File 5a33a12f-domctl-improve-locking-during-domain-destruction.patch of Package xen.13143
References: bsc#1035442
# Commit 228ab9992ffb1d8f9d2475f2581e68b2913acb88
# Date 2017-12-15 11:17:19 +0100
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
domctl: improve locking during domain destruction
There is no need to hold the global domctl lock across domain_kill() -
the domain lock is fully sufficient here, and parallel cleanup after
multiple domains performs quite a bit better this way.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Index: xen-4.10.1-testing/xen/common/domain.c
===================================================================
--- xen-4.10.1-testing.orig/xen/common/domain.c
+++ xen-4.10.1-testing/xen/common/domain.c
@@ -619,13 +619,21 @@ int domain_kill(struct domain *d)
if ( d == current->domain )
return -EINVAL;
- /* Protected by domctl_lock. */
+ /* Protected by d->domain_lock. */
switch ( d->is_dying )
{
case DOMDYING_alive:
+ domain_unlock(d);
domain_pause(d);
+ domain_lock(d);
+ /*
+ * With the domain lock dropped, d->is_dying may have changed. Call
+ * ourselves recursively if so, which is safe as then we won't come
+ * back here.
+ */
+ if ( d->is_dying != DOMDYING_alive )
+ return domain_kill(d);
d->is_dying = DOMDYING_dying;
- spin_barrier(&d->domain_lock);
evtchn_destroy(d);
gnttab_release_mappings(d);
tmem_destroy(d->tmem_client);
Index: xen-4.10.1-testing/xen/common/domctl.c
===================================================================
--- xen-4.10.1-testing.orig/xen/common/domctl.c
+++ xen-4.10.1-testing/xen/common/domctl.c
@@ -665,11 +665,14 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xe
break;
case XEN_DOMCTL_destroydomain:
+ domctl_lock_release();
+ domain_lock(d);
ret = domain_kill(d);
+ domain_unlock(d);
if ( ret == -ERESTART )
ret = hypercall_create_continuation(
__HYPERVISOR_domctl, "h", u_domctl);
- break;
+ goto domctl_out_unlock_domonly;
case XEN_DOMCTL_setnodeaffinity:
{