On Sun, 7 Oct 2001, Linus Torvalds wrote:
> > I just noticed that when reading from an umounted block device, the pages
> > are not cached between runs, i.e. the cache is dropped on close(). If the
> > block device contains a mounted filesystem, the pages are not dropped.
> > Is this intentional?
Actually, they are dropped as soon as there's no openers left. mounted
fs counts as opener, so does opened file.
> It's intentional, although something that can probably be discussed. The
> reasons for it are:
> - devices with broken or unreliable disk change mechanisms
> - the current dynamic [de-]allocation of block device data structures.
> - historical coherency reasons.
- current logics for driver use count. Block ones do MOD_INC_US_COUNT
on->open() and MOD_DEC_USE_COUNT on ->release().
-
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This archive was generated by hypermail 2b29 : Sun Oct 07 2001 - 21:00:45 EST