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Fri, 6 Jan 2023 13:41:46 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8B44B2004D; Fri, 6 Jan 2023 13:41:46 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1467120043; Fri, 6 Jan 2023 13:41:41 +0000 (GMT) Received: from tarunpc (unknown [9.43.87.176]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTPS; Fri, 6 Jan 2023 13:41:40 +0000 (GMT) From: Tarun Sahu To: alexlzhu@fb.com, linux-mm@kvack.org, kernel-team@fb.com Cc: willy@infradead.org, hannes@cmpxchg.org, riel@surriel.com, yuzhao@google.com, ningzhang@linux.alibaba.com, Alexander Zhu Subject: Re: [PATCH v6 5/5] mm: THP low utilization shrinker In-Reply-To: References: Date: Fri, 06 Jan 2023 19:11:36 +0530 Message-ID: <87pmbrok4v.fsf@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: iM9mwoUvMSoamJQ6fAiNm5IRMc7TtCEL X-Proofpoint-GUID: Hc9dQpluzkcBR_R-kqVO-jXY0ChHaLWZ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2023-01-06_08,2023-01-06_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 clxscore=1011 priorityscore=1501 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 adultscore=0 impostorscore=0 lowpriorityscore=0 mlxscore=0 mlxlogscore=949 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301060107 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2794580012 X-Stat-Signature: 4eiiq49sy4y3du1yt8bngx7rmqdbkbre X-HE-Tag: 1673012523-281256 X-HE-Meta: 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 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: Hi Alex, I think it would better to have the 90% under utilization threshold for shrinker to be defined as macro rather than hard coded? like, /* * The threshold to determine if thp is under utilized and can be * shrunk. */ #define THP_NRML_UTILIZED_BUCKET THP_UTIL_BUCKET_NR - 1 This way, it is more clear. --skip > +bool can_shrink_thp(struct folio *folio) > +{ > + int bucket, num_utilized_pages; > + > + if (!folio || !folio_test_anon(folio) || !folio_test_transhuge(folio)) > + return false; > + > + num_utilized_pages = thp_number_utilized_pages(folio); > + bucket = thp_utilization_bucket(num_utilized_pages); > + > + return bucket >= 0 && bucket < THP_UTIL_BUCKET_NR - 1; This can be return bucket >= 0 && bucket < THP_NRML_UTILIZED_BUCKET; > +} > + > static void thp_scan_next_zone(void) > { > struct timespec64 current_time; > @@ -170,6 +183,9 @@ static void thp_util_scan(unsigned long pfn_end) > if (bucket < 0) > continue; > > + if (bucket < THP_UTIL_BUCKET_NR - 1) Similarly, this one. There might be other instances too. > + add_underutilized_thp(page); > + > thp_scan.buckets[bucket].nr_thps++; > thp_scan.buckets[bucket].nr_zero_pages += (HPAGE_PMD_NR - num_utilized_pages); > } > -- > 2.30.2