From: Marcelo Tosatti <mtosatti@redhat.com>
To: Glauber Costa <glommer@parallels.com>
Cc: kvm@vger.kernel.org, johnstul@us.ibm.com, jeremy@goop.org,
zamsden@gmail.com, gleb@redhat.com, avi@redhat.com,
pbonzini@redhat.com
Subject: Re: [patch 12/18] x86: vdso: pvclock gettime support
Date: Wed, 31 Oct 2012 01:16:59 -0200 [thread overview]
Message-ID: <20121031031659.GB9913@amt.cnet> (raw)
In-Reply-To: <508F8693.9050503@parallels.com>
On Tue, Oct 30, 2012 at 11:49:39AM +0400, Glauber Costa wrote:
> On 10/29/2012 10:42 PM, Marcelo Tosatti wrote:
> > On Mon, Oct 29, 2012 at 06:59:35PM +0400, Glauber Costa wrote:
> >> On 10/24/2012 05:13 PM, Marcelo Tosatti wrote:
> >>> Improve performance of time system calls when using Linux pvclock,
> >>> by reading time info from fixmap visible copy of pvclock data.
> >>>
> >>> Originally from Jeremy Fitzhardinge.
> >>>
> >>> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> >>>
> >>> Index: vsyscall/arch/x86/vdso/vclock_gettime.c
> >>> ===================================================================
> >>> --- vsyscall.orig/arch/x86/vdso/vclock_gettime.c
> >>> +++ vsyscall/arch/x86/vdso/vclock_gettime.c
> >>> @@ -22,6 +22,7 @@
> >>> #include <asm/hpet.h>
> >>> #include <asm/unistd.h>
> >>> #include <asm/io.h>
> >>> +#include <asm/pvclock.h>
> >>>
> >>> #define gtod (&VVAR(vsyscall_gtod_data))
> >>>
> >>> @@ -62,6 +63,69 @@ static notrace cycle_t vread_hpet(void)
> >>> return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + 0xf0);
> >>> }
> >>>
> >>> +#ifdef CONFIG_PARAVIRT_CLOCK_VSYSCALL
> >>> +
> >>> +static notrace const struct pvclock_vsyscall_time_info *get_pvti(int cpu)
> >>> +{
> >>> + const aligned_pvti_t *pvti_base;
> >>> + int idx = cpu / (PAGE_SIZE/PVTI_SIZE);
> >>> + int offset = cpu % (PAGE_SIZE/PVTI_SIZE);
> >>> +
> >>> + BUG_ON(PVCLOCK_FIXMAP_BEGIN + idx > PVCLOCK_FIXMAP_END);
> >>> +
> >>> + pvti_base = (aligned_pvti_t *)__fix_to_virt(PVCLOCK_FIXMAP_BEGIN+idx);
> >>> +
> >>> + return &pvti_base[offset].info;
> >>> +}
> >>> +
> >>
> >> Unless I am missing something, if gcc decides to not inline get_pvti,
> >> this will break, right? I believe you need to mark that function with
> >> __always_inline.
> >
> > Can't see why. Please enlighten me.
> >
>
> I can be wrong, I don't deal with this vdso code for quite a while - so
> forgive me if my memory tricked me.
>
> But wasn't it the case that vdso functions could not call functions in
> the kernel address space outside the mapped page? Or does this
> restriction only apply to accessing data?
Only code in the vdso page is executed, but this particular function is
in the vdso so its fine.
next prev parent reply other threads:[~2012-10-31 3:27 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-24 13:13 [patch 00/18] pvclock vsyscall support + KVM hypervisor support (v2) Marcelo Tosatti
2012-10-24 13:13 ` [patch 01/18] KVM: x86: retain pvclock guest stopped bit in guest memory Marcelo Tosatti
2012-10-24 13:13 ` [patch 02/18] x86: pvclock: make sure rdtsc doesnt speculate out of region Marcelo Tosatti
2012-10-24 13:13 ` [patch 03/18] x86: pvclock: remove pvclock_shadow_time Marcelo Tosatti
2012-10-30 9:23 ` Avi Kivity
2012-10-30 9:24 ` Avi Kivity
2012-10-24 13:13 ` [patch 04/18] x86: pvclock: create helper for pvclock data retrieval Marcelo Tosatti
2012-10-24 13:13 ` [patch 05/18] x86: pvclock: fix flags usage race Marcelo Tosatti
2012-10-24 13:13 ` [patch 06/18] x86: pvclock: introduce helper to read flags Marcelo Tosatti
2012-10-24 13:13 ` [patch 07/18] sched: add notifier for cross-cpu migrations Marcelo Tosatti
2012-10-24 13:13 ` [patch 08/18] x86: pvclock: generic pvclock vsyscall initialization Marcelo Tosatti
2012-10-29 14:18 ` Glauber Costa
2012-10-29 14:54 ` Marcelo Tosatti
2012-10-29 17:46 ` Jeremy Fitzhardinge
2012-10-29 14:39 ` Glauber Costa
2012-10-24 13:13 ` [patch 09/18] KVM: x86: introduce facility to support vsyscall pvclock, via MSR Marcelo Tosatti
2012-10-29 14:45 ` Glauber Costa
2012-10-29 17:44 ` Jeremy Fitzhardinge
2012-10-29 18:40 ` Marcelo Tosatti
2012-10-30 7:41 ` Glauber Costa
2012-10-30 9:39 ` Avi Kivity
2012-10-31 3:12 ` Marcelo Tosatti
2012-11-02 10:21 ` Glauber Costa
2012-10-30 7:38 ` Glauber Costa
