From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753665AbcEYIWC (ORCPT ); Wed, 25 May 2016 04:22:02 -0400 Received: from e23smtp02.au.ibm.com ([202.81.31.144]:47752 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752777AbcEYIVb (ORCPT ); Wed, 25 May 2016 04:21:31 -0400 X-IBM-Helo: d23dlp01.au.ibm.com X-IBM-MailFrom: xinhui.pan@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: Pan Xinhui To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, peterz@infradead.org, mingo@redhat.com, paulmck@linux.vnet.ibm.com, jeremy@goop.org, chrisw@sous-sol.org, akataria@vmware.com, rusty@rustcorp.com.au, Pan Xinhui Subject: [PATCH v3 3/6] powerpc: lib/locks.c: Add cpu yield/wake helper function Date: Wed, 25 May 2016 16:18:06 +0800 Message-Id: <1464164289-6124-4-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1464164289-6124-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> References: <1464164289-6124-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16052508-0005-0000-0000-000007F049AD X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pv-qspinlock core has pv_wait/pv_kick which will give a better performace by yielding and kicking cpu at some cases. lets support them by adding two corresponding helper functions. Signed-off-by: Pan Xinhui --- arch/powerpc/include/asm/spinlock.h | 4 ++++ arch/powerpc/lib/locks.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h index 4359ee6..3b65372 100644 --- a/arch/powerpc/include/asm/spinlock.h +++ b/arch/powerpc/include/asm/spinlock.h @@ -56,9 +56,13 @@ /* We only yield to the hypervisor if we are in shared processor mode */ #define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr)) extern void __spin_yield(arch_spinlock_t *lock); +extern void __spin_yield_cpu(int cpu); +extern void __spin_wake_cpu(int cpu); extern void __rw_yield(arch_rwlock_t *lock); #else /* SPLPAR */ #define __spin_yield(x) barrier() +#define __spin_yield_cpu(x) barrier() +#define __spin_wake_cpu(x) barrier() #define __rw_yield(x) barrier() #define SHARED_PROCESSOR 0 #endif diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c index a9ebd71..3a58834 100644 --- a/arch/powerpc/lib/locks.c +++ b/arch/powerpc/lib/locks.c @@ -23,6 +23,39 @@ #include #include +void __spin_yield_cpu(int cpu) +{ + unsigned int holder_cpu = cpu, yield_count; + + if (cpu == -1) { + plpar_hcall_norets(H_CONFER, -1, 0); + return; + } + BUG_ON(holder_cpu >= nr_cpu_ids); + yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count); + if ((yield_count & 1) == 0) { + /* if target cpu is running, confer slices to lpar*/ + plpar_hcall_norets(H_CONFER, -1, 0); + return; + } + plpar_hcall_norets(H_CONFER, + get_hard_smp_processor_id(holder_cpu), yield_count); +} +EXPORT_SYMBOL_GPL(__spin_yield_cpu); + +void __spin_wake_cpu(int cpu) +{ + unsigned int holder_cpu = cpu, yield_count; + + BUG_ON(holder_cpu >= nr_cpu_ids); + yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count); + if ((yield_count & 1) == 0) + return; /* virtual cpu is currently running */ + plpar_hcall_norets(H_PROD, + get_hard_smp_processor_id(holder_cpu)); +} +EXPORT_SYMBOL_GPL(__spin_wake_cpu); + #ifndef CONFIG_QUEUED_SPINLOCKS void __spin_yield(arch_spinlock_t *lock) { -- 1.9.1