libceph: add ceph_kv{malloc,free}() and switch to them

Encapsulate kmalloc vs vmalloc memory allocation and freeing logic into
two helpers, ceph_kvmalloc() and ceph_kvfree(), and switch to them.

ceph_kvmalloc() kmalloc()'s a maximum of 8 pages, anything bigger is
vmalloc()'ed with __GFP_HIGHMEM set.  This changes the existing
behaviour:

- for buffers (ceph_buffer_new()), from trying to kmalloc() everything
  and using vmalloc() just as a fallback

- for messages (ceph_msg_new()), from going to vmalloc() for anything
  bigger than a page

- for messages (ceph_msg_new()), from disallowing vmalloc() to use high
  memory

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 43d8177a52e1..67d7721d237e 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/statfs.h>
 #include <linux/string.h>
+#include <linux/vmalloc.h>
 #include <linux/nsproxy.h>
 #include <net/net_namespace.h>
 
@@ -170,6 +171,25 @@ int ceph_compare_options(struct ceph_options *new_opt,
 }
 EXPORT_SYMBOL(ceph_compare_options);
 
+void *ceph_kvmalloc(size_t size, gfp_t flags)
+{
+	if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
+		void *ptr = kmalloc(size, flags | __GFP_NOWARN);
+		if (ptr)
+			return ptr;
+	}
+
+	return __vmalloc(size, flags | __GFP_HIGHMEM, PAGE_KERNEL);
+}
+
+void ceph_kvfree(const void *ptr)
+{
+	if (is_vmalloc_addr(ptr))
+		vfree(ptr);
+	else
+		kfree(ptr);
+}
+
 
 static int parse_fsid(const char *str, struct ceph_fsid *fsid)
 {