Re: [patch 1/1] MM: detach_vmas_to_be_unmapped fix

From: Andrew Morton
Date: Tue Feb 27 2007 - 15:28:26 EST


> On Fri, 23 Feb 2007 08:27:00 -0800 akuster <akuster@xxxxxxxxxx> wrote:
> Wolfgang Wander submitted a fix to address a mmap fragmentation issue.
> The git patch ( 1363c3cd8603a913a27e2995dccbd70d5312d8e6 ) is somewhat
> different and yields different results when running Wolfgang's test case
> leakme.c.
>
> IMHO, the vm start and end address are swapped in arch_unmap_area and
> arch_unmap_area_topdown functions.
>
> Prior to this patch arch_unmap_area() used area->vm_start and
> arch_unmap_area_topdown used area->vm_end in the git patch the following
> change showed up.
>
> if (mm->unmap_area == arch_unmap_area)
> addr = prev ? prev->vm_start : mm->mmap_base;
> else
> addr = vma ? vma->vm_end : mm->mmap_base;
>
> Using Wolfgang Wander's leakme.c test, I get the same results seen with
> his original "Avoiding mmap fragmentation" patch as I do after swapping
> the start & end address in the above code segment. The patch I
> submitted addresses this typo issue.

That's still not an adequate or terribly useful changlog, sorry.

Please tell us exactly what this patch does, without referring to some other
patch which I cannot remember nor presently access.

I particular, before-and-after testing results would be useful so we can
see what the effect of this change is.

Also, please send a Signed-of-by: for this work, thanks.
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