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Thu, 12 Nov 2026 12:59:40 +0000 X-Mizu-Trace-ID: 9721da014f7e0601 X-Migadu-Flow: FLOW_OUT From: "Xu Xin (vivo)" To: xu.xin@linux.dev Cc: chengming.zhou@linux.dev, david@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org Subject: [PATCH 1/2] mm/ksm: extract helper functions for scan cycle cleanup Date: Thu, 12 Nov 2026 20:59:28 +0800 Message-Id: <20261112125928.177598-1-xu.xin@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20261112125754.176930-1-xu.xin@linux.dev> References: <20261112125754.176930-1-xu.xin@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam06 X-Stat-Signature: 4ei11unw3rkz393sa5xtax3wi4pp4wia X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Queue-Id: 676D61C0002 X-Rspam-User: X-HE-Tag: 1794488381-243821 X-HE-Meta: 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 1BJHIla+ /ELCdPmglD5rukYhabMvwm4BArpdd4CWnHI5pZ4zMA4TRqLTlCXpkg/kNTtf1Ft1wkfprYDuEMHH+IPeTXqI+F9LnddR+vKhiUyFhRcSxhSabUOZJV2fiIvL8OnXpXQGH0prlZVahVaV5zSxHAuVqs4z0U+1RDbDtqaaKpXlS0JZZPczbNdmJs40Bz9JnOCjDTOplO2zFObdU8hwNIKvr3pwUHMqEzMXazOvK 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 Since scan_get_next_rmap_item() is getting too large, extract two new helper functions, ksm_prune_migrate_nodes() and ksm_reset_unstable_trees(), to reduce indentation levels, isolate local variables, and improve the readability of the main scan loop. No functional change intended. Signed-off-by: Xu Xin (vivo) --- mm/ksm.c | 56 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 33 insertions(+), 23 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index 5e24b5ca8dc8..49977bcf04f7 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2609,6 +2609,37 @@ static struct mm_walk_ops ksm_next_page_ops = { .walk_lock = PGWALK_RDLOCK, }; +static void ksm_prune_migrate_nodes(void) +{ + struct ksm_stable_node *stable_node, *next; + struct folio *folio; + + if (ksm_merge_across_nodes) + return; + + /* + * Whereas stale stable_nodes on the stable_tree itself + * get pruned in the regular course of stable_tree_search(), + * those moved out to the migrate_nodes list can accumulate: + * so prune them once before each full scan. + */ + list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) { + folio = ksm_get_folio(stable_node, KSM_GET_FOLIO_NOLOCK); + + if (folio) + folio_put(folio); + cond_resched(); + } +} + +static void ksm_reset_unstable_trees(void) +{ + int nid; + + for (nid = 0; nid < ksm_nr_node_ids; nid++) + root_unstable_tree[nid] = RB_ROOT; +} + static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) { struct mm_struct *mm; @@ -2617,7 +2648,6 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) struct vm_area_struct *vma; struct ksm_rmap_item *rmap_item; struct vma_iterator vmi; - int nid; if (list_empty(&ksm_mm_head.slot.mm_node)) return NULL; @@ -2639,28 +2669,8 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) */ lru_add_drain_all(); - /* - * Whereas stale stable_nodes on the stable_tree itself - * get pruned in the regular course of stable_tree_search(), - * those moved out to the migrate_nodes list can accumulate: - * so prune them once before each full scan. - */ - if (!ksm_merge_across_nodes) { - struct ksm_stable_node *stable_node, *next; - struct folio *folio; - - list_for_each_entry_safe(stable_node, next, - &migrate_nodes, list) { - folio = ksm_get_folio(stable_node, - KSM_GET_FOLIO_NOLOCK); - if (folio) - folio_put(folio); - cond_resched(); - } - } - - for (nid = 0; nid < ksm_nr_node_ids; nid++) - root_unstable_tree[nid] = RB_ROOT; + ksm_prune_migrate_nodes(); + ksm_reset_unstable_trees(); spin_lock(&ksm_mmlist_lock); slot = list_entry(mm_slot->slot.mm_node.next, -- 2.34.1