On Fri, 22 Feb 2013, Ric Mason wrote: > > What's the root reason merge_across_nodes setting just can be changed only > when there are no ksm shared pages in system? Simplicity. Why add code (moving nodes from tree to tree, handling the collisions) for a rare case that doesn't need to be fast? > Can they be unmerged and merged again during ksmd scan? That's more or less what happens, isn't it? Perhaps you're asking why the admin has to echo 2 >run; echo 0 >merge; echo 1 >run instead of that all happening automatically inside the echo 0 > merge? If I'd implemented it myself, I might have chosen to do it that way; but neither I nor other reviewers felt strongly enough to change that, though we could do so. Hugh -- 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>