From: "Jürgen Groß" <jgross@suse.com>
To: Borislav Petkov <bp@alien8.de>
Cc: xen-devel@lists.xenproject.org, x86@kernel.org,
virtualization@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
kvm@vger.kernel.org, Deep Shah <sdeep@vmware.com>,
"VMware, Inc." <pv-drivers@vmware.com>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v6 02/12] x86/paravirt: switch time pvops functions to use static_call()
Date: Wed, 10 Mar 2021 08:51:22 +0100 [thread overview]
Message-ID: <e06cc359-6300-a26b-c307-9ef8d963b0c1@suse.com> (raw)
In-Reply-To: <20210309185737.GE699@zn.tnic>
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On 09.03.21 19:57, Borislav Petkov wrote:
> On Tue, Mar 09, 2021 at 02:48:03PM +0100, Juergen Gross wrote:
>> @@ -167,6 +168,17 @@ static u64 native_steal_clock(int cpu)
>> return 0;
>> }
>>
>> +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
>> +DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock);
>> +
>> +bool paravirt_using_native_sched_clock = true;
>> +
>> +void paravirt_set_sched_clock(u64 (*func)(void))
>> +{
>> + static_call_update(pv_sched_clock, func);
>> + paravirt_using_native_sched_clock = (func == native_sched_clock);
>> +}
>
> What's the point of this function if there's a global
> paravirt_using_native_sched_clock variable now?
It is combining the two needed actions: update the static call and
set the paravirt_using_native_sched_clock boolean.
> Looking how the bit of information whether native_sched_clock is used,
> is needed in tsc.c, it probably would be cleaner if you add a
>
> set_sched_clock_native(void);
>
> or so, to tsc.c instead and call that here and make that long var name a
> a shorter and static one in tsc.c instead.
I need to transfer a boolean value, so it would need to be
set_sched_clock_native(bool state);
In the end the difference is only marginal IMO.
Just had another idea: I could add a function to static_call.h for
querying the current function. This would avoid the double book keeping
and could probably be used later when switching other pv_ops calls to
static_call, too (e.g. pv_is_native_spin_unlock()).
What do you think?
Juergen
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next prev parent reply other threads:[~2021-03-10 7:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 13:48 [PATCH v6 00/12] x86: major paravirt cleanup Juergen Gross
2021-03-09 13:48 ` [PATCH v6 01/12] static_call: move struct static_call_key definition to static_call_types.h Juergen Gross
2021-03-09 13:48 ` [PATCH v6 02/12] x86/paravirt: switch time pvops functions to use static_call() Juergen Gross
2021-03-09 18:57 ` Borislav Petkov
2021-03-10 7:51 ` Jürgen Groß [this message]
2021-03-10 14:13 ` Borislav Petkov
2021-03-09 13:48 ` [PATCH v6 03/12] x86/alternative: drop feature parameter from ALTINSTR_REPLACEMENT() Juergen Gross
2021-03-09 13:48 ` [PATCH v6 04/12] x86/alternative: support not-feature Juergen Gross
2021-03-10 6:07 ` Borislav Petkov
2021-03-10 7:52 ` Jürgen Groß
2021-03-10 14:15 ` Borislav Petkov
2021-03-10 14:41 ` Jürgen Groß
2021-03-09 13:48 ` [PATCH v6 05/12] x86/alternative: support ALTERNATIVE_TERNARY Juergen Gross
2021-03-10 14:27 ` Borislav Petkov
2021-03-10 14:42 ` Jürgen Groß
2021-03-09 13:48 ` [PATCH v6 06/12] x86: add new features for paravirt patching Juergen Gross
2021-03-09 13:48 ` [PATCH v6 07/12] x86/paravirt: remove no longer needed 32-bit pvops cruft Juergen Gross
2021-03-09 13:48 ` [PATCH v6 08/12] x86/paravirt: simplify paravirt macros Juergen Gross
2021-03-09 13:48 ` [PATCH v6 09/12] x86/paravirt: switch iret pvops to ALTERNATIVE Juergen Gross
2021-03-09 13:48 ` [PATCH v6 10/12] x86/paravirt: add new macros PVOP_ALT* supporting pvops in ALTERNATIVEs Juergen Gross
2021-03-09 13:48 ` [PATCH v6 11/12] x86/paravirt: switch functions with custom code to ALTERNATIVE Juergen Gross
2021-03-09 13:48 ` [PATCH v6 12/12] x86/paravirt: have only one paravirt patch function Juergen Gross
2021-03-09 16:06 ` [PATCH v6 13/12] x86/alternative: merge include files Juergen Gross
2021-03-09 16:06 ` [PATCH v6 14/12] x86/alternative: don't open code ALTERNATIVE_TERNARY() in _static_cpu_has() Juergen Gross
2021-03-11 12:50 ` [PATCH v6 00/12] x86: major paravirt cleanup Borislav Petkov
2021-03-11 12:51 ` Borislav Petkov
2021-03-11 13:09 ` Jürgen Groß
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