diff options
| author | Ian Campbell <ian.campbell@citrix.com> | 2009-12-01 11:47:15 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-12-18 14:04:57 -0800 |
| commit | 7a0eb0721ef8015e1d17fb1cc017179eedf8cc2c (patch) | |
| tree | 6d623c7c100a147345309e7f3ff5e1ff5f48fd12 /drivers/xen | |
| parent | ebe5f3b81f1d3677882b5b1c382321096c7d1851 (diff) | |
xen: explicitly create/destroy stop_machine workqueues outside suspend/resume region.
commit b4606f2165153833247823e8c04c5e88cb3d298b upstream.
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 <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/manage.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index 2fb7d39b814..c4997930afc 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -79,6 +79,12 @@ static void do_suspend(void) shutting_down = SHUTDOWN_SUSPEND; + err = stop_machine_create(); + if (err) { + printk(KERN_ERR "xen suspend: failed to setup stop_machine %d\n", err); + goto out; + } + #ifdef CONFIG_PREEMPT /* If the kernel is preemptible, we need to freeze all the processes to prevent them from being in the middle of a pagetable update @@ -86,7 +92,7 @@ static void do_suspend(void) err = freeze_processes(); if (err) { printk(KERN_ERR "xen suspend: freeze failed %d\n", err); - goto out; + goto out_destroy_sm; } #endif @@ -129,7 +135,11 @@ out_resume: out_thaw: #ifdef CONFIG_PREEMPT thaw_processes(); + +out_destroy_sm: #endif + stop_machine_destroy(); + out: shutting_down = SHUTDOWN_INVALID; } |