On Wednesday 10 October 2007 00:52, Linus Torvalds wrote: > On Tue, 9 Oct 2007, Nick Piggin wrote: > > I have done some tests which indicate a couple of very basic common tools > > don't do much zero-page activity (ie. kbuild). And also combined with > > some logical arguments to say that a "sane" app wouldn't be using > > zero_page much. (basically -- if the app cares about memory or cache > > footprint and is using many pages of zeroes, then it should have a more > > compressed representation of zeroes anyway). > > One of the things that zero-page has been used for is absolutely *huge* > (but sparse) arrays in Fortan programs. > > At least in traditional fortran, it was very hard to do dynamic > allocations, so people would allocate the *maximum* array statically, and > then not necessarily use everything. I don't know if the pages ever even > got paged in,
In which case, they would not be using the ZERO_PAGE? If they were paging in (ie. reading) huge reams of zeroes, then maybe their algorithms aren't so good anyway? (I don't know). > but this is the kind of usage which is *not* insane. Yeah, that's why I use the double quotes... I wonder how to find out, though. I guess I could ask SGI if they could ask around -- but that still comes back to the problem of not being able to ever conclusively show that there are no real users of the ZERO_PAGE. Where do you suggest I go from here? Is there any way I can convince you to try it? Make it a config option? (just kidding) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
