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 7B8EEC3A589 for ; Fri, 16 Aug 2019 01:48:17 +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 0065A206C1 for ; Fri, 16 Aug 2019 01:48:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0065A206C1 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 468mRy4mVRzDrCC for ; Fri, 16 Aug 2019 11:48:14 +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 468mPH6SyMzDqxD for ; Fri, 16 Aug 2019 11:45:55 +1000 (AEST) Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x7G1gLCp124665 for ; Thu, 15 Aug 2019 21:45:52 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0b-001b2d01.pphosted.com with ESMTP id 2udf87qbe5-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 15 Aug 2019 21:45:52 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 16 Aug 2019 02:45:45 +0100 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x7G1jiem52625546 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 16 Aug 2019 01:45:44 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8F95042041; Fri, 16 Aug 2019 01:45:44 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ED31342042; Fri, 16 Aug 2019 01:45:43 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 16 Aug 2019 01:45:43 +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 C7F43A01EB; Fri, 16 Aug 2019 11:45:42 +1000 (AEST) From: "Alastair D'Silva" To: christophe leroy Date: Fri, 16 Aug 2019 11:45:42 +1000 In-Reply-To: <366f94bd-c61b-d454-b202-d3feb81a14c3@c-s.fr> References: <20190815041057.13627-1-alastair@au1.ibm.com> <20190815041057.13627-5-alastair@au1.ibm.com> <366f94bd-c61b-d454-b202-d3feb81a14c3@c-s.fr> 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: 19081601-0028-0000-0000-0000039037CA X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19081601-0029-0000-0000-000024524FF1 Message-Id: <9fa2526f6ba1cecffb85b1fa5199f7a616e5fa91.camel@au1.ibm.com> Subject: RE: [PATCH 4/6] powerpc: Chunk calls to flush_dcache_range in arch_*_memory X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-08-15_11:, , 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-1908160016 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: Greg Kroah-Hartman , David Hildenbrand , linux-kernel@vger.kernel.org, Nicholas Piggin , Mike Rapoport , Qian Cai , 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 Thu, 2019-08-15 at 09:36 +0200, christophe leroy wrote: > > Le 15/08/2019 à 06:10, Alastair D'Silva a écrit : > > From: Alastair D'Silva > > > > When presented with large amounts of memory being hotplugged > > (in my test case, ~890GB), the call to flush_dcache_range takes > > a while (~50 seconds), triggering RCU stalls. > > > > This patch breaks up the call into 16GB chunks, calling > > cond_resched() inbetween to allow the scheduler to run. > > Is 16GB small enough ? If 890GB takes 50s, 16GB still takes about 1s. > I'd use 1GB chuncks to remain below 100ms. > > > Signed-off-by: Alastair D'Silva > > --- > > arch/powerpc/mm/mem.c | 16 ++++++++++++++-- > > 1 file changed, 14 insertions(+), 2 deletions(-) > > > > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > > index 5400da87a804..fb0d5e9aa11b 100644 > > --- a/arch/powerpc/mm/mem.c > > +++ b/arch/powerpc/mm/mem.c > > @@ -104,11 +104,14 @@ int __weak remove_section_mapping(unsigned > > long start, unsigned long end) > > return -ENODEV; > > } > > > > +#define FLUSH_CHUNK_SIZE (16ull * 1024ull * 1024ull * 1024ull) > > Can we use SZ_16GB ? Sure, I'll go with 1GB as you recommended above > > + > > int __ref arch_add_memory(int nid, u64 start, u64 size, > > struct mhp_restrictions *restrictions) > > { > > unsigned long start_pfn = start >> PAGE_SHIFT; > > unsigned long nr_pages = size >> PAGE_SHIFT; > > + unsigned long i; > > int rc; > > > > resize_hpt_for_hotplug(memblock_phys_mem_size()); > > @@ -120,7 +123,11 @@ int __ref arch_add_memory(int nid, u64 start, > > u64 size, > > start, start + size, rc); > > return -EFAULT; > > } > > - flush_dcache_range(start, start + size); > > + > > + for (i = 0; i < size; i += FLUSH_CHUNK_SIZE) { > > + flush_dcache_range(start + i, min(start + size, start + > > i + FLUSH_CHUNK_SIZE)); > > Isn't the line a bit long (I have not checked). > > > + cond_resched(); > > + } > > > > return __add_pages(nid, start_pfn, nr_pages, restrictions); > > } > > @@ -131,13 +138,18 @@ void __ref arch_remove_memory(int nid, u64 > > start, u64 size, > > unsigned long start_pfn = start >> PAGE_SHIFT; > > unsigned long nr_pages = size >> PAGE_SHIFT; > > struct page *page = pfn_to_page(start_pfn) + > > vmem_altmap_offset(altmap); > > + unsigned long i; > > int ret; > > > > __remove_pages(page_zone(page), start_pfn, nr_pages, altmap); > > > > /* Remove htab bolted mappings for this section of memory */ > > start = (unsigned long)__va(start); > > - flush_dcache_range(start, start + size); > > + for (i = 0; i < size; i += FLUSH_CHUNK_SIZE) { > > + flush_dcache_range(start + i, min(start + size, start + > > i + FLUSH_CHUNK_SIZE)); > > + cond_resched(); > > + } > > + > > ret = remove_section_mapping(start, start + size); > > WARN_ON_ONCE(ret); > > > > > > Christophe > > --- > L'absence de virus dans ce courrier électronique a été vérifiée par > le logiciel antivirus Avast. > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.avast.com_antivirus&d=DwIDaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=cT4tgeEQ0Ll3SIlZDHE5AEXyKy6uKADMtf9_Eb7-vec&m=TBT2NNM2DXqDWHhSb_WdFPcfAjYk9hP2cvGksF001cQ&s=XURKAOQQ4h3_RhJlezSguD2kpSitAF-uBhQqVZLU4GU&e= > -- Alastair D'Silva Open Source Developer Linux Technology Centre, IBM Australia mob: 0423 762 819