Re: [Qemu-devel] [RFC PATCH V5 2/4] colo-compare: track connection and enqueue packet

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

On 07/08/2016 12:07 PM, Jason Wang wrote:
>
>
> On 2016年06月23日 19:34, Zhang Chen wrote:
>> In this patch we use kernel jhash table to track
>> connection, and then enqueue net packet like this:
>>
>> + CompareState ++
>> |               |
>> +---------------+   +---------------+         +---------------+
>> |conn list      +--->conn +--------->conn           |
>> +---------------+   +---------------+         +---------------+
>> |               |     |           |             |          |
>> +---------------+ +---v----+  +---v----+    +---v----+ +---v----+
>>                    |primary |  |secondary    |primary | |secondary
>>                    |packet  |  |packet  +    |packet  | |packet +
>>                    +--------+  +--------+    +--------+ +--------+
>>                        |           |             |          |
>>                    +---v----+  +---v----+    +---v----+ +---v----+
>>                    |primary |  |secondary    |primary | |secondary
>>                    |packet  |  |packet  +    |packet  | |packet +
>>                    +--------+  +--------+    +--------+ +--------+
>>                        |           |             |          |
>>                    +---v----+  +---v----+    +---v----+ +---v----+
>>                    |primary |  |secondary    |primary | |secondary
>>                    |packet  |  |packet  +    |packet  | |packet +
>>                    +--------+  +--------+    +--------+ +--------+
>
> A paragraph to describe the above would be more than welcomed.

I will add some comments for it.

>
>> Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>   include/qemu/jhash.h |  61 ++++++++++++++++
>>   net/Makefile.objs    |   1 +
>>   net/colo-base.c      | 194 
>> +++++++++++++++++++++++++++++++++++++++++++++++++++
>>   net/colo-base.h      |  88 +++++++++++++++++++++++
>>   net/colo-compare.c   | 138 +++++++++++++++++++++++++++++++++++-
>>   trace-events         |   3 +
>>   6 files changed, 483 insertions(+), 2 deletions(-)
>>   create mode 100644 include/qemu/jhash.h
>>   create mode 100644 net/colo-base.c
>>   create mode 100644 net/colo-base.h
>>
>> diff --git a/include/qemu/jhash.h b/include/qemu/jhash.h
>> new file mode 100644
>> index 0000000..0fcd875
>> --- /dev/null
>> +++ b/include/qemu/jhash.h
>> @@ -0,0 +1,61 @@
>> +/* jhash.h: Jenkins hash support.
>> +  *
>> +  * Copyright (C) 2006. Bob Jenkins (bob_jenkins@burtleburtle.net)
>> +  *
>> +  * http://burtleburtle.net/bob/hash/
>> +  *
>> +  * These are the credits from Bob's sources:
>> +  *
>> +  * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
>> +  *
>> +  * These are functions for producing 32-bit hashes for hash table 
>> lookup.
>> +  * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and 
>> final()
>> +  * are externally useful functions.  Routines to test the hash are
>> +included
>> +  * if SELF_TEST is defined.  You can use this free for any purpose.
>> +It's in
>> +  * the public domain.  It has no warranty.
>> +  *
>> +  * Copyright (C) 2009-2010 Jozsef Kadlecsik (kadlec@blackhole.kfki.hu)
>> +  *
>> +  * I've modified Bob's hash to be useful in the Linux kernel, and
>> +  * any bugs present are my fault.
>> +  * Jozsef
>> +  */
>> +
>> +#ifndef QEMU_JHASH_H__
>> +#define QEMU_JHASH_H__
>> +
>> +#include "qemu/bitops.h"
>> +
>> +/*
>> + * hashtable relation copy from linux kernel jhash
>> + */
>> +
>> +/* __jhash_mix -- mix 3 32-bit values reversibly. */
>> +#define __jhash_mix(a, b, c)                \
>> +{                                           \
>> +    a -= c;  a ^= rol32(c, 4);  c += b;     \
>> +    b -= a;  b ^= rol32(a, 6);  a += c;     \
>> +    c -= b;  c ^= rol32(b, 8);  b += a;     \
>> +    a -= c;  a ^= rol32(c, 16); c += b;     \
>> +    b -= a;  b ^= rol32(a, 19); a += c;     \
>> +    c -= b;  c ^= rol32(b, 4);  b += a;     \
>> +}
>> +
>> +/* __jhash_final - final mixing of 3 32-bit values (a,b,c) into c */
>> +#define __jhash_final(a, b, c)  \
>> +{                               \
>> +    c ^= b; c -= rol32(b, 14);  \
>> +    a ^= c; a -= rol32(c, 11);  \
>> +    b ^= a; b -= rol32(a, 25);  \
>> +    c ^= b; c -= rol32(b, 16);  \
>> +    a ^= c; a -= rol32(c, 4);   \
>> +    b ^= a; b -= rol32(a, 14);  \
>> +    c ^= b; c -= rol32(b, 24);  \
>> +}
>> +
>> +/* An arbitrary initial parameter */
>> +#define JHASH_INITVAL           0xdeadbeef
>> +
>> +#endif /* QEMU_JHASH_H__ */
>
> Please split jhash into another patch.

