Messages in this thread | | | Date | Thu, 08 Apr 2004 10:05:42 -0700 | From | "Martin J. Bligh" <> | Subject | Re: NUMA API for Linux |
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> On Wed, 7 Apr 2004, Andrew Morton wrote: >> >> Your patch takes the CONFIG_NUMA vma from 64 bytes to 68. It would be nice >> to pull those 4 bytes back somehow. > > How significant is this vma size issue? > > anon_vma objrmap will add 20 bytes to each vma (on 32-bit arches): > 8 for prio_tree, 12 for anon_vma linkage in vma, > sometimes another 12 for the anon_vma head itself.
Ewwww. Isn't some of that shared most of the time though?
> anonmm objrmap adds just the 8 bytes for prio_tree, > remaining overhead 28 bytes per mm.
28 bytes per *mm* is nothing, and I still think the prio_tree is completely unneccesary. Nobody has ever demonstrated a real benchmark that needs it, as far as I recall.
> Seems hard on Andi to begrudge him 4.
I don't care about the 4 bytes much (other than that the current 64 happens to be a nice size). I just don't see the point in making copies of the binding structure all the time ;-) Refcounts aren't that hard ... didn't Greg do a kref just recently? ...
M.
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