From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: [PATCH 06/21] xenpaging: print info when free request slots drop below 2 Date: Fri, 26 Nov 2010 14:49:07 +0100 Message-ID: <20101126134903.463930315@aepfle.de> References: <20101126134901.384130351@aepfle.de> Return-path: Content-Disposition: inline; filename=xen-unstable.xenpaging.mem_event_check_ring-free_requests.patch List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org 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. Signed-off-by: Olaf Hering --- xen/arch/x86/mm/mem_event.c | 5 +++++ 1 file changed, 5 insertions(+) --- xen-unstable.hg-4.1.22433.orig/xen/arch/x86/mm/mem_event.c +++ xen-unstable.hg-4.1.22433/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 )