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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , John Fastabend , =?utf-8?q?Thomas_Hellstr=C3=B6m?= , Alice Ryhl , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Boqun Feng , Boqun Feng Cc: netfilter-devel@vger.kernel.org, bpf@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, coreteam@netfilter.org, netdev@vger.kernel.org, Jim Cromie X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1786987349; l=4389; i=jim.cromie@gmail.com; s=20260203; h=from:subject:message-id; bh=ZoAPPwe75kYWQBnnaiZlpzm8KKVLAq8UQwudQC9NlbE=; b=KNAOo/eQMuy5erfpSMg/oT8JjN3sqRwBgko6OmdykAuJj2sOkIfPf1RxIxulBDQLthiMvgmmd NmWIc7T/EjfBohB3EMTwfUSxsxhPMAP5h7s7rWhuP12qQAR2uE+yRiK X-Developer-Key: i=jim.cromie@gmail.com; a=ed25519; pk=C6E5ODlPQo7ZBynATXH9wg7K6HxP0pIXyf4s38Qw0XE= X-Endpoint-Received: by B4 Relay for jim.cromie@gmail.com/20260203 with auth_id=958 X-Original-From: Jim Cromie Reply-To: jim.cromie@gmail.com X-Rspam-User: X-Rspamd-Queue-Id: B4688C0003 X-Rspamd-Server: rspam07 X-Stat-Signature: jsz4bb4pxmknsjreb693aom1p1azr5wm X-HE-Tag: 1786987354-905384 X-HE-Meta: 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 nxbeCVMp 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Jim Cromie Shrink the static compile-time list_entries[] array and its tracking bitmap from MAX_LOCKDEP_ENTRIES (32,768 entries, ~1.31 MB BSS) down to a 4096-entry early boot bootstrap buffer (~160 KB BSS). During early boot before mem_init(), lockdep records initial spinlock dependencies in the static bootstrap buffer. Once the buddy page allocator is online, alloc_list_entry() seamlessly spills all subsequent lock dependency allocations directly into lockdep_pool in 64KB direct-map folios. Adds a core_initcall telemetry hook (lockdep_boot_report) to log the exact count of bootstrap entries consumed prior to buddy initialization. Empirical boot telemetry confirms zero regressions and validates the two-tier spillway on x86 SMP: - Pre-buddy watermark: 668/4096 bootstrap entries consumed (16.3%). - Post-buddy scaling: 5,058 total direct dependencies and 22,577 indirect paths validated, with 962 entries operating dynamically inside lockdep_pool direct-map folios. Reclaims ~1.15 MB of static unswappable kernel .bss memory (88% reduction) while enabling unbounded lockdep scaling on dense NUMA/container workloads. Signed-off-by: Jim Cromie --- kernel/locking/lockdep.c | 33 +++++++++++++++++++++++++++------ 1 file changed, 27 insertions(+), 6 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index c8975c9282bb..5968a976bf8e 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -229,9 +229,11 @@ static inline int debug_locks_off_graph_unlock(void) return ret; } +#define BOOTSTRAP_LOCKDEP_ENTRIES 4096UL + unsigned long nr_list_entries; -static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; -static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES); +static struct lock_list list_entries[BOOTSTRAP_LOCKDEP_ENTRIES]; +static DECLARE_BITMAP(list_entries_in_use, BOOTSTRAP_LOCKDEP_ENTRIES); /* * All data structures here are protected by the global debug_lock. @@ -6271,6 +6273,12 @@ static void remove_class_from_lock_chains(struct pending_free *pf, } } +static inline bool is_bootstrap_entry(const struct lock_list *entry) +{ + return entry >= list_entries && + entry < list_entries + ARRAY_SIZE(list_entries); +} + /* * Remove all references to a lock class. The caller must hold the graph lock. */ @@ -6287,26 +6295,30 @@ static void zap_class(struct pending_free *pf, struct lock_class *class) list_for_each_entry_safe(entry, tmp, &class->locks_after, entry) { list_for_each_entry_safe(other, other_tmp, &entry->links_to->locks_before, entry) { if (other->links_to == class) { - __clear_bit(other - list_entries, list_entries_in_use); + if (is_bootstrap_entry(other)) + __clear_bit(other - list_entries, list_entries_in_use); nr_list_entries--; list_del_rcu(&other->entry); break; } } - __clear_bit(entry - list_entries, list_entries_in_use); + if (is_bootstrap_entry(entry)) + __clear_bit(entry - list_entries, list_entries_in_use); nr_list_entries--; list_del_rcu(&entry->entry); } list_for_each_entry_safe(entry, tmp, &class->locks_before, entry) { list_for_each_entry_safe(other, other_tmp, &entry->links_to->locks_after, entry) { if (other->links_to == class) { - __clear_bit(other - list_entries, list_entries_in_use); + if (is_bootstrap_entry(other)) + __clear_bit(other - list_entries, list_entries_in_use); nr_list_entries--; list_del_rcu(&other->entry); break; } } - __clear_bit(entry - list_entries, list_entries_in_use); + if (is_bootstrap_entry(entry)) + __clear_bit(entry - list_entries, list_entries_in_use); nr_list_entries--; list_del_rcu(&entry->entry); } @@ -6718,6 +6730,15 @@ void __init lockdep_init(void) sizeof(((struct task_struct *)NULL)->held_locks)); } +static int __init lockdep_boot_report(void) +{ + pr_info("lockdep: %lu/%lu bootstrap entries used before buddy init, folio_pool active\n", + min_t(unsigned long, nr_list_entries, ARRAY_SIZE(list_entries)), + ARRAY_SIZE(list_entries)); + return 0; +} +core_initcall(lockdep_boot_report); + static void print_freed_lock_bug(struct task_struct *curr, const void *mem_from, const void *mem_to, struct held_lock *hlock) -- 2.55.0