From patchwork Mon Nov 4 02:32:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alastair D'Silva X-Patchwork-Id: 1188752 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 475xxn2Dy9z9sPL for ; Mon, 4 Nov 2019 13:46:05 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=au1.ibm.com Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 475xxn10lDzF4yp for ; Mon, 4 Nov 2019 13:46:05 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) 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 475xhk5yV0zF4dv for ; Mon, 4 Nov 2019 13:34:46 +1100 (AEDT) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id xA42WRd4026933 for ; Sun, 3 Nov 2019 21:34:43 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2w292ekq33-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 03 Nov 2019 21:34:43 -0500 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) Mon, 4 Nov 2019 02:34:37 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xA42Y1uZ39256520 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 4 Nov 2019 02:34:02 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8E53011C04C; Mon, 4 Nov 2019 02:34:36 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3AC5511C04A; Mon, 4 Nov 2019 02:34:36 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 4 Nov 2019 02:34:36 +0000 (GMT) Received: from adsilva.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 6E9DDA01D6; Mon, 4 Nov 2019 13:34:34 +1100 (AEDT) From: "Alastair D'Silva" To: alastair@d-silva.org Subject: [PATCH v5 5/6] powerpc: Chunk calls to flush_dcache_range in arch_*_memory Date: Mon, 4 Nov 2019 13:32:57 +1100 X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191104023305.9581-1-alastair@au1.ibm.com> References: <20191104023305.9581-1-alastair@au1.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 19110402-0028-0000-0000-000003B25911 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19110402-0029-0000-0000-00002474AAB4 Message-Id: <20191104023305.9581-6-alastair@au1.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-11-04_02:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 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-1911040026 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 , Paul Mackerras , Greg Kroah-Hartman , Qian Cai , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, Andrew Morton , Allison Randal Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 54d61ba15e93..a7b662fc02c8 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 += chunk) { + flush_dcache_range(i, min(stop, start + chunk)); + 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);