> may be some benefits in some cases, I think it's a weak justification for > always zeroing pages on free. There are much better reasons for zero on free, including the improved latency when pages are faulted in. For virtualisation there are two interfaces that would probably make more sense 1. 'This page is of no further interest, you may fault it back in as random data' 2. 'This page is discardable, if I touch it *and* you have discarded it then please serve me an exception, if you've not discarded it them give it me back" If I remember my 390 bits the S/390 goes further including the ability to say "if I think this page is in memory but in fact the hypervisor is going to page it off disc then throw me an exception so I can do clever things with the delay time" > > - finally, it can reduce infoleaks, although this is hard to measure. > > > It obscures them. Actually not. If you are doing debug work you zero on free and check for mysterious non zeroing before reusing the page. Without that its a win in the sense it wipes material (but crypto does that anyway), but it replaces that with the risk of a zeroed page being scibbled upon by the kernel and leaking kernel scribbles into allocated user pages. Alan -- 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>