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[103.168.172.201]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6f50f44f5a2sm64779936d6.78.2025.05.05.21.20.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 May 2025 21:20:58 -0700 (PDT) Received: from phl-compute-08.internal (phl-compute-08.phl.internal [10.202.2.48]) by mailfauth.phl.internal (Postfix) with ESMTP id 7F2881200068; Tue, 6 May 2025 00:20:58 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-08.internal (MEProxy); Tue, 06 May 2025 00:20:58 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvkeeftdduucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdggtfgfnhhsuhgsshgtrhhisggv pdfurfetoffkrfgpnffqhgenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpih gvnhhtshculddquddttddmnecujfgurhephffvvefufffkofgjfhgggfestdekredtredt tdenucfhrhhomhepuehoqhhunhcuhfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrih hlrdgtohhmqeenucggtffrrghtthgvrhhnpefghfffvefhhfdvgfejgfekvdelgfekgeev ueehlefhiedvgeffjefgteeugfehieenucffohhmrghinhepkhgvrhhnvghlrdhorhhgne cuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepsghoqhhu nhdomhgvshhmthhprghuthhhphgvrhhsohhnrghlihhthidqieelvdeghedtieegqdduje ejkeehheehvddqsghoqhhunhdrfhgvnhhgpeepghhmrghilhdrtghomhesfhhigihmvgdr nhgrmhgvpdhnsggprhgtphhtthhopeduvddpmhhouggvpehsmhhtphhouhhtpdhrtghpth htohepmhhinhhgoheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepphgvthgvrhiisehi nhhfrhgruggvrggurdhorhhgpdhrtghpthhtohepmhhinhhgohesrhgvughhrghtrdgtoh hmpdhrtghpthhtohepfihilhhlsