Date: Mon, 30 Jul 2012 17:39:43 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Attilio Rao <attilio@freebsd.org> Cc: Davide Italiano <davide@freebsd.org>, svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r238907 - projects/calloutng/sys/kern Message-ID: <20120730143943.GY2676@deviant.kiev.zoral.com.ua> In-Reply-To: <CAJ-FndBmXkyJJ=fCkEpVm84E56A2_EoM6kbch03e4RMEM6WCGQ@mail.gmail.com> References: <201207301350.q6UDobCI099069@svn.freebsd.org> <CAJ-FndBJNNBNDUEDsDBUvwoVExZpnXmoJmpY58gE3QQbw3hRGA@mail.gmail.com> <CACYV=-HmOwZ=E8Pw3-mUw0994SbvZaA3eMfcwM0fDTu_zykBJg@mail.gmail.com> <CAJ-FndBmXkyJJ=fCkEpVm84E56A2_EoM6kbch03e4RMEM6WCGQ@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--zNkIgqbxA+tiK/WQ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jul 30, 2012 at 03:24:26PM +0100, Attilio Rao wrote: > On 7/30/12, Davide Italiano <davide@freebsd.org> wrote: > > On Mon, Jul 30, 2012 at 4:02 PM, Attilio Rao <attilio@freebsd.org> wrot= e: > > Thanks for the comment, Attilio. > > Yes, it's exactly what you thought. If direct flag is equal to one > > you're sure you're processing a callout which runs directly from > > hardware interrupt context. In this case, the running thread cannot > > sleep and it's likely you have TDP_NOSLEEPING flags set, failing the > > KASSERT() in THREAD_NO_SLEEPING() and leading to panic if kernel is > > compiled with INVARIANTS. > > In case you're running from SWI context (direct equals to zero) code > > remains the same as before. > > I think what I'm doing works due the assumption thread running never > > sleeps. Do you suggest some other way to handle this? >=20 > Possibly the quicker way to do this is to have a way to deal with the > TDP_NOSLEEPING flag in recursed way, thus implement the same logic as > VFS_LOCK_GIANT() does, for example. > You will need to change the few callers of THREAD_NO_SLEEPING(), but > the patch should be no longer than 10/15 lines. There are already curthread_pflags_set/restore KPI designed exactly to hand= le nested private thread flags. Also, I wonder, should you assert somehow that direct dispatch cannot block as well ? --zNkIgqbxA+tiK/WQ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (FreeBSD) iEYEARECAAYFAlAWnK8ACgkQC3+MBN1Mb4j5WwCg6LbznxGnAdFUAWhKH4tuWs5/ e7YAnj9sBgT6t3r7sfRJ09cMmmu0Rlq3 =YxNw -----END PGP SIGNATURE----- --zNkIgqbxA+tiK/WQ--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20120730143943.GY2676>