diff --git a/sys/kern/subr_param.c b/sys/kern/subr_param.c
index 517f8233778b..d8f390bbd5a8 100644
--- a/sys/kern/subr_param.c
+++ b/sys/kern/subr_param.c
@@ -291,10 +291,7 @@ init_param2(long physpages)
 	 * Physical buffers are pre-allocated buffers (struct buf) that
 	 * are used as temporary holders for I/O, such as paging I/O.
 	 */
-	nswbuf = min(nbuf / 4, 256);
 	TUNABLE_INT_FETCH("kern.nswbuf", &nswbuf);
-	if (nswbuf < NSWBUF_MIN)
-		nswbuf = NSWBUF_MIN;
 
 	/*
 	 * The default for maxpipekva is min(1/64 of the kernel address space,
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 3766c7d8d55f..b44172939c47 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -1124,6 +1124,12 @@ kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est)
 			nbuf = buf_sz / BKVASIZE;
 	}
 
+	if (nswbuf == 0) {
+		nswbuf = min(nbuf / 4, 256);
+		if (nswbuf < NSWBUF_MIN)
+			nswbuf = NSWBUF_MIN;
+	}
+
 	/*
 	 * Reserve space for the buffer cache buffers
 	 */