Messages in this thread | | | Subject | Re: [PATCH] Physical Memory Management [0/1] | From | Peter Zijlstra <> | Date | Thu, 14 May 2009 19:10:00 +0200 |
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On Thu, 2009-05-14 at 10:07 -0700, Andrew Morton wrote: > On Thu, 14 May 2009 15:04:55 +0200 > Micha__ Nazarewicz <m.nazarewicz@samsung.com> wrote: > > > On Thu, 14 May 2009 14:05:02 +0200, Peter Zijlstra wrote: > > > And who says your pre-allocated pool won't fragment with repeated PMM > > > use? > > > > Yes, this is a good question. What's more, there's no good answer. ;) > > > > We do have capability in page reclaim to deliberately free up > physically contiguous pages (known as "lumpy reclaim"). > > It would be interesting were someone to have a go at making that > available to userspace: ask the kernel to give you 1MB of physically > contiguous memory. There are reasons why this can fail, but migrating > pages can be used to improve the success rate, and userspace can be > careful to not go nuts using mlock(), etc. > > The returned memory would of course need to be protected from other > reclaim/migration/etc activity.
I thought we already exposed this, its called hugetlbfs ;-)
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