From: Rik van Riel <riel@redhat.com>
To: Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org, aquini@redhat.com,
walken@google.com, eric.dumazet@gmail.com, lwoodman@redhat.com,
knoel@redhat.com, chegu_vinod@hp.com,
raghavendra.kt@linux.vnet.ibm.com, mingo@redhat.com
Subject: Re: [PATCH -v4 5/5] x86,smp: limit spinlock delay on virtual machines
Date: Mon, 04 Feb 2013 08:50:33 -0500 [thread overview]
Message-ID: <510FBCA9.4070700@redhat.com> (raw)
In-Reply-To: <20130126124716.GB21395@pd.tnic>
On 01/26/2013 07:47 AM, Borislav Petkov wrote:
> On Sat, Jan 26, 2013 at 01:00:43PM +0100, Ingo Molnar wrote:
>>> +void __init init_spinlock_delay(void)
>>> +{
>>> + if (x86_hyper)
>>> + max_spinlock_delay = MAX_SPINLOCK_DELAY_GUEST;
>>
>> I realize that you took existing code and extended it, but that
>> chunk of code looks pretty disgusting visually now - at minimum
>> it should be vertically aligned as most other kernel code does.
>>
>> The comment should also tell that the unit of these values is
>> 'spinlock-op loops' or so.
Will do.
> Also, with currently making PARAVIRT_GUEST optional, x86_hyper is maybe
> a bad choice of a variable to test.
>
> Maybe instead to this:
>
> if (IS_ENABLED(CONFIG_PARAVIRT_GUEST))
> ...
We need to know whether we are actually running on top of a
hypervisor, not whether we have the code compiled in to do
so.
After all, the majority of distribution kernels will have
CONFIG_PARAVIRT_GUEST set, but the majority of those kernels
will be running bare metal...
--
All rights reversed
next prev parent reply other threads:[~2013-02-04 13:50 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-25 19:05 [PATCH -v4 0/5] x86,smp: make ticket spinlock proportional backoff w/ auto tuning Rik van Riel
2013-01-25 19:16 ` [PATCH -v4 1/5] x86,smp: move waiting on contended ticket lock out of line Rik van Riel
2013-01-25 19:17 ` [PATCH -v4 2/5] x86,smp: proportional backoff for ticket spinlocks Rik van Riel
2013-01-25 19:17 ` [PATCH -v4 3/5] x86,smp: auto tune spinlock backoff delay factor Rik van Riel
2013-01-26 12:03 ` Ingo Molnar
2013-01-25 19:18 ` [PATCH -v4 4/5] x86,smp: keep spinlock delay values per hashed spinlock address Rik van Riel
2013-01-27 13:04 ` Michel Lespinasse
2013-02-06 20:10 ` Rik van Riel
2013-02-09 23:50 ` Michel Lespinasse
2013-01-25 19:19 ` [PATCH -v4 5/5] x86,smp: limit spinlock delay on virtual machines Rik van Riel
2013-01-26 12:00 ` Ingo Molnar
2013-01-26 12:47 ` Borislav Petkov
2013-02-04 13:50 ` Rik van Riel [this message]
2013-02-04 14:02 ` Borislav Petkov
2013-02-06 17:05 ` Rik van Riel
2013-01-28 18:18 ` Stefano Stabellini
2013-01-25 19:20 ` [DEBUG PATCH -v4 6/5] x86,smp: add debugging code to track spinlock delay value Rik van Riel
2013-01-26 7:21 ` [PATCH -v4 0/5] x86,smp: make ticket spinlock proportional backoff w/ auto tuning Mike Galbraith
2013-01-26 12:05 ` Ingo Molnar
2013-01-26 13:10 ` Mike Galbraith
2013-01-28 6:49 ` Raghavendra K T
2013-02-03 15:28 ` Chegu Vinod
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