2012-10-24 13:13 ` [patch 10/18] x86: kvm guest: pvclock vsyscall support Marcelo Tosatti
2012-10-24 13:13 ` [patch 11/18] x86: vsyscall: pass mode to gettime backend Marcelo Tosatti
2012-10-29 14:47 ` Glauber Costa
2012-10-29 18:41 ` Marcelo Tosatti
2012-10-30 7:42 ` Glauber Costa
2012-10-24 13:13 ` [patch 12/18] x86: vdso: pvclock gettime support Marcelo Tosatti
2012-10-29 14:59 ` Glauber Costa
2012-10-29 18:42 ` Marcelo Tosatti
2012-10-30 7:49 ` Glauber Costa
2012-10-31 3:16 ` Marcelo Tosatti [this message]
2012-10-24 13:13 ` [patch 13/18] KVM: x86: pass host_tsc to read_l1_tsc Marcelo Tosatti
2012-10-29 15:04 ` Glauber Costa
2012-10-29 18:45 ` Marcelo Tosatti
2012-10-30 7:55 ` Glauber Costa
2012-10-24 13:13 ` [patch 14/18] time: export time information for KVM pvclock Marcelo Tosatti
2012-11-10 1:02 ` John Stultz
2012-11-13 21:07 ` Marcelo Tosatti
2012-10-24 13:13 ` [patch 15/18] KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag Marcelo Tosatti
2012-10-30 8:34 ` Glauber Costa
2012-10-31 3:19 ` [patch 15/18] KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag\ Marcelo Tosatti
2012-10-24 13:13 ` [patch 16/18] KVM: x86: notifier for clocksource changes Marcelo Tosatti
2012-10-24 13:13 ` [patch 17/18] KVM: x86: add kvm_arch_vcpu_postcreate callback, move TSC initialization Marcelo Tosatti
2012-10-24 13:13 ` [patch 18/18] KVM: x86: require matched TSC offsets for master clock Marcelo Tosatti
2012-10-31 22:46 ` [patch 00/16] pvclock vsyscall support + KVM hypervisor support (v3) Marcelo Tosatti
2012-10-31 22:46 ` [patch 01/16] KVM: x86: retain pvclock guest stopped bit in guest memory Marcelo Tosatti
2012-11-01 10:39 ` Gleb Natapov
2012-11-01 20:51 ` Marcelo Tosatti
2012-11-01 13:44 ` Glauber Costa
2012-10-31 22:46 ` [patch 02/16] x86: pvclock: make sure rdtsc doesnt speculate out of region Marcelo Tosatti
2012-11-01 11:48 ` Gleb Natapov
2012-11-01 13:49 ` Glauber Costa
2012-11-01 13:51 ` Gleb Natapov
2012-11-01 20:56 ` Marcelo Tosatti
2012-11-01 22:13 ` Gleb Natapov
2012-11-01 22:21 ` Marcelo Tosatti
2012-11-02 6:02 ` Gleb Natapov
2012-10-31 22:46 ` [patch 03/16] x86: pvclock: remove pvclock_shadow_time Marcelo Tosatti
2012-11-01 13:52 ` Glauber Costa
2012-10-31 22:47 ` [patch 04/16] x86: pvclock: create helper for pvclock data retrieval Marcelo Tosatti
2012-11-01 14:04 ` Glauber Costa
2012-11-01 20:57 ` Marcelo Tosatti
2012-10-31 22:47 ` [patch 05/16] x86: pvclock: introduce helper to read flags Marcelo Tosatti
2012-11-01 14:07 ` Glauber Costa
2012-11-01 21:08 ` Marcelo Tosatti
2012-10-31 22:47 ` [patch 06/16] sched: add notifier for cross-cpu migrations Marcelo Tosatti
2012-11-01 14:08 ` Glauber Costa
2012-10-31 22:47 ` [patch 07/16] x86: pvclock: generic pvclock vsyscall initialization Marcelo Tosatti
2012-11-01 14:19 ` Glauber Costa
2012-10-31 22:47 ` [patch 08/16] KVM: x86: introduce facility to support vsyscall pvclock, via MSR Marcelo Tosatti
2012-11-01 14:28 ` Glauber Costa
2012-11-01 21:39 ` Marcelo Tosatti
2012-11-02 10:23 ` Glauber Costa
2012-11-02 13:00 ` Marcelo Tosatti
2012-11-05 8:03 ` Glauber Costa
2012-10-31 22:47 ` [patch 09/16] x86: kvm guest: pvclock vsyscall support Marcelo Tosatti
2012-11-02 9:42 ` Glauber Costa
2012-11-05 8:35 ` Marcelo Tosatti
2012-10-31 22:47 ` [patch 10/16] x86: vdso: pvclock gettime support Marcelo Tosatti
2012-11-01 14:41 ` Glauber Costa
2012-11-01 21:42 ` Marcelo Tosatti
2012-11-02 0:33 ` Marcelo Tosatti
2012-11-02 10:25 ` Glauber Costa
2012-11-14 10:42 ` Gleb Natapov
2012-11-14 22:42 ` Marcelo Tosatti
2012-10-31 22:47 ` [patch 11/16] KVM: x86: pass host_tsc to read_l1_tsc Marcelo Tosatti
2012-10-31 22:47 ` [patch 12/16] time: export time information for KVM pvclock Marcelo Tosatti
2012-10-31 22:47 ` [patch 13/16] KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag Marcelo Tosatti
2012-10-31 22:47 ` [patch 14/16] KVM: x86: notifier for clocksource changes Marcelo Tosatti
2012-10-31 22:47 ` [patch 15/16] KVM: x86: add kvm_arch_vcpu_postcreate callback, move TSC initialization Marcelo Tosatti
2012-10-31 22:47 ` [patch 16/16] KVM: x86: require matched TSC offsets for master clock Marcelo Tosatti
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