Commit eac303bf authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge
Browse files

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: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
parent 4a7b005d

arch/x86/xen/multicalls.c

+22 −5
Original line number Original line Diff line number Diff line
@@ -55,6 +55,7 @@ DEFINE_PER_CPU(unsigned long, xen_mc_irq_flags); 
void xen_mc_flush(void)

void xen_mc_flush(void)

{

{

	struct mc_buffer *b = &__get_cpu_var(mc_buffer);

	struct mc_buffer *b = &__get_cpu_var(mc_buffer);

	struct multicall_entry *mc;

	int ret = 0;

	int ret = 0;

	unsigned long flags;

	unsigned long flags;

	int i;

	int i;
@@ -67,7 +68,24 @@ void xen_mc_flush(void) 




	trace_xen_mc_flush(b->mcidx, b->argidx, b->cbidx);

	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

#if MC_DEBUG

		memcpy(b->debug, b->entries,

		memcpy(b->debug, b->entries,

		       b->mcidx * sizeof(struct multicall_entry));

		       b->mcidx * sizeof(struct multicall_entry));
@@ -94,11 +112,10 @@ void xen_mc_flush(void) 
			}

			}

		}

		}

#endif

#endif

	}





	b->mcidx = 0;

	b->mcidx = 0;

	b->argidx = 0;

	b->argidx = 0;

	} else

		BUG_ON(b->argidx != 0);





	for (i = 0; i < b->cbidx; i++) {

	for (i = 0; i < b->cbidx; i++) {

		struct callback *cb = &b->callbacks[i];

		struct callback *cb = &b->callbacks[i];