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authorJuergen Gross <jgross@suse.com>2021-10-05 16:34:33 +0300
committerJuergen Gross <jgross@suse.com>2021-10-06 08:45:00 +0300
commit319933a80fd4f07122466a77f93e5019d71be74c (patch)
tree8d38777d006804051d157f800ee1844813286b2b /drivers/xen
parent9c11112c0ec7ec322cd495320c3ab9fa8bdc1bbc (diff)
downloadlinux-319933a80fd4f07122466a77f93e5019d71be74c.tar.xz
xen/balloon: fix cancelled balloon action
In case a ballooning action is cancelled the new kernel thread handling the ballooning might end up in a busy loop. Fix that by handling the cancelled action gracefully. While at it introduce a short wait for the BP_WAIT case. Cc: stable@vger.kernel.org Fixes: 8480ed9c2bbd56 ("xen/balloon: use a kernel thread instead a workqueue") Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Jason Andryuk <jandryuk@gmail.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20211005133433.32008-1-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/balloon.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 43ebfe36ac27..3a50f097ed3e 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -491,12 +491,12 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
}
/*
- * Stop waiting if either state is not BP_EAGAIN and ballooning action is
- * needed, or if the credit has changed while state is BP_EAGAIN.
+ * Stop waiting if either state is BP_DONE and ballooning action is
+ * needed, or if the credit has changed while state is not BP_DONE.
*/
static bool balloon_thread_cond(enum bp_state state, long credit)
{
- if (state != BP_EAGAIN)
+ if (state == BP_DONE)
credit = 0;
return current_credit() != credit || kthread_should_stop();
@@ -516,10 +516,19 @@ static int balloon_thread(void *unused)
set_freezable();
for (;;) {
- if (state == BP_EAGAIN)
- timeout = balloon_stats.schedule_delay * HZ;
- else
+ switch (state) {
+ case BP_DONE:
+ case BP_ECANCELED:
timeout = 3600 * HZ;
+ break;
+ case BP_EAGAIN:
+ timeout = balloon_stats.schedule_delay * HZ;
+ break;
+ case BP_WAIT:
+ timeout = HZ;
+ break;
+ }
+
credit = current_credit();
wait_event_freezable_timeout(balloon_thread_wq,