..308bc48

--- /dev/null

+++ b/thermal.c

@@ -0,0 +1,83 @@

+/*

+ * This program is free software; you can redistribute it and/or modify

+ * it under the terms of the GNU General Public License version 2 as

+ * published by the Free Software Foundation.

+ */

+

+#include <stdio.h>

+

+#include <netlink/genl/genl.h>

+#include <netlink/genl/family.h>

+#include <netlink/genl/ctrl.h>

+

+#include "irqbalance.h"

+

+cpumask_t thermal_banned_cpus;

+

+static gboolean prepare_netlink(void)

+{

+	gboolean error = TRUE;

+

+	log(TO_ALL, LOG_ERR, "thermal: not yet implement to alloc memory for netlink.\n");

+	return error;

+}

+

+#define NL_FAMILY_NAME	"nlctrl"

+

+static gboolean establish_netlink(void)

+{

+	gboolean error = TRUE;

+

+	log(TO_ALL, LOG_ERR, "thermal: not yet implemented to establish netlink.\n");

+	return error;

+}

+

+static gboolean register_netlink_handler(nl_recvmsg_msg_cb_t handler __attribute__((unused)))

+{

+	gboolean error = TRUE;

+

+	log(TO_ALL, LOG_ERR, "thermal: not yet implemented to register thermal handler.\n");

+	return error;

+}

+

+static gboolean set_netlink_nonblocking(void)

+{

+	gboolean error = TRUE;

+

+	log(TO_ALL, LOG_ERR, "thermal: not yet implemented to set nonblocking socket.\n");

+	return error;

+}

+

+void deinit_thermal(void)

+{

+	return;

+}

+

+/*

+ * return value: TRUE with an error; otherwise, FALSE

+ */

+gboolean init_thermal(void)

+{

+	gboolean error;

+

+	error = prepare_netlink();

+	if (error)

+		goto err_out;

+

+	error = establish_netlink();

+	if (error)

+		goto err_out;

+

+	error = register_netlink_handler(NULL);

+	if (error)

+		goto err_out;

+

+	error = set_netlink_nonblocking();

+	if (error)

+		goto err_out;

+

+	return FALSE;

+err_out:

+	deinit_thermal();

+	return TRUE;

+}

diff --git a/thermal.h b/thermal.h

new file mode 100644

index 0000000..657d54e

--- /dev/null

+++ b/thermal.h

@@ -0,0 +1,15 @@

+#ifndef __LINUX_THERMAL_H_

+#define __LINUX_THERMAL_H_

+

+#include <glib.h>

+

+#ifdef HAVE_THERMAL

+gboolean init_thermal(void);

+void deinit_thermal(void);

+extern cpumask_t thermal_banned_cpus;

+#else

+static inline gboolean init_thermal(void) { return FALSE; }

+#define deinit_thermal() do { } while (0)

+#endif

+

+#endif /* __LINUX_THERMAL_H_ */

-- 

2.33.1