Messages in this thread | | | Date | Fri, 22 Feb 2013 12:50:25 -0800 (PST) | From | Hugh Dickins <> | Subject | Re: [PATCH 1/7] ksm: add some comments |
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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
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