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Re: [Qemu-devel] [PATCH 7/9] pc: acpi: drop not needed intermediate bitm
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH 7/9] pc: acpi: drop not needed intermediate bitmap cpu->found_cpus |
Date: |
Fri, 5 Feb 2016 17:44:49 +0100 |
On Fri, 5 Feb 2016 17:19:50 +0100
Igor Mammedov <address@hidden> wrote:
> On Fri, 5 Feb 2016 13:39:07 -0200
> Eduardo Habkost <address@hidden> wrote:
>
> > On Thu, Feb 04, 2016 at 12:47:33PM +0100, Igor Mammedov wrote:
> > > cpu->found_cpus bitmap is used for setting present
> > > flag in CPON AML package at start up. But it takes
> > > a bunch of code to fill bitmap and cloud be simplified
> > > by calling qemu_get_cpu_by_arch_id(apic_id) directly.
> > >
> > > Hence do so and remove not used anymore bitmap
> > > with related utilities, which saves us ~32LOC
> > > and also would simplify consolidating APCI parts
> > > of CPU hotplug.
> > >
> > > Signed-off-by: Igor Mammedov <address@hidden>
> >
> > This makes the code loops through all smp_cpus CPUs max_cpus
> > times, instead of just looping through the smp_cpus CPUs once.
> Yep, that looks bad.
> I'll redo it using possible_cpu_arch_ids(), it is a little
> bit bigger refactoring.
I think I'll make bitmap local to build_processor_devices() as it's
needed only for building CPON package, that way it will go along
with related legacy hotplug and won't get in the way of new hotplug.
>
> >
> > I'm all for making the code simpler, and there's an upper bound:
> > looking at CPU objects 64k times (because MAX_CPUMASK_BITS is
> > 255). But I want to make sure we agree this is an optimization we
> > want to drop.
> >
>
>
- [Qemu-devel] [PATCH 3/9] pc: acpi: cleanup qdev_get_machine() calls, (continued)
[Qemu-devel] [PATCH 7/9] pc: acpi: drop not needed intermediate bitmap cpu->found_cpus, Igor Mammedov, 2016/02/04
[Qemu-devel] [PATCH 8/9] pc: move apic_id_limit to PCMachineState, Igor Mammedov, 2016/02/04
[Qemu-devel] [PATCH 9/9] pc: acpi: clarify why possible LAPIC entries must be present in MADT, Igor Mammedov, 2016/02/04
[Qemu-devel] [PATCH 1/9] cpu: rename cpu_exists() to qemu_get_cpu_by_arch_id(), Igor Mammedov, 2016/02/04