Messages in this thread | | | Date | Thu, 22 Jan 2015 11:22:39 -0500 | From | Rik van Riel <> | Subject | Re: [PATCH] mm, vmacache: Add kconfig VMACACHE_SHIFT |
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On 01/22/2015 11:19 AM, Davidlohr Bueso wrote: > On Thu, 2015-01-22 at 15:57 +0800, WANG Chao wrote: >> Hi, Davidlohr >> >> On 01/21/15 at 11:46pm, Davidlohr Bueso wrote: >>> On Thu, 2015-01-22 at 14:29 +0800, WANG Chao wrote: >>>> Add a new kconfig option VMACACHE_SHIFT (as a power of 2) to specify the >>>> number of slots vma cache has for each thread. Range is chosen 0-4 (1-16 >>>> slots) to consider both overhead and performance penalty. Default is 2 >>>> (4 slots) as it originally is, which provides good enough balance. >>>> >>> >>> Nack. I don't feel comfortable making scalability features of core code >>> configurable. >> >> Out of respect, is this a general rule not making scalability features >> of core code configurable? > > I doubt its a rule, just common sense. Users have no business > configuring such low level details. The optimizations need to > transparently work for everyone.
There may sometimes be a good reason for making this kind of thing configurable, but since there were no performance numbers in the changelog, I have not seen any such reason for this particular change :)
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