Split to a independent patch in this patch set or not?


>
>> diff --git a/net/Makefile.objs b/net/Makefile.objs
>> index ba92f73..119589f 100644
>> --- a/net/Makefile.objs
>> +++ b/net/Makefile.objs
>> @@ -17,3 +17,4 @@ common-obj-y += filter.o
>>   common-obj-y += filter-buffer.o
>>   common-obj-y += filter-mirror.o
>>   common-obj-y += colo-compare.o
>> +common-obj-y += colo-base.o
>> diff --git a/net/colo-base.c b/net/colo-base.c
>> new file mode 100644
>> index 0000000..7e263e8
>> --- /dev/null
>> +++ b/net/colo-base.c
>> @@ -0,0 +1,194 @@
>> +/*
>> + * COarse-grain LOck-stepping Virtual Machines for Non-stop Service 
>> (COLO)
>> + * (a.k.a. Fault Tolerance or Continuous Replication)
>> + *
>> + * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
>> + * Copyright (c) 2016 FUJITSU LIMITED
>> + * Copyright (c) 2016 Intel Corporation
>> + *
>> + * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2 or
>> + * later.  See the COPYING file in the top-level directory.
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "qemu/error-report.h"
>> +#include "net/colo-base.h"
>> +
>> +uint32_t connection_key_hash(const void *opaque)
>> +{
>> +    const ConnectionKey *key = opaque;
>> +    uint32_t a, b, c;
>> +
>> +    /* Jenkins hash */
>> +    a = b = c = JHASH_INITVAL + sizeof(*key);
>> +    a += key->src.s_addr;
>> +    b += key->dst.s_addr;
>> +    c += (key->src_port | key->dst_port << 16);
>> +    __jhash_mix(a, b, c);
>> +
>> +    a += key->ip_proto;
>> +    __jhash_final(a, b, c);
>> +
>> +    return c;
>> +}
>> +
>> +int connection_key_equal(const void *key1, const void *key2)
>> +{
>> +    return memcmp(key1, key2, sizeof(ConnectionKey)) == 0;
>> +}
>> +
>> +int parse_packet_early(Packet *pkt)
>> +{
>> +    int network_length;
>> +    uint8_t *data = pkt->data;
>> +    uint16_t l3_proto;
>> +    ssize_t l2hdr_len = eth_get_l2_hdr_length(data);
>> +
>> +    if (pkt->size < ETH_HLEN) {
>> +        error_report("pkt->size < ETH_HLEN");
>> +        return 1;
>> +    }
>> +    pkt->network_layer = data + ETH_HLEN;
>> +    l3_proto = eth_get_l3_proto(data, l2hdr_len);
>> +    if (l3_proto != ETH_P_IP) {
>> +        return 1;
>> +    }
>> +
>> +    network_length = pkt->ip->ip_hl * 4;
>> +    if (pkt->size < ETH_HLEN + network_length) {
>> +        error_report("pkt->size < network_layer + network_length");
>> +        return 1;
>> +    }
>> +    pkt->transport_layer = pkt->network_layer + network_length;
>> +    if (!pkt->transport_layer) {
>> +        error_report("pkt->transport_layer is valid");
>> +        return 1;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +void fill_connection_key(Packet *pkt, ConnectionKey *key, int mode)
>> +{
>> +    uint32_t tmp_ports;
>> +
>> +    key->ip_proto = pkt->ip->ip_p;
>> +
>> +    switch (key->ip_proto) {
>> +    case IPPROTO_TCP:
>> +    case IPPROTO_UDP:
>> +    case IPPROTO_DCCP:
>> +    case IPPROTO_ESP:
>> +    case IPPROTO_SCTP:
>> +    case IPPROTO_UDPLITE:
>> +        tmp_ports = *(uint32_t *)(pkt->transport_layer);
>> +        if (mode) {
>
> Looks like mode is unnecessary here, you can actually compare and swap 
> duing hashing to avoid mode here.

