Messages in this thread | | | From | "Pallipadi, Venkatesh" <> | Date | Thu, 23 Oct 2008 21:13:57 -0700 | Subject | RE: [RFC] remap_pfn_range: store vm_pgoff for all linear_over_vma_region mappings |
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>-----Original Message----- >From: Nick Piggin [mailto:npiggin@suse.de] >Sent: Thursday, October 23, 2008 6:08 PM >To: Pallipadi, Venkatesh >Cc: hugh@veritas.com; apkm@linux-os.sc.intel.com; Ingo Molnar; >linux-kernel >Subject: Re: [RFC] remap_pfn_range: store vm_pgoff for all >linear_over_vma_region mappings > >On Thu, Oct 23, 2008 at 03:09:14PM -0700, Venki Pallipadi wrote: >> >> While working on x86 PAT, we are having some hurdles with tracking >> remap_pfn_range() regions, as later we do not have any >information to say >> whether that PFNMAP mapping is linear for the entire vma range or >> it is smaller granularity regions within the vma. >> >> A simple solution to this is to use vm_pgoff as an indicator for >> linear mapping over the vma region. Currently, remap_pfn_range >> only sets vm_pgoff only for COW mappings. Below patch changes the >> logic and sets the vm_pgoff irrespective of COW. >> >> >From our understanding of the code, this should not break anyone. >> Just sending it as an RFC to get feedback on whether it is OK to do >> something like this or are there any corner cases that we may >> break or watch out for. >> >> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> >> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> > >Hmm, I can'tthink of why it would break, but I would like to see an >entire patch. Obviously you won't try to decode this vma stuff >directly from the PAT code, but just call mm helpers... ? >
Yes. We are thinking of it as a call similar to is_cow_mapping(). May be is_linear_vma_mapping() or something like that. We should have the rest of the patches by next week.
Thanks, Venki
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