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Re: [Qemu-devel] [PATCH 06/15] exec: use mmap for subpages
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 06/15] exec: use mmap for subpages |
Date: |
Tue, 28 Jun 2016 12:48:15 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 28/06/2016 11:01, Peter Lieven wrote:
> a lot of subpages are created and freed at startup, but RCU delays
> the freeing so the heap gets fragmented.
>
> Signed-off-by: Peter Lieven <address@hidden>
I agree that subpages are bad for malloc because they are large (>
4KiB). It is worth doing something special about them. However, on
32-bit systems mmap-ing them has the same risk of fragmenting the
process address space, as malloc has of fragmenting the brk heap.
Allocation and freeing of subpages always happens under the BQL, so
perhaps a simple freelist is better? Another interesting (but harder)
possibility could be to build the radix tree lazily.
Paolo
- Re: [Qemu-devel] [PATCH 07/15] qapi: use mmap for QmpInputVisitor, (continued)
- [Qemu-devel] [PATCH 10/15] vmware_svga: use mmap for scratch pad, Peter Lieven, 2016/06/28
- [Qemu-devel] [PATCH 04/15] coroutine: add a knob to disable the shared release pool, Peter Lieven, 2016/06/28
- [Qemu-devel] [PATCH 05/15] util: add a helper to mmap private anonymous memory, Peter Lieven, 2016/06/28
- [Qemu-devel] [PATCH 06/15] exec: use mmap for subpages, Peter Lieven, 2016/06/28
- Re: [Qemu-devel] [PATCH 06/15] exec: use mmap for subpages,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Paolo Bonzini, 2016/06/28
- Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Peter Lieven, 2016/06/28
- Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Paolo Bonzini, 2016/06/28
- Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Peter Lieven, 2016/06/28
- Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Paolo Bonzini, 2016/06/28
- Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Dr. David Alan Gilbert, 2016/06/28
- Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Peter Lieven, 2016/06/28
- Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Peter Lieven, 2016/06/28