RDS: IB: add few useful cache stasts

Tracks the ib receive cache total, incoming and frag allocations.

Signed-off-by: Santosh Shilimkar <[e-mail]>

net/rds/ib.h

···
 	u64			i_ack_recv;	/* last ACK received */
 	struct rds_ib_refill_cache i_cache_incs;
 	struct rds_ib_refill_cache i_cache_frags;
+	atomic_t		i_cache_allocs;
 
 	/* sending acks */
 	unsigned long		i_ack_flags;
···
 	uint64_t	s_ib_rx_refill_from_cq;
 	uint64_t	s_ib_rx_refill_from_thread;
 	uint64_t	s_ib_rx_alloc_limit;
+	uint64_t	s_ib_rx_total_frags;
+	uint64_t	s_ib_rx_total_incs;
 	uint64_t	s_ib_rx_credit_updates;
 	uint64_t	s_ib_ack_sent;
 	uint64_t	s_ib_ack_send_failure;
···
 	uint64_t	s_ib_rdma_mr_1m_reused;
 	uint64_t	s_ib_atomic_cswp;
 	uint64_t	s_ib_atomic_fadd;
+	uint64_t	s_ib_recv_added_to_cache;
+	uint64_t	s_ib_recv_removed_from_cache;
 };
 
 extern struct workqueue_struct *rds_ib_wq;
···
 /* ib_stats.c */
 DECLARE_PER_CPU(struct rds_ib_statistics, rds_ib_stats);
 #define rds_ib_stats_inc(member) rds_stats_inc_which(rds_ib_stats, member)
+#define rds_ib_stats_add(member, count) \
+		rds_stats_add_which(rds_ib_stats, member, count)
 unsigned int rds_ib_stats_info_copy(struct rds_info_iterator *iter,
 				    unsigned int avail);
 

net/rds/ib_recv.c

···
 	rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg));
 
 	rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags);
+	atomic_add(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs);
+	rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE);
 }
 
 /* Recycle inc after freeing attached frags */
···
 			atomic_dec(&rds_ib_allocation);
 			return NULL;
 		}
+		rds_ib_stats_inc(s_ib_rx_total_incs);
 	}
 	INIT_LIST_HEAD(&ibinc->ii_frags);
 	rds_inc_init(&ibinc->ii_inc, ic->conn, ic->conn->c_faddr);
···
 	cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags);
 	if (cache_item) {
 		frag = container_of(cache_item, struct rds_page_frag, f_cache_entry);
+		atomic_sub(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs);
+		rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE);
 	} else {
 		frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask);
 		if (!frag)
···
 			kmem_cache_free(rds_ib_frag_slab, frag);
 			return NULL;
 		}
+		rds_ib_stats_inc(s_ib_rx_total_frags);
 	}
 
 	INIT_LIST_HEAD(&frag->f_item);

net/rds/ib_stats.c

···
 	"ib_rx_refill_from_cq",
 	"ib_rx_refill_from_thread",
 	"ib_rx_alloc_limit",
+	"ib_rx_total_frags",
+	"ib_rx_total_incs",
 	"ib_rx_credit_updates",
 	"ib_ack_sent",
 	"ib_ack_send_failure",