migrate_pages internals: lazy copy

[Karaoui mohamed lamine]

Hi Vladis,

Thanks for this response.
I was trying to use the Clavis scheduler: http://clavis.sourceforge.net/
In this scheduler they go through an important effort to migrate only
currently used pages of a thread (using AMD IBS hardware counters). This
could be implemented more neatly using page tables at the kernel level...

Regards,


2018-01-19 14:26 GMT-05:00 <valdis.kletnieks at vt.edu>:

> On Fri, 19 Jan 2018 13:57:18 -0500, Karaoui mohamed lamine said:
> >
> > Does the "migrate_pages" syscall migrate memory pages in a *lazy* manner?
> > if not, is there another syscall or patch that does it?
>
> man 2 migrate_pages says:
>
> RETURN VALUE
>        On  success  migrate_pages() returns the number of pages that could
> not be moved (i.e., a return of zero means
>        that all pages were successfully moved).  On error, it returns -1,
> and sets errno to indicate the error.
>
> which implies that it doesn't return until an attempt has been made to
> migrate all relevant
> pages. And that rules out lazy migration.
>
> What problem are you trying to solve by doing it in a lazy manner?
>
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