1 files changed, 47 insertions, 122 deletions

diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
index 1b2b73ff0a6e..0d82003e76ad 100644
--- a/arch/x86/xen/multicalls.c
+++ b/arch/x86/xen/multicalls.c
@@ -30,12 +30,13 @@
 
 #define MC_BATCH	32
 
-#define MC_DEBUG	1
+#define MC_DEBUG	0
 
 #define MC_ARGS		(MC_BATCH * 16)
 
 
 struct mc_buffer {
+	unsigned mcidx, argidx, cbidx;
 	struct multicall_entry entries[MC_BATCH];
 #if MC_DEBUG
 	struct multicall_entry debug[MC_BATCH];
@@ -46,85 +47,15 @@ struct mc_buffer {
 		void (*fn)(void *);
 		void *data;
 	} callbacks[MC_BATCH];
-	unsigned mcidx, argidx, cbidx;
 };
 
 static DEFINE_PER_CPU(struct mc_buffer, mc_buffer);
 DEFINE_PER_CPU(unsigned long, xen_mc_irq_flags);
 
-/* flush reasons 0- slots, 1- args, 2- callbacks */
-enum flush_reasons
-{
-	FL_SLOTS,
-	FL_ARGS,
-	FL_CALLBACKS,
-
-	FL_N_REASONS
-};
-
-#ifdef CONFIG_XEN_DEBUG_FS
-#define NHYPERCALLS	40		/* not really */
-
-static struct {
-	unsigned histo[MC_BATCH+1];
-
-	unsigned issued;
-	unsigned arg_total;
-	unsigned hypercalls;
-	unsigned histo_hypercalls[NHYPERCALLS];
-
-	unsigned flush[FL_N_REASONS];
-} mc_stats;
-
-static u8 zero_stats;
-
-static inline void check_zero(void)
-{
-	if (unlikely(zero_stats)) {
-		memset(&mc_stats, 0, sizeof(mc_stats));
-		zero_stats = 0;
-	}
-}
-
-static void mc_add_stats(const struct mc_buffer *mc)
-{
-	int i;
-
-	check_zero();
-
-	mc_stats.issued++;
-	mc_stats.hypercalls += mc->mcidx;
-	mc_stats.arg_total += mc->argidx;
-
-	mc_stats.histo[mc->mcidx]++;
-	for(i = 0; i < mc->mcidx; i++) {
-		unsigned op = mc->entries[i].op;
-		if (op < NHYPERCALLS)
-			mc_stats.histo_hypercalls[op]++;
-	}
-}
-
-static void mc_stats_flush(enum flush_reasons idx)
-{
-	check_zero();
-
-	mc_stats.flush[idx]++;
-}
-
-#else  /* !CONFIG_XEN_DEBUG_FS */
-
-static inline void mc_add_stats(const struct mc_buffer *mc)
-{
-}
-
-static inline void mc_stats_flush(enum flush_reasons idx)
-{
-}
-#endif	/* CONFIG_XEN_DEBUG_FS */
-
 void xen_mc_flush(void)
 {
 	struct mc_buffer *b = &__get_cpu_var(mc_buffer);
+	struct multicall_entry *mc;
 	int ret = 0;
 	unsigned long flags;
 	int i;
@@ -135,9 +66,26 @@ void xen_mc_flush(void)
 	   something in the middle */
 	local_irq_save(flags);
 
-	mc_add_stats(b);
+	trace_xen_mc_flush(b->mcidx, b->argidx, b->cbidx);
+
+	switch (b->mcidx) {
+	case 0:
+		/* no-op */
+		BUG_ON(b->argidx != 0);
+		break;
+
+	case 1:
+		/* Singleton multicall - bypass multicall machinery
+		   and just do the call directly. */
+		mc = &b->entries[0];
+
+		mc->result = privcmd_call(mc->op,
+					  mc->args[0], mc->args[1], mc->args[2], 
+					  mc->args[3], mc->args[4]);
+		ret = mc->result < 0;
+		break;
 
-	if (b->mcidx) {
+	default:
 #if MC_DEBUG
 		memcpy(b->debug, b->entries,
 		       b->mcidx * sizeof(struct multicall_entry));
@@ -164,11 +112,10 @@ void xen_mc_flush(void)
 			}
 		}
 #endif
+	}
 
