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, 2 insertions, 11 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 252ad4e..2ed1304 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3131,13 +3131,7 @@ struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags,
 
 	/* front */
 	if (front_len) {
-		if (front_len > PAGE_CACHE_SIZE) {
-			m->front.iov_base = __vmalloc(front_len, flags,
-						      PAGE_KERNEL);
-			m->front_is_vmalloc = true;
-		} else {
-			m->front.iov_base = kmalloc(front_len, flags);
-		}
+		m->front.iov_base = ceph_kvmalloc(front_len, flags);
 		if (m->front.iov_base == NULL) {
 			dout("ceph_msg_new can't allocate %d bytes\n",
 			     front_len);
@@ -3259,10 +3253,7 @@ static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip)
 void ceph_msg_kfree(struct ceph_msg *m)
 {
 	dout("msg_kfree %p\n", m);
-	if (m->front_is_vmalloc)
-		vfree(m->front.iov_base);
-	else
-		kfree(m->front.iov_base);
+	ceph_kvfree(m->front.iov_base);
 	kmem_cache_free(ceph_msg_cache, m);
 }