Rod Evans wrote:
> Roland Mainz wrote:
> > Offtopic: "truss" knows about |mmap()| flags and translates them to
> > ASCII text but |mmapobj()| flags are only shown as hexadecimal values...
> > should I file a RFE for that ?
>
> Yes, please do.
Done, see CR #6861993 ('"truss" does not understand flags used by
mmapobj(2)') ...
> > I don't want to assume any fixed address space location... my question
> > is more which kind of optimisations are done and how the kernel is
> > involved... for example does the kernel reserve a certain chunk of
> > address space for such libraries (e.g. for 64bit applications reserve
> > 0x0400000000000000-0x0500000000000000 to make sure it can map libc&co.
> > across all 64bit processes into the same locations to reduce MMU
> > overhead (e.g. that MMU entries can be shared between processes)) ?
>
> This is really a question for the VM (kernel) folks.
CC:'ing on-discuss at opensolaris.org to get some feedback from them...
> The point of mmapobj() was to remove all mapping requests from
> ld.so.1, and have the kernel do "what's best". Now, what is
> best is probably still being determined. The use of large pages,
> the same mapping for frequently used objects, etc. etc. are
> all decisions that the VM can make based on it's knowledge of
> the platform, the file being mapped and the size of the mappings
> required.
Ok...
> What's being done right now, is probably not very different to
> the mappings that ld.so.1 has achieved before, but again, the
> VM folks would know. There are VM projects underway, and these
> projects can now implement mmapobj() to their advantage.
Ok...
... is any of these projects already active or is this still "planning
only" ?
----
Bye,
Roland
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