Hi, For some reason, I want to write protect a special page, but I don't know how to set it as read-only. I am reading the book "Understanding The Linux Virtual Memory Manager". In section 5.6.4, there is saying: "During fork, the PTEs of the two processes are made read-only so that when a write occurs there will be a page fault. Linux recognises a COW page because even though the PTE is write protected, the controlling VMA shows the region is writable." My question is, if I really want write protect a page, say, I don't want a copy-on-write happens, I just hope the page is really read-only, can I achieve that by setting "the controlling VMA" as non-writable? Or how to do that? Thank you! Regards Jidong -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>