From: Steven Smith <ssmith@weybridge.uk.xensource.com>
Date: Wed, 26 Aug 2009 14:43:51 +0000 (+0100)
Subject: Batch vmq unmap grant operations.
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=refs%2Fheads%2Fnapi-plus-vmdq;p=people%2Fssmith%2Fnc2-2.6.27.git

Batch vmq unmap grant operations.

Signed-off-by: Jose Renato Santos <jsantos@hpl.hp.com>
---

diff --git a/drivers/xen/netchannel2/chan.c b/drivers/xen/netchannel2/chan.c
index 98a1f908..185f6221 100644
--- a/drivers/xen/netchannel2/chan.c
+++ b/drivers/xen/netchannel2/chan.c
@@ -894,10 +894,13 @@ static int process_ring(struct napi_struct *napi,
                    This must happen before we flush the rings, since
                    that's when the PACKET messages will be made
                    visible to the other end. */
-                if (ncrp == &nc->rings)
+                if (ncrp == &nc->rings) {
                         flush_hypercall_batcher(&nc->batcher,
                                                 nc2_posted_on_gntcopy_fail);
-
+#ifdef CONFIG_XEN_NETDEV2_VMQ
+			vmq_flush_unmap_hypercall();
+#endif
+		}
                 flush_rings(ncrp);
 
                 while ((skb = __skb_dequeue(&ncrp->release_on_flush_batcher))){
diff --git a/drivers/xen/netchannel2/vmq.c b/drivers/xen/netchannel2/vmq.c
index 6ef65393..39b07b59 100644
--- a/drivers/xen/netchannel2/vmq.c
+++ b/drivers/xen/netchannel2/vmq.c
@@ -47,6 +47,39 @@
 #define VMQ_QUEUE_ENABLED   2
 #define VMQ_QUEUE_CLOSING   3
 
+#define VMQ_MAX_UNMAP_OPS 256
+struct vmq_unmap_grants {
+        unsigned n;
+        gnttab_unmap_grant_ref_t gop[VMQ_MAX_UNMAP_OPS];
+};
+typedef struct vmq_unmap_grants vmq_unmap_grants_t;
+
+vmq_unmap_grants_t vmq_unmap_grants;
+
+static inline void vmq_flush_unmap_grants(void)
+{
+        if (vmq_unmap_grants.n == 0)
+                return;
+
+        if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 
+				      vmq_unmap_grants.gop,
+				      vmq_unmap_grants.n))
+            BUG();
+	vmq_unmap_grants.n = 0;
+}
+
+static inline gnttab_unmap_grant_ref_t *vmq_next_unmap_gop(void)
+{
+        if (vmq_unmap_grants.n == VMQ_MAX_UNMAP_OPS)
+                vmq_flush_unmap_grants();
+        return &vmq_unmap_grants.gop[vmq_unmap_grants.n++];
+}
+
+void vmq_flush_unmap_hypercall(void)
+{
+	vmq_flush_unmap_grants();
+}
+
 static inline unsigned long vmq_idx_to_pfn(nc2_vmq_t *vmq, unsigned int idx)
 {
         return page_to_pfn(vmq->pages[idx]);
@@ -271,19 +304,18 @@ static void nc2_vmq_unmap_buf(struct netchannel2 *nc,
 {
 	nc2_vmq_t *vmq = &nc->vmq;
 	unsigned long pfn;
-	gnttab_unmap_grant_ref_t gop;
+	gnttab_unmap_grant_ref_t *gop;
 	unsigned prod;
-	int ret;
 
 	pfn = vmq_idx_to_pfn(vmq, idx);	
 	/* Already unmapped? */
 	if (!phys_to_machine_mapping_valid(pfn))
 		return;
-	gnttab_set_unmap_op(&gop, vmq_idx_to_kaddr(vmq, idx),
+
+	gop = vmq_next_unmap_gop();
+	gnttab_set_unmap_op(gop, vmq_idx_to_kaddr(vmq, idx),
 			    GNTMAP_host_map,
 			    vmq->buffer[idx].buf->grant_handle);
-	ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &gop, 1);
-	BUG_ON(ret);
 
 	vmq->nbufs--;
 
@@ -321,6 +353,8 @@ static void nc2_vmq_free_mapped_bufs(struct netchannel2 *nc)
 		nc2_vmq_unmap_buf(nc, idx, 1);
 	}
 
+	vmq_flush_unmap_grants();
+
 	vmq->mapped_pages_cons = cons;
 
 }
@@ -342,7 +376,9 @@ static void nc2_vmq_free_skb(struct sk_buff *skb)
 		idx = nc2_vmq_page_index(frags[i].page);
 		nc2_vmq_unmap_buf(nc, idx, 1);
 	}
-	
+
+	vmq_flush_unmap_grants();
+
 	shinfo->frag_list = NULL;
 	shinfo->nr_frags = 0;
 	
@@ -762,7 +798,7 @@ void xmit_vmq(struct netchannel2 *nc, struct sk_buff *skb,
 	}
 
 	/* Avoid unmapping frags grants when skb is freed later */
-	/* by nc2_vmq_fre_skb() */
+	/* by nc2_vmq_free_skb() */
 	skb_shinfo(skb)->nr_frags = 0;
 }
 
diff --git a/drivers/xen/netchannel2/vmq.h b/drivers/xen/netchannel2/vmq.h
index 0af7924e..91cba694 100644
--- a/drivers/xen/netchannel2/vmq.h
+++ b/drivers/xen/netchannel2/vmq.h
@@ -9,6 +9,7 @@ void do_vmq_work(struct netchannel2 *nc);
 int nc2_is_vmq_packet(struct netchannel2 *nc, struct sk_buff *skb);
 void xmit_vmq(struct netchannel2 *nc, struct sk_buff *skb,
               volatile void *msg);
+void vmq_flush_unmap_hypercall(void);
 
 #define vmq_get(_b)						\
 		atomic_inc(&(_b)->refcnt);