Messages in this thread | | | Date | Fri, 21 Apr 2006 09:41:57 +0200 | From | Nick Piggin <> | Subject | Re: [patch 1/5] mm: remap_vmalloc_range |
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On Fri, Apr 21, 2006 at 12:29:38AM -0700, Andrew Morton wrote: > > When replacing calls to remap_pfn_rage() with calls to remap_valloc_range(): > > - remap_pfn_range() sets VM_IO|VM_RESERVED|VM_PFNMAP on the user's vma. > remap_valloc_range() sets only VM_RESERVED.
Yep, it doesn't use PFNMAPs (we can always user the underlying struct page), nor is it IO space. The only change that should be seen, as noted in patch 4/5, is that get_user_pages will work on all mappings now. I don't think there is a downside to this?
> > - remap_pfn_range() has special handling for COWable user vma's, but > remap_valloc_range() does not.
That's only for PFNMAPs. COW should continue to work fine.
> > - are vma->vm_start and vma->vm_end always a multiple of PAGE_SIZE? (I > always forget). If not, remap_valloc_range() looks a tad buggy.
I hope so.
> > > pls explain. > > > - remap_valloc_range() can use ~PAGE_MASK, not PAGE_SIZE-1
I initially did that when coding the function in mm/memory.c, but when adding all the vmalloc range checking I tried to stick with vmalloc convention.
> > - remap_valloc_range() would lose a whole buncha typecasts if you use the > gcc pointer-arith-with-void* extension.
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