session: reserve memory for rbtree

Type: fix

Change-Id: I2b89f6e4c09297e3712d88cd25c80a806d3005aa
Signed-off-by: Florin Coras <fcoras@cisco.com>
diff --git a/src/svm/fifo_segment.h b/src/svm/fifo_segment.h
index d363c60..02d45d3 100644
--- a/src/svm/fifo_segment.h
+++ b/src/svm/fifo_segment.h
@@ -35,6 +35,7 @@
 {
   FIFO_SEGMENT_F_IS_PREALLOCATED = 1 << 0,
   FIFO_SEGMENT_F_WILL_DELETE = 1 << 1,
+  FIFO_SEGMENT_F_MEM_LIMIT = 1 << 2,
 } fifo_segment_flags_t;
 
 typedef struct fifo_segment_slice_
@@ -51,6 +52,7 @@
   ssvm_shared_header_t *ssvm_sh;	/**< Pointer to fs ssvm shared hdr */
   uword n_free_bytes;			/**< Segment free bytes */
   u32 n_active_fifos;			/**< Number of active fifos */
+  u32 n_reserved_bytes;			/**< Bytes not to be allocated */
   u32 max_log2_chunk_size;		/**< Max log2(chunk size) for fs */
   u8 flags;				/**< Segment flags */
   u8 n_slices;				/**< Number of slices */