Date: Sat, 19 Jul 2014 12:57:24 -0700 From: Marcel Moolenaar <marcel@xcllnt.net> To: Konstantin Belousov <kostikbel@gmail.com> Cc: amd64@freebsd.org, arch@freebsd.org Subject: Re: KDB entry on NMI Message-ID: <18C85F15-FC9E-480C-BFB9-4CD0894FD93A@xcllnt.net> In-Reply-To: <20140719182909.GU93733@kib.kiev.ua> References: <20140718160708.GO93733@kib.kiev.ua> <A26F3461-4654-4749-A719-C2E543F4A126@xcllnt.net> <20140719182909.GU93733@kib.kiev.ua>
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--Apple-Mail=_9EC7C332-AEF2-47D7-BE1B-8C3AA7C81F99 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii On Jul 19, 2014, at 11:29 AM, Konstantin Belousov <kostikbel@gmail.com> = wrote: >>=20 >> One may call kdb_enter on different CPUs at the same time and it's >> also possible to call panic on multiple CPUs at the same time (but >> we serialize panic() right now). What if we let kdb_enter at al deal >> with concurrency, instead of doing it specifically for NMIs? > Then, on 80-threads machine I get the 80 ddb sessions on NMI = broadcast, > like now. With your proposal, it will be somewhat better, since > sessions are serialized, so I can do the reboot from the first one. There's value to send the NMI to all CPUs: you'll be pretty sure that if there's a CPU that can handle it, it will get the NMI. Sending it to a single CPU has the downside that if that CPU is unable to handle the NMI (corrupted page tables, locked on some chipset access, held in reset, powering down, whatever one can think of) you're out of luck. Are we acking the NMI on all CPUs right now? --=20 Marcel Moolenaar marcel@xcllnt.net --Apple-Mail=_9EC7C332-AEF2-47D7-BE1B-8C3AA7C81F99 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org iEYEARECAAYFAlPKzaQACgkQpgWlLWHuifbMMwCeMnNysi89BXze/Aatu3VkRZk8 G9cAnj7IsKTxaQh5eZ3xtNcwSryWBfHl =m2cx -----END PGP SIGNATURE----- --Apple-Mail=_9EC7C332-AEF2-47D7-BE1B-8C3AA7C81F99--
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