Thanks for your reply! I used one patch solve my problem someone posted last
night in the mailing list.
At 2016-03-14 21:02:13, "Kyle Larose" <eomereadig at gmail.com> wrote:
>Hello,
>
>On Sun, Mar 13, 2016 at 10:38 AM, ?? <zhangwqh at 126.com> wrote:
>> Hi all,
>> When I use the dpdk lookup function, I met the segment fault problem. Can
>> anybody help to look at why this happens. I will put the aim what I want to
>> do and the related piece of code, and my debug message,
>>
>>
>> This problem is that in dpdk multi process - client and server example,
>> dpdk-2.2.0/examples/multi_process/client_server_mp
>> My aim is that server create a hash table, then share it to client. Client
>> will write the hash table, server will read the hash table. I am using
>> dpdk hash table. What I did is that server create a hash table (table and
>> array entries), return the table address. I use memzone pass the table
>> address to client. In client, the second lookup gets segment fault. The
>> system gets crashed. I will put some related code here.
>> create hash table function:
>>
>
>Let me see if I understand correctly. You're allocating a hash table
>on huge-page backed memory.
>You pass a pointer to that table over a shared memory structure.
>
>Is that correct?
>
>I don't think something being in a huge-page necessarily means it is
>shared. That is, allocating your hash table using rte_calloc in the
>primary isn't sufficient to make it available in the secondary.
>
>Further, even if it was, I do not think that it would work, because
>there are a bunch of pointers involved (i.e. ft->data). As far as I'm
>aware, each process has its own "view" of the shared memory. It maps
>it into its own local address space, and gives it an address according
>to what is currently available there.
>
>Most of my IPC with DPDK has involved passing packets around; I'm not
>sure what the strategy is for hash tables. Synchronization issues
>aside, I think you will need to put the hash table in its entirety in
>shared memory, and avoid global pointers: either offset into the
>shared memory, or have a structure with no pointers at all. From that,
>you can probably build up local pointers.
>
>Maybe somebody else can correct me or come up with a better idea.
>
>Hope that helps,
>
>Kyle
>
>
>> struct onvm_ft*
>>
>> onvm_ft_create(int cnt, int entry_size) {
>>
>> struct rte_hash* hash;
>>
>> struct onvm_ft* ft;
>>
>> struct rte_hash_parameters ipv4_hash_params = {
>>
>> .name = NULL,
>>
>> .entries = cnt,
>>
>> .key_len = sizeof(struct onvm_ft_ipv4_5tuple),
>>
>> .hash_func = NULL,
>>
>> .hash_func_init_val = 0,
>>
>> };
>>
>>
>>
>>
>> char s[64];
>>
>> /* create ipv4 hash table. use core number and cycle counter to get
>> a unique name. */
>>
>> ipv4_hash_params.name = s;
>>
>> ipv4_hash_params.socket_id = rte_socket_id();
>>
>> snprintf(s, sizeof(s), "onvm_ft_%d-%"PRIu64, rte_lcore_id(),
>> rte_get_tsc_cycles());
>>
>> hash = rte_hash_create(&ipv4_hash_params);
>>
>> if (hash == NULL) {
>>
>> return NULL;
>>
>> }
>>
>> ft = (struct onvm_ft*)rte_calloc("table", 1, sizeof(struct onvm_ft),
>> 0);
>>
>> if (ft == NULL) {
>>
>> rte_hash_free(hash);
>>
>> return NULL;
>>
>> }
>>
>> ft->hash = hash;
>>
>> ft->cnt = cnt;
>>
>> ft->entry_size = entry_size;
>>
>> /* Create data array for storing values */
>>
>> ft->data = rte_calloc("entry", cnt, entry_size, 0);
>>
>> if (ft->data == NULL) {
>>
>> rte_hash_free(hash);
>>
>> rte_free(ft);
>>
>> return NULL;
>>
>> }
>>
>> return ft;
>>
>> }
>>
>>
>>
>>
>> related structure:
>>
>> struct onvm_ft {
>>
>> struct rte_hash* hash;
>>
>> char* data;
>>
>> int cnt;
>>
>> int entry_size;
>>
>> };
>>
>>
>>
>>
>> in server side, I will call the create function, use memzone share it to
>> client. The following is what I do:
>>
>> related variables:
>>
>> struct onvm_ft *sdn_ft;
>>
>> struct onvm_ft **sdn_ft_p;
>>
>> const struct rte_memzone *mz_ftp;
>>
>>
>>
>>
>> sdn_ft = onvm_ft_create(1024, sizeof(struct onvm_flow_entry));
>>
>> if(sdn_ft == NULL) {
>>
>> rte_exit(EXIT_FAILURE, "Unable to create flow table\n");
>>
>> }
>>
>> mz_ftp = rte_memzone_reserve(MZ_FTP_INFO, sizeof(struct onvm_ft *),
>>
>> rte_socket_id(), NO_FLAGS);
>>
>> if (mz_ftp == NULL) {
>>
>> rte_exit(EXIT_FAILURE, "Canot reserve memory zone for flow
>> table pointer\n");
>>
>> }
>>
>> memset(mz_ftp->addr, 0, sizeof(struct onvm_ft *));
>>
>> sdn_ft_p = mz_ftp->addr;
>>
>> *sdn_ft_p = sdn_ft;
>>
>>
>>
>>
>> In client side:
>>
>> struct onvm_ft *sdn_ft;
>>
>> static void
>>
>> map_flow_table(void) {
>>
>> const struct rte_memzone *mz_ftp;
>>
>> struct onvm_ft **ftp;
>>
>>
>>
>>
>> mz_ftp = rte_memzone_lookup(MZ_FTP_INFO);
>>
>> if (mz_ftp == NULL)
>>
>> rte_exit(EXIT_FAILURE, "Cannot get flow table pointer\n");
>>
>> ftp = mz_ftp->addr;
>>
>> sdn_ft = *ftp;
>>
>> }
>>
>>
>>
>>
>> The following is my debug message: I set a breakpoint in lookup table line.