-		b->mcidx = 0;
-		b->argidx = 0;
-	} else
-		BUG_ON(b->argidx != 0);
+	b->mcidx = 0;
+	b->argidx = 0;
 
 	for (i = 0; i < b->cbidx; i++) {
 		struct callback *cb = &b->callbacks[i];
@@ -188,18 +135,21 @@ struct multicall_space __xen_mc_entry(size_t args)
 	struct multicall_space ret;
 	unsigned argidx = roundup(b->argidx, sizeof(u64));
 
+	trace_xen_mc_entry_alloc(args);
+
 	BUG_ON(preemptible());
 	BUG_ON(b->argidx >= MC_ARGS);
 
-	if (b->mcidx == MC_BATCH ||
-	    (argidx + args) >= MC_ARGS) {
-		mc_stats_flush(b->mcidx == MC_BATCH ? FL_SLOTS : FL_ARGS);
+	if (unlikely(b->mcidx == MC_BATCH ||
+		     (argidx + args) >= MC_ARGS)) {
+		trace_xen_mc_flush_reason((b->mcidx == MC_BATCH) ?
+					  XEN_MC_FL_BATCH : XEN_MC_FL_ARGS);
 		xen_mc_flush();
 		argidx = roundup(b->argidx, sizeof(u64));
 	}
 
 	ret.mc = &b->entries[b->mcidx];
-#ifdef MC_DEBUG
+#if MC_DEBUG
 	b->caller[b->mcidx] = __builtin_return_address(0);
 #endif
 	b->mcidx++;
@@ -218,20 +168,25 @@ struct multicall_space xen_mc_extend_args(unsigned long op, size_t size)
 	BUG_ON(preemptible());
 	BUG_ON(b->argidx >= MC_ARGS);
 
-	if (b->mcidx == 0)
-		return ret;
-
-	if (b->entries[b->mcidx - 1].op != op)
-		return ret;
+	if (unlikely(b->mcidx == 0 ||
+		     b->entries[b->mcidx - 1].op != op)) {
+		trace_xen_mc_extend_args(op, size, XEN_MC_XE_BAD_OP);
+		goto out;
+	}
 
-	if ((b->argidx + size) >= MC_ARGS)
-		return ret;
+	if (unlikely((b->argidx + size) >= MC_ARGS)) {
+		trace_xen_mc_extend_args(op, size, XEN_MC_XE_NO_SPACE);
+		goto out;
+	}
 
 	ret.mc = &b->entries[b->mcidx - 1];
 	ret.args = &b->args[b->argidx];
 	b->argidx += size;
 
 	BUG_ON(b->argidx >= MC_ARGS);
+
+	trace_xen_mc_extend_args(op, size, XEN_MC_XE_OK);
+out:
 	return ret;
 }
 
@@ -241,43 +196,13 @@ void xen_mc_callback(void (*fn)(void *), void *data)
 	struct callback *cb;
 
 	if (b->cbidx == MC_BATCH) {
-		mc_stats_flush(FL_CALLBACKS);
+		trace_xen_mc_flush_reason(XEN_MC_FL_CALLBACK);
 		xen_mc_flush();
 	}
 
+	trace_xen_mc_callback(fn, data);
+
 	cb = &b->callbacks[b->cbidx++];
 	cb->fn = fn;
 	cb->data = data;
 }
-
-#ifdef CONFIG_XEN_DEBUG_FS
-
-static struct dentry *d_mc_debug;
-
-static int __init xen_mc_debugfs(void)
-{
-	struct dentry *d_xen = xen_init_debugfs();
-
-	if (d_xen == NULL)
-		return -ENOMEM;
-
-	d_mc_debug = debugfs_create_dir("multicalls", d_xen);
-
-	debugfs_create_u8("zero_stats", 0644, d_mc_debug, &zero_stats);
-
-	debugfs_create_u32("batches", 0444, d_mc_debug, &mc_stats.issued);
-	debugfs_create_u32("hypercalls", 0444, d_mc_debug, &mc_stats.hypercalls);
-	debugfs_create_u32("arg_total", 0444, d_mc_debug, &mc_stats.arg_total);
-
-	xen_debugfs_create_u32_array("batch_histo", 0444, d_mc_debug,
-				     mc_stats.histo, MC_BATCH);
-	xen_debugfs_create_u32_array("hypercall_histo", 0444, d_mc_debug,
-				     mc_stats.histo_hypercalls, NHYPERCALLS);
-	xen_debugfs_create_u32_array("flush_reasons", 0444, d_mc_debug,
-				     mc_stats.flush, FL_N_REASONS);
-
-	return 0;
-}
-fs_initcall(xen_mc_debugfs);
-
-#endif	/* CONFIG_XEN_DEBUG_FS */