From: Ingo Molnar <mingo@kernel.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, Stoney Wang <song-bo.wang@hp.com>,
stable@kernel.org
Subject: Re: [PATCH] x86, apic: Check fadt x2apic phys in x2apic_phys_probe()
Date: Wed, 6 Feb 2013 14:16:55 +0100 [thread overview]
Message-ID: <20130206131655.GH8696@gmail.com> (raw)
In-Reply-To: <CAE9FiQXn1P0RGD-O3jeFNgAdsfv4EQyH8g7r0x3KBFfh20fF=Q@mail.gmail.com>
* Yinghai Lu <yinghai@kernel.org> wrote:
> On Tue, Feb 5, 2013 at 4:24 AM, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > * Yinghai Lu <yinghai@kernel.org> wrote:
> >
> >> From: Stoney Wang <song-bo.wang@hp.com>
> >>
> >> When HP ProLiant DL980 G7 Server boot without x2apic_phys, there will be
> >> intermittent lost interrupts and could result in a hang or data loss.
> >
> > What does 'boot without x2apic_phys' mean?
> >
> > Does it mean x2apic_phys=0 boot command line? Or, because
> > x2apic_phys is off by default, does it simply mean that if it's
> > booted with a default kernel, without any workaround specified
> > on the boot command line?
>
> means that user does not append "x2apic_phys" in boot command line.
The user does not append a whole lot of other
behavior-modification command line options either! There's no
apic=0 line either. Nor smp=0.
Adding this essentially irrelevant piece of information to the
*FIRST*, most important sentence of the changelog is thus not
just confusing but utterly misleading. Communications 101.
Instead it should say something like:
When a HP ProLiant DL980 G7 Server boots a regular kernel,
there will be intermittent lost interrupts which could
result in a hang or (in extreme cases) data loss.
The reason is that this system only supports x2apic physical
mode, while the kernel boots with a logical-cluster default
setting.
This bug can be worked around by specifying the x2apic_phys=1
boot option, but we want to handle this sytem without
requiring manual workarounds.
Right? Writing a clean changelog is like writing clean code -
you have to learn it if you want to contribute to the kernel
smoothly. Think of it as an engineering task: the other required
half of modifying kernel code.
Thanks,
Ingo
next prev parent reply other threads:[~2013-02-06 13:17 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-15 1:50 [PATCH] x86/apic: check FADT settings after enable x2apic Stoney Wang
2013-01-28 5:05 ` Wang, Song-Bo (Stoney)
2013-01-28 6:57 ` Yinghai Lu
2013-01-28 10:11 ` Ingo Molnar
2013-01-28 18:10 ` Yinghai Lu
2013-01-29 7:47 ` Ingo Molnar
2013-01-29 8:43 ` Wang, Song-Bo (Stoney)
2013-01-29 8:49 ` Ingo Molnar
2013-01-29 21:30 ` Yinghai Lu
2013-01-29 21:52 ` Yinghai Lu
2013-01-31 11:32 ` Ingo Molnar
2013-01-31 15:56 ` Yinghai Lu
2013-02-04 6:41 ` Wang, Song-Bo (Stoney)
2013-02-04 11:03 ` Ingo Molnar
2013-02-04 20:29 ` [PATCH] x86, apic: Check fadt x2apic phys in x2apic_phys_probe() Yinghai Lu
2013-02-05 12:24 ` Ingo Molnar
2013-02-05 16:53 ` Yinghai Lu
2013-02-06 13:16 ` Ingo Molnar [this message]
2013-02-06 17:10 ` Yinghai Lu
2013-02-07 18:53 ` [PATCH v4] " Yinghai Lu
2013-02-11 12:37 ` [tip:x86/urgent] x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems tip-bot for Stoney Wang
2013-02-18 8:52 ` [PATCH v4] x86, apic: Check fadt x2apic phys in x2apic_phys_probe() Lin-Bao Zhang
2013-02-18 17:13 ` Yinghai Lu
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