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b=D6q3gpTpKYEmJrHIaehomVhi1poKU/XVJMTpb4cma30HCgRYKwXEi0yg94psAaPV9 +jfeWPrBd1TSAnMyF9xk9WcIi0wKWkhiDH8FAKfcEbx0CLASo9cMQC7p5v0MKsj+Pr qiLAT7mWhjo5FcN/Sdq6IfwKEPvwmn763Q8I3DukPb4Kxpexmxi6gJbEuDgYMpXTPg AiBno42Cq1EmQ8F0bRjOdxLrt4o+sV5AedjjqedD/VQt9n/KwEqkLF6QDV2I6+/QXM 0AA88mroPgaAl7s0I53yYK/sCANQL2fpCcqCWSqvtUZjRpGZSpWlAWyg9fKJ0c0wXx cHaPLHcrGWwQA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v3 2/3] mm/migrate: introduce async non-temporal migration mode Reply-To: sashiko-reviews@lists.linux.dev To: "Huan Nguyen" , tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, trondmy@kernel.org, anna@kernel.org, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, jackmanb@google.com, hannes@cmpxchg.org, shivankg@amd.com Cc: rientjes@google.com, dave@stgolabs.net, nifan.cxl@gmail.com, fvdl@google.com, jic23@kernel.org, rkodsara@amd.com, bharata@amd.com, sj@kernel.org, weixugc@google.com, xuezhengchu@huawei.com, yiannis@zptcorp.com, yiannis.nikolakop@gmail.com, dimitrios.palyvos@zptcorp.com, alirad.malek@zptcorp.com, ryan.roberts@arm.com, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, "Chuck Lever" , "Jeff Layton" In-Reply-To: <20261103223025.2482227-3-nhuhuan@google.com> References: <20260730-rfc-nt-demote-v2-0-452dbe3b5073@zptcorp.com> <20261103223025.2482227-1-nhuhuan@google.com> <20261103223025.2482227-3-nhuhuan@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 04 Nov 2026 22:31:56 +0000 X-Stat-Signature: iqusak79rqiz7gictoprwzitdrkry56c 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: 2C6C680005 X-HE-Tag: 1793831520-864580 X-HE-Meta: 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 7aHBt86U 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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(= s) to consider: - [Medium] mm/compaction: enum migrate_mode ordering breaks compact_zone() = async check -- commit 047765d971a4b565eac5e2dd50bc528791c2e77e Author: Huan Nguyen mm/migrate: introduce async non-temporal migration mode This commit introduces MIGRATE_ASYNC_NONTEMPORAL to migrate cold folios using non-temporal stores via folio_mc_copy_nt() in __migrate_folio(), and adds migrate_is_async() to update callers across compaction, NFS, and migration. > diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h > index 05102d4d2490e..fd752fddc972e 100644 > --- a/include/linux/migrate_mode.h > +++ b/include/linux/migrate_mode.h > @@ -12,6 +12,7 @@ enum migrate_mode { > MIGRATE_ASYNC, > MIGRATE_SYNC_LIGHT, > MIGRATE_SYNC, > + MIGRATE_ASYNC_NONTEMPORAL, > }; [Severity: Medium] Does placing MIGRATE_ASYNC_NONTEMPORAL after MIGRATE_SYNC in enum migrate_mode break the relational check in compact_zone()? In mm/compaction.c, compact_zone() checks (cc->mode < MIGRATE_SYNC) when a page fails to migrate within a pageblock: mm/compaction.c:compact_zone() { ... /* * If an ASYNC or SYNC_LIGHT fails to migrate a page * within the pageblock_order-aligned block and * fast_find_migrateblock may be used then scan the * remainder of the pageblock. * ... */ if (!pageblock_aligned(cc->migrate_pfn) && !cc->ignore_skip_hint && !cc->finish_pageblock && (cc->mode < MIGRATE_SYNC)) { cc->finish_pageblock =3D true; ... goto rescan; } ... } Because MIGRATE_ASYNC_NONTEMPORAL has an enum value greater than MIGRATE_SYNC, (cc->mode < MIGRATE_SYNC) evaluates to false when compact_zon= e() runs with cc->mode =3D=3D MIGRATE_ASYNC_NONTEMPORAL and migration fails mid-pageblock. That causes compact_zone() to skip setting cc->finish_pageblock =3D true and jumping to rescan, leaving the pageblock partially scanned without marking it skip so fast_find_migrateblock() can repeatedly revisit it. Should MIGRATE_ASYNC_NONTEMPORAL be placed before MIGRATE_SYNC_LIGHT in enum migrate_mode (matching the ordering in include/trace/events/migrate.h), or should compact_zone() check cc->mode !=3D MIGRATE_SYNC like isolate_migratepages() does? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261103223025.2482= 227-1-nhuhuan@google.com?part=3D2