vm: centralize VM_BATCHQUEUE_SIZE definition

Remove the platform-specific definitions of VM_BATCHQUEUE_SIZE
for amd64 and powerpc64, and instead treat all 64-bit platforms
identically.  This has the effect of increasing the arm64
and riscv VM_BATCHQUEUE_SIZE to match that of other platforms.

Reviewed by: jhb, markj
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D37707

sys/amd64/include/vmparam.h

@@ -289,12 +289,6 @@
 
 #define	ZERO_REGION_SIZE	(2 * 1024 * 1024)	/* 2MB */
 
-/*
- * Use a fairly large batch size since we expect amd64 systems to have lots of
- * memory.
- */
-#define	VM_BATCHQUEUE_SIZE	63
-
 /*
  * The pmap can create non-transparent large page mappings.
  */

sys/powerpc/include/vmparam.h

@@ -258,14 +258,6 @@ extern	int vm_level_0_order;
 #define	ZERO_REGION_SIZE	(64 * 1024)	/* 64KB */
 #endif
 
-/*
- * Use a fairly large batch size since we expect ppc64 systems to have lots of
- * memory.
- */
-#ifdef __powerpc64__
-#define	VM_BATCHQUEUE_SIZE	63
-#endif
-
 /*
  * On 32-bit OEA, the only purpose for which sf_buf is used is to implement
  * an opaque pointer required by the machine-independent parts of the kernel.

sys/vm/vm_pagequeue.h

@@ -74,7 +74,9 @@ struct vm_pagequeue {
 	uint64_t	pq_pdpages;
 } __aligned(CACHE_LINE_SIZE);
 
-#ifndef VM_BATCHQUEUE_SIZE
+#if __SIZEOF_LONG__ == 8
+#define	VM_BATCHQUEUE_SIZE	63
+#else
 #define	VM_BATCHQUEUE_SIZE	15
 #endif