1 files changed, 47 insertions, 122 deletions

diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
index 1b2b73ff0a6..0d82003e76a 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 */