From c8d36e21923359b6b22dc1eb9ce77115f0342e17 Mon Sep 17 00:00:00 2001
From: Alexander Motin <mav@FreeBSD.org>
Date: Thu, 5 Jan 2023 12:31:55 -0500
Subject: [PATCH] Pack zrlock_t by 8 bytes

On FreeBSD this reduces this structure size from 64 to 56 bytes.
dnode_handle_t respectively reduces from 72 to 64 bytes. It sounds
like a waste to need 72 bytes to be able to relocate 808 bytes of
dnode_t, which relocation on FreeBSD is not even supported.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:  Alexander Motin <mav@FreeBSD.org>
Sponsored by:   iXsystems, Inc.
Closes #14317
---
 include/sys/zrlock.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/sys/zrlock.h b/include/sys/zrlock.h
index b6eba1a18f..c8c656dc55 100644
--- a/include/sys/zrlock.h
+++ b/include/sys/zrlock.h
@@ -34,9 +34,8 @@ extern "C" {
 
 typedef struct zrlock {
 	kmutex_t zr_mtx;
-	volatile int32_t zr_refcount;
 	kcondvar_t zr_cv;
-	uint16_t zr_pad;
+	volatile int32_t zr_refcount;
 #ifdef	ZFS_DEBUG
 	kthread_t *zr_owner;
 	const char *zr_caller;