[dpdk-dev] [PATCH 1/2] librte_ip_frag: add function to delete expired entries

[Alex Kiselev <alex@therouter.net>]

add new function rte_frag_table_del_expired_entries()
that scans the list of recently used packets and delete the expired ones.

A fragmented packets is supposed to live no longer than max_cycles,
but the lib deletes an expired packet only occasionally when it scans
a bucket to find an empty slot while adding a new packet.
Therefore a fragment might sit in the table forever.

Signed-off-by: Alex Kiselev <alex@therouter.net>
---
 lib/librte_ip_frag/ip_frag_common.h        | 18 ++++++++++++
 lib/librte_ip_frag/ip_frag_internal.c      | 18 ------------
 lib/librte_ip_frag/rte_ip_frag.h           | 19 +++++++++++-
 lib/librte_ip_frag/rte_ip_frag_common.c    | 46 ++++++++++++++++++++++++++++++
 lib/librte_ip_frag/rte_ip_frag_version.map |  6 ++++
 5 files changed, 88 insertions(+), 19 deletions(-)

diff --git a/lib/librte_ip_frag/ip_frag_common.h b/lib/librte_ip_frag/ip_frag_common.h
index 197acf8d8..0fdcc7d0f 100644
--- a/lib/librte_ip_frag/ip_frag_common.h
+++ b/lib/librte_ip_frag/ip_frag_common.h
@@ -25,6 +25,12 @@
 #define IPv6_KEY_BYTES_FMT \
 	"%08" PRIx64 "%08" PRIx64 "%08" PRIx64 "%08" PRIx64
 
+#ifdef RTE_LIBRTE_IP_FRAG_TBL_STAT
+#define	IP_FRAG_TBL_STAT_UPDATE(s, f, v)	((s)->f += (v))
+#else
+#define	IP_FRAG_TBL_STAT_UPDATE(s, f, v)	do {} while (0)
+#endif /* IP_FRAG_TBL_STAT */
+
 /* internal functions declarations */
 struct rte_mbuf * ip_frag_process(struct ip_frag_pkt *fp,
 		struct rte_ip_frag_death_row *dr, struct rte_mbuf *mb,
@@ -149,4 +155,16 @@ ip_frag_reset(struct ip_frag_pkt *fp, uint64_t tms)
 	fp->frags[IP_FIRST_FRAG_IDX] = zero_frag;
 }
 
+/* local frag table helper functions */
+static inline void
+ip_frag_tbl_del(struct rte_ip_frag_tbl *tbl, struct rte_ip_frag_death_row *dr,
+	struct ip_frag_pkt *fp)
+{
+	ip_frag_free(fp, dr);
+	ip_frag_key_invalidate(&fp->key);
+	TAILQ_REMOVE(&tbl->lru, fp, lru);
+	tbl->use_entries--;
+	IP_FRAG_TBL_STAT_UPDATE(&tbl->stat, del_num, 1);
+}
+
 #endif /* _IP_FRAG_COMMON_H_ */
diff --git a/lib/librte_ip_frag/ip_frag_internal.c b/lib/librte_ip_frag/ip_frag_internal.c
index 2560c7713..97470a872 100644
--- a/lib/librte_ip_frag/ip_frag_internal.c
+++ b/lib/librte_ip_frag/ip_frag_internal.c
@@ -14,24 +14,6 @@
 #define	IP_FRAG_TBL_POS(tbl, sig)	\
 	((tbl)->pkt + ((sig) & (tbl)->entry_mask))
 
-#ifdef RTE_LIBRTE_IP_FRAG_TBL_STAT
-#define	IP_FRAG_TBL_STAT_UPDATE(s, f, v)	((s)->f += (v))
-#else
-#define	IP_FRAG_TBL_STAT_UPDATE(s, f, v)	do {} while (0)
-#endif /* IP_FRAG_TBL_STAT */
-
-/* local frag table helper functions */
-static inline void
-ip_frag_tbl_del(struct rte_ip_frag_tbl *tbl, struct rte_ip_frag_death_row *dr,
-	struct ip_frag_pkt *fp)
-{
-	ip_frag_free(fp, dr);
-	ip_frag_key_invalidate(&fp->key);
-	TAILQ_REMOVE(&tbl->lru, fp, lru);
-	tbl->use_entries--;
-	IP_FRAG_TBL_STAT_UPDATE(&tbl->stat, del_num, 1);
-}
-
 static inline void
 ip_frag_tbl_add(struct rte_ip_frag_tbl *tbl,  struct ip_frag_pkt *fp,
 	const struct ip_frag_key *key, uint64_t tms)
diff --git a/lib/librte_ip_frag/rte_ip_frag.h b/lib/librte_ip_frag/rte_ip_frag.h
index b3f3f78df..3c694df92 100644
--- a/lib/librte_ip_frag/rte_ip_frag.h
+++ b/lib/librte_ip_frag/rte_ip_frag.h
@@ -65,10 +65,13 @@ struct ip_frag_pkt {
 
