From: Ondřej Surý <ondrej@sury.org>
Date: Tue, 14 Dec 2021 20:49:53 +0000 (+0100)
Subject: Add #define ISC_OS_CACHELINE_SIZE 64
X-Git-Tag: v9.17.22~9^2~4
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4f78f9d72a5dc3f6a596251e662d00cb80cd5e6d;p=thirdparty%2Fbind9.git

Add #define ISC_OS_CACHELINE_SIZE 64

Add library ctor and dtor for isc_os compilation unit which initializes
the numbers of the CPUs and also checks whether L1 cacheline size is
really 64 if the sysconf() call is available.
---

diff --git a/lib/isc/Makefile.am b/lib/isc/Makefile.am
index 70358f8a821..c6f800d5c68 100644
--- a/lib/isc/Makefile.am
+++ b/lib/isc/Makefile.am
@@ -168,6 +168,7 @@ libisc_la_SOURCES =		\
 	openssl_shim.c		\
 	openssl_shim.h		\
 	os.c			\
+	os_p.h			\
 	parseint.c		\
 	pool.c			\
 	portset.c		\
diff --git a/lib/isc/include/isc/os.h b/lib/isc/include/isc/os.h
index f9e90e0d82c..96c9f0f3ea0 100644
--- a/lib/isc/include/isc/os.h
+++ b/lib/isc/include/isc/os.h
@@ -14,9 +14,17 @@
 /*! \file isc/os.h */
 
 #include <isc/lang.h>
+#include <isc/types.h>
 
 ISC_LANG_BEGINDECLS
 
+/*%<
+ * Hardcode the L1 cacheline size of the CPU to 64, this is checked in
+ * the os.c library constructor if operating system provide means to
+ * get the L1 cacheline size using sysconf().
+ */
+#define ISC_OS_CACHELINE_SIZE 64
+
 unsigned int
 isc_os_ncpus(void);
 /*%<
diff --git a/lib/isc/lib.c b/lib/isc/lib.c
index 5f9173ff4cb..e591b08780f 100644
--- a/lib/isc/lib.c
+++ b/lib/isc/lib.c
@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "mem_p.h"
+#include "os_p.h"
 #include "tls_p.h"
 #include "trampoline_p.h"
 
@@ -37,6 +38,7 @@ isc__shutdown(void) ISC_DESTRUCTOR;
 
 void
 isc__initialize(void) {
+	isc__os_initialize();
 	isc__mem_initialize();
 	isc__tls_initialize();
 	isc__trampoline_initialize();
@@ -48,4 +50,5 @@ isc__shutdown(void) {
 	isc__trampoline_shutdown();
 	isc__tls_shutdown();
 	isc__mem_shutdown();
+	isc__os_shutdown();
 }
diff --git a/lib/isc/os.c b/lib/isc/os.c
index 6a75b609766..660d94af578 100644
--- a/lib/isc/os.c
+++ b/lib/isc/os.c
@@ -9,12 +9,15 @@
  * information regarding copyright ownership.
  */
 
-#include <isc/once.h>
+#include <inttypes.h>
+
 #include <isc/os.h>
+#include <isc/types.h>
 #include <isc/util.h>
 
-static isc_once_t ncpus_once = ISC_ONCE_INIT;
-static unsigned int ncpus = 0;
+#include "os_p.h"
+
+static unsigned int isc__os_ncpus = 0;
 
 #ifdef HAVE_SYSCONF
 
@@ -54,23 +57,33 @@ sysctl_ncpus(void) {
 static void
 ncpus_initialize(void) {
 #if defined(HAVE_SYSCONF)
-	ncpus = sysconf_ncpus();
+	isc__os_ncpus = sysconf_ncpus();
 #endif /* if defined(HAVE_SYSCONF) */
 #if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME)
-	if (ncpus <= 0) {
-		ncpus = sysctl_ncpus();
+	if (isc__os_ncpus <= 0) {
+		isc__os_ncpus = sysctl_ncpus();
 	}
 #endif /* if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) */
-	if (ncpus <= 0) {
-		ncpus = 1;
+	if (isc__os_ncpus == 0) {
+		isc__os_ncpus = 1;
 	}
 }
 
 unsigned int
 isc_os_ncpus(void) {
-	isc_result_t result = isc_once_do(&ncpus_once, ncpus_initialize);
-	RUNTIME_CHECK(result == ISC_R_SUCCESS);
-	INSIST(ncpus > 0);
+	return (isc__os_ncpus);
+}
+
+void
+isc__os_initialize(void) {
+	ncpus_initialize();
+#if defined(HAVE_SYSCONF) && defined(_SC_LEVEL1_DCACHE_LINESIZE)
+	long s = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
+	RUNTIME_CHECK((size_t)s == (size_t)ISC_OS_CACHELINE_SIZE);
+#endif
+}
 
-	return (ncpus);
+void
+isc__os_shutdown(void) {
+	/* empty, but defined for completeness */;
 }
diff --git a/lib/isc/os_p.h b/lib/isc/os_p.h
new file mode 100644
index 00000000000..0c28a06975e
--- /dev/null
+++ b/lib/isc/os_p.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#pragma once
+
+#include <stdio.h>
+
+#include <isc/os.h>
+
+/*! \file */
+
+void
+isc__os_initialize(void);
+
+void
+isc__os_shutdown(void);
diff --git a/util/copyrights b/util/copyrights
index 150f956e9d9..e57b83189ee 100644
--- a/util/copyrights
+++ b/util/copyrights
@@ -1790,6 +1790,7 @@
 ./lib/isc/openssl_shim.c			C	2018,2019,2020,2021,2022
 ./lib/isc/openssl_shim.h			C	2020,2021,2022
 ./lib/isc/os.c					C	2000,2001,2004,2005,2007,2016,2018,2019,2020,2021,2022
+./lib/isc/os_p.h				C	2022
 ./lib/isc/parseint.c				C	2001,2002,2003,2004,2005,2007,2012,2016,2018,2019,2020,2021,2022
 ./lib/isc/pool.c				C	2013,2015,2016,2018,2019,2020,2021,2022
 ./lib/isc/portset.c				C	2008,2016,2017,2018,2019,2020,2021,2022