From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C4D2C3A5A5 for ; Tue, 3 Sep 2019 06:33:07 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A271620882 for ; Tue, 3 Sep 2019 06:33:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A271620882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=au1.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46MxwJ0gLXzDqX8 for ; Tue, 3 Sep 2019 16:33:04 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=au1.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=alastair@au1.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=au1.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 46MxpF2nCCzDqX8 for ; Tue, 3 Sep 2019 16:27:49 +1000 (AEST) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x836Rj5M025986 for ; Tue, 3 Sep 2019 02:27:46 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0b-001b2d01.pphosted.com with ESMTP id 2usjb513rs-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 03 Sep 2019 02:27:46 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 3 Sep 2019 07:27:22 +0100 Received: from b06cxnps4075.portsmouth.uk.ibm.com (9.149.109.197) by e06smtp04.uk.ibm.com (192.168.101.134) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 3 Sep 2019 07:27:18 +0100 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x836RHRc40763552 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 3 Sep 2019 06:27:17 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2584C11C05B; Tue, 3 Sep 2019 06:27:17 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CDDEE11C054; Tue, 3 Sep 2019 06:27:16 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 3 Sep 2019 06:27:16 +0000 (GMT) Received: from adsilva.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 50186A00EC; Tue, 3 Sep 2019 16:27:15 +1000 (AEST) Subject: Re: [PATCH v2 6/6] powerpc: Don't flush caches when adding memory From: "Alastair D'Silva" To: Christophe Leroy Date: Tue, 03 Sep 2019 16:27:15 +1000 In-Reply-To: References: <20190903052407.16638-1-alastair@au1.ibm.com> <20190903052407.16638-7-alastair@au1.ibm.com> Organization: IBM Australia Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.2 (3.32.2-1.fc30) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19090306-0016-0000-0000-000002A5F738 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19090306-0017-0000-0000-000033065C4F Message-Id: <864c4b01a9c12f82a32de264fbb0b2acb39592e4.camel@au1.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-09-03_01:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909030071 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Hildenbrand , linux-kernel@vger.kernel.org, Nicholas Piggin , Mike Rapoport , Qian Cai , Greg Kroah-Hartman , Paul Mackerras , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, Andrew Morton , Allison Randal Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 2019-09-03 at 08:23 +0200, Christophe Leroy wrote: > > Le 03/09/2019 à 07:24, Alastair D'Silva a écrit : > > From: Alastair D'Silva > > > > This operation takes a significant amount of time when hotplugging > > large amounts of memory (~50 seconds with 890GB of persistent > > memory). > > > > This was orignally in commit fb5924fddf9e > > ("powerpc/mm: Flush cache on memory hot(un)plug") to support > > memtrace, > > but the flush on add is not needed as it is flushed on remove. > > > > Signed-off-by: Alastair D'Silva > > --- > > arch/powerpc/mm/mem.c | 7 ------- > > 1 file changed, 7 deletions(-) > > > > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > > index 854aaea2c6ae..2a14b5b93e19 100644 > > --- a/arch/powerpc/mm/mem.c > > +++ b/arch/powerpc/mm/mem.c > > @@ -111,7 +111,6 @@ int __ref arch_add_memory(int nid, u64 start, > > u64 size, > > { > > unsigned long start_pfn = start >> PAGE_SHIFT; > > unsigned long nr_pages = size >> PAGE_SHIFT; > > - u64 i; > > int rc; > > > > resize_hpt_for_hotplug(memblock_phys_mem_size()); > > @@ -124,12 +123,6 @@ int __ref arch_add_memory(int nid, u64 start, > > u64 size, > > return -EFAULT; > > } > > > > - for (i = 0; i < size; i += FLUSH_CHUNK_SIZE) { > > - flush_dcache_range(start + i, > > - min(start + size, start + i + > > FLUSH_CHUNK_SIZE)); > > - cond_resched(); > > - } > > - > > So you are removing the code you added in patch 4. Why not move this > one > before patch 4 ? > I put them in this order so that if someone did want the flushes in arch_add_memory, they could drop the later patch, but not trigger RCU stalls. -- Alastair D'Silva Open Source Developer Linux Technology Centre, IBM Australia mob: 0423 762 819