From ec6a6e8691153d025b8f82a0317f40f908aad17e Mon Sep 17 00:00:00 2001
From: Kevin Bowling <kevin.bowling@kev009.com>
Date: Thu, 19 Aug 2021 12:17:08 -0700
Subject: [PATCH] Detect HAVE_LARGE_STACKS at compile time (#12384)

Move HAVE_LARGE_STACKS definitions to header and set when appropriate.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Kevin Bowling <kbowling@FreeBSD.org>
Closes #12350
---
 config/Rules.am                               |  1 -
 config/kernel-config-defined.m4               | 31 -------------------
 include/os/freebsd/zfs/sys/zfs_context_os.h   |  4 +++
 include/os/linux/zfs/sys/zfs_context_os.h     |  5 +++
 .../include/os/freebsd/sys/zfs_context_os.h   |  1 +
 .../include/os/linux/sys/zfs_context_os.h     |  3 ++
 6 files changed, 13 insertions(+), 32 deletions(-)

diff --git a/config/Rules.am b/config/Rules.am
index 99587eab2bf8..09d684c34ae0 100644
--- a/config/Rules.am
+++ b/config/Rules.am
@@ -39,7 +39,6 @@ AM_CPPFLAGS  = -D_GNU_SOURCE
 AM_CPPFLAGS += -D_REENTRANT
 AM_CPPFLAGS += -D_FILE_OFFSET_BITS=64
 AM_CPPFLAGS += -D_LARGEFILE64_SOURCE
-AM_CPPFLAGS += -DHAVE_LARGE_STACKS=1
 AM_CPPFLAGS += -DLIBEXECDIR=\"$(libexecdir)\"
 AM_CPPFLAGS += -DRUNSTATEDIR=\"$(runstatedir)\"
 AM_CPPFLAGS += -DSBINDIR=\"$(sbindir)\"
diff --git a/config/kernel-config-defined.m4 b/config/kernel-config-defined.m4
index 9b9468269ca3..c7d18b49b14e 100644
--- a/config/kernel-config-defined.m4
+++ b/config/kernel-config-defined.m4
@@ -19,7 +19,6 @@ AC_DEFUN([ZFS_AC_KERNEL_CONFIG_DEFINED], [
 		])
 	])
 
-	ZFS_AC_KERNEL_SRC_CONFIG_THREAD_SIZE
 	ZFS_AC_KERNEL_SRC_CONFIG_DEBUG_LOCK_ALLOC
 	ZFS_AC_KERNEL_SRC_CONFIG_TRIM_UNUSED_KSYMS
 	ZFS_AC_KERNEL_SRC_CONFIG_ZLIB_INFLATE
@@ -29,42 +28,12 @@ AC_DEFUN([ZFS_AC_KERNEL_CONFIG_DEFINED], [
 	ZFS_LINUX_TEST_COMPILE_ALL([config])
 	AC_MSG_RESULT([done])
 
-	ZFS_AC_KERNEL_CONFIG_THREAD_SIZE
 	ZFS_AC_KERNEL_CONFIG_DEBUG_LOCK_ALLOC
 	ZFS_AC_KERNEL_CONFIG_TRIM_UNUSED_KSYMS
 	ZFS_AC_KERNEL_CONFIG_ZLIB_INFLATE
 	ZFS_AC_KERNEL_CONFIG_ZLIB_DEFLATE
 ])
 
-dnl #
-dnl # Check configured THREAD_SIZE
-dnl #
-dnl # The stack size will vary by architecture, but as of Linux 3.15 on x86_64
-dnl # the default thread stack size was increased to 16K from 8K.  Therefore,
-dnl # on newer kernels and some architectures stack usage optimizations can be
-dnl # conditionally applied to improve performance without negatively impacting
-dnl # stability.
-dnl #
-AC_DEFUN([ZFS_AC_KERNEL_SRC_CONFIG_THREAD_SIZE], [
-	ZFS_LINUX_TEST_SRC([config_thread_size], [
-		#include <linux/module.h>
-	],[
-		#if (THREAD_SIZE < 16384)
-		#error "THREAD_SIZE is less than 16K"
-		#endif
-	])
-])
-
-AC_DEFUN([ZFS_AC_KERNEL_CONFIG_THREAD_SIZE], [
-	AC_MSG_CHECKING([whether kernel was built with 16K or larger stacks])
-	ZFS_LINUX_TEST_RESULT([config_thread_size], [
-		AC_MSG_RESULT([yes])
-		AC_DEFINE(HAVE_LARGE_STACKS, 1, [kernel has large stacks])
-	],[
-		AC_MSG_RESULT([no])
-	])
-])
-
 dnl #
 dnl # Check CONFIG_DEBUG_LOCK_ALLOC
 dnl #
diff --git a/include/os/freebsd/zfs/sys/zfs_context_os.h b/include/os/freebsd/zfs/sys/zfs_context_os.h
index 8dbe907d098c..a32eb52c53c1 100644
--- a/include/os/freebsd/zfs/sys/zfs_context_os.h
+++ b/include/os/freebsd/zfs/sys/zfs_context_os.h
@@ -41,6 +41,10 @@
 #include <sys/ccompat.h>
 #include <linux/types.h>
 
+#if KSTACK_PAGES * PAGE_SIZE >= 16384
+#define	HAVE_LARGE_STACKS	1
+#endif
+
 #define	cond_resched()		kern_yield(PRI_USER)
 
 #define	taskq_create_sysdc(a, b, d, e, p, dc, f) \
diff --git a/include/os/linux/zfs/sys/zfs_context_os.h b/include/os/linux/zfs/sys/zfs_context_os.h
index de7015b929b6..981a6b8a63e5 100644
--- a/include/os/linux/zfs/sys/zfs_context_os.h
+++ b/include/os/linux/zfs/sys/zfs_context_os.h
@@ -25,5 +25,10 @@
 
 #include <linux/dcache_compat.h>
 #include <linux/utsname_compat.h>
+#include <linux/module.h>
+
+#if THREAD_SIZE >= 16384
+#define	HAVE_LARGE_STACKS	1
+#endif
 
 #endif
diff --git a/lib/libspl/include/os/freebsd/sys/zfs_context_os.h b/lib/libspl/include/os/freebsd/sys/zfs_context_os.h
index f5a136d22125..b9bf487c2aef 100644
--- a/lib/libspl/include/os/freebsd/sys/zfs_context_os.h
+++ b/lib/libspl/include/os/freebsd/sys/zfs_context_os.h
@@ -29,6 +29,7 @@
 #ifndef ZFS_CONTEXT_OS_H_
 #define	ZFS_CONTEXT_OS_H_
 
+#define	HAVE_LARGE_STACKS	1
 #define	ZFS_EXPORTS_PATH	"/etc/zfs/exports"
 
 #endif
diff --git a/lib/libspl/include/os/linux/sys/zfs_context_os.h b/lib/libspl/include/os/linux/sys/zfs_context_os.h
index 008e57df4eae..81ced5207749 100644
--- a/lib/libspl/include/os/linux/sys/zfs_context_os.h
+++ b/lib/libspl/include/os/linux/sys/zfs_context_os.h
@@ -22,4 +22,7 @@
 
 #ifndef ZFS_CONTEXT_OS_H
 #define	ZFS_CONTEXT_OS_H
+
+#define	HAVE_LARGE_STACKS	1
+
 #endif