diff options
| author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-12-17 17:32:28 -0800 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2011-07-18 15:43:45 -0700 |
| commit | eac303bf2ef63e7f7b6971badea0ff7bf08a2b22 (patch) | |
| tree | fe992cb61954a55733208f60a2e6b393cc5698aa | |
| parent | 4a7b005dbfa554e7cc7fbc08e0299a9b7a91ef3b (diff) | |
xen/multicall: special-case singleton hypercalls
Singleton calls seem to end up being pretty common, so just
directly call the hypercall rather than going via multicall.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
| -rw-r--r-- | arch/x86/xen/multicalls.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c index cc71f7cf1adc..2474553d1f26 100644 --- a/arch/x86/xen/multicalls.c +++ b/arch/x86/xen/multicalls.c @@ -55,6 +55,7 @@ DEFINE_PER_CPU(unsigned long, xen_mc_irq_flags); 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; @@ -67,7 +68,24 @@ void xen_mc_flush(void) trace_xen_mc_flush(b->mcidx, b->argidx, b->cbidx); - if (b->mcidx) { + 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; + + default: #if MC_DEBUG memcpy(b->debug, b->entries, b->mcidx * sizeof(struct multicall_entry)); @@ -94,11 +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]; |