Messages in this thread | | | Date | Sat, 4 Jan 2014 07:31:43 +0000 | From | Minchan Kim <> | Subject | Re: [RFC PATCHv3 00/11] Intermix Lowmem and vmalloc |
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Hello,
On Fri, Jan 03, 2014 at 02:08:52PM -0800, Laura Abbott wrote: > On 1/3/2014 10:23 AM, Dave Hansen wrote: > >On 01/02/2014 01:53 PM, Laura Abbott wrote: > >>The goal here is to allow as much lowmem to be mapped as if the block of memory > >>was not reserved from the physical lowmem region. Previously, we had been > >>hacking up the direct virt <-> phys translation to ignore a large region of > >>memory. This did not scale for multiple holes of memory however. > > > >How much lowmem do these holes end up eating up in practice, ballpark? > >I'm curious how painful this is going to get. > > > > In total, the worst case can be close to 100M with an average case > around 70M-80M. The split and number of holes vary with the layout > but end up with 60M-80M one hole and the rest in the other.
One more thing I'd like to know is how bad direct virt <->phys tranlsation in scale POV and how often virt<->phys tranlsation is called in your worload so what's the gain from this patch?
Thanks.
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