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b=GbeGebs+QUn3jnRHP8H/X0iAG0/MR8w7VFKKOv/EKzzmWUdLi4RZj+lg1hO5wCMsZ Wgi+ypK+m1n3RQGUb+m9Hw7ZtJ7a75BMJji9CxafQpvrKPLhD3ooo5UmnEmZOQ+HZP 3xz/vNSzLtwyLKRfkk0Qj4ihfJyKjyvoDxHxnx9tU8AaUsVxF+mCUcqSr2DXtcUJTr iJ1YulLn6UDY07RXdW56/zCvtyDzd78hstM1xAyRl2rimjYu4qcmnpe8FJRdxv2sr1 +GRDZTCUt7bIL2mGX1W0NF0tPNRWdfrw7FrcN0prSW+WrLPI7t+fHBwTZT1PVHmDf7 1ObnP/EPMklCA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v7 03/16] mm/mglru: reclaim from the oldest populated gen Reply-To: sashiko-reviews@lists.linux.dev To: =?utf-8?b?QmFycnkgU29uZyAoWGlhb21pKQ==?= , akpm@linux-foundation.org Cc: axelrasmussen@google.com, baolin.wang@linux.alibaba.com, baoquan.he@linux.dev, hannes@cmpxchg.org, hui.zhu@linux.dev, kasong@tencent.com, kunwu.chan@gmail.com, liam@infradead.org, lianux.mm@gmail.com, linux-mm@kvack.org, liuxiang.277@bytedance.com, lyugaofei@xiaomi.com, mhocko@kernel.org, mhocko@suse.com, qi.zheng@linux.dev, ridong.chen@linux.dev, rppt@kernel.org, ryncsn@gmail.com, shakeel.butt@linux.dev, surenb@google.com, wangzicheng@honor.com, weixugc@google.com, yuanchu@google.com, zhangbo56@xiaomi.com, zhuhui@kylinos.cn, sidchintamaneni@gmail.com In-Reply-To: <20261111232603.9934-4-baohua@kernel.org> References: <20261111232603.9934-1-baohua@kernel.org> <20261111232603.9934-4-baohua@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 12 Nov 2026 05:00:55 +0000 X-Stat-Signature: 8mgck4wf4gq9nx6u8hgtdosz9qnyks49 X-Rspam-User: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 50469A0006 X-HE-Tag: 1794459658-428501 X-HE-Meta: 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 TCZ078hZ 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Thank you for your contribution! Sashiko AI review found 1 potential issue to consider: - [Low] mm/mglru: uninitialized sc.priority in lru_gen_seq_write() skews scan_folios() -- commit c250a15f7ef946582fda6b278da38054c0ad3a66 Author: Kairui Song mm/mglru: reclaim from the oldest populated gen This commit updates scan_folios() to scan from the oldest populated generation when sc->priority is raised from DEF_PRIORITY, passing that generation down to sort_folio() and folio_inc_gen(). Link: https://lore.kernel.org/linux-mm/20260726122123.7614-4-baohua@kernel.= org/ [1] > diff --git a/mm/vmscan.c b/mm/vmscan.c > index f98cd483f014a..20199232dd70c 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c [ ... ] > @@ -4758,17 +4756,27 @@ static int scan_folios(unsigned long nr_to_scan, = struct lruvec *lruvec, > int scanned =3D 0; > int isolated =3D 0; > int skipped =3D 0; > + unsigned long min_seq; > unsigned long remaining =3D nr_to_scan; > struct lru_gen_folio *lrugen =3D &lruvec->lrugen; > =20 > VM_WARN_ON_ONCE(nr_to_scan > MAX_LRU_BATCH); > VM_WARN_ON_ONCE(!list_empty(list)); > =20 > + /* > + * Respect the gen hotness distribution at low priority to avoid > + * aging and scan cost, but prefer to satisfy the reclaimers request > + * when under pressure to respect swappiness more and reduce IO cost. > + */ > + if (sc->priority =3D=3D DEF_PRIORITY) > + min_seq =3D lrugen->min_seq[type]; > + else > + min_seq =3D lruvec_populated_min_seq(lruvec, type, lrugen->max_seq - M= IN_NR_GENS + 1); [Severity: Low] Does debugfs eviction via lru_gen_seq_write() take the raised-priority branch here because sc.priority is left zero-initialized? lru_gen_seq_write() allocates struct scan_control sc on the stack without setting .priority =3D DEF_PRIORITY, so sc.priority is 0. When an eviction command runs while one type's oldest generation is empty and the other type keeps get_nr_gens() above MIN_NR_GENS, scan_folios() treats the call as raised priority and advances min_seq up to max_seq - MIN_NR_GENS + = 1, evicting folios from generations younger than the requested min_gen_nr (including active generations that run_eviction() rejects). --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261111232603.9934= -1-baohua@kernel.org?part=3D3