Date: Fri, 21 Sep 2007 15:47:21 -0700 From: "Moore, Robert" <robert.moore@intel.com> To: "Jung-uk Kim" <jkim@FreeBSD.org>, "John Baldwin" <jhb@FreeBSD.org> Cc: freebsd-acpi@FreeBSD.org, freebsd-current@FreeBSD.org Subject: RE: [PATCH] OsdSynch.c modernization Message-ID: <B28E9812BAF6E2498B7EC5C427F293A403469D43@orsmsx415.amr.corp.intel.com> In-Reply-To: <200709211827.29763.jkim@FreeBSD.org> References: <200709181516.11207.jkim@FreeBSD.org><200709211715.17940.jhb@freebsd.org> <200709211827.29763.jkim@FreeBSD.org>
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I can look around a bit, but I don't think we'd make any system calls while holding a spinlock.=20 Bob >-----Original Message----- >From: owner-freebsd-acpi@freebsd.org [mailto:owner-freebsd- >acpi@freebsd.org] On Behalf Of Jung-uk Kim >Sent: Friday, September 21, 2007 3:27 PM >To: John Baldwin >Cc: freebsd-acpi@FreeBSD.org; freebsd-current@FreeBSD.org >Subject: Re: [PATCH] OsdSynch.c modernization > >On Friday 21 September 2007 05:15 pm, John Baldwin wrote: >> On Tuesday 18 September 2007 03:16:07 pm Jung-uk Kim wrote: >> > I have rewritten sys/dev/acpica/Osd/OsdSynch.c to match the >> > modern ACPI-CA and -CURRENT: >> > >> > http://people.freebsd.org/~jkim/acpica/OsdSynch.diff >> >> Why do you use a loop around tsleep() rather than just use >> sx_xlock() (which will block) for the WAIT_FOREVER case when >> waiting on a semaphore? > >You mean for AcpiOsAcquireMutex()? sx_xlock() cannot be waken up by >the wait channel. > >> Why don't you just use a spin mutex for the spin lock? >> That is a far better fit than the sx lock stuff you are doing. >> Manually doing spinlock_enter() (wrongly btw, you should use >> critical_enter(), not sched_pin() otherwise you can be preempted) >> just to avoid the assertion failure is just going to result in >> obscure hangs. Does ACPI-CA want to malloc() while holding an ACPI >> spin lock or something? > >I thought exactly the same when I started rewriting it (almost half >year ago!). I have tried all of the above, spent numerous sleepless >nights, and miserably failed. :-( > >Spin mutex is too restrictive (e.g., it cannot be used with other >locks gracefully). critical_enter() causes: > >panic: blockable sleep lock (sleep mutex) 32 @ >/usr/src/sys/vm/uma_core.c:1830 cpuid =3D 0 >KDB: enter: panic >[thread pid 21 tid 100013 ] >Stopped at kdb_enter+0x32: leave > >http://docs.freebsd.org/cgi/mid.cgi?200709121927.46465.jkim > >I guess it wants to malloc() while holding spin lock although I >haven't traced it down. > >I intend to investigate and fix further after RELENG_7 is branched and >I really like to hear more ideas from you. > >Thanks, > >Jung-uk Kim >_______________________________________________ >freebsd-acpi@freebsd.org mailing list >http://lists.freebsd.org/mailman/listinfo/freebsd-acpi >To unsubscribe, send any mail to "freebsd-acpi-unsubscribe@freebsd.org"
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