David Gibson <dwg@xxxxxxxxxxx> writes: > On Tue, Apr 30, 2013 at 09:12:09AM +0530, Aneesh Kumar K.V wrote: >> David Gibson <dwg@xxxxxxxxxxx> writes: >> >> > On Mon, Apr 29, 2013 at 01:07:22AM +0530, Aneesh Kumar K.V wrote: >> >> From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> >> >> >> >> On archs like powerpc that support different hugepage sizes, HPAGE_SHIFT >> >> and other derived values like HPAGE_PMD_ORDER are not constants. So move >> >> that to hugepage_init >> > >> > These seems to miss the point. Those variables may be defined in >> > terms of HPAGE_SHIFT right now, but that is of itself kind of broken. >> > The transparent hugepage mechanism only works if the hugepage size is >> > equal to the PMD size - and PMD_SHIFT remains a compile time constant. >> > >> > There's no reason having transparent hugepage should force the PMD >> > size of hugepage to be the default for other purposes - it should be >> > possible to do THP as long as PMD-sized is a possible hugepage size. >> > >> >> THP code does >> >> #define HPAGE_PMD_SHIFT HPAGE_SHIFT >> #define HPAGE_PMD_MASK HPAGE_MASK >> #define HPAGE_PMD_SIZE HPAGE_SIZE >> >> I had two options, one to move all those in terms of PMD_SHIFT > > This is a much better option that you've taken now, and really > shouldn't be that hard. The THP code is much more strongly tied to > the fact that it is a PMD than the fact that it's the same size as > explicit huge pages. > Ok I tried the above and that turned out to be much simpler. I will have to make sure i didn't break other archs that support THP. -aneesh -- 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>