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 1189FC4360C for ; Fri, 27 Sep 2019 06:48:41 +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 B863020863 for ; Fri, 27 Sep 2019 06:48:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B863020863 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=au1.ibm.com Authentication-Results: mail.kernel.org; spf=tempfail 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 46fj7B4M1czDqwM for ; Fri, 27 Sep 2019 16:48:38 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=au1.ibm.com (client-ip=148.163.156.1; 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 (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 46fj5N0GFQzDqvV for ; Fri, 27 Sep 2019 16:47:03 +1000 (AEST) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x8R6kiqu026902 for ; Fri, 27 Sep 2019 02:46:59 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2v9byptg1j-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 27 Sep 2019 02:46:58 -0400 Received: from localhost by e06smtp05.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, 27 Sep 2019 07:46:50 +0100 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x8R6knIB54460588 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 27 Sep 2019 06:46:49 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6546EA408A; Fri, 27 Sep 2019 06:46:49 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C17CDA4093; Fri, 27 Sep 2019 06:46:48 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 27 Sep 2019 06:46:48 +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 2E6A4A00F9; Fri, 27 Sep 2019 16:46:46 +1000 (AEST) From: "Alastair D'Silva" To: Mark Marshall Date: Fri, 27 Sep 2019 16:46:46 +1000 In-Reply-To: References: <20190926045419.22827-1-alastair@au1.ibm.com> <20190926045419.22827-6-alastair@au1.ibm.com> Organization: IBM Australia Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.4 (3.32.4-1.fc30) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19092706-0020-0000-0000-0000037232A8 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19092706-0021-0000-0000-000021C8019F Message-Id: Subject: RE: [PATCH v4 5/6] powerpc: Chunk calls to flush_dcache_range in arch_*_memory X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-09-27_04:, , 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=8.0.1-1908290000 definitions=main-1909270062 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: Michal Hocko , 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 Fri, 2019-09-27 at 08:37 +0200, Mark Marshall wrote: > Comment below... > > On Thu, 26 Sep 2019 at 12:18, Alastair D'Silva > wrote: > > 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 1GB chunks, calling > > cond_resched() inbetween to allow the scheduler to run. > > > > Signed-off-by: Alastair D'Silva > > --- > > arch/powerpc/mm/mem.c | 27 +++++++++++++++++++++++++-- > > 1 file changed, 25 insertions(+), 2 deletions(-) > > > > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > > index cff947cb2a84..a2758e473d58 100644 > > --- a/arch/powerpc/mm/mem.c > > +++ b/arch/powerpc/mm/mem.c > > @@ -104,6 +104,27 @@ int __weak remove_section_mapping(unsigned > > long start, unsigned long end) > > return -ENODEV; > > } > > > > +#define FLUSH_CHUNK_SIZE SZ_1G > > +/** > > + * flush_dcache_range_chunked(): Write any modified data cache > > blocks out to > > + * memory and invalidate them, in chunks of up to FLUSH_CHUNK_SIZE > > + * Does not invalidate the corresponding instruction cache blocks. > > + * > > + * @start: the start address > > + * @stop: the stop address (exclusive) > > + * @chunk: the max size of the chunks > > + */ > > +static void flush_dcache_range_chunked(unsigned long start, > > unsigned long stop, > > + unsigned long chunk) > > +{ > > + unsigned long i; > > + > > + for (i = start; i < stop; i += FLUSH_CHUNK_SIZE) { > Here you ignore the function parameter "chunk" and use the define > FLUSH_CHUNK_SIZE. > You should do one or the other; use the parameter or remove it. Good catch, thankyou :) > > + flush_dcache_range(i, min(stop, start + > > FLUSH_CHUNK_SIZE)); > > + cond_resched(); > > + } > > +} > > + > > int __ref arch_add_memory(int nid, u64 start, u64 size, > > struct mhp_restrictions *restrictions) > > { > > @@ -120,7 +141,8 @@ int __ref arch_add_memory(int nid, u64 start, > > u64 size, > > start, start + size, rc); > > return -EFAULT; > > } > > - flush_dcache_range(start, start + size); > > + > > + flush_dcache_range_chunked(start, start + size, > > FLUSH_CHUNK_SIZE); > > > > return __add_pages(nid, start_pfn, nr_pages, restrictions); > > } > > @@ -137,7 +159,8 @@ void __ref arch_remove_memory(int nid, u64 > > start, u64 size, > > > > /* Remove htab bolted mappings for this section of memory > > */ > > start = (unsigned long)__va(start); > > - flush_dcache_range(start, start + size); > > + flush_dcache_range_chunked(start, start + size, > > FLUSH_CHUNK_SIZE); > > + > > ret = remove_section_mapping(start, start + size); > > WARN_ON_ONCE(ret); > > > > -- > > 2.21.0 > > -- Alastair D'Silva Open Source Developer Linux Technology Centre, IBM Australia mob: 0423 762 819