Messages in this thread | | | Subject | Re: [PATCH 2/3] make new alloc_pages_exact() | From | Dave Hansen <> | Date | Thu, 28 Apr 2011 09:02:57 -0700 |
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On Wed, 2011-04-27 at 16:42 -0500, Timur Tabi wrote: > Dave Hansen wrote: > >> Is there an easy way to verify that alloc_pages_exact(5MB) really does allocate > >> > only 5MB and not 8MB? > > > I'm not sure why you're asking. How do we know that the _normal_ > > allocator only gives us 4k when we ask for 4k? Well, that's just how it > > works. If alloc_pages_exact() returns success, you know it's got the > > amount of memory that you asked for, and only that plus a bit of masking > > for page alignment. > > > > Have you seen alloc_pages_exact() behaving in some other way? > > I've never tested this part of alloc_pages_exact(), even when I wrote (the first > version of) it. I just took it on faith that it actually did what it was > supposed to do.
I did actually go add a bunch of printks to it at one point. It did seem to be working just fine and freeing the right amount of memory.
-- Dave
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