From patchwork Wed Nov 2 09:08:31 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: xinhui X-Patchwork-Id: 690246 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3t7xH76mdlz9vDl for ; Wed, 2 Nov 2016 16:19:31 +1100 (AEDT) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3t7xH7607mzDvjX for ; Wed, 2 Nov 2016 16:19:31 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3t7x8Y6yhXzDvMr for ; Wed, 2 Nov 2016 16:13:49 +1100 (AEDT) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uA25DTSH055958 for ; Wed, 2 Nov 2016 01:13:48 -0400 Received: from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com [202.81.31.141]) by mx0a-001b2d01.pphosted.com with ESMTP id 26f8xujbht-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 02 Nov 2016 01:13:48 -0400 Received: from localhost by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 2 Nov 2016 15:13:43 +1000 Received: from d23relay08.au.ibm.com (d23relay08.au.ibm.com [9.185.71.33]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 4DA133578053 for ; Wed, 2 Nov 2016 16:13:43 +1100 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id uA25Dh4F16777396 for ; Wed, 2 Nov 2016 16:13:43 +1100 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id uA25DfXO007709 for ; Wed, 2 Nov 2016 16:13:43 +1100 Received: from ltcalpine2-lp13.aus.stglabs.ibm.com (ltcalpine2-lp13.aus.stglabs.ibm.com [9.40.195.196]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id uA25CnXi006036; Wed, 2 Nov 2016 16:13:36 +1100 From: Pan Xinhui To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, linux-s390@vger.kernel.org, xen-devel-request@lists.xenproject.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org Subject: [PATCH v7 04/11] powerpc/spinlock: support vcpu preempted check Date: Wed, 2 Nov 2016 05:08:31 -0400 X-Mailer: git-send-email 2.4.11 In-Reply-To: <1478077718-37424-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> References: <1478077718-37424-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16110205-0048-0000-0000-000001D11D46 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16110205-0049-0000-0000-000046DD5DC6 Message-Id: <1478077718-37424-5-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-11-02_02:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1611020096 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kernellwp@gmail.com, jgross@suse.com, dave@stgolabs.net, David.Laight@ACULAB.COM, rkrcmar@redhat.com, peterz@infradead.org, konrad.wilk@oracle.com, will.deacon@arm.com, Pan Xinhui , borntraeger@de.ibm.com, mingo@redhat.com, paulus@samba.org, pbonzini@redhat.com, paulmck@linux.vnet.ibm.com, boqun.feng@gmail.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" This is to fix some lock holder preemption issues. Some other locks implementation do a spin loop before acquiring the lock itself. Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It takes the cpu as parameter and return true if the cpu is preempted. Then kernel can break the spin loops upon the retval of vcpu_is_preempted. As kernel has used this interface, So lets support it. Only pSeries need support it. And the fact is PowerNV is built into same kernel image with pSeries. So we need return false if we are runnig as PowerNV. The another fact is that lppaca->yiled_count keeps zero on PowerNV. So we can just skip the machine type check. Suggested-by: Boqun Feng Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Pan Xinhui --- arch/powerpc/include/asm/spinlock.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h index fa37fe9..8c1b913 100644 --- a/arch/powerpc/include/asm/spinlock.h +++ b/arch/powerpc/include/asm/spinlock.h @@ -52,6 +52,14 @@ #define SYNC_IO #endif +#ifdef CONFIG_PPC_PSERIES +#define vcpu_is_preempted vcpu_is_preempted +static inline bool vcpu_is_preempted(int cpu) +{ + return !!(be32_to_cpu(lppaca_of(cpu).yield_count) & 1); +} +#endif + static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock) { return lock.slock == 0;