From 228ab9992ffb1d8f9d2475f2581e68b2913acb88 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 15 Dec 2017 11:17:19 +0100 Subject: [PATCH] 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 Reviewed-by: Andrew Cooper --- xen/common/domain.c | 12 ++++++++++-- xen/common/domctl.c | 5 ++++- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/xen/common/domain.c b/xen/common/domain.c index 7484693a87..7af8d12512 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -615,13 +615,21 @@ 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); diff --git a/xen/common/domctl.c b/xen/common/domctl.c index 3c6fa4ec67..50f74221fa 100644 --- a/xen/common/domctl.c +++ b/xen/common/domctl.c @@ -665,11 +665,14 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl) 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: { -- 2.30.2