On Sun, 6 Mar 2011, Hugh Dickins wrote: > >> That was so for a long time, but I stopped it just over a year ago > >> with commit a70caa8ba48f21f46d3b4e71b6b8d14080bbd57a, stop ptlock > >> enlarging struct page. > > > > Strange. I just played around with in in January and the page struct size > > changes when I build kernels with full debugging. I have some > > cmpxchg_double patches here that depend on certain alignment in the page > > struct. Debugging causes all that stuff to get out of whack so that I had > > to do some special patches to make sure fields following the spinlock are > > properly aligned when the sizes change. > > That puzzles me, it's not my experience and I don't have an > explanation: do you have time to investigate? > > Uh oh, you're going to tell me you're working on an out-of-tree > architecture with a million cpus ;) In that case, yes, I'm afraid > I'll have to update the SPLIT_PTLOCK_CPUS defaulting (for a million - > 1 even). No I am not working on any out of tree structure. Just regular dual socket server boxes with 24 processors (which is a normal business machine configuration these days). But then there is also CONFIG_GENERIC_LOCKBREAK. That does not affect things? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>