From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <521C1FFF.5060203@hitachi.com> Date: Tue, 27 Aug 2013 12:41:51 +0900 From: Yoshihiro YUNOMAE MIME-Version: 1.0 To: Don Zickus Cc: "Eric W. Biederman" , Ingo Molnar , linux-kernel@vger.kernel.org, Andi Kleen , "H. Peter Anvin" , Gleb Natapov , Konrad Rzeszutek Wilk , Joerg Roedel , x86@kernel.org, stable@vger.kernel.org, Marcelo Tosatti , Hidehiro Kawai , Sebastian Andrzej Siewior , Ingo Molnar , Zhang Yanfei , yrl.pp-manager.tt@hitachi.com, Masami Hiramatsu , Thomas Gleixner , Seiji Aguchi , Andrew Morton Subject: Re: Re: Re: [PATCH] [BUGFIX] crash/ioapic: Prevent crash_kexec() from deadlocking of ioapic_lock References: <20130819081220.24406.15846.stgit@yunodevel> <20130819094623.GA30389@gmail.com> <5212B31A.6090504@hitachi.com> <871u5or7qn.fsf@tw-ebiederman.twitter.com> <20130820142740.GO239280@redhat.com> <5215CDEF.30004@hitachi.com> <20130822131137.GL5564@redhat.com> In-Reply-To: <20130822131137.GL5564@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: Hi Don, Sorry for the late reply. (2013/08/22 22:11), Don Zickus wrote: > On Thu, Aug 22, 2013 at 05:38:07PM +0900, Yoshihiro YUNOMAE wrote: >>> So, I agree with Eric, let's remove the disable_IO_APIC() stuff and keep >>> the code simpler. >> >> Thank you for commenting about my patch. >> I didn't know you already have submitted the patches for this deadlock >> problem. >> >> I can't answer definitively right now that no problems are induced by >> removing disable_IO_APIC(). However, my patch should be work well (and >> has already been merged to -tip tree). So how about taking my patch at >> first, and then discussing the removal of disabled_IO_APIC()? > > It doesn't matter to me. My orignal patch last year was similar to yours > until it was suggested that we were working around a problem which was we > shouldn't touch the IO_APIC code on panic. Then I wrote the removal of > disable_IO_APIC patch and did lots of testing on it. I don't think I have > seen any issues with it (just the removal of disabling the lapic stuff). Yes, you really did a lot of testing about this problem according to your patch(https://lkml.org/lkml/2012/1/31/391). Although you said jiffies calibration code does not need the PIT in http://lists.infradead.org/pipermail/kexec/2012-February/006017.html, I don't understand yet why we can remove disable_IO_APIC. Would you please explain about the calibration codes? By the way, can we remove disable_IO_APIC even if an old dump capture kernel is used? Thanks, Yoshihiro YUNOMAE > Regardless, your patch fixes a similar problem we saw on RHEL, so I am > happy either way. The removal of the disable_IO_APIC() just makes the > code look cleaner. > > Cheers, > Don > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- Yoshihiro YUNOMAE Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: yoshihiro.yunomae.ez@hitachi.com