Dave Hansen wrote: > On Mon, 2009-08-24 at 23:51 +0200, Toon Moene wrote: >> [ I found this e-mail address while surfing http://linux-mm.org - >> hope it's relevant. ] >> >> Is it possible to boot the Linux kernel in such a way as to *only* >> enable "huge" pages ? > > Possible, ever? Yes. > > But, it's not something that anyone has actually implemented in Linux or > given that much thought to. If someone were to do this, they would > probably have to take the existing pagetable code and basically shift > everything down a level. Get rid of the pud level on x86_64, and > collapse it into the pmd. Then, take the existing pmd pages, and use > them like pte pages. Then, go and fix up all the places where a 2MB > base page breaks x86 for random reasons, or where people assume that > they need N pages instead of N*PAGE_SIZE bytes. > > It might be fun and entertaining, but it would be a lot of work. There > are lots of little things that would break like the hard-coded 4k-page > early boot pagetables. That's not even *considering* what it would do > to userspace. Userspace would probably freak out pretty badly.
Thanks for both of your answers (David Gibson's was shorter, but related the same rationale ;-) The days of OS kernel hacking are 20 years behind me now, but I see that it is not as simple as Solaris' "you just compile with -xpagesize=4M". OK, that just means I have to concentrate on other optimization paths. Thanks, -- Toon Moene - e-mail: t...@moene.org - phone: +31 346 214290 Saturnushof 14, 3738 XG Maartensdijk, The Netherlands At home: http://moene.org/~toon/ Progress of GNU Fortran: http://gcc.gnu.org/gcc-4.5/changes.html ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Libhugetlbfs-devel mailing list Libhugetlbfs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libhugetlbfs-devel
