1 files changed, 27 insertions, 0 deletions

diff --git a/fs/ceph/msgpool.h b/fs/ceph/msgpool.h
new file mode 100644
index 000000000000..bc834bfcd720
--- /dev/null
+++ b/fs/ceph/msgpool.h
@@ -0,0 +1,27 @@
+#ifndef _FS_CEPH_MSGPOOL
+#define _FS_CEPH_MSGPOOL
+
+#include "messenger.h"
+
+/*
+ * we use memory pools for preallocating messages we may receive, to
+ * avoid unexpected OOM conditions.
+ */
+struct ceph_msgpool {
+        spinlock_t lock;
+        int front_len;          /* preallocated payload size */
+        struct list_head msgs;  /* msgs in the pool; each has 1 ref */
+        int num, min;           /* cur, min # msgs in the pool */
+        bool blocking;
+        wait_queue_head_t wait;
+};
+
+extern int ceph_msgpool_init(struct ceph_msgpool *pool,
+                             int front_len, int size, bool blocking);
+extern void ceph_msgpool_destroy(struct ceph_msgpool *pool);
+extern int ceph_msgpool_resv(struct ceph_msgpool *, int delta);
+extern struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *,
+                                         int front_len);
+extern void ceph_msgpool_put(struct ceph_msgpool *, struct ceph_msg *);
+
+#endif