diff options
Diffstat (limited to 'arch/x86/xen/multicalls.c')
| -rw-r--r-- | arch/x86/xen/multicalls.c | 169 |
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 */ |