From: Peter Zijlstra <peterz@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Juergen Gross <jgross@suse.com>, Nadav Amit <namit@vmware.com>,
Ingo Molnar <mingo@redhat.com>, Andy Lutomirski <luto@kernel.org>,
Borislav Petkov <bp@alien8.de>,
linux-kernel@vger.kernel.org,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Sasha Levin <sashal@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
linux-hyperv@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
xen-devel@lists.xenproject.org
Subject: Re: [RFC PATCH 5/6] x86/mm/tlb: Flush remote and local TLBs concurrently
Date: Mon, 27 May 2019 14:32:06 +0200 [thread overview]
Message-ID: <20190527123206.GC2623@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <e9c0dc1f-799a-b6e3-8d41-58f0a6b693cd@redhat.com>
On Mon, May 27, 2019 at 12:21:59PM +0200, Paolo Bonzini wrote:
> On 27/05/19 11:47, Peter Zijlstra wrote:
> > --- a/arch/x86/kernel/kvm.c
> > +++ b/arch/x86/kernel/kvm.c
> > @@ -580,7 +580,7 @@ static void __init kvm_apf_trap_init(voi
> >
> > static DEFINE_PER_CPU(cpumask_var_t, __pv_tlb_mask);
> >
> > -static void kvm_flush_tlb_others(const struct cpumask *cpumask,
> > +static void kvm_flush_tlb_multi(const struct cpumask *cpumask,
> > const struct flush_tlb_info *info)
> > {
> > u8 state;
> > @@ -594,6 +594,9 @@ static void kvm_flush_tlb_others(const s
> > * queue flush_on_enter for pre-empted vCPUs
> > */
> > for_each_cpu(cpu, flushmask) {
> > + if (cpu == smp_processor_id())
> > + continue;
> > +
>
> Even this would be just an optimization; the vCPU you're running on
> cannot be preempted. You can just change others to multi.
Yeah, I know, but it felt weird so I added the explicit skip. No strong
feelings though.
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Juergen Gross <jgross@suse.com>, Sasha Levin <sashal@kernel.org>,
linux-hyperv@vger.kernel.org,
Dave Hansen <dave.hansen@linux.intel.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
kvm@vger.kernel.org, Haiyang Zhang <haiyangz@microsoft.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
xen-devel@lists.xenproject.org, Nadav Amit <namit@vmware.com>,
Thomas Gleixner <tglx@linutronix.de>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [RFC PATCH 5/6] x86/mm/tlb: Flush remote and local TLBs concurrently
Date: Mon, 27 May 2019 14:32:06 +0200 [thread overview]
Message-ID: <20190527123206.GC2623@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <e9c0dc1f-799a-b6e3-8d41-58f0a6b693cd@redhat.com>
On Mon, May 27, 2019 at 12:21:59PM +0200, Paolo Bonzini wrote:
> On 27/05/19 11:47, Peter Zijlstra wrote:
> > --- a/arch/x86/kernel/kvm.c
> > +++ b/arch/x86/kernel/kvm.c
> > @@ -580,7 +580,7 @@ static void __init kvm_apf_trap_init(voi
> >
> > static DEFINE_PER_CPU(cpumask_var_t, __pv_tlb_mask);
> >
> > -static void kvm_flush_tlb_others(const struct cpumask *cpumask,
> > +static void kvm_flush_tlb_multi(const struct cpumask *cpumask,
> > const struct flush_tlb_info *info)
> > {
> > u8 state;
> > @@ -594,6 +594,9 @@ static void kvm_flush_tlb_others(const s
> > * queue flush_on_enter for pre-empted vCPUs
> > */
> > for_each_cpu(cpu, flushmask) {
> > + if (cpu == smp_processor_id())
> > + continue;
> > +
>
> Even this would be just an optimization; the vCPU you're running on
> cannot be preempted. You can just change others to multi.
Yeah, I know, but it felt weird so I added the explicit skip. No strong
feelings though.
