> (1) You really don't want to migrate the code pages of shared libraries > that are mapped into the process address space. This causes a > useless shuffling of pages which really doesn't help system > performance. On the other hand, if a shared library is some > private thing that is only used by the processes being migrated, > then you should move that.
I think the better solution for this would be to finally integrate Steve L.'s file attribute code (and find some solution to make it persistent, e.g. using xattrs with a new inode flag) and then "lock" the shared libraries to their policy using a new attribute flag. > > (2) You really only want to migrate pages once. If a file is mapped > into several of the pid's that are being migrated, then you want > to figure this out and issue one call to have it moved wrt one of > the pid's. > (The page migration code from the memory hotplug patch will handle > updating the pte's of the other processs (thank goodness for > rmap...)) I don't get this. Surely the migration code will check if a page is already in the target node, and when that is the case do nothing. How could this "double migration" happen? > > (3) In the case where a particular file is mapped into different > processes at different file offsets (and we are migrating both > of the processes), one has to examine the file offsets to figure > out if the mappings overlap or not. If they overlap, then you've > got to issue two calls, each of which describes a non-overlapping > region; both calls taken together would cover the entire range > of pages mapped to the file. Similarly if the ranges do not > overlap. That sounds like a quite obscure corner case which I'm not sure is worth all the complexity. -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
