From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Waiman Long <longman@redhat.com>, Peter Zijlstra <peterz@infradead.org>
Cc: linux-arch@vger.kernel.org, "Juergen Gross" <jgross@suse.com>,
"Jeremy Fitzhardinge" <jeremy@goop.org>,
xen-devel@lists.xenproject.org, kvm@vger.kernel.org,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Pan Xinhui" <xinhui.pan@linux.vnet.ibm.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
"Chris Wright" <chrisw@sous-sol.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Alok Kataria" <akataria@vmware.com>
Subject: Re: [Xen-devel] [PATCH v2] x86/paravirt: Don't make vcpu_is_preempted() a callee-save function
Date: Tue, 14 Feb 2017 16:18:55 +0000 [thread overview]
Message-ID: <5c3c2a13-b397-6e9f-8772-a8aaa3f70771__38874.8171310455$1487089949$gmane$org@citrix.com> (raw)
In-Reply-To: <fc65322b-902e-6589-f64c-62be5abdb093@redhat.com>
On 14/02/17 14:46, Waiman Long wrote:
> On 02/14/2017 04:39 AM, Peter Zijlstra wrote:
>> On Mon, Feb 13, 2017 at 05:34:01PM -0500, Waiman Long wrote:
>>> It is the address of &steal_time that will exceed the 32-bit limit.
>> That seems extremely unlikely. That would mean we have more than 4G
>> worth of per-cpu variables declared in the kernel.
> I have some doubt about if the compiler is able to properly use
> RIP-relative addressing for this. Anyway, it seems like constraints
> aren't allowed for asm() when not in the function context, at least for
> the the compiler that I am using (4.8.5). So it is a moot point.
You can work the issue of not having parameters in a plain asm()
statement by using an asm-offset, stringizing it, and have C put the
string fragments back together.
"cmpb $0, " STR(STEAL_TIME_preempted) "(%rax);"
~Andrew
next prev parent reply other threads:[~2017-02-14 16:18 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-10 15:43 [PATCH v2] x86/paravirt: Don't make vcpu_is_preempted() a callee-save function Waiman Long
2017-02-10 15:43 ` Waiman Long
2017-02-10 16:19 ` Peter Zijlstra
2017-02-10 16:19 ` Peter Zijlstra
2017-02-10 16:19 ` Peter Zijlstra
2017-02-10 16:35 ` Waiman Long
2017-02-10 16:35 ` Waiman Long
2017-02-10 17:00 ` Waiman Long
2017-02-10 17:00 ` Waiman Long
2017-02-10 17:00 ` Waiman Long
2017-02-13 10:47 ` Peter Zijlstra
2017-02-13 10:47 ` Peter Zijlstra
2017-02-13 10:47 ` Peter Zijlstra
2017-02-13 10:53 ` Peter Zijlstra
2017-02-13 10:53 ` Peter Zijlstra
2017-02-13 10:53 ` Peter Zijlstra
2017-02-13 19:42 ` Waiman Long
2017-02-13 19:42 ` Waiman Long
2017-02-13 19:42 ` Waiman Long
2017-02-13 20:12 ` Waiman Long
2017-02-13 20:12 ` Waiman Long
2017-02-13 21:52 ` Peter Zijlstra
2017-02-13 21:52 ` Peter Zijlstra
2017-02-13 21:52 ` Peter Zijlstra
2017-02-13 22:00 ` hpa
2017-02-13 22:00 ` hpa
2017-02-13 22:00 ` hpa
2017-02-13 22:07 ` hpa
2017-02-13 22:07 ` hpa
2017-02-13 22:07 ` hpa
2017-02-13 22:34 ` Waiman Long
2017-02-13 22:34 ` Waiman Long
2017-02-13 22:34 ` Waiman Long
2017-02-13 22:36 ` hpa
2017-02-13 22:36 ` hpa
2017-02-13 22:36 ` hpa
2017-02-14 9:39 ` Peter Zijlstra
2017-02-14 9:39 ` Peter Zijlstra
2017-02-14 9:39 ` Peter Zijlstra
2017-02-14 14:46 ` Waiman Long
2017-02-14 14:46 ` Waiman Long
2017-02-14 14:46 ` Waiman Long
2017-02-14 16:03 ` Peter Zijlstra
2017-02-14 16:03 ` Peter Zijlstra
2017-02-14 16:03 ` Peter Zijlstra
2017-02-14 16:18 ` Andrew Cooper [this message]
2017-02-14 16:18 ` Andrew Cooper
2017-02-14 16:18 ` [Xen-devel] " Andrew Cooper
2017-02-13 20:12 ` Waiman Long
2017-02-13 20:06 ` hpa
2017-02-13 20:06 ` hpa
2017-02-13 21:57 ` Peter Zijlstra
2017-02-13 21:57 ` Peter Zijlstra
2017-02-13 21:57 ` Peter Zijlstra
2017-02-13 22:24 ` Waiman Long
2017-02-13 22:24 ` Waiman Long
2017-02-13 22:31 ` Peter Zijlstra
2017-02-13 22:31 ` Peter Zijlstra
2017-02-13 22:31 ` Peter Zijlstra
2017-02-13 22:24 ` Waiman Long
2017-02-13 20:06 ` hpa
2017-02-13 19:41 ` Waiman Long
2017-02-13 19:41 ` Waiman Long
2017-02-13 19:41 ` Waiman Long
2017-02-10 16:35 ` Waiman Long
2017-02-10 16:22 ` Paolo Bonzini
2017-02-10 16:22 ` Paolo Bonzini
2017-02-10 16:22 ` Paolo Bonzini
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