From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: "Jeremy Fitzhardinge" <jeremy@goop.org>,
"Chris Wright" <chrisw@sous-sol.org>,
"Alok Kataria" <akataria@vmware.com>,
"Rusty Russell" <rusty@rustcorp.com.au>,
"Ingo Molnar" <mingo@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-arch@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
xen-devel@lists.xenproject.org, kvm@vger.kernel.org,
"Pan Xinhui" <xinhui.pan@linux.vnet.ibm.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Juergen Gross" <jgross@suse.com>
Subject: Re: [PATCH v2] x86/paravirt: Don't make vcpu_is_preempted() a callee-save function
Date: Mon, 13 Feb 2017 11:53:43 +0100 [thread overview]
Message-ID: <20170213105343.GJ6536@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20170213104716.GM6515@twins.programming.kicks-ass.net>
On Mon, Feb 13, 2017 at 11:47:16AM +0100, Peter Zijlstra wrote:
> That way we'd end up with something like:
>
> asm("
> push %rdi;
> movslq %edi, %rdi;
> movq __per_cpu_offset(,%rdi,8), %rax;
> cmpb $0, %[offset](%rax);
> setne %al;
> pop %rdi;
> " : : [offset] "i" (((unsigned long)&steal_time) + offsetof(struct steal_time, preempted)));
>
> And if we could get rid of the sign extend on edi we could avoid all the
> push-pop nonsense, but I'm not sure I see how to do that (then again,
> this asm foo isn't my strongest point).
Maybe:
movsql %edi, %rax;
movq __per_cpu_offset(,%rax,8), %rax;
cmpb $0, %[offset](%rax);
setne %al;
?
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: linux-arch@vger.kernel.org, "Juergen Gross" <jgross@suse.com>,
"Jeremy Fitzhardinge" <jeremy@goop.org>,
x86@kernel.org, kvm@vger.kernel.org,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Pan Xinhui" <xinhui.pan@linux.vnet.ibm.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
"Chris Wright" <chrisw@sous-sol.org>,
"Ingo Molnar" <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
xen-devel@lists.xenproject.org,
"Alok Kataria" <akataria@vmware.com>,
"Thomas Gleixner" <tglx@linutronix.de>
Subject: Re: [PATCH v2] x86/paravirt: Don't make vcpu_is_preempted() a callee-save function
Date: Mon, 13 Feb 2017 11:53:43 +0100 [thread overview]
Message-ID: <20170213105343.GJ6536@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20170213104716.GM6515@twins.programming.kicks-ass.net>
On Mon, Feb 13, 2017 at 11:47:16AM +0100, Peter Zijlstra wrote:
> That way we'd end up with something like:
>
> asm("
> push %rdi;
> movslq %edi, %rdi;
> movq __per_cpu_offset(,%rdi,8), %rax;
> cmpb $0, %[offset](%rax);
> setne %al;
> pop %rdi;
> " : : [offset] "i" (((unsigned long)&steal_time) + offsetof(struct steal_time, preempted)));
>
> And if we could get rid of the sign extend on edi we could avoid all the
> push-pop nonsense, but I'm not sure I see how to do that (then again,
> this asm foo isn't my strongest point).
Maybe:
movsql %edi, %rax;
movq __per_cpu_offset(,%rax,8), %rax;
cmpb $0, %[offset](%rax);
setne %al;
?
next prev parent reply other threads:[~2017-02-13 10:54 UTC|newest]
Thread overview: 69+ 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 [this message]
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 ` [Xen-devel] " Andrew Cooper
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
-- strict thread matches above, loose matches on Subject: below --
2017-02-10 15:43 Waiman Long
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