Date: Wed, 14 Nov 2012 08:06:33 -0800 From: Alfred Perlstein <bright@mu.org> To: Markus Gebert <markus.gebert@hostpoint.ch> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: thread taskq / unp_gc() using 100% cpu and stalling unix socket IPC Message-ID: <6177E5C2-7FF6-42D7-B1E0-C09803BF6383@mu.org> In-Reply-To: <4DDA6862-6BE5-4EF4-B6B5-141DD9123C36@hostpoint.ch> References: <6908B498-6978-4995-B081-8D504ECB5C0A@hostpoint.ch> <007F7A73-75F6-48A6-9C01-E7C179CDA48A@hostpoint.ch> <50A3104E.5000107@mu.org> <4DDA6862-6BE5-4EF4-B6B5-141DD9123C36@hostpoint.ch>
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On Nov 14, 2012, at 2:42 AM, Markus Gebert <markus.gebert@hostpoint.ch> wrot= e: >=20 > On 14.11.2012, at 04:30, Alfred Perlstein <bright@mu.org> wrote: >=20 >> A couple of ideas: >=20 > Thanks. >=20 >> 1) convert the taskqueue to a callout, but only allow one to be queued at= a time. set the granularity. >=20 > I think Konstantin's patch is going in this direction. Yes. Looks good.=20 >=20 >=20 >> 2) I think you only need to actually run garbage collection on the off-ch= ance that you pass unix file descriptors, otherwise you can get away with re= fcounting. >=20 > Hm, isn't that whats done currently? gc is only scheduled if fds are infli= ght while uipc_detach() is called. >=20 It looks to me as if it runs the gc when ANY type are in flight.=20 If you added refcounting then you could trust the refcounting so long as no u= nix sockets were in flight as its only the unix sockets that can cause cycle= s in a refcount based graph.=20 >=20 >> It's hard for me to express the exact logic needed for this though. I t= hink you would need some way to simply do refcounting until there was a unix= socket descriptor in flight, then switch to gc. Either that or make a sys= ctl that allows you administratively deny passing of unix descriptors and ju= st use refcounting. >=20 >=20 >=20 > Markus >=20
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