Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756083Ab1FTWPk (ORCPT ); Mon, 20 Jun 2011 18:15:40 -0400 Received: from claw.goop.org ([74.207.240.146]:53660 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755806Ab1FTWP2 (ORCPT ); Mon, 20 Jun 2011 18:15:28 -0400 From: Jeremy Fitzhardinge To: Xen Devel Cc: Konrad Rzeszutek Wilk , Steven Rostedt , Ingo Molnar , Linux Kernel Mailing List , Jeremy Fitzhardinge Subject: [PATCH 14/15] xen/multicall: special-case singleton hypercalls Date: Mon, 20 Jun 2011 15:15:10 -0700 Message-Id: X-Mailer: git-send-email 1.7.5.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1867 Lines: 71 From: Jeremy Fitzhardinge 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 --- 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 b9b9811..eb022fd 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]; -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/