I get your point.

>
>> +            key->src = pkt->ip->ip_src;
>> +            key->dst = pkt->ip->ip_dst;
>> +            key->src_port = ntohs(tmp_ports & 0xffff);
>> +            key->dst_port = ntohs(tmp_ports >> 16);
>> +        } else {
>> +            key->dst = pkt->ip->ip_src;
>> +            key->src = pkt->ip->ip_dst;
>> +            key->dst_port = ntohs(tmp_ports & 0xffff);
>> +            key->src_port = ntohs(tmp_ports >> 16);
>> +        }
>> +        break;
>> +    case IPPROTO_AH:
>> +        tmp_ports = *(uint32_t *)(pkt->transport_layer + 4);
>> +        if (mode) {
>> +            key->src = pkt->ip->ip_src;
>> +            key->dst = pkt->ip->ip_dst;
>> +            key->src_port = ntohs(tmp_ports & 0xffff);
>> +            key->dst_port = ntohs(tmp_ports >> 16);
>> +        } else {
>> +            key->dst = pkt->ip->ip_src;
>> +            key->src = pkt->ip->ip_dst;
>> +            key->dst_port = ntohs(tmp_ports & 0xffff);
>> +            key->src_port = ntohs(tmp_ports >> 16);
>> +        }
>> +        break;
>> +    default:
>> +        key->src_port = 0;
>> +        key->dst_port = 0;
>> +        break;
>> +    }
>> +}
>
> This seems could be reused, please use a independent patch for 
> connection key stuffs.

In this patch set or not?
If not, we make a new .c and .h for this?

