From ed3c6642578f231ca34564a71f6c21f54be4ddda Mon Sep 17 00:00:00 2001
From: Pawel Jakub Dawidek <pjd@FreeBSD.org>
Date: Sun, 16 May 2010 15:14:59 +0000
Subject: [PATCH] Allow to configure UMA usage for ZIO data via loader and turn
 it on by default for amd64. On i386 I saw performance degradation when UMA
 was used, but for amd64 it should help.

MFC after:	3 days
---
 .../opensolaris/uts/common/fs/zfs/zio.c       | 60 ++++++++++---------
 1 file changed, 31 insertions(+), 29 deletions(-)

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
index 7f5416dd1c4c..512a70f13028 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
@@ -33,6 +33,17 @@
 #include <sys/zio_compress.h>
 #include <sys/zio_checksum.h>
 
+#if defined(__amd64__)
+static int zio_use_uma = 1;
+#else
+static int zio_use_uma = 0;
+#endif
+SYSCTL_DECL(_vfs_zfs);
+SYSCTL_NODE(_vfs_zfs, OID_AUTO, zio, CTLFLAG_RW, 0, "ZFS ZIO");
+TUNABLE_INT("vfs.zfs.zio.use_uma", &zio_use_uma);
+SYSCTL_INT(_vfs_zfs_zio, OID_AUTO, use_uma, CTLFLAG_RDTUN, &zio_use_uma, 0,
+    "Use uma(9) for ZIO allocations");
+
 /*
  * ==========================================================================
  * I/O priority table
@@ -69,10 +80,8 @@ char *zio_type_name[ZIO_TYPES] = {
  * ==========================================================================
  */
 kmem_cache_t *zio_cache;
-#ifdef ZIO_USE_UMA
 kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
-#endif
 
 #ifdef _KERNEL
 extern vmem_t *zio_alloc_arena;
@@ -88,13 +97,13 @@ extern vmem_t *zio_alloc_arena;
 void
 zio_init(void)
 {
-#ifdef ZIO_USE_UMA
 	size_t c;
-#endif
 	zio_cache = kmem_cache_create("zio_cache", sizeof (zio_t), 0,
 	    NULL, NULL, NULL, NULL, NULL, 0);
 
-#ifdef ZIO_USE_UMA
+	if (!zio_use_uma)
+		goto end;
+
 	/*
 	 * For small buffers, we want a cache for each multiple of
 	 * SPA_MINBLOCKSIZE.  For medium-size buffers, we want a cache
@@ -138,15 +147,13 @@ zio_init(void)
 		if (zio_data_buf_cache[c - 1] == NULL)
 			zio_data_buf_cache[c - 1] = zio_data_buf_cache[c];
 	}
-#endif
-
+end:
 	zio_inject_init();
 }
 
 void
 zio_fini(void)
 {
-#ifdef ZIO_USE_UMA
 	size_t c;
 	kmem_cache_t *last_cache = NULL;
 	kmem_cache_t *last_data_cache = NULL;
@@ -164,7 +171,6 @@ zio_fini(void)
 		}
 		zio_data_buf_cache[c] = NULL;
 	}
-#endif
 
 	kmem_cache_destroy(zio_cache);
 
@@ -186,15 +192,14 @@ zio_fini(void)
 void *
 zio_buf_alloc(size_t size)
 {
-#ifdef ZIO_USE_UMA
 	size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
 
 	ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
 
-	return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE));
-#else
-	return (kmem_alloc(size, KM_SLEEP));
-#endif
+	if (zio_use_uma)
+		return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE));
+	else
+		return (kmem_alloc(size, KM_SLEEP));
 }
 
 /*
@@ -206,43 +211,40 @@ zio_buf_alloc(size_t size)
 void *
 zio_data_buf_alloc(size_t size)
 {
-#ifdef ZIO_USE_UMA
 	size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
 
 	ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
 
-	return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE));
-#else
-	return (kmem_alloc(size, KM_SLEEP));
-#endif
+	if (zio_use_uma)
+		return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE));
+	else
+		return (kmem_alloc(size, KM_SLEEP));
 }
 
 void
 zio_buf_free(void *buf, size_t size)
 {
-#ifdef ZIO_USE_UMA
 	size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
 
 	ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
 
-	kmem_cache_free(zio_buf_cache[c], buf);
-#else
-	kmem_free(buf, size);
-#endif
+	if (zio_use_uma)
+		kmem_cache_free(zio_buf_cache[c], buf);
+	else
+		kmem_free(buf, size);
 }
 
 void
 zio_data_buf_free(void *buf, size_t size)
 {
-#ifdef ZIO_USE_UMA
 	size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
 
 	ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
 
-	kmem_cache_free(zio_data_buf_cache[c], buf);
-#else
-	kmem_free(buf, size);
-#endif
+	if (zio_use_uma)
+		kmem_cache_free(zio_data_buf_cache[c], buf);
+	else
+		kmem_free(buf, size);
 }
 
 /*