Messages in this thread | | | Subject | Re: [PATCH v11 4/6] mm: function to offer a page block on the free list | From | Rik van Riel <> | Date | Tue, 20 Jun 2017 12:44:09 -0400 |
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On Mon, 2017-06-12 at 07:10 -0700, Dave Hansen wrote:
> The hypervisor is going to throw away the contents of these pages, > right? As soon as the spinlock is released, someone can allocate a > page, and put good data in it. What keeps the hypervisor from > throwing > away good data?
That looks like it may be the wrong API, then?
We already have hooks called arch_free_page and arch_alloc_page in the VM, which are called when pages are freed, and allocated, respectively.
Nitesh Lal (on the CC list) is working on a way to efficiently batch recently freed pages for free page hinting to the hypervisor.
If that is done efficiently enough (eg. with MADV_FREE on the hypervisor side for lazy freeing, and lazy later re-use of the pages), do we still need the harder to use batch interface from this patch?
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