>
>> +
>> +Connection *connection_new(ConnectionKey *key)
>> +{
>> +    Connection *conn = g_slice_new(Connection);
>> +
>> +    conn->ip_proto = key->ip_proto;
>> +    conn->processing = false;
>> +    g_queue_init(&conn->primary_list);
>> +    g_queue_init(&conn->secondary_list);
>> +
>> +    return conn;
>> +}
>> +
>> +void connection_destroy(void *opaque)
>> +{
>> +    Connection *conn = opaque;
>> +
>> +    g_queue_foreach(&conn->primary_list, packet_destroy, NULL);
>> +    g_queue_free(&conn->primary_list);
>> +    g_queue_foreach(&conn->secondary_list, packet_destroy, NULL);
>> +    g_queue_free(&conn->secondary_list);
>> +    g_slice_free(Connection, conn);
>> +}
>> +
>> +Packet *packet_new(const void *data, int size)
>> +{
>> +    Packet *pkt = g_slice_new(Packet);
>> +
>> +    pkt->data = g_memdup(data, size);
>> +    pkt->size = size;
>> +
>> +    return pkt;
>> +}
>> +
>> +void packet_destroy(void *opaque, void *user_data)
>> +{
>> +    Packet *pkt = opaque;
>> +
>> +    g_free(pkt->data);
>> +    g_slice_free(Packet, pkt);
>> +}
>> +
>> +/*
>> + * Clear hashtable, stop this hash growing really huge
>> + */
>> +void connection_hashtable_reset(GHashTable *connection_track_table)
>> +{
>> +    g_hash_table_remove_all(connection_track_table);
>> +}
>> +
>> +/* if not found, create a new connection and add to hash table */
>> +Connection *connection_get(GHashTable *connection_track_table,
>> +                           ConnectionKey *key,
>> +                           uint32_t *hashtable_size)
>> +{
>> +    /* FIXME: protect connection_track_table */
>
> I fail to understand why need protection here.

No need this...will remove it.

>
>> +    Connection *conn = g_hash_table_lookup(connection_track_table, 
>> key);
>> +
>> +    if (conn == NULL) {
>> +        ConnectionKey *new_key = g_memdup(key, sizeof(*key));
>> +
>> +        conn = connection_new(key);
>> +
>> +        (*hashtable_size) += 1;
>> +        if (*hashtable_size > HASHTABLE_MAX_SIZE) {
>> +            error_report("colo proxy connection hashtable full, 
>> clear it");
>
> Is this a hint that we need a synchronization?

NO...we needn't.

>
>> + connection_hashtable_reset(connection_track_table);
>> +            *hashtable_size = 0;
>> +            /* TODO:clear conn_list */
>
> If we don't clear conn_list, looks like a bug, so probably need to do 
> this in this patch.

OK~~

>
>> +        }
>> +
>> +        g_hash_table_insert(connection_track_table, new_key, conn);
>> +    }
>> +
>> +    return conn;
>> +}
>> diff --git a/net/colo-base.h b/net/colo-base.h
>> new file mode 100644
>> index 0000000..01c1a5d
>> --- /dev/null
>> +++ b/net/colo-base.h
>> @@ -0,0 +1,88 @@
>> +/*
>> + * COarse-grain LOck-stepping Virtual Machines for Non-stop Service 
>> (COLO)
>> + * (a.k.a. Fault Tolerance or Continuous Replication)
>> + *
>> + * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
>> + * Copyright (c) 2016 FUJITSU LIMITED
>> + * Copyright (c) 2016 Intel Corporation
>> + *
>> + * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2 or
>> + * later.  See the COPYING file in the top-level directory.
>> + */
>> +
>> +#ifndef QEMU_COLO_BASE_H
>> +#define QEMU_COLO_BASE_H
>> +
>> +#include "slirp/slirp.h"
>> +#include "qemu/jhash.h"
>> +#include "qemu/rcu.h"
>
> Don't see any rcu usage in this patch.

will remove it.

>
>> +
>> +#define HASHTABLE_MAX_SIZE 16384
>> +
>> +typedef enum colo_conn_state {
>
> This looks like can only take care of TCP, so probably add "tcp" in 
> its name.

yes.

>
>> +     COLO_CONN_IDLE,
>> +
>> +    /* States on the primary: For incoming connection */
>> +     COLO_CONN_PRI_IN_SYN,   /* Received Syn */
>> +     COLO_CONN_PRI_IN_PSYNACK, /* Received syn/ack from primary, but 
>> not
>> +                                yet from secondary */
>> +     COLO_CONN_PRI_IN_SSYNACK, /* Received syn/ack from secondary, but
>> +                                  not yet from primary */
>> +     COLO_CONN_PRI_IN_SYNACK,  /* Received syn/ack from both */
>> +     COLO_CONN_PRI_IN_ESTABLISHED, /* Got the ACK */
>> +
>> +    /* States on the secondary: For incoming connection */
>> +     COLO_CONN_SEC_IN_SYNACK,      /* We sent a syn/ack */
>> +     COLO_CONN_SEC_IN_ACK,         /* Saw the ack but didn't yet see 
>> our syn/ack */
>> +     COLO_CONN_SEC_IN_ESTABLISHED, /* Got the ACK from the outside */
>
> Should we care about any FIN state here?

