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[96.255.20.138]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-5070d53f0fcsm38640631cf.9.2026.02.22.00.49.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 22 Feb 2026 00:49:36 -0800 (PST) From: Gregory Price To: lsf-pc@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, damon@lists.linux.dev, kernel-team@meta.com, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, dave@stgolabs.net, jonathan.cameron@huawei.com, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com, longman@redhat.com, akpm@linux-foundation.org, david@kernel.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, osalvador@suse.de, 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, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, yury.norov@gmail.com, linux@rasmusvillemoes.dk, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com, jackmanb@google.com, sj@kernel.org, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, muchun.song@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, jannh@google.com, linmiaohe@huawei.com, nao.horiguchi@gmail.com, pfalcato@suse.de, rientjes@google.com, shakeel.butt@linux.dev, riel@surriel.com, harry.yoo@oracle.com, cl@gentwo.org, roman.gushchin@linux.dev, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, zhengqi.arch@bytedance.com, terry.bowman@amd.com Subject: [RFC PATCH v4 11/27] mm/huge_memory.c: add private node folio split notification callback Date: Sun, 22 Feb 2026 03:48:26 -0500 Message-ID: <20260222084842.1824063-12-gourry@gourry.net> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260222084842.1824063-1-gourry@gourry.net> References: <20260222084842.1824063-1-gourry@gourry.net> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Some private node services may need to update internal metadata when a THP folio is split. ZONE_DEVICE already has a split callback via pgmap->ops; private nodes can provide the same capability. Just like zone_device, some private node services may want to know about a folio being split. Add this optional callback to the ops struct and add a wrapper for zone_device and private node callback dispatch to be consolidated. Wire this into __folio_split() where the zone_device check was made. Signed-off-by: Gregory Price --- include/linux/node_private.h | 33 +++++++++++++++++++++++++++++++++ mm/huge_memory.c | 6 ++++-- 2 files changed, 37 insertions(+), 2 deletions(-) diff --git a/include/linux/node_private.h b/include/linux/node_private.h index 09ea7c4cb13c..f9dd2d25c8a5 100644 --- a/include/linux/node_private.h +++ b/include/linux/node_private.h @@ -3,6 +3,7 @@ #define _LINUX_NODE_PRIVATE_H #include +#include #include #include #include @@ -44,11 +45,19 @@ struct vm_fault; * Returns: true if handled (skip return to buddy) * false if no op (return to buddy) * + * @folio_split: Notification that a folio on this private node is being split. + * [folio-referenced callback] + * Called from the folio split path via folio_managed_split_cb(). + * @folio is the original folio; @new_folio is the newly created folio, + * or NULL when called for the final (original) folio after all sub-folios + * have been split off. + * * @flags: Operation exclusion flags (NP_OPS_* constants). * */ struct node_private_ops { bool (*free_folio)(struct folio *folio); + void (*folio_split)(struct folio *folio, struct folio *new_folio); unsigned long flags; }; @@ -150,6 +159,24 @@ static inline bool zone_private_flags(struct zone *z, unsigned long flag) return node_private_flags(zone_to_nid(z)) & flag; } +static inline void node_private_split_cb(struct folio *folio, + struct folio *new_folio) +{ + const struct node_private_ops *ops = folio_node_private_ops(folio); + + if (ops && ops->folio_split) + ops->folio_split(folio, new_folio); +} + +static inline void folio_managed_split_cb(struct folio *original_folio, + struct folio *new_folio) +{ + if (folio_is_zone_device(original_folio)) + zone_device_private_split_cb(original_folio, new_folio); + else if (folio_is_private_node(original_folio)) + node_private_split_cb(original_folio, new_folio); +} + #else /* !CONFIG_NUMA */ static inline bool folio_is_private_node(struct folio *folio) @@ -198,6 +225,12 @@ static inline bool zone_private_flags(struct zone *z, unsigned long flag) return false; } +static inline void folio_managed_split_cb(struct folio *original_folio, + struct folio *new_folio) +{ + if (folio_is_zone_device(original_folio)) + zone_device_private_split_cb(original_folio, new_folio); +} #endif /* CONFIG_NUMA */ #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 40cf59301c21..2ecae494291a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -3850,7 +3851,7 @@ static int __folio_freeze_and_split_unmapped(struct folio *folio, unsigned int n next = folio_next(new_folio); - zone_device_private_split_cb(folio, new_folio); + folio_managed_split_cb(folio, new_folio); folio_ref_unfreeze(new_folio, folio_cache_ref_count(new_folio) + 1); @@ -3889,7 +3890,8 @@ static int __folio_freeze_and_split_unmapped(struct folio *folio, unsigned int n folio_put_refs(new_folio, nr_pages); } - zone_device_private_split_cb(folio, NULL); + folio_managed_split_cb(folio, NULL); + /* * Unfreeze @folio only after all page cache entries, which * used to point to it, have been updated with new folios. -- 2.53.0