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Juergen Gross <jgross@suse.com>, Sasha Levin <sashal@kernel.org>,
linux-hyperv@vger.kernel.org,
Dave Hansen <dave.hansen@linux.intel.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
kvm@vger.kernel.org, Haiyang Zhang <haiyangz@microsoft.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
xen-devel@lists.xenproject.org, Nadav Amit <namit@vmware.com>,
Thomas Gleixner <tglx@linutronix.de>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [Xen-devel] [RFC PATCH 5/6] x86/mm/tlb: Flush remote and local TLBs concurrently
Date: Mon, 27 May 2019 14:32:06 +0200 [thread overview]
Message-ID: <20190527123206.GC2623@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <e9c0dc1f-799a-b6e3-8d41-58f0a6b693cd@redhat.com>
On Mon, May 27, 2019 at 12:21:59PM +0200, Paolo Bonzini wrote:
> On 27/05/19 11:47, Peter Zijlstra wrote:
> > --- a/arch/x86/kernel/kvm.c
> > +++ b/arch/x86/kernel/kvm.c
> > @@ -580,7 +580,7 @@ static void __init kvm_apf_trap_init(voi
> >
> > static DEFINE_PER_CPU(cpumask_var_t, __pv_tlb_mask);
> >
> > -static void kvm_flush_tlb_others(const struct cpumask *cpumask,
> > +static void kvm_flush_tlb_multi(const struct cpumask *cpumask,
> > const struct flush_tlb_info *info)
> > {
> > u8 state;
> > @@ -594,6 +594,9 @@ static void kvm_flush_tlb_others(const s
> > * queue flush_on_enter for pre-empted vCPUs
> > */
> > for_each_cpu(cpu, flushmask) {
> > + if (cpu == smp_processor_id())
> > + continue;
> > +
>
> Even this would be just an optimization; the vCPU you're running on
> cannot be preempted. You can just change others to multi.
Yeah, I know, but it felt weird so I added the explicit skip. No strong
feelings though.
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next prev parent reply other threads:[~2019-05-27 12:32 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-25 8:21 [RFC PATCH 0/6] x86/mm: Flush remote and local TLBs concurrently Nadav Amit
2019-05-25 8:21 ` [RFC PATCH 1/6] smp: Remove smp_call_function() and on_each_cpu() return values Nadav Amit
2019-05-25 8:21 ` [RFC PATCH 2/6] cpumask: Purify cpumask_next() Nadav Amit
2019-05-25 8:32 ` Ingo Molnar
2019-05-27 8:30 ` Peter Zijlstra
2019-05-27 17:34 ` Nadav Amit
2019-05-25 8:22 ` [RFC PATCH 3/6] smp: Run functions concurrently in smp_call_function_many() Nadav Amit
2019-05-27 9:15 ` Peter Zijlstra
2019-05-27 17:39 ` Nadav Amit
2019-05-25 8:22 ` [RFC PATCH 4/6] x86/mm/tlb: Refactor common code into flush_tlb_on_cpus() Nadav Amit
2019-05-27 9:24 ` Peter Zijlstra
2019-05-27 18:59 ` Nadav Amit
2019-05-27 19:14 ` Peter Zijlstra
2019-05-25 8:22 ` [RFC PATCH 5/6] x86/mm/tlb: Flush remote and local TLBs concurrently Nadav Amit
2019-05-25 8:22 ` [Xen-devel] " Nadav Amit
2019-05-25 8:22 ` Nadav Amit via Virtualization
2019-05-25 8:38 ` Nadav Amit
2019-05-25 8:38 ` Nadav Amit
2019-05-25 8:38 ` [Xen-devel] " Nadav Amit
2019-05-25 8:38 ` Nadav Amit via Virtualization
2019-05-25 8:54 ` Juergen Gross
2019-05-25 8:54 ` [Xen-devel] " Juergen Gross
2019-05-27 9:47 ` Peter Zijlstra
2019-05-27 9:47 ` Peter Zijlstra
2019-05-27 9:47 ` [Xen-devel] " Peter Zijlstra
2019-05-27 10:21 ` Paolo Bonzini
2019-05-27 10:21 ` Paolo Bonzini
2019-05-27 10:21 ` [Xen-devel] " Paolo Bonzini
2019-05-27 12:32 ` Peter Zijlstra
2019-05-27 12:32 ` Peter Zijlstra [this message]
2019-05-27 12:32 ` [Xen-devel] " Peter Zijlstra
2019-05-27 12:32 ` Peter Zijlstra
2019-05-27 12:45 ` Paolo Bonzini
2019-05-27 12:45 ` Paolo Bonzini
2019-05-27 12:45 ` [Xen-devel] " Paolo Bonzini
2019-05-27 12:45 ` Paolo Bonzini
2019-05-27 10:21 ` Paolo Bonzini
2019-05-27 17:49 ` Nadav Amit
2019-05-27 17:49 ` [Xen-devel] " Nadav Amit
2019-05-27 17:49 ` Nadav Amit
2019-05-27 17:49 ` Nadav Amit via Virtualization
2019-05-27 9:47 ` Peter Zijlstra
2019-05-25 8:54 ` Juergen Gross
2019-05-25 8:54 ` Juergen Gross
2019-05-25 8:22 ` Nadav Amit
2019-05-25 8:22 ` [RFC PATCH 6/6] x86/mm/tlb: Optimize local TLB flushes Nadav Amit
2019-05-27 8:28 ` [RFC PATCH 0/6] x86/mm: Flush remote and local TLBs concurrently Peter Zijlstra
2019-05-27 9:59 ` Peter Zijlstra
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