On Thu, 9 Aug 2007 11:59:43 +0200 Matthias Hensler <email@example.com> wrote:
Did we ever see the /proc/meminfo and /proc/vmstat output during the stall?
If Richard's patch has indeed fixed it then this confirms that we're seeing
contention over the dirty-memory limits. Richard's patch isn't really the
right one because it allows unlimited dirty-memory windup in some situations
(large number of disks with small writes, or when we perform queue congestion
As you're seeing this happening when multiple disks are being written to it is
possible that the per-device-dirty-threshold patches which recently went into
-mm (and which appear to have a bug) will fix it.
But I worry that the stall appears to persist *forever*. That would indicate
that we have a dirty-memory accounting leak, or that for some reason the
system has decided to stop doing writeback to one or more queues (might be
caused by an error in a lower-level driver's queue congestion state management).
If it is the latter, then it could be that running "sync" will clear the
problem. Temporarily, at least. Because sync will ignore the queue congestion