search for: seq_prev

Displaying 7 results from an estimated 7 matches for "seq_prev".

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2017 Feb 17
1
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
...linutronix.de> writes: > On Wed, 15 Feb 2017, Vitaly Kuznetsov wrote: >> Actually, we already have an implementation of TSC page update in KVM >> (see arch/x86/kvm/hyperv.c, kvm_hv_setup_tsc_page()) and the update does >> the following: >> >> 0) stash seq into seq_prev >> 1) seq = 0 making all reads from the page invalid >> 2) smp_wmb() >> 3) update tsc_scale, tsc_offset >> 4) smp_wmb() >> 5) set seq = seq_prev + 1 > > I hope they handle the case where seq_prev overflows and becomes 0 :) > >> As far as I understand thi...
2017 Feb 17
1
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
...linutronix.de> writes: > On Wed, 15 Feb 2017, Vitaly Kuznetsov wrote: >> Actually, we already have an implementation of TSC page update in KVM >> (see arch/x86/kvm/hyperv.c, kvm_hv_setup_tsc_page()) and the update does >> the following: >> >> 0) stash seq into seq_prev >> 1) seq = 0 making all reads from the page invalid >> 2) smp_wmb() >> 3) update tsc_scale, tsc_offset >> 4) smp_wmb() >> 5) set seq = seq_prev + 1 > > I hope they handle the case where seq_prev overflows and becomes 0 :) > >> As far as I understand thi...
2017 Feb 15
2
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
...Hyper-V team. As we have TSC page clocksource for quite a while now and no bugs were reported there should be something. Actually, we already have an implementation of TSC page update in KVM (see arch/x86/kvm/hyperv.c, kvm_hv_setup_tsc_page()) and the update does the following: 0) stash seq into seq_prev 1) seq = 0 making all reads from the page invalid 2) smp_wmb() 3) update tsc_scale, tsc_offset 4) smp_wmb() 5) set seq = seq_prev + 1 As far as I understand this helps with situations you described above as guest will notice either invalid value of 0 or seq change. In case the implementation in re...
2017 Feb 15
2
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
...Hyper-V team. As we have TSC page clocksource for quite a while now and no bugs were reported there should be something. Actually, we already have an implementation of TSC page update in KVM (see arch/x86/kvm/hyperv.c, kvm_hv_setup_tsc_page()) and the update does the following: 0) stash seq into seq_prev 1) seq = 0 making all reads from the page invalid 2) smp_wmb() 3) update tsc_scale, tsc_offset 4) smp_wmb() 5) set seq = seq_prev + 1 As far as I understand this helps with situations you described above as guest will notice either invalid value of 0 or seq change. In case the implementation in re...
2017 Feb 16
0
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
On Wed, 15 Feb 2017, Vitaly Kuznetsov wrote: > Actually, we already have an implementation of TSC page update in KVM > (see arch/x86/kvm/hyperv.c, kvm_hv_setup_tsc_page()) and the update does > the following: > > 0) stash seq into seq_prev > 1) seq = 0 making all reads from the page invalid > 2) smp_wmb() > 3) update tsc_scale, tsc_offset > 4) smp_wmb() > 5) set seq = seq_prev + 1 I hope they handle the case where seq_prev overflows and becomes 0 :) > As far as I understand this helps with situations you describe...
2017 Feb 14
2
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
Thomas Gleixner <tglx at linutronix.de> writes: > On Tue, 14 Feb 2017, Vitaly Kuznetsov wrote: > >> Hi, >> >> while we're still waiting for a definitive ACK from Microsoft that the >> algorithm is good for SMP case (as we can't prevent the code in vdso from >> migrating between CPUs) I'd like to send v2 with some modifications to keep
2017 Feb 14
2
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
Thomas Gleixner <tglx at linutronix.de> writes: > On Tue, 14 Feb 2017, Vitaly Kuznetsov wrote: > >> Hi, >> >> while we're still waiting for a definitive ACK from Microsoft that the >> algorithm is good for SMP case (as we can't prevent the code in vdso from >> migrating between CPUs) I'd like to send v2 with some modifications to keep