STRUCT KSM_STABLE_NODE(9)

💖 struct ksm_stable_node 💖

okay so bestie, welcome to the Kernel API Manual — this is the page for struct ksm_stable_node(9), and the NAME tea is literally node of the stable rbtree. That's the assignment, no cap. 🌸

✨ NAME ✨

struct ksm_stable_node — node of the stable rbtree. She's a node in the stable rbtree, periodt. 💅

🧚 SYNOPSIS 🧚

Here's the struct exactly, bestie — keep every character, including those semicolons after the preprocessor lines, iykyk:

struct ksm_stable_node {
    union {
      struct rb_node node;
      struct {
        struct list_head *head;
        struct {
          struct hlist_node hlist_dup;
          struct list_head list;
        };
      };
    };
    struct hlist_head hlist;
    union {
      unsigned long kpfn;
      unsigned long chain_prune_time;
    };
  #define STABLE_NODE_CHAIN -1024;
    int rmap_hlist_len;
  #ifdef CONFIG_NUMA;
    int nid;
  #endif;
 };

🎀 Members 🎀

Vibe check time, member by member, in order — every anonymous union/struct stays because the lore matters:

• {unnamed_union} — anonymous.
• node — rb node of this ksm page in the stable tree.
• {unnamed_struct} — anonymous.
• head — (overlaying parent) migrate_nodes indicates temporarily on that list.
• {unnamed_struct} — anonymous.
• hlist_dup — linked into the stable_node->hlist with a stable_node chain.
• list — linked into migrate_nodes, pending placement in the proper node tree.
• hlist — hlist head of rmap_items using this ksm page.
• {unnamed_union} — anonymous.
• kpfn — page frame number of this ksm page (perhaps temporarily on wrong nid).
• chain_prune_time — time of the last full garbage collection.
• rmap_hlist_len — number of rmap_item entries in hlist or STABLE_NODE_CHAIN.
• nid — NUMA node id of stable tree in which linked (may not match kpfn).

🦋 SEE ALSO 🦋

Go peek at these, bestie — the whole friend group is here:

• Kernel file ./mm/ksm.c Overview(9)
• struct ksm_mm_slot(9)
• struct ksm_scan(9)
• struct ksm_rmap_item(9)
• struct advisor_ctx(9)
• replace_page(9)
• ksm_do_scan(9)
• ksm_vma_flags(9)
• ksm_enable_merge_any(9)
• ksm_disable_merge_any(9)

with so much love from source ./mm, October 2026, for struct ksm_stable_node(9) 💖✨🦋