On Fri, Oct 26, 2001 at 06:35:02PM +0100, Alan Cox wrote:
> > Does this mean the ac tree now uses the AA VM, or is this a merge
> > with everything but the VM, like the earlier 2.4.1x-ac trees?
>
> It still uses buffer cache based raw disk access (so things like DVD players
btw, AFIK the fact dvd player can hang some millisecond across a
close/open cycle, isn't really because of the blkdev in pagecache but
simply because the <2.4.10 buffer cache layer wasn't able to do proper
readahead on the blkdev. Now we do readahead properly and so in turn
the the lack of media-change trust of the vfs shows up. So as far I can
tell the right fix have no influence on the blkdev in pagecache, but it
only consists in resurrecting the media-change detection with a
per-device bitflag whitelist. I cannot see other source of stalls across
a close/open cycle.
Andrea
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This archive was generated by hypermail 2b29 : Wed Oct 31 2001 - 21:00:31 EST