Re: [PATCH] ummunotify: Userspace support for MMU notifications

From: Peter Zijlstra
Date: Tue Apr 13 2010 - 14:03:32 EST


On Tue, 2010-04-13 at 10:57 -0700, Roland Dreier wrote:
> Are those system calls the only possible way that virtual to physical
> mappings can change? Can't page migration or something like that
> potentially affect things? And even if you did have hooks into every
> system call that mattered (keep in mind that relying on glibc is not
> enough, since an MPI application may not use glibc) would decoding them
> and figuring out what happened really be preferable to a single event
> type that tells you exactly what address range was affected?

Yeah, virtual<->physical maps can change through swapping, page
migration, memory compaction, huge-page aggregation (the latter two not
yet being upstream).

Even mlock() doesn't pin virtual<->physical maps.
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