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Tue, 11 Aug 2020 08:47:40 +0000 (GMT) Received: from [9.199.59.108] (unknown [9.199.59.108]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 11 Aug 2020 08:47:40 +0000 (GMT) Subject: Re: [PATCH] mm/vunmap: Add cond_resched() in vunmap_pmd_range To: Andrew Morton Cc: linux-mm@kvack.org, Harish Sriram References: <20200807075933.310240-1-aneesh.kumar@linux.ibm.com> <20200810214655.a3f82fc8ccd671a392164a09@linux-foundation.org> From: "Aneesh Kumar K.V" Message-ID: <48b8fdc6-92aa-4d4f-736e-a3d72cf93eff@linux.ibm.com> Date: Tue, 11 Aug 2020 14:17:39 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200810214655.a3f82fc8ccd671a392164a09@linux-foundation.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-08-11_08:2020-08-06,2020-08-11 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 suspectscore=0 priorityscore=1501 impostorscore=0 bulkscore=0 adultscore=0 malwarescore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008110055 X-Rspamd-Queue-Id: 18D4F18229818 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 8/11/20 10:16 AM, Andrew Morton wrote: > On Fri, 7 Aug 2020 13:29:33 +0530 "Aneesh Kumar K.V" wrote: > >> Like zap_pte_range add cond_resched so that we can avoid softlockups as reported >> below. On non-preemptible kernel with large I/O map region (like the one we get >> when using persistent memory with sector mode), an unmap of the namespace can report >> below softlockups. >> >> ... >> >> --- a/mm/vmalloc.c >> +++ b/mm/vmalloc.c >> @@ -102,6 +102,8 @@ static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, >> if (pmd_none_or_clear_bad(pmd)) >> continue; >> vunmap_pte_range(pmd, addr, next, mask); >> + >> + cond_resched(); >> } while (pmd++, addr = next, addr != end); >> } > > That looks sane. I'll aim for merging it in 5.9-rc2ish, with a > cc:stable, OK? > Sure. I was not so particular about stable because it was only a softlockup warning. -aneesh