On Mon, Aug 12, 2013 at 03:28:06PM -0700, Andy Lutomirski wrote: > > > > You could have #undefed _mfrob and __frob after using them, but whatever. Sure, for some reason I forgot to do that. Will send update on top. > > I saved this patch to wave at the x86 guys for 3.12. I plan to merge > > mm-save-soft-dirty-bits-on-file-pages.patch for 3.11. > > > >> Guys, is there a reason for "if _PAGE_BIT_FILE < _PAGE_BIT_PROTNONE" > >> test present in this pgtable-2level.h file at all? I can't imagine > >> where it can be false on x86. > > > > I doubt if "Guys" read this. x86 maintainers cc'ed. Thanks! > > +#define _mfrob(v,r,m,l) ((((v) >> (r)) & (m)) << (l)) > > +#define __frob(v,r,l) (((v) >> (r)) << (l)) > > + > > #ifdef CONFIG_MEM_SOFT_DIRTY > > If I'm understanding this right, the idea is to take the bits in the > range a..b of v and stick them at c..d, where a-b == c-d. Would it > make sense to change this to look something like > > #define __frob(v, inmsb, inlsb, outlsb) ((v >> inlsb) & ((1<<(inmsb - > inlsb + 1)-1) << outlsb) There is a case when you don't need a mask completely. And because this pte conversion is on hot path and time critical I kept generated code as it was (even if that lead to slightly less clear source code). > For extra fun, there could be an __unfrob macro that takes the same > inmsg, inlsb, outlsb parameters but undoes it so that it's (more) > clear that the operations that are supposed to be inverses are indeed > inverses. -- 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>