From 0d16f75ded6be36f19c71a9aed64efdaf450579e Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Fri, 26 Nov 2010 14:22:11 +0000 Subject: [PATCH] xenpaging: optimize p2m_mem_paging_populate p2m_mem_paging_populate will always put another request in the ring. To reduce pressure on the ring, place only required requests in the ring. If the gfn was already processed by another thread, and the current vcpu does not need to be paused, p2m_mem_paging_resume will do nothing with the request. And also xenpaging will drop the request if the vcpu does not need a wakeup. Signed-off-by: Olaf Hering --- xen/arch/x86/mm/p2m.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c index d7da4ad1f2..9620866ef3 100644 --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -2757,12 +2757,12 @@ void p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn) p2m_type_t p2mt; struct domain *d = p2m->domain; - memset(&req, 0, sizeof(req)); - /* Check that there's space on the ring for this request */ if ( mem_event_check_ring(d) ) return; + memset(&req, 0, sizeof(req)); + /* Fix p2m mapping */ /* XXX: It seems inefficient to have this here, as it's only needed * in one case (ept guest accessing paging out page) */ @@ -2781,6 +2781,11 @@ void p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn) vcpu_pause_nosync(v); req.flags |= MEM_EVENT_FLAG_VCPU_PAUSED; } + else if ( p2mt != p2m_ram_paging_out && p2mt != p2m_ram_paged ) + { + /* gfn is already on its way back and vcpu is not paused */ + return; + } /* Send request to pager */ req.gfn = gfn; -- 2.30.2