On Wed, Feb 19, 2014 at 07:46:41PM -0800, David Rientjes wrote: > On Wed, 19 Feb 2014, Marcelo Tosatti wrote: > > > We agree that, in the future, we'd like to provide the ability to > > dynamically allocate and free 1GB pages at runtime. > > > > Extending the kernel command line interface is a first step. > > > > Do you have a concrete objection to that first step ? > > > > Yes, my concrete objection is that the command line interface is > unnecessary if you can dynamically allocate and free 1GB pages at runtime > unless memory will be so fragmented that it cannot be done when userspace > is brought up. That is not your use case, thus this support is not > needed. I think Mel also brought up this point. > > There's no "first step" about it, this is unnecessary for your use case if > you can do it at runtime. I'm not sure what's so surprising about this. > > > > You can't specify an interleave behavior with Luiz's command line > > > interface so now we'd have two different interfaces for allocating > > > hugepage sizes depending on whether you're specifying a node or not. > > > It's "hugepagesz=1G hugepages=16" vs "hugepage_node=1:16:1G" (and I'd have > > > to look at previous messages in this thread to see if that means 16 1GB > > > pages on node 1 or 1 1GB pages on node 16.) > > > > What syntax do you prefer and why ? > > > > I'm not sure it's interesting to talk about since this patchset is > unnecessary if you can do it at runtime, but since "hugepagesz=" and > "hugepages=" have existed for many kernel releases, we must maintain > backwards compatibility. Thus, it seems, the easiest addition would have > been "hugepagesnode=" which I've mentioned several times, there's no > reason to implement yet another command line option purely as a shorthand > which hugepage_node=1:2:1G is and in a very cryptic way. There is one point from Davidlohr Bueso in favour of the proposed command line interface. Did you consider that aspect? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>