On Thu, 2007-09-20 at 15:36 -0700, Andrew Morton wrote:
The lockup I'm seeing intermittently occurs when I have 2+ tasks copying
large files (1Gb+) on sda & a small read-mainly mysql db app running on
sdb. The lockup seems to happen just after the copies finish -- there
are lots of dirty pages but nothing left to write them until kupdate
gets round to it.
BTW kupdate can loop for long periods of time when a disk is under this
kind of load -- I regularly see it take over 20 seconds. and often it's
unable to start as there are no pdflush threads available.
No there doesn't seem to be any activity at all -- my machine is
completely unresponsive only sysrq works.
I'm not able to run anything in this state, but sysrq-s doesn't make any