[dpdk-stable] [dpdk-dev] [PATCH v4] eal: fix proc type auto detection

[Van Haaren, Harry]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of David Marchand
> Sent: Monday, August 12, 2019 11:04 AM
> To: Burakov, Anatoly <anatoly.burakov at intel.com>
> Cc: dev <dev at dpdk.org>; Richardson, Bruce <bruce.richardson at intel.com>;
> Stephen Hemminger <stephen at networkplumber.org>; dpdk stable <stable at dpdk.org>
> Subject: Re: [dpdk-dev] [PATCH v4] eal: fix proc type auto detection
> 
> On Wed, Jul 24, 2019 at 6:08 PM Anatoly Burakov
> <anatoly.burakov at intel.com> wrote:
> >
> > Currently, primary process holds an exclusive lock on the config
> > file, thereby preventing other primaries from spinning up. However,
> > when the primary dies, the lock is no longer being held, even though
> > there might be other secondary processes still running.
> >
> > The fix is two-fold. First of all, downgrade the primary process's
> > exclusive lock to a shared lock once we have it. Second of all,
> > also take out shared locks on the config from the secondaries. We
> > are using fcntl() locks, which get dropped when the file handle is
> > closed, so also remove the closure of config file handle.
> >
> > Fixes: af75078fece3 ("first public release")
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>


Apologies I'm late to the conversation.

Will the rte_eal_primary_proc_alive() function still detect the primary
as alive, and not confuse secondaries with primaries in this new method?

Currently, the pri_proc_alive() code uses lockf(fd, F_TEST, 0); to detect
if a primary is alive. I'm not familiar enough with shared locks to know 
if the new behavior would be consistent with the old.

-H