libspl: move physmem to sys/systm.h; initialise at libspl_init()

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Rob Norris <[email protected]>
Closes #17861

Author: robn

include/sys/zfs_context.h

@@ -127,6 +127,10 @@ extern "C" {
 #include <sys/kmem.h>
 #include <sys/zfs_delay.h>
 #include <sys/vnode.h>
+#include <sys/random.h>
+#include <sys/callb.h>
+#include <sys/trace.h>
+#include <sys/systm.h>
 
 #include <sys/zfs_context_os.h>
 
@@ -206,7 +210,6 @@ extern char *vn_dumpdir;
 #define	NN_DIVISOR_1000	(1U << 0)
 #define	NN_NUMBUF_SZ	(6)
 
-extern uint64_t physmem;
 extern const char *random_path;
 extern const char *urandom_path;
 

lib/libspl/include/Makefile.am

@@ -59,6 +59,7 @@ libspl_sys_HEADERS = \
 	%D%/sys/string.h \
 	%D%/sys/sunddi.h \
 	%D%/sys/systeminfo.h \
+	%D%/sys/systm.h \
 	%D%/sys/thread.h \
 	%D%/sys/taskq.h \
 	%D%/sys/time.h \

lib/libspl/include/sys/systm.h

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: CDDL-1.0
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or https://opensource.org/licenses/CDDL-1.0.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
+ * Copyright (c) 2012, Joyent, Inc. All rights reserved.
+ */
+
+#ifndef _LIBSPL_SYS_SYSTM_H
+#define	_LIBSPL_SYS_SYSTM_H
+
+extern uint64_t physmem;
+
+#endif

lib/libspl/libspl.c

@@ -20,14 +20,22 @@
  * CDDL HEADER END
  */
 /*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
+ * Copyright (c) 2016 Actifio, Inc. All rights reserved.
+ * Copyright (c) 2025, Klara, Inc.
  * Copyright (c) 2025, Rob Norris <[email protected]>
  */
 
 #include <libspl.h>
+#include <unistd.h>
+
+uint64_t physmem;
 
 void
 libspl_init(void)
 {
+	physmem = sysconf(_SC_PHYS_PAGES);
 }
 
 void

lib/libzpool/kernel.c

@@ -60,7 +60,6 @@
  * Emulation of kernel services in userland.
  */
 
-uint64_t physmem;
 uint32_t hostid;
 struct utsname hw_utsname;
 
@@ -509,8 +508,6 @@ kernel_init(int mode)
 
 	umem_nofail_callback(umem_out_of_memory);
 
-	physmem = sysconf(_SC_PHYS_PAGES);
-
 	dprintf("physmem = %llu pages (%.2f GB)\n", (u_longlong_t)physmem,
 	    (double)physmem * sysconf(_SC_PAGE_SIZE) / (1ULL << 30));