From: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
To: Nick Piggin <npiggin@suse.de>
Cc: "hugh@veritas.com" <hugh@veritas.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: RE: [RFC] remap_pfn_range: store vm_pgoff for all linear_over_vma_region mappings
Date: Thu, 23 Oct 2008 21:13:57 -0700 [thread overview]
Message-ID: <7E82351C108FA840AB1866AC776AEC4637DDFA48@orsmsx505.amr.corp.intel.com> (raw)
In-Reply-To: <20081024010803.GB5004@wotan.suse.de>
>-----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
prev parent reply other threads:[~2008-10-24 4:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-23 22:09 [RFC] remap_pfn_range: store vm_pgoff for all linear_over_vma_region mappings Venki Pallipadi
2008-10-23 22:43 ` Venki Pallipadi
2008-10-24 1:08 ` Nick Piggin
2008-10-24 4:13 ` Pallipadi, Venkatesh [this message]
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