From: Andrew Morton <akpm@linux-foundation.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/6] mm: Add vm_insert_pfn_prot
Date: Fri, 11 Dec 2015 14:33:00 -0800 [thread overview]
Message-ID: <20151211143300.0ac516fbd219a67954698f9a@linux-foundation.org> (raw)
In-Reply-To: <c35a9ff9b8ef452964adbf3d828edceff45b70a8.1449803537.git.luto@kernel.org>
On Thu, 10 Dec 2015 19:21:43 -0800 Andy Lutomirski <luto@kernel.org> wrote:
> The x86 vvar mapping contains pages with differing cacheability
> flags. This is currently only supported using (io_)remap_pfn_range,
> but those functions can't be used inside page faults.
Foggy. What does "support" mean here?
> Add vm_insert_pfn_prot to support varying cacheability within the
> same non-COW VMA in a more sane manner.
Here, "support" presumably means "insertion of pfns". Can we spell all
this out more completely please?
> x86 needs this to avoid a CRIU-breaking and memory-wasting explosion
> of VMAs when supporting userspace access to the HPET.
>
OtherwiseAck.
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next prev parent reply other threads:[~2015-12-11 22:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-11 3:21 [PATCH 0/6] mm, x86/vdso: Special IO mapping improvements Andy Lutomirski
2015-12-11 3:21 ` [PATCH 1/6] mm: Add a vm_special_mapping .fault method Andy Lutomirski
2015-12-11 22:28 ` Andrew Morton
2015-12-14 9:17 ` Ingo Molnar
2015-12-11 3:21 ` [PATCH 2/6] mm: Add vm_insert_pfn_prot Andy Lutomirski
2015-12-11 22:33 ` Andrew Morton [this message]
2015-12-11 22:44 ` Andy Lutomirski
2015-12-11 3:21 ` [PATCH 3/6] x86/vdso: Track each mm's loaded vdso image as well as its base Andy Lutomirski
2015-12-11 3:21 ` [PATCH 4/6] x86,vdso: Use .fault for the vdso text mapping Andy Lutomirski
2015-12-11 3:21 ` [PATCH 5/6] x86,vdso: Use .fault instead of remap_pfn_range for the vvar mapping Andy Lutomirski
2015-12-11 3:21 ` [PATCH 6/6] x86/vdso: Disallow vvar access to vclock IO for never-used vclocks Andy Lutomirski
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