Messages in this thread | | | Date | Mon, 28 Jul 2014 19:14:56 +0100 | From | Will Deacon <> | Subject | Re: [PATCH 2/2] ARM: LPAE: reduce damage caused by idmap to virtual memory layout |
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On Tue, Jul 22, 2014 at 04:36:35PM +0100, Konstantin Khlebnikov wrote: > idmap layout combines both phisical and virtual addresses. > Everything works fine if ram physically lays below PAGE_OFFSET. > Otherwise idmap starts punching huge holes in virtual memory layout. > It maps ram by 2MiB sections, but when it allocates new pmd page it > cuts 1GiB at once. > > This patch makes a copy of all affected pmds from init_mm. > Only few (usually one) 2MiB sections will be lost. > This is not eliminates problem but makes it 512 times less likely.
I'm struggling to understand your commit message, but making a problem `512 times less likely' does sound like a bit of a hack to me. Can't we fix this properly instead?
Will
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