Currently we don't care.

>
>> +} colo_conn_state;
>> +
>> +typedef struct Packet {
>> +    void *data;
>> +    union {
>> +        uint8_t *network_layer;
>> +        struct ip *ip;
>> +    };
>> +    uint8_t *transport_layer;
>> +    int size;
>> +} Packet;
>
> We may start to consider shares codes between e.g hw/net/net_tx_pkt.c.

I read it.the file be added to qemu a mouth ago.
it need time to be stable.maybe it will change.
So I think this job should be do after colo-compare be merged...

>
>> +
>> +typedef struct ConnectionKey {
>> +    /* (src, dst) must be grouped, in the same way than in IP header */
>> +    struct in_addr src;
>> +    struct in_addr dst;
>> +    uint16_t src_port;
>> +    uint16_t dst_port;
>> +    uint8_t ip_proto;
>> +} QEMU_PACKED ConnectionKey;
>> +
>> +typedef struct Connection {
>> +    /* connection primary send queue: element type: Packet */
>> +    GQueue primary_list;
>> +    /* connection secondary send queue: element type: Packet */
>> +    GQueue secondary_list;
>> +    /* flag to enqueue unprocessed_connections */
>> +    bool processing;
>> +    uint8_t ip_proto;
>> +    /* be used by filter-rewriter */
>> +    colo_conn_state state;
>> +    tcp_seq  primary_seq;
>> +    tcp_seq  secondary_seq;
>> +} Connection;
>> +
>> +uint32_t connection_key_hash(const void *opaque);
>> +int connection_key_equal(const void *opaque1, const void *opaque2);
>> +int parse_packet_early(Packet *pkt);
>> +void fill_connection_key(Packet *pkt, ConnectionKey *key, int mode);
>> +Connection *connection_new(ConnectionKey *key);
>> +void connection_destroy(void *opaque);
>> +Connection *connection_get(GHashTable *connection_track_table,
>> +                           ConnectionKey *key,
>> +                           uint32_t *hashtable_size);
>> +void connection_hashtable_reset(GHashTable *connection_track_table);
>> +Packet *packet_new(const void *data, int size);
>> +void packet_destroy(void *opaque, void *user_data);
>> +
>> +#endif /* QEMU_COLO_BASE_H */
>> diff --git a/net/colo-compare.c b/net/colo-compare.c
>> index a3e1456..4231fe7 100644
>> --- a/net/colo-compare.c
>> +++ b/net/colo-compare.c
>> @@ -28,6 +28,7 @@
>>   #include "qemu/sockets.h"
>>   #include "qapi-visit.h"
>>   #include "trace.h"
>> +#include "net/colo-base.h"
>>     #define TYPE_COLO_COMPARE "colo-compare"
>>   #define COLO_COMPARE(obj) \
>> @@ -38,6 +39,28 @@
>>   static QTAILQ_HEAD(, CompareState) net_compares =
>>          QTAILQ_HEAD_INITIALIZER(net_compares);
>>   +/*
>> +  + CompareState ++
>> +  |               |
>> +  +---------------+   +---------------+ +---------------+
>> +  |conn list      +--->conn +--------->conn           |
>> +  +---------------+   +---------------+ +---------------+
>> +  |               |     |           |             |          |
>> +  +---------------+ +---v----+  +---v----+    +---v----+ +---v----+
>> +                    |primary |  |secondary    |primary | |secondary
>> +                    |packet  |  |packet  +    |packet  | |packet  +
>> +                    +--------+  +--------+    +--------+ +--------+
>> +                        |           |             |          |
>> +                    +---v----+  +---v----+    +---v----+ +---v----+
>> +                    |primary |  |secondary    |primary | |secondary
>> +                    |packet  |  |packet  +    |packet  | |packet  +
>> +                    +--------+  +--------+    +--------+ +--------+
>> +                        |           |             |          |
>> +                    +---v----+  +---v----+    +---v----+ +---v----+
>> +                    |primary |  |secondary    |primary | |secondary
>> +                    |packet  |  |packet  +    |packet  | |packet  +
>> +                    +--------+  +--------+    +--------+ +--------+
>> +*/
>>   typedef struct CompareState {
>>       Object parent;
>>   @@ -50,12 +73,103 @@ typedef struct CompareState {
>>       QTAILQ_ENTRY(CompareState) next;
>>       SocketReadState pri_rs;
>>       SocketReadState sec_rs;
>> +
>> +    /* connection list: the connections belonged to this NIC could 
>> be found
>> +     * in this list.
>> +     * element type: Connection
>> +     */
>> +    GQueue conn_list;
>> +    QemuMutex conn_list_lock; /* to protect conn_list */
>
> Why need this mutex?