>> To narrow down the problem, I just send one flow. So the second time and the
>> first time, the packets are the same.
>>
>> For the first time, it works. I print out the parameters: inside the
>> onvm_ft_lookup function, if there is a related entry, it will return the
>> address by flow_entry.
>>
>> Breakpoint 1, datapath_handle_read (dp=0x7ffff00008c0) at
>> /home/zhangwei1984/openNetVM-master/openNetVM/examples/flow_table/sdn.c:191
>>
>> 191 ret = onvm_ft_lookup(sdn_ft, fk,
>> (char**)&flow_entry);
>>
>> (gdb) print *sdn_ft
>>
>> $1 = {hash = 0x7fff32cce740, data = 0x7fff32cb0480 "", cnt = 1024,
>> entry_size = 56}
>>
>> (gdb) print *fk
>>
>> $2 = {src_addr = 419496202, dst_addr = 453050634, src_port = 53764, dst_port
>> = 11798, proto = 17 '\021'}
>>
>> (gdb) s
>>
>> onvm_ft_lookup (table=0x7fff32cbe4c0, key=0x7fff32b99d00,
>> data=0x7ffff68d2b00) at
>> /home/zhangwei1984/openNetVM-master/openNetVM/onvm/shared/onvm_flow_table.c:151
>>
>> 151 softrss = onvm_softrss(key);
>>
>> (gdb) n
>>
>> 152 printf("software rss %d\n", softrss);
>>
>> (gdb)
>>
>> software rss 403183624
>>
>> 154 tbl_index = rte_hash_lookup_with_hash(table->hash, (const void
>> *)key, softrss);
>>
>> (gdb) print table->hash
>>
>> $3 = (struct rte_hash *) 0x7fff32cce740
>>
>> (gdb) print *key
>>
>> $4 = {src_addr = 419496202, dst_addr = 453050634, src_port = 53764, dst_port
>> = 11798, proto = 17 '\021'}
>>
>> (gdb) print softrss
>>
>> $5 = 403183624
>>
>> (gdb) c
>>
>>
>>
>>
>> After I hit c, it will do the second lookup,
>>
>> Breakpoint 1, datapath_handle_read (dp=0x7ffff00008c0) at
>> /home/zhangwei1984/openNetVM-master/openNetVM/examples/flow_table/sdn.c:191
>>
>> 191 ret = onvm_ft_lookup(sdn_ft, fk,
>> (char**)&flow_entry);
>>
>> (gdb) print *sdn_ft
>>
>>
>> $7 = {hash = 0x7fff32cce740, data = 0x7fff32cb0480 "", cnt = 1024,
>> entry_size = 56}
>>
>> (gdb) print *fk
>>
>> $8 = {src_addr = 419496202, dst_addr = 453050634, src_port = 53764, dst_port
>> = 11798, proto = 17 '\021'}
>>
>> (gdb) s
>>
>> onvm_ft_lookup (table=0x7fff32cbe4c0, key=0x7fff32b99c00,
>> data=0x7ffff68d2b00) at
>> /home/zhangwei1984/openNetVM-master/openNetVM/onvm/shared/onvm_flow_table.c:151
>>
>> 151 softrss = onvm_softrss(key);
>>
>> (gdb) n
>>
>> 152 printf("software rss %d\n", softrss);
>>
>> (gdb) n
>>
>> software rss 403183624
>>
>> 154 tbl_index = rte_hash_lookup_with_hash(table->hash, (const void
>> *)key, softrss);
>>
>> (gdb) print table->hash
>>
>> $9 = (struct rte_hash *) 0x7fff32cce740
>>
>> (gdb) print *key
>>
>> $10 = {src_addr = 419496202, dst_addr = 453050634, src_port = 53764,
>> dst_port = 11798, proto = 17 '\021'}
>>
>> (gdb) print softrss
>>
>> $11 = 403183624
>>
>> (gdb) n
>>
>>
>>
>>
>>
>> Program received signal SIGSEGV, Segmentation fault.
>>
>> 0x000000000045fb97 in __rte_hash_lookup_bulk ()
>>
>> (gdb) bt
>>
>> #0 0x000000000045fb97 in __rte_hash_lookup_bulk ()
>>
>> #1 0x0000000000000000 in ?? ()
>>
>>
>>
>>
>> From the debug message, the parameters are exactly the same. I do not know
>> why it has the segmentation fault.
>>
>> my lookup function:
>>
>> int
>>
>> onvm_ft_lookup(struct onvm_ft* table, struct onvm_ft_ipv4_5tuple *key,
>> char** data) {
>>
>> int32_t tbl_index;
>>
>> uint32_t softrss;
>>
>>
>>
>>
>> softrss = onvm_softrss(key);
>>
>> printf("software rss %d\n", softrss);
>>
>>
>>
>>
>> tbl_index = rte_hash_lookup_with_hash(table->hash, (const void
>> *)key, softrss);
>>
>> if (tbl_index >= 0) {
>>
>> *data = onvm_ft_get_data(table, tbl_index);
>>
>> return 0;
>>
>> }
>>
>> else {
>>
>> return tbl_index;
>>
>> }
>>
>> }
