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Re: [Qemu-devel] [PATCH] exec: limit system memory size
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] exec: limit system memory size |
Date: |
Mon, 04 Nov 2013 12:22:35 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130923 Thunderbird/17.0.9 |
Il 04/11/2013 12:14, Michael S. Tsirkin ha scritto:
>> >
>> > This patch looks good; however, on top of it can you test
>> > kvm-unit-tests with TARGET_PHYS_ADDR_SPACE_BITS=64 and see whether
>> > there is a measurable slowdown (in the inl_from_qemu tests)? If not,
>> > we can just get rid of TARGET_PHYS_ADDR_SPACE_BITS in exec.c.
> I'd rather we fixed a bug first - we need to fix it on stable too - any
> cleanups can come on top.
This is not necessarily a cleanup. Getting rid of
TARGET_PHYS_ADDR_SPACE_BITS in exec.c means fixing device-to-device DMA
bugs for example.
Of course a smaller patch can be done that avoids the renaming of L2_*
constants.
> Also, I'm not sure what will this test tell
> us: inl reads io space, not memory, right?
The number of levels in the dispatch radix tree is independent of the
size of the AddressSpace; it is P_L2_LEVELS for both the 64K io space
and the 2^TARGET_PHYS_ADDRESS_SPACE_BITS memory space.
Paolo
Re: [Qemu-devel] [PATCH] exec: limit system memory size, Paolo Bonzini, 2013/11/04