On Tue, 14 Jan 2014, Dave Hansen wrote: > On 01/14/2014 12:07 PM, Christoph Lameter wrote: > > One easy way to shrink struct page is to simply remove the feature. The > > patchset looked a bit complicated and does many other things. > > Sure. There's a clear path if you only care about 'struct page' size, > or if you only care about making the slub fast path as fast as possible. > We've got three variables, though: > > 1. slub fast path speed The fast path does use this_cpu_cmpxchg_double which is something different from a cmpxchg_double and its not used on struct page. > Arranged in three basic choices: > > 1. Big 'struct page', fast, medium complexity code > 2. Small 'struct page', slow, lowest complexity The numbers that I see seem to indicate that a big struct page means slow. > The question is what we should do by _default_, and what we should be > recommending for our customers via the distros. Are you saying that you > think we should completely rule out even having option 1 in mainline? If option 1 is slower than option 2 then we do not need it. -- 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>