From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Tan, Jianfeng" <jianfeng.tan@intel.com>
Subject: Re: [PATCH v2 3/4] eal: add synchronous multi-process
 communication
Date: Wed, 17 Jan 2018 21:15:53 +0800
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Cc: "Richardson, Bruce" <bruce.richardson@intel.com>,
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To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
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On 1/17/2018 9:09 PM, Tan, Jianfeng wrote:
>
>
> On 1/17/2018 6:50 PM, Ananyev, Konstantin wrote:
>
[...]
>> +int
>> +rte_eal_mp_request(const char *action_name,
>> +           void *params,
>> +           int len_p,
>> +           int fds[],
>> +           int fds_in,
>> +           int fds_out)
>> +{
>> +    int i, j;
>> +    int sockfd;
>> +    int nprocs;
>> +    int ret = 0;
>> +    struct mp_msghdr *req;
>> +    struct timeval tv;
>> +    char buf[MAX_MSG_LENGTH];
>> +    struct mp_msghdr *hdr;
>> +
>> +    RTE_LOG(DEBUG, EAL, "request: %s\n", action_name);
>> +
>> +    if (fds_in > SCM_MAX_FD || fds_out > SCM_MAX_FD) {
>> +        RTE_LOG(ERR, EAL, "Cannot send more than %d FDs\n", 
>> SCM_MAX_FD);
>> +        rte_errno = -E2BIG;
>> +        return 0;
>> +    }
>> +
>> +    req = format_msg(action_name, params, len_p, fds_in, MP_REQ);
>> +    if (req == NULL)
>> +        return 0;
>> +
>> +    if ((sockfd = open_unix_fd(0)) < 0) {
>> +        free(req);
>> +        return 0;
>> +    }
>> +
>> +    tv.tv_sec = 5;  /* 5 Secs Timeout */
>> +    tv.tv_usec = 0;
>> +    if (setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO,
>> +            (const void *)&tv, sizeof(struct timeval)) < 0)
>> +        RTE_LOG(INFO, EAL, "Failed to set recv timeout\n");
>>
>> I f you set it just for one call, why do you not restore it?
>
> Yes, original code is buggy, I should have put it into the critical 
> section.
>
> Do you mean we just create once and use for ever? if yes, we could put 
> the open and setting into mp_init().

A second thought, we shall not put the setting into mp_init(). It'll be 
set to non-blocking as of sending msg, but blocking as of receiving msg.

Thanks,
Jianfeng