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Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-
From: |
Jamie Lokier |
Subject: |
Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets |
Date: |
Mon, 10 Nov 2008 08:02:34 +0000 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
andrzej zaborowski wrote:
> Hi,
>
> 2008/11/1 Kirill A. Shutemov <address@hidden>:
> > On Sat, Nov 01, 2008 at 04:51:10PM +0000, Jamie Lokier wrote:
> >> Kirill A. Shutemov wrote:
> >> > + /* Unmap and try again with new page */
> >> > + munmap(ptr, size);
> >> > addr += qemu_host_page_size;
> >>
> >> Won't this be rather slow if it has to skip a large mapped area, one
> >> page at a time?
> >
> > If we skip more than one page we increase memory fragmentation.
>
> This approach makes sense, however the iterating over all pages may
> indeed have performance consequences, plus it would be great if people
> who better know linux-user/ than me commented. I'll assume that
> everyone is happy with this otherwise.
Just briefly to mention that binary search using shorter
probe-mappings can eliminate the page-by-page iteration in this case,
but alas I don't have time in this email to explain how :-)
-- Jamie
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Jamie Lokier, 2008/11/01
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Kirill A. Shutemov, 2008/11/01
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, andrzej zaborowski, 2008/11/09
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Kirill A. Shutemov, 2008/11/10
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets,
Jamie Lokier <=
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, andrzej zaborowski, 2008/11/10
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Kirill A. Shutemov, 2008/11/10
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Jamie Lokier, 2008/11/10
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Kirill A. Shutemov, 2008/11/14
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Paul Brook, 2008/11/14
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Jamie Lokier, 2008/11/14
- Re: [Qemu-devel] [PATCH, v2] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets, Kirill A. Shutemov, 2008/11/14