will remove it.

>
>> +    /* hashtable to save connection */
>> +    GHashTable *connection_track_table;
>> +    /* to save unprocessed_connections */
>> +    GQueue unprocessed_connections;
>> +    /* proxy current hash size */
>> +    uint32_t hashtable_size;
>>   } CompareState;
>>     typedef struct CompareClass {
>>       ObjectClass parent_class;
>>   } CompareClass;
>>   +enum {
>> +    PRIMARY_IN = 0,
>> +    SECONDARY_IN,
>> +};
>> +
>> +static int compare_chr_send(CharDriverState *out,
>> +                            const uint8_t *buf,
>> +                            uint32_t size);
>> +
>> +/*
>> + * Return 0 on success, if return -1 means the pkt
>> + * is unsupported(arp and ipv6) and will be sent later
>> + */
>> +static int packet_enqueue(CompareState *s, int mode)
>> +{
>> +    ConnectionKey key = {{ 0 } };
>> +    Packet *pkt = NULL;
>> +    Connection *conn;
>> +
>> +    if (mode == PRIMARY_IN) {
>> +        pkt = packet_new(s->pri_rs.buf, s->pri_rs.packet_len);
>> +    } else {
>> +        pkt = packet_new(s->sec_rs.buf, s->sec_rs.packet_len);
>> +    }
>> +
>> +    if (parse_packet_early(pkt)) {
>> +        packet_destroy(pkt, NULL);
>> +        pkt = NULL;
>> +        return -1;
>> +    }
>> +    fill_connection_key(pkt, &key, PRIMARY_IN);
>> +
>> +    conn = connection_get(s->connection_track_table,
>> +                          &key,
>> +                          &s->hashtable_size);
>> +    if (!conn->processing) {
>> +        qemu_mutex_lock(&s->conn_list_lock);
>> +        g_queue_push_tail(&s->conn_list, conn);
>> +        qemu_mutex_unlock(&s->conn_list_lock);
>> +        conn->processing = true;
>> +    }
>> +
>> +    if (mode == PRIMARY_IN) {
>> +        g_queue_push_tail(&conn->primary_list, pkt);
>> +    } else {
>> +        g_queue_push_tail(&conn->secondary_list, pkt);
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int compare_chr_send(CharDriverState *out,
>> +                            const uint8_t *buf,
>> +                            uint32_t size)
>> +{
>> +    int ret = 0;
>> +    uint32_t len = htonl(size);
>> +
>> +    if (!size) {
>> +        return 0;
>> +    }
>> +
>> +    ret = qemu_chr_fe_write_all(out, (uint8_t *)&len, sizeof(len));
>> +    if (ret != sizeof(len)) {
>> +        goto err;
>> +    }
>> +
>> +    ret = qemu_chr_fe_write_all(out, (uint8_t *)buf, size);
>> +    if (ret != size) {
>> +        goto err;
>> +    }
>> +
>> +    return 0;
>> +
>> +err:
>> +    return ret < 0 ? ret : -EIO;
>> +}
>> +
>>   static char *compare_get_pri_indev(Object *obj, Error **errp)
>>   {
>>       CompareState *s = COLO_COMPARE(obj);
>> @@ -103,12 +217,21 @@ static void compare_set_outdev(Object *obj, 
>> const char *value, Error **errp)
>>     static void compare_pri_rs_finalize(SocketReadState *pri_rs)
>>   {
>> -    /* if packet_enqueue pri pkt failed we will send unsupported 
>> packet */
>> +    CompareState *s = container_of(pri_rs, CompareState, pri_rs);
>> +
>> +    if (packet_enqueue(s, PRIMARY_IN)) {
>> +        trace_colo_compare_main("primary: unsupported packet in");
>> +        compare_chr_send(s->chr_out, pri_rs->buf, pri_rs->packet_len);
>> +    }
>
> Do we have a upper limit on the maximum numbers of packets could be 
> queued? If not, guest may easily trigger OOM.

