From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Guo, Jia" <jia.guo@intel.com>
Subject: Re: [PATCH v2 1/2] eal: add uevent api for hot plug
Date: Wed, 5 Jul 2017 11:02:55 +0800
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Cc: dev@dpdk.org, helin.zhang@intel.com, jingjing.wu@intel.com
To: Thomas Monjalon <thomas@monjalon.net>
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hi, thomas


On 7/5/2017 7:45 AM, Thomas Monjalon wrote:
> Hi,
>
> This is an interesting step for hotplug in DPDK.
>
> 28/06/2017 13:07, Jeff Guo:
>> +       netlink_fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
> It is monitoring the whole system...
>
>> +int
>> +rte_uevent_get(int fd, struct rte_uevent *uevent)
>> +{
>> +       int ret;
>> +       char buf[RTE_UEVENT_MSG_LEN];
>> +
>> +       memset(uevent, 0, sizeof(struct rte_uevent));
>> +       memset(buf, 0, RTE_UEVENT_MSG_LEN);
>> +
>> +       ret = recv(fd, buf, RTE_UEVENT_MSG_LEN - 1, MSG_DONTWAIT);
> ... and it is read from this function called by one driver.
> It cannot work without a global dispatch.
the rte_uevent-connect is called in func of pci_uio_alloc_resource, so 
each socket is created by  by each uio device. so i think that would not 
affect each driver isolate to use it.
> It must be a global mechanism, probably a service core.
> The question is also to know whether it should be a mandatory
> service in DPDK or an optional helper?
a global mechanism would be good, but so far, include mlx driver, we all 
handle the hot plug event in driver by app's registered callback. maybe 
a better global would be try in the future. but now is would work for all
pci uio device.
and more, if in pci uio device to use hot plug , i think it might be 
mandatory.