Messages in this thread |  | | Date | Tue, 7 Nov 2017 09:55:47 -0600 (CST) | | From | Christopher Lameter <> | | Subject | Re: [PATCH RFC v2 4/4] mm/mempolicy: add nodes_empty check in SYSC_migrate_pages |
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On Tue, 7 Nov 2017, Vlastimil Babka wrote:
> > Migrate pages moves the pages of a single process there is no TARGET > > process. > > migrate_pages(2) takes a pid argument > > "migrate_pages() attempts to move all pages of the process pid that > are in memory nodes old_nodes to the memory nodes in new_nodes. "
Ok missed that. Most use cases here are on the current process.
Fundamentally a process can have shared pages outside of the cpuset that a process is restricted to. Thus I would think that migration to any of the allowed nodes of the current process that is calling migrate pages is ok. The caller wants this and the caller has a right to allocate on these nodes. It would be strange if migrate_pages would allow allocation outside of the current cpuset.
> > Thus thehe *target* nodes need to be a subset of the current cpu set.
And therefore the above still holds.
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