Date: Tue, 10 Apr 2012 13:55:31 +0100 From: Attilio Rao <attilio@freebsd.org> To: Marius Strobl <marius@alchemy.franken.de> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, John Baldwin <jhb@freebsd.org> Subject: Re: svn commit: r234074 - in head/sys: amd64/amd64 i386/i386 Message-ID: <CAJ-FndDNAOdiEv008nOqhez13oWbKvPkgZDW2M7FEsxMMmRusw@mail.gmail.com> In-Reply-To: <20120410114118.GB93449@alchemy.franken.de> References: <201204092241.q39MfJZn081610@svn.freebsd.org> <20120409230949.GB68111@alchemy.franken.de> <CAJ-FndDzh50_Xb%2B08EnhAVBnu1vFLo0d5MX%2BQwAOTcq_ewwDJQ@mail.gmail.com> <20120410114118.GB93449@alchemy.franken.de>
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Il 10 aprile 2012 12:41, Marius Strobl <marius@alchemy.franken.de> ha scritto: > On Tue, Apr 10, 2012 at 01:03:56AM +0100, Attilio Rao wrote: >> Il 10 aprile 2012 00:09, Marius Strobl <marius@alchemy.franken.de> ha scritto: >> > On Mon, Apr 09, 2012 at 10:41:19PM +0000, Attilio Rao wrote: >> >> Author: attilio >> >> Date: Mon Apr ??9 22:41:19 2012 >> >> New Revision: 234074 >> >> URL: http://svn.freebsd.org/changeset/base/234074 >> >> >> >> Log: >> >> ?? BSP is not added to the mask of valid target CPUs for interrupts >> >> ?? in set_apic_interrupt_ids(). Besides, set_apic_interrupts_ids() is not >> >> ?? called in the !SMP case too. >> >> ?? Fix this by: >> >> ?? - Adding the BSP as an interrupt target directly in cpu_startup(). >> >> ?? - Remove an obsolete optimization where the BSP are skipped in >> >> ?? ?? set_apic_interrupt_ids(). >> >> >> >> ?? Reported by: ?? ?? ?? ??jh >> >> ?? Reviewed by: ?? ?? ?? ??jhb >> >> ?? MFC after: ??3 days >> >> ?? X-MFC: ?? ?? ?? ?? ?? ?? ??r233961 >> >> ?? Pointy hat to: ?? ?? ??me >> >> >> >> Modified: >> >> ?? head/sys/amd64/amd64/machdep.c >> >> ?? head/sys/amd64/amd64/mp_machdep.c >> >> ?? head/sys/i386/i386/machdep.c >> >> ?? head/sys/i386/i386/mp_machdep.c >> >> >> >> Modified: head/sys/amd64/amd64/machdep.c >> >> ============================================================================== >> >> --- head/sys/amd64/amd64/machdep.c ?? ??Mon Apr ??9 22:01:43 2012 ?? ?? ?? ??(r234073) >> >> +++ head/sys/amd64/amd64/machdep.c ?? ??Mon Apr ??9 22:41:19 2012 ?? ?? ?? ??(r234074) >> >> @@ -295,6 +295,11 @@ cpu_startup(dummy) >> >> ?? ?? ?? vm_pager_bufferinit(); >> >> >> >> ?? ?? ?? cpu_setregs(); >> >> + >> >> + ?? ?? /* >> >> + ?? ?? ??* Add BSP as an interrupt target. >> >> + ?? ?? ??*/ >> >> + ?? ?? intr_add_cpu(0); >> >> ??} >> > >> > If I'm not mistaken, intr_add_cpu() is under #ifdef SMP, so it should be >> > here as well. >> >> You are right, sorry, I did forgot to test without SMP. >> I think we still need intr_add_cpu() on cpu_startup() because of the >> case smp_disabled = 1. >> I think the attached patch should make its dirty job, opinion? > > I currently fail to see why the latter approach would be necessary, > i.e. IMO wrapping the intr_add_cpu() calls in cpu_startup() should > be sufficient. In case the kernel is compiled without SMP support, > interrupt balancing support isn't available in the first place and > the BSP is always the only available target (see the UP version of > intr_next_cpu() at the end of x86/x86/intr_machdep.c), so there's > no need to add the BSP as a valid target. If an SMP kernel is run > on a UP machine or with SMP disabled, interrupt balancing support > is available but the intr_add_cpu() calls in cpu_startup() will add > the BSP as (the only) target, so everything should be fine. Maybe > you can elaborate on why you think an SMP kernel with SMP disabled > needs special handling. I do not understand what you mean. Right now there is a compile time issue where for !SMP kernel it won't compile and this is what I'm trying to fix now, so I don't understand what do you mean here. Attilio -- Peace can only be achieved by understanding - A. Einstein
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