[PATCH] staging/lustre: Always try kmalloc first for OBD_ALLOC_LARGE

[green@linuxhacker.ru]

From: Oleg Drokin <green@linuxhacker.ru>

Create libcfs_kvzalloc and libcfs_kvzalloc_cpt are
are designed to replace OBD_ALLOC_LARGE and OBD_CPT_ALLOC_LARGE.

Not a drop-in replacement as they also take gfp flags armument
for more flexibility.

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
---
This is how I envision the OBD_ALLOC_LARGE replacement.

BTW, it appears we also have LIBCFS_ALLOC and friends that we probably dont' need either.

Thanks your your great help!

 .../staging/lustre/include/linux/libcfs/libcfs.h   |  4 ++
 .../staging/lustre/lustre/include/obd_support.h    | 24 ++-------
 drivers/staging/lustre/lustre/libcfs/Makefile      |  1 +
 .../staging/lustre/lustre/libcfs/linux/linux-mem.c | 59 ++++++++++++++++++++++
 4 files changed, 67 insertions(+), 21 deletions(-)
 create mode 100644 drivers/staging/lustre/lustre/libcfs/linux/linux-mem.c

diff --git a/drivers/staging/lustre/include/linux/libcfs/libcfs.h b/drivers/staging/lustre/include/linux/libcfs/libcfs.h
index 4410d7f..947df7e 100644
--- a/drivers/staging/lustre/include/linux/libcfs/libcfs.h
+++ b/drivers/staging/lustre/include/linux/libcfs/libcfs.h
@@ -184,4 +184,8 @@ static inline void *__container_of(void *ptr, unsigned long shift)
 
 #define _LIBCFS_H
 
+void *libcfs_kvzalloc(size_t size, gfp_t flags);
+void *libcfs_kvzalloc_cpt(struct cfs_cpt_table *cptab, int cpt, size_t size,
+			  gfp_t flags);
+
 #endif /* _LIBCFS_H */
diff --git a/drivers/staging/lustre/lustre/include/obd_support.h b/drivers/staging/lustre/lustre/include/obd_support.h
index 2991d2e..379266d 100644
--- a/drivers/staging/lustre/lustre/include/obd_support.h
+++ b/drivers/staging/lustre/lustre/include/obd_support.h
@@ -676,37 +676,19 @@ do {									      \
 	 __OBD_VMALLOC_VEROBSE(ptr, cptab, cpt, size)
 
 
-/* Allocations above this size are considered too big and could not be done
- * atomically.
- *
- * Be very careful when changing this value, especially when decreasing it,
- * since vmalloc in Linux doesn't perform well on multi-cores system, calling
- * vmalloc in critical path would hurt performance badly. See LU-66.
- */
-#define OBD_ALLOC_BIG (4 * PAGE_CACHE_SIZE)
-
 #define OBD_ALLOC_LARGE(ptr, size)					    \
 do {									  \
-	if (size > OBD_ALLOC_BIG)					     \
-		OBD_VMALLOC(ptr, size);				       \
-	else								  \
-		OBD_ALLOC(ptr, size);					 \
+	ptr = libcfs_kvzalloc(size, GFP_NOFS);				  \
 } while (0)
 
 #define OBD_CPT_ALLOC_LARGE(ptr, cptab, cpt, size)			      \
 do {									      \
-	if (size > OBD_ALLOC_BIG)					      \
-		OBD_CPT_VMALLOC(ptr, cptab, cpt, size);			      \
-	else								      \
-		OBD_CPT_ALLOC(ptr, cptab, cpt, size);			      \
+	ptr = libcfs_kvzalloc_cpt(cptab, cpt, size, GFP_NOFS);		      \
 } while (0)
 
 #define OBD_FREE_LARGE(ptr, size)					     \
 do {									  \
-	if (size > OBD_ALLOC_BIG)					     \
-		OBD_VFREE(ptr, size);					 \
-	else								  \
-		OBD_FREE(ptr, size);					  \
+	kvfree(ptr);							  \
 } while (0)
 
 
diff --git a/drivers/staging/lustre/lustre/libcfs/Makefile b/drivers/staging/lustre/lustre/libcfs/Makefile
index 2996a48..fabdd3e 100644
--- a/drivers/staging/lustre/lustre/libcfs/Makefile
+++ b/drivers/staging/lustre/lustre/libcfs/Makefile
@@ -7,6 +7,7 @@ libcfs-linux-objs += linux-curproc.o
 libcfs-linux-objs += linux-module.o
 libcfs-linux-objs += linux-crypto.o
 libcfs-linux-objs += linux-crypto-adler.o
+libcfs-linux-objs += linux-mem.o
 
 libcfs-linux-objs := $(addprefix linux/,$(libcfs-linux-objs))
 
diff --git a/drivers/staging/lustre/lustre/libcfs/linux/linux-mem.c b/drivers/staging/lustre/lustre/libcfs/linux/linux-mem.c
new file mode 100644
index 0000000..1b068ae
--- /dev/null
+++ b/drivers/staging/lustre/lustre/libcfs/linux/linux-mem.c
@@ -0,0 +1,59 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2015, Oleg Drokin <green@linuxhacker.ru>
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ */
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include "../../../include/linux/libcfs/libcfs.h"
+
+void *libcfs_kvzalloc(size_t size, gfp_t flags)
+{
+	void *ret;
+
+	ret = kzalloc(size, flags | __GFP_NOWARN);
+	if (!ret)
+		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
+	return ret;
+}
+EXPORT_SYMBOL(libcfs_kvzalloc);
+
+void *libcfs_kvzalloc_cpt(struct cfs_cpt_table *cptab, int cpt, size_t size,
+			  gfp_t flags)
+{
+	void *ret;
+
+	ret = kzalloc_node(size, flags | __GFP_NOWARN,
+			   cfs_cpt_spread_node(cptab, cpt));
+	if (!ret) {
+		WARN_ON(!(flags & (__GFP_FS|__GFP_HIGH)));
+		ret = vmalloc_node(size, cfs_cpt_spread_node(cptab, cpt));
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(libcfs_kvzalloc_cpt);
-- 
2.1.0