We need a g_queue to do this job? It upper than the limit we drop the 
packet?

Thanks
Zhang Chen

>
>>   }
>>     static void compare_sec_rs_finalize(SocketReadState *sec_rs)
>>   {
>> -    /* if packet_enqueue sec pkt failed we will notify trace */
>> +    CompareState *s = container_of(sec_rs, CompareState, sec_rs);
>> +
>> +    if (packet_enqueue(s, SECONDARY_IN)) {
>> +        trace_colo_compare_main("secondary: unsupported packet in");
>> +    }
>>   }
>>     /*
>> @@ -161,6 +284,15 @@ static void colo_compare_complete(UserCreatable 
>> *uc, Error **errp)
>>       net_socket_rs_init(&s->pri_rs, compare_pri_rs_finalize);
>>       net_socket_rs_init(&s->sec_rs, compare_sec_rs_finalize);
>>   +    g_queue_init(&s->conn_list);
>> +    qemu_mutex_init(&s->conn_list_lock);
>> +    s->hashtable_size = 0;
>> +
>> +    s->connection_track_table = 
>> g_hash_table_new_full(connection_key_hash,
>> + connection_key_equal,
>> +                                                      g_free,
>> + connection_destroy);
>> +
>>       return;
>>   }
>>   @@ -203,6 +335,8 @@ static void colo_compare_finalize(Object *obj)
>>       if (!QTAILQ_EMPTY(&net_compares)) {
>>           QTAILQ_REMOVE(&net_compares, s, next);
>>       }
>> +    qemu_mutex_destroy(&s->conn_list_lock);
>> +    g_queue_free(&s->conn_list);
>>         g_free(s->pri_indev);
>>       g_free(s->sec_indev);
>> diff --git a/trace-events b/trace-events
>> index ca7211b..703de1a 100644
>> --- a/trace-events
>> +++ b/trace-events
>> @@ -1916,3 +1916,6 @@ aspeed_vic_update_fiq(int flags) "Raising FIQ: %d"
>>   aspeed_vic_update_irq(int flags) "Raising IRQ: %d"
>>   aspeed_vic_read(uint64_t offset, unsigned size, uint32_t value) 
>> "From 0x%" PRIx64 " of size %u: 0x%" PRIx32
>>   aspeed_vic_write(uint64_t offset, unsigned size, uint32_t data) "To 
>> 0x%" PRIx64 " of size %u: 0x%" PRIx32
>> +
>> +# net/colo-compare.c
>> +colo_compare_main(const char *chr) ": %s"
>
>
>
> .
>

-- 
Thanks
zhangchen