 #define IP_FRAG_DEATH_ROW_LEN 32 /**< death row size (in packets) */
 
+/* death row size in mbufs */
+#define IP_FRAG_DEATH_ROW_MBUF_LEN (IP_FRAG_DEATH_ROW_LEN * (IP_MAX_FRAG_NUM + 1))
+
 /** mbuf death row (packets to be freed) */
 struct rte_ip_frag_death_row {
 	uint32_t cnt;          /**< number of mbufs currently on death row */
-	struct rte_mbuf *row[IP_FRAG_DEATH_ROW_LEN * (IP_MAX_FRAG_NUM + 1)];
+	struct rte_mbuf *row[IP_FRAG_DEATH_ROW_MBUF_LEN];
 	/**< mbufs to be freed */
 };
 
@@ -325,6 +328,20 @@ void rte_ip_frag_free_death_row(struct rte_ip_frag_death_row *dr,
 void
 rte_ip_frag_table_statistics_dump(FILE * f, const struct rte_ip_frag_tbl *tbl);
 
+/**
+ * Delete expired fragments
+ * 
+ * @param tbl
+ *   Table to delete expired fragments from
+ * @param dr
+ *   Death row to free buffers to
+ * @param tms
+ *   Current timestamp
+ */
+void __rte_experimental
+rte_frag_table_del_expired_entries(struct rte_ip_frag_tbl *tbl,
+	struct rte_ip_frag_death_row *dr, uint64_t tms);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_ip_frag/rte_ip_frag_common.c b/lib/librte_ip_frag/rte_ip_frag_common.c
index 659a17951..f62b5d169 100644
--- a/lib/librte_ip_frag/rte_ip_frag_common.c
+++ b/lib/librte_ip_frag/rte_ip_frag_common.c
@@ -121,3 +121,49 @@ rte_ip_frag_table_statistics_dump(FILE *f, const struct rte_ip_frag_tbl *tbl)
 		fail_nospace,
 		fail_total - fail_nospace);
 }
+
+/* Delete expired fragments */
+void __rte_experimental
+rte_frag_table_del_expired_entries(struct rte_ip_frag_tbl *tbl,
+	struct rte_ip_frag_death_row *dr, uint64_t tms)
+{
+	uint64_t max_cycles;
+	struct ip_frag_pkt *fp;
+
+	max_cycles = tbl->max_cycles;
+
+	TAILQ_FOREACH(fp, &tbl->lru, lru)
+		if (max_cycles + fp->start < tms) {
+			/* check that death row has enough space */
+			if (IP_FRAG_DEATH_ROW_MBUF_LEN - dr->cnt >= fp->last_idx)
+				ip_frag_tbl_del(tbl, dr, fp);
+			else
+				return;
+		}
+		else
+			return;
+}
+
+#ifdef RTE_IP_FRAG_DEBUG
+
+void
+rte_frag_table_print(struct rte_ip_frag_tbl *tbl)
+{
+	uint32_t i, cnt;
+	printf("entries in use: %u, mbuf holded %u\n", tbl->use_entries,
+			  tbl->nb_mbufs);
+	struct ip_frag_pkt *fp;
+	TAILQ_FOREACH(fp, &tbl->lru, lru)
+		if (!ip_frag_key_is_empty(&fp->key)) {
+
+			/* cnt mbufs in the packet */
+			cnt = 0;
+			for (i=0; i!=fp->last_idx; i++)
+				if (fp->frags[i].mb != NULL)
+					cnt++;
+
+			printf("start %"PRIu64", mbuf cnt %u\n", fp->start, cnt);
+		}
+}
+
+#endif /* RTE_IP_FRAG_DEBUG */
diff --git a/lib/librte_ip_frag/rte_ip_frag_version.map b/lib/librte_ip_frag/rte_ip_frag_version.map
index d1acf07cb..d40d5515f 100644
--- a/lib/librte_ip_frag/rte_ip_frag_version.map
+++ b/lib/librte_ip_frag/rte_ip_frag_version.map
@@ -18,3 +18,9 @@ DPDK_17.08 {
     rte_ip_frag_table_destroy;
 
 } DPDK_2.0;
+
+EXPERIMENTAL {
+	global:
+
+	rte_frag_table_del_expired_entries;
+};
-- 
2.16.1.windows.1