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Re: [Qemu-devel] [RFC PATCH 0/8] MemoryRegion and FlatView refcounting,
From: |
liu ping fan |
Subject: |
Re: [Qemu-devel] [RFC PATCH 0/8] MemoryRegion and FlatView refcounting, replace hostmem with memory_region_find |
Date: |
Wed, 8 May 2013 14:20:04 +0800 |
On Mon, May 6, 2013 at 10:25 PM, Paolo Bonzini <address@hidden> wrote:
> Hi,
>
> this is an alternative approach to refactoring of dataplane's HostMem
> code. Here, I take Ping Fan's idea of RCU-style updating of the
> region list and apply it to the AddressSpace's FlatView. With this
In fact, I am worrying about the priority of MemoryListener, if it is
true, then we should drop RCU-style idea. Also if it is true, there is
already a bug with hostmem listener. It should use region_del, not
region_nop to reconstruct the local view. But just let me have a deep
thinking.
Regards,
Pingfan
> change, dataplane can simply use memory_region_find instead of
> hostmem.
>
> This is a somewhat larger change, but I prefer it for two reasons.
>
> 1) it splits the task of adding BQL-less memory dispatch in two parts,
> tacking memory_region_find first (which is simpler because locking
> is left to the caller).
>
> 2) HostMem duplicates a lot of the FlatView logic, and adding the
> RCU-style update in FlatView benefits everyone.
>
> The missing ingredients here are:
>
> 1) remember and unreference the MemoryRegions that are used in
> a vring entry. In order to implement this, it is probably simpler
> to change vring.c to use virtio.c's VirtQueueElement data structure.
> We want something like that anyway in order to support migration.
>
> 2) add an owner field to MemoryRegion, and set it for all MemoryRegions
> for hot-unpluggable devices. In this series, ref/unref are stubs.
>
> For simplicity I based the patches on my IOMMU rebase. I placed the
> tree at git://github.com/bonzini/qemu.git, branch iommu.
>
> Paolo
>
> Paolo Bonzini (8):
> memory: add ref/unref calls
> exec: check MRU in qemu_ram_addr_from_host
> memory: return MemoryRegion from qemu_ram_addr_from_host
> memory: ref/unref memory across address_space_map/unmap
> memory: access FlatView from a local variable
> memory: use a new FlatView pointer on every topology update
> memory: add reference counting to FlatView
> dataplane: replace hostmem with memory_region_find
>
> exec.c | 63 +++++++++---
> hw/core/loader.c | 1 +
> hw/display/exynos4210_fimd.c | 6 +
> hw/display/framebuffer.c | 10 +-
> hw/i386/kvm/ioapic.c | 2 +
> hw/i386/kvmvapic.c | 1 +
> hw/misc/vfio.c | 2 +
> hw/virtio/dataplane/Makefile.objs | 2 +-
> hw/virtio/dataplane/hostmem.c | 176
> ---------------------------------
> hw/virtio/dataplane/vring.c | 56 +++++++++--
> hw/virtio/vhost.c | 2 +
> hw/virtio/virtio-balloon.c | 1 +
> hw/xen/xen_pt.c | 4 +
> include/exec/cpu-common.h | 2 +-
> include/exec/memory.h | 9 ++
> include/hw/virtio/dataplane/hostmem.h | 57 -----------
> include/hw/virtio/dataplane/vring.h | 3 +-
> kvm-all.c | 2 +
> memory.c | 142 +++++++++++++++++++++-----
> target-arm/kvm.c | 2 +
> target-i386/kvm.c | 4 +-
> target-sparc/mmu_helper.c | 1 +
> xen-all.c | 2 +
> 23 files changed, 253 insertions(+), 297 deletions(-)
> delete mode 100644 hw/virtio/dataplane/hostmem.c
> delete mode 100644 include/hw/virtio/dataplane/hostmem.h
>
- [Qemu-devel] [RFC PATCH 0/8] MemoryRegion and FlatView refcounting, replace hostmem with memory_region_find, Paolo Bonzini, 2013/05/06
- [Qemu-devel] [RFC PATCH 2/8] exec: check MRU in qemu_ram_addr_from_host, Paolo Bonzini, 2013/05/06
- [Qemu-devel] [RFC PATCH 1/8] memory: add ref/unref calls, Paolo Bonzini, 2013/05/06
- [Qemu-devel] [RFC PATCH 4/8] memory: ref/unref memory across address_space_map/unmap, Paolo Bonzini, 2013/05/06
- [Qemu-devel] [RFC PATCH 3/8] memory: return MemoryRegion from qemu_ram_addr_from_host, Paolo Bonzini, 2013/05/06
- [Qemu-devel] [RFC PATCH 5/8] memory: access FlatView from a local variable, Paolo Bonzini, 2013/05/06
- [Qemu-devel] [RFC PATCH 6/8] memory: use a new FlatView pointer on every topology update, Paolo Bonzini, 2013/05/06
- [Qemu-devel] [RFC PATCH 7/8] memory: add reference counting to FlatView, Paolo Bonzini, 2013/05/06
- [Qemu-devel] [RFC PATCH 8/8] dataplane: replace hostmem with memory_region_find, Paolo Bonzini, 2013/05/06
- Re: [Qemu-devel] [RFC PATCH 0/8] MemoryRegion and FlatView refcounting, replace hostmem with memory_region_find,
liu ping fan <=
Re: [Qemu-devel] [RFC PATCH 0/8] MemoryRegion and FlatView refcounting, replace hostmem with memory_region_find, Stefan Hajnoczi, 2013/05/08
Re: [Qemu-devel] [RFC PATCH 0/8] MemoryRegion and FlatView refcounting, replace hostmem with memory_region_find, Stefan Hajnoczi, 2013/05/08