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Re: [Qemu-devel] [PATCH 06/15] postcopy: Record largest page size
From: |
Juan Quintela |
Subject: |
Re: [Qemu-devel] [PATCH 06/15] postcopy: Record largest page size |
Date: |
Mon, 30 Jan 2017 20:22:03 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) |
"Dr. David Alan Gilbert" <address@hidden> wrote:
> * Juan Quintela (address@hidden) wrote:
>> "Dr. David Alan Gilbert (git)" <address@hidden> wrote:
>> > From: "Dr. David Alan Gilbert" <address@hidden>
>> >
>> > Record the largest page size in use; we'll need it soon for allocating
>> > temporary buffers.
>> >
>> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
>>
>> Not that I object, but .... could we store this in ram_list, and update it
>> it at RAMBlock creation time? Why searh for the value later when we can
>> store it from the beggining. Instead of putting it on migration_state,
>> put it on the ram_list itself?
>>
>
> We could, but the code does get quite a bit more complicated for little gain,
> given that we currently read it exactly once.
> The update at creation time would be easier, but then you have to also
> update at deletion time and that has to run along the list just like this.
> (or cache based on the ram_list.version)
As I am so lazy, I would only update it at creation time, and never at
deletion time. But I can see that some people could object. Anyways it
don't matter a lot, it is used only once, and on the other hand, we
don't care a lot if we have a bit bigger than needed buffer. Just a
case of taste I guess.
Later, Juan.
- Re: [Qemu-devel] [PATCH 05/15] postcopy: enhance ram_discard_range for hugepages, (continued)
[Qemu-devel] [PATCH 04/15] Fold postcopy_ram_discard_range into ram_discard_range, Dr. David Alan Gilbert (git), 2017/01/06
[Qemu-devel] [PATCH 03/15] postcopy: Chunk discards for hugepages, Dr. David Alan Gilbert (git), 2017/01/06
[Qemu-devel] [PATCH 06/15] postcopy: Record largest page size, Dr. David Alan Gilbert (git), 2017/01/06
[Qemu-devel] [PATCH 08/15] postcopy: Use temporary for placing zero huge pages, Dr. David Alan Gilbert (git), 2017/01/06
[Qemu-devel] [PATCH 07/15] postcopy: Plumb pagesize down into place helpers, Dr. David Alan Gilbert (git), 2017/01/06
[Qemu-devel] [PATCH 09/15] postcopy: Load huge pages in one go, Dr. David Alan Gilbert (git), 2017/01/06
[Qemu-devel] [PATCH 10/15] postcopy: Mask fault addresses to huge page boundary, Dr. David Alan Gilbert (git), 2017/01/06
[Qemu-devel] [PATCH 11/15] postcopy: Send whole huge pages, Dr. David Alan Gilbert (git), 2017/01/06