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From: Paolo Bonzini <pbonzini@redhat.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added
Date: Tue, 19 Sep 2017 16:23:13 +0200	[thread overview]
Message-ID: <89a582f4-e4b8-a8ae-8e8e-2fa83e1fd31d@redhat.com> (raw)
In-Reply-To: <2f185edf-3281-e01f-5859-cc43a5df413e@ozlabs.ru>

On 19/09/2017 16:12, Alexey Kardashevskiy wrote:
>>> What is the exact concern about the "[PATCH qemu v3 01/13] memory: Postpone
>>> flatview and dispatch tree building till all devices are added"? Is it that
>>> you missed that modern AS thing in virtio and thought we can do well even
>>> without it?
>> I am afraid that some of the special sysbus devices (not PCI, those go
>> through the bus master DMA region and it's empty on startup) might write
>> to memory during initialization.
> 
> And somehow QEMU guarantees that all RAM MRs are rendered to FlatViews even
> though some might be added via -device (can they btw?)?

I don't know, but as discussed on IRC, I think this is a pretty
different change from the rest of the series---which should have zero
change except for going faster---so I'd prefer to keep it out for now
and see where optimization can get us.

Paolo

  reply	other threads:[~2017-09-19 14:23 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-18 10:16 [Qemu-devel] [PATCH qemu v3 00/13] memory: Reduce memory use Alexey Kardashevskiy
2017-09-18 10:16 ` [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added Alexey Kardashevskiy
2017-09-18 14:54   ` Paolo Bonzini
2017-09-19  2:09     ` Alexey Kardashevskiy
2017-09-19  6:57       ` Alexey Kardashevskiy
2017-09-19  7:40         ` Paolo Bonzini
2017-09-19  7:57           ` Alexey Kardashevskiy
2017-09-19  7:59             ` Paolo Bonzini
2017-09-19  7:42         ` Paolo Bonzini
2017-09-19 10:39           ` Alexey Kardashevskiy
2017-09-19 10:47             ` Paolo Bonzini
2017-09-19 14:12               ` Alexey Kardashevskiy
2017-09-19 14:23                 ` Paolo Bonzini [this message]
2017-09-18 10:16 ` [Qemu-devel] [PATCH qemu v3 02/13] exec: Explicitely export target AS from address_space_translate_internal Alexey Kardashevskiy
2017-09-18 14:28   ` Eric Blake
2017-09-19  0:15     ` Alexey Kardashevskiy
2017-09-18 10:16 ` [Qemu-devel] [PATCH qemu v3 03/13] memory: Open code FlatView rendering Alexey Kardashevskiy
2017-09-18 14:28   ` Eric Blake
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 04/13] memory: Move FlatView allocation to a helper Alexey Kardashevskiy
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 05/13] memory: Move AddressSpaceDispatch from AddressSpace to FlatView Alexey Kardashevskiy
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 06/13] memory: Remove AddressSpace pointer from AddressSpaceDispatch Alexey Kardashevskiy
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 07/13] memory: Switch memory from using AddressSpace to FlatView Alexey Kardashevskiy
2017-09-18 14:06   ` Alexey Kardashevskiy
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 08/13] memory: Cleanup after switching " Alexey Kardashevskiy
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 09/13] memory: Rename mem_begin/mem_commit/mem_add helpers Alexey Kardashevskiy
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 10/13] memory: Store physical root MR in FlatView Alexey Kardashevskiy
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 11/13] memory: Share FlatView's and dispatch trees between address spaces Alexey Kardashevskiy
2017-09-18 14:37   ` Paolo Bonzini
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 12/13] memory: Get rid of address_space_init_shareable Alexey Kardashevskiy
2017-09-18 10:17 ` [Qemu-devel] [PATCH qemu v3 13/13] memory: Add flat views to HMP "info mtree" Alexey Kardashevskiy
2017-09-18 10:36 ` [Qemu-devel] [PATCH qemu v3 00/13] memory: Reduce memory use no-reply
2017-09-18 14:59 ` Paolo Bonzini
2017-09-19  0:19   ` Alexey Kardashevskiy

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