On 10/22/2014 10:30 AM, Dominik Dingel wrote: > As use_skey is already the condition on which we call s390_enable_skey > we need to introduce a new flag for the mm->context on which we decide > if zero page mapping is allowed. Can you explain better why "mm->context.use_skey = 1" cannot be done before the walk_page_range? Where does the walk or __s390_enable_skey or (after the next patch) ksm_madvise rely on "mm->context.forbids_zeropage && !mm->context.use_skey"? The only reason I can think of, is that the next patch does not reset "mm->context.forbids_zeropage" to 0 if the ksm_madvise fails. Why doesn't it do that---or is it a bug? Thanks, and sorry for the flurry of questions! :) Paolo -- 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>