[Qemu-devel] [RFC PATCH V3 3/4] colo-compare: introduce packet comparison thread

[Zhang Chen]

if packets are same, we send primary packet and drop secondary
packet, otherwise notify COLO do checkpoint.

Signed-off-by: Zhang Chen <address@hidden>
Signed-off-by: Li Zhijian <address@hidden>
Signed-off-by: Wen Congyang <address@hidden>
---
 net/colo-compare.c | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 trace-events       |   2 +
 2 files changed, 128 insertions(+)

diff --git a/net/colo-compare.c b/net/colo-compare.c
index dc57eac..4b5a2d4 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -26,6 +26,7 @@
 #include "qemu/jhash.h"
 #include "net/eth.h"
 
+#define DEBUG_TCP_COMPARE 1
 #define TYPE_COLO_COMPARE "colo-compare"
 #define COLO_COMPARE(obj) \
     OBJECT_CHECK(CompareState, (obj), TYPE_COLO_COMPARE)
@@ -90,6 +91,13 @@ typedef struct CompareState {
     GQueue unprocessed_connections;
     /* proxy current hash size */
     uint32_t hashtable_size;
+
+    /* notify compare thread */
+    QemuEvent event;
+    /* compare thread, a thread for each NIC */
+    QemuThread thread;
+    int thread_status;
+
 } CompareState;
 
 typedef struct CompareClass {
@@ -132,6 +140,15 @@ enum {
     SECONDARY_IN,
 };
 
+enum {
+    /* compare thread isn't started */
+    COMPARE_THREAD_NONE,
+    /* compare thread is running */
+    COMPARE_THREAD_RUNNING,
+    /* compare thread exit */
+    COMPARE_THREAD_EXIT,
+};
+
 static void packet_destroy(void *opaque, void *user_data);
 static int compare_chr_send(CharDriverState *out,
                             const uint8_t *buf,
@@ -336,6 +353,94 @@ static void packet_destroy(void *opaque, void *user_data)
     g_slice_free(Packet, pkt);
 }
 
+static inline void colo_dump_packet(Packet *pkt)
+{
+    int i;
+    for (i = 0; i < pkt->size; i++) {
+        printf("%02x ", ((uint8_t *)pkt->data)[i]);
+    }
+    printf("\n");
+}
+
+/*
+ * The IP packets sent by primary and secondary
+ * will be compared in here
+ * TODO support ip fragment, Out-Of-Order
+ * return:    0  means packet same
+ *            > 0 || < 0 means packet different
+ */
+static int colo_packet_compare(Packet *ppkt, Packet *spkt)
+{
+    trace_colo_compare_with_int("ppkt size", ppkt->size);
+    trace_colo_compare_with_char("ppkt ip_src", inet_ntoa(ppkt->ip->ip_src));
+    trace_colo_compare_with_char("ppkt ip_dst", inet_ntoa(ppkt->ip->ip_dst));
+    trace_colo_compare_with_int("spkt size", spkt->size);
+    trace_colo_compare_with_char("spkt ip_src", inet_ntoa(spkt->ip->ip_src));
+    trace_colo_compare_with_char("spkt ip_dst", inet_ntoa(spkt->ip->ip_dst));
+
+    if (ppkt->size == spkt->size) {
+        return memcmp(ppkt->data, spkt->data, spkt->size);
+    } else {
+        return -1;
+    }
+}
+
+static int colo_packet_compare_all(Packet *spkt, Packet *ppkt)
+{
+    trace_colo_compare_main("compare all");
+    return colo_packet_compare(ppkt, spkt);
+}
+
+/*
+ * called from the compare thread on the primary
+ * for compare connection
+ */
+static void colo_compare_connection(void *opaque, void *user_data)
+{
+    Connection *conn = opaque;
+    Packet *pkt = NULL;
+    GList *result = NULL;
+    int ret;
+
+    qemu_mutex_lock(&conn->list_lock);
+    while (!g_queue_is_empty(&conn->primary_list) &&
+           !g_queue_is_empty(&conn->secondary_list)) {
+        pkt = g_queue_pop_head(&conn->primary_list);
+        result = g_queue_find_custom(&conn->secondary_list,
+                              pkt, (GCompareFunc)colo_packet_compare_all);
+
+        if (result) {
+            ret = compare_chr_send(pkt->s->chr_out, pkt->data, pkt->size);
+            if (ret < 0) {
+                error_report("colo_send_primary_packet failed");
+            }
+            trace_colo_compare_main("packet same and release packet");
+            g_queue_remove(&conn->secondary_list, result->data);
+        } else {
+            trace_colo_compare_main("packet different");
+            g_queue_push_head(&conn->primary_list, pkt);
+            /* TODO: colo_notify_checkpoint();*/
+            break;
+        }
+    }
+    qemu_mutex_unlock(&conn->list_lock);
+}
+
+static void *colo_compare_thread(void *opaque)
+{
+    CompareState *s = opaque;
+
+    while (s->thread_status == COMPARE_THREAD_RUNNING) {
+        qemu_event_wait(&s->event);
+        qemu_event_reset(&s->event);
+        qemu_mutex_lock(&s->conn_list_lock);
+        g_queue_foreach(&s->conn_list, colo_compare_connection, NULL);
+        qemu_mutex_unlock(&s->conn_list_lock);
+    }
+
+    return NULL;
+}
+
 static int compare_chr_send(CharDriverState *out,
                             const uint8_t *buf,
                             uint32_t size)
@@ -440,6 +545,8 @@ static void compare_pri_chr_in(void *opaque, const uint8_t 
*buf, int size)
         if (packet_enqueue(s, PRIMARY_IN)) {
             trace_colo_compare_main("primary: unsupported packet in");
             compare_chr_send(s->chr_out, s->pri_rs.buf, s->pri_rs.packet_len);
+        } else {
+            qemu_event_set(&s->event);
         }
     } else if (ret == -1) {
         qemu_chr_add_handlers(s->chr_pri_in, NULL, NULL, NULL, NULL);
@@ -461,6 +568,8 @@ static void compare_sec_chr_in(void *opaque, const uint8_t 
*buf, int size)
             trace_colo_compare_main("secondary: unsupported packet in");
             /* should we send sec arp pkt? */
             compare_chr_send(s->chr_out, s->sec_rs.buf, s->sec_rs.packet_len);
+        } else {
+            qemu_event_set(&s->event);
         }
     } else if (ret == -1) {
         qemu_chr_add_handlers(s->chr_sec_in, NULL, NULL, NULL, NULL);
@@ -519,6 +628,8 @@ static void compare_set_outdev(Object *obj, const char 
*value, Error **errp)
 static void colo_compare_complete(UserCreatable *uc, Error **errp)
 {
     CompareState *s = COLO_COMPARE(uc);
+    char thread_name[64];
+    static int compare_id;
 
     if (!s->pri_indev || !s->sec_indev || !s->outdev) {
         error_setg(errp, "colo compare needs 'primary_in' ,"
@@ -564,6 +675,7 @@ static void colo_compare_complete(UserCreatable *uc, Error 
**errp)
     QTAILQ_INSERT_TAIL(&net_compares, s, next);
 
     g_queue_init(&s->conn_list);
+    qemu_event_init(&s->event, false);
     qemu_mutex_init(&s->conn_list_lock);
     s->hashtable_size = 0;
 
@@ -572,6 +684,13 @@ static void colo_compare_complete(UserCreatable *uc, Error 
**errp)
                                                       g_free,
                                                       connection_destroy);
 
+    s->thread_status = COMPARE_THREAD_RUNNING;
+    sprintf(thread_name, "compare %d", compare_id);
+    qemu_thread_create(&s->thread, thread_name,
+                       colo_compare_thread, s,
+                       QEMU_THREAD_JOINABLE);
+    compare_id++;
+
     return;
 }
 
@@ -607,6 +726,13 @@ static void colo_compare_class_finalize(ObjectClass *oc, 
void *data)
         QTAILQ_REMOVE(&net_compares, s, next);
     }
     qemu_mutex_destroy(&s->conn_list_lock);
+
+    if (s->thread.thread) {
+        s->thread_status = COMPARE_THREAD_EXIT;
+        qemu_event_set(&s->event);
+        qemu_thread_join(&s->thread);
+    }
+    qemu_event_destroy(&s->event);
 }
 
 static void colo_compare_init(Object *obj)
diff --git a/trace-events b/trace-events
index 8862288..978c47f 100644
--- a/trace-events
+++ b/trace-events
@@ -1919,3 +1919,5 @@ aspeed_vic_write(uint64_t offset, unsigned size, uint32_t 
data) "To 0x%" PRIx64
 
 # net/colo-compare.c
 colo_compare_main(const char *chr) "chr: %s"
+colo_compare_with_int(const char *sta, int size) ": %s = %d"
+colo_compare_with_char(const char *sta, const char *stb) ": %s = %s"
-- 
1.9.1