From 65247f2603233cdecf003fce96280c28786defe6 Mon Sep 17 00:00:00 2001
From: hujun5 <hujun5@xiaomi.com>
Date: Thu, 18 Sep 2025 09:24:28 +0800
Subject: [PATCH] seqlock: change UP_DMB to UP_RMB to improve performance

read_seq Loop 20,000,000 times
before
233333376
after
183333375

Signed-off-by: hujun5 <hujun5@xiaomi.com>
---
 include/nuttx/seqlock.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/nuttx/seqlock.h b/include/nuttx/seqlock.h
index a6106fbf8e7..d501bb08eac 100644
--- a/include/nuttx/seqlock.h
+++ b/include/nuttx/seqlock.h
@@ -105,7 +105,7 @@ unsigned int read_seqbegin(FAR const seqcount_t *s)
   while (predict_false((seq = s->sequence) & 1));
 
 #ifdef CONFIG_SMP
-  UP_DMB();
+  SMP_RMB();
 #endif
 
   return seq;