Subject: xenpaging: print info when free request slots drop below 2 Add debugging aid to free request slots in the ring buffer. It should not happen that the ring gets full, print info anyway if it happens. (xen-unstable changeset: 22439:3bbb3969236c) Signed-off-by: Olaf Hering --- xen/arch/x86/mm/mem_event.c | 5 +++++ 1 file changed, 5 insertions(+) Index: xen-4.0.2-testing/xen/arch/x86/mm/mem_event.c =================================================================== --- xen-4.0.2-testing.orig/xen/arch/x86/mm/mem_event.c +++ xen-4.0.2-testing/xen/arch/x86/mm/mem_event.c @@ -152,6 +152,11 @@ int mem_event_check_ring(struct domain * mem_event_ring_lock(d); free_requests = RING_FREE_REQUESTS(&d->mem_event.front_ring); + if ( unlikely(free_requests < 2) ) + { + gdprintk(XENLOG_INFO, "free request slots: %d\n", free_requests); + WARN_ON(free_requests == 0); + } ring_full = free_requests < MEM_EVENT_RING_THRESHOLD; if ( (curr->domain->domain_id == d->domain_id) && ring_full )