[Xen-devel] [PATCH 08/17] xenpaging: make vcpu_sleep_nosync() optional in mem_event_check_ring()

[Olaf Hering <olaf@xxxxxxxxx>]

Add a new option to mem_event_check_ring() to disable the
vcpu_sleep_nosync. This is needed for an upcoming patch which sends a
one-way request to the pager.

Also add a micro-optimization, check ring_full first because its value
was just evaluated.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>

---
 xen/arch/x86/mm/mem_event.c     |    4 ++--
 xen/arch/x86/mm/mem_sharing.c   |    2 +-
 xen/arch/x86/mm/p2m.c           |    2 +-
 xen/include/asm-x86/mem_event.h |    2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

--- xen-unstable.hg-4.1.22459.orig/xen/arch/x86/mm/mem_event.c
+++ xen-unstable.hg-4.1.22459/xen/arch/x86/mm/mem_event.c
@@ -143,7 +143,7 @@ void mem_event_unpause_vcpus(struct doma
             vcpu_wake(v);
 }
 
-int mem_event_check_ring(struct domain *d)
+int mem_event_check_ring(struct domain *d, int do_vcpu_sleep)
 {
     struct vcpu *curr = current;
     int free_requests;
@@ -159,7 +159,7 @@ int mem_event_check_ring(struct domain *
     }
     ring_full = free_requests < MEM_EVENT_RING_THRESHOLD;
 
-    if ( (curr->domain->domain_id == d->domain_id) && ring_full )
+    if ( ring_full && do_vcpu_sleep && (curr->domain->domain_id == 
d->domain_id) )
     {
         set_bit(_VPF_mem_event, &curr->pause_flags);
         vcpu_sleep_nosync(curr);
--- xen-unstable.hg-4.1.22459.orig/xen/arch/x86/mm/mem_sharing.c
+++ xen-unstable.hg-4.1.22459/xen/arch/x86/mm/mem_sharing.c
@@ -321,7 +321,7 @@ static struct page_info* mem_sharing_all
     }
         
     /* XXX: Need to reserve a request, not just check the ring! */
-    if(mem_event_check_ring(d)) return page;
+    if(mem_event_check_ring(d, 1)) return page;
 
     req.flags |= MEM_EVENT_FLAG_OUT_OF_MEM;
     req.gfn = gfn;
--- xen-unstable.hg-4.1.22459.orig/xen/arch/x86/mm/p2m.c
+++ xen-unstable.hg-4.1.22459/xen/arch/x86/mm/p2m.c
@@ -2758,7 +2758,7 @@ void p2m_mem_paging_populate(struct p2m_
     struct domain *d = p2m->domain;
 
     /* Check that there's space on the ring for this request */
-    if ( mem_event_check_ring(d) )
+    if ( mem_event_check_ring(d, 1) )
         return;
 
     memset(&req, 0, sizeof(req));
--- xen-unstable.hg-4.1.22459.orig/xen/include/asm-x86/mem_event.h
+++ xen-unstable.hg-4.1.22459/xen/include/asm-x86/mem_event.h
@@ -24,7 +24,7 @@
 #ifndef __MEM_EVENT_H__
 #define __MEM_EVENT_H__
 
-int mem_event_check_ring(struct domain *d);
+int mem_event_check_ring(struct domain *d, int do_vcpu_sleep);
 void mem_event_put_request(struct domain *d, mem_event_request_t *req);
 void mem_event_get_response(struct domain *d, mem_event_response_t *rsp);
 void mem_event_unpause_vcpus(struct domain *d);


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