From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Srivatsa S. Bhat" Subject: [PATCH 16/27] mn10300: Fix horrible logic in smp_prepare_cpus() Date: Fri, 01 Jun 2012 14:43:54 +0530 Message-ID: <20120601091348.31979.97139.stgit@srivatsabhat.in.ibm.com> References: <20120601090952.31979.24799.stgit@srivatsabhat.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from e23smtp09.au.ibm.com ([202.81.31.142]:42628 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932418Ab2FAJ5N (ORCPT ); Fri, 1 Jun 2012 05:57:13 -0400 Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 1 Jun 2012 10:03:27 +1000 In-Reply-To: <20120601090952.31979.24799.stgit@srivatsabhat.in.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: peterz@infradead.org, paulmck@linux.vnet.ibm.com Cc: rusty@rustcorp.com.au, mingo@kernel.org, yong.zhang0@gmail.com, akpm@linux-foundation.org, vatsa@linux.vnet.ibm.com, rjw@sisk.pl, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, srivatsa.bhat@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, David Howells , Koichi Yasutake , Thomas Gleixner Yong Zhang , linux-am33-list@redhat.com In smp_prepare_cpus(), after max_cpus are booted, instead of breaking from the loop, the 'continue' statement is used which results in unnecessarily wasting time by looping NR_CPUS times! Many things around this could be pulled into generic code in the future, but for now, fix this particular piece of code locally (because I am unable to convince myself to ignore it even temporarily, given that it is such a gem!). And also rewrite the 'if' statement in a more natural way. Cc: David Howells Cc: Koichi Yasutake Cc: Thomas Gleixner Cc: Yong Zhang Cc: linux-am33-list@redhat.com Signed-off-by: Srivatsa S. Bhat --- arch/mn10300/kernel/smp.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c index e62c223..b19e75d2 100644 --- a/arch/mn10300/kernel/smp.c +++ b/arch/mn10300/kernel/smp.c @@ -695,9 +695,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus) /* Boot secondary CPUs (for which phy_id > 0) */ for (phy_id = 0; phy_id < NR_CPUS; phy_id++) { + if (cpucount + 1 >= max_cpus) + break; /* Don't boot primary CPU */ - if (max_cpus <= cpucount + 1) - continue; if (phy_id != 0) do_boot_cpu(phy_id); set_cpu_possible(phy_id, true); From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp09.au.ibm.com ([202.81.31.142]:42628 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932418Ab2FAJ5N (ORCPT ); Fri, 1 Jun 2012 05:57:13 -0400 Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 1 Jun 2012 10:03:27 +1000 From: "Srivatsa S. Bhat" Subject: [PATCH 16/27] mn10300: Fix horrible logic in smp_prepare_cpus() Date: Fri, 01 Jun 2012 14:43:54 +0530 Message-ID: <20120601091348.31979.97139.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20120601090952.31979.24799.stgit@srivatsabhat.in.ibm.com> References: <20120601090952.31979.24799.stgit@srivatsabhat.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: tglx@linutronix.de, peterz@infradead.org, paulmck@linux.vnet.ibm.com Cc: rusty@rustcorp.com.au, mingo@kernel.org, yong.zhang0@gmail.com, akpm@linux-foundation.org, vatsa@linux.vnet.ibm.com, rjw@sisk.pl, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, srivatsa.bhat@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, David Howells , Koichi Yasutake Yong Zhang , linux-am33-list@redhat.com Message-ID: <20120601091354.3svIBBL91hxcHMyWWh9ofw4J85n8fyVZLHh0c_V_Qiw@z> In smp_prepare_cpus(), after max_cpus are booted, instead of breaking from the loop, the 'continue' statement is used which results in unnecessarily wasting time by looping NR_CPUS times! Many things around this could be pulled into generic code in the future, but for now, fix this particular piece of code locally (because I am unable to convince myself to ignore it even temporarily, given that it is such a gem!). And also rewrite the 'if' statement in a more natural way. Cc: David Howells Cc: Koichi Yasutake Cc: Thomas Gleixner Cc: Yong Zhang Cc: linux-am33-list@redhat.com Signed-off-by: Srivatsa S. Bhat --- arch/mn10300/kernel/smp.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c index e62c223..b19e75d2 100644 --- a/arch/mn10300/kernel/smp.c +++ b/arch/mn10300/kernel/smp.c @@ -695,9 +695,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus) /* Boot secondary CPUs (for which phy_id > 0) */ for (phy_id = 0; phy_id < NR_CPUS; phy_id++) { + if (cpucount + 1 >= max_cpus) + break; /* Don't boot primary CPU */ - if (max_cpus <= cpucount + 1) - continue; if (phy_id != 0) do_boot_cpu(phy_id); set_cpu_possible(phy_id, true);