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SubjectRe: how mmap() works?
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On Sun, Apr 01, 2001 at 03:28:05PM -0500, Tim Hockin wrote:
> > Without syncing, Linux writes whenever it thinks it's appropriate, e.g.
> > when pages have to be freed (I think also when the bdflush writes back
> > data, i.e. every 30 seconds by default).
>
> what about mmap() on non-filesystem files (/dev/mem, /proc/bus/pci...) ?

They map physically present memory directly and do not have to be
synced, since all writes go directly to their destination (which is of
course not possible with disk files). I'm not that sure if PCI is a bit
special case though, since not all architectures can access it like
memory.

--
Andreas E. Bombe <andreas.bombe@munich.netsurf.de> DSA key 0x04880A44
http://home.pages.de/~andreas.bombe/ http://linux1394.sourceforge.net/
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