From: Ian Campbell Date: Tue, 1 Dec 2009 11:47:15 +0000 (+0000) Subject: xen: explicitly create/destroy stop_machine workqueues outside suspend/resume region. X-Git-Tag: v2.6.33-rc1~327^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b4606f2165153833247823e8c04c5e88cb3d298b;p=pandora-kernel.git xen: explicitly create/destroy stop_machine workqueues outside suspend/resume region. I have observed cases where the implicit stop_machine_destroy() done by stop_machine() hangs while destroying the workqueues, specifically in kthread_stop(). This seems to be because timer ticks are not restarted until after stop_machine() returns. Fortunately stop_machine provides a facility to pre-create/post-destroy the workqueues so use this to ensure that workqueues are only destroyed after everything is really up and running again. I only actually observed this failure with 2.6.30. It seems that newer kernels are somehow more robust against doing kthread_stop() without timer interrupts (I tried some backports of some likely looking candidates but did not track down the commit which added this robustness). However this change seems like a reasonable belt&braces thing to do. Signed-off-by: Ian Campbell Signed-off-by: Jeremy Fitzhardinge Cc: Stable Kernel --- Reading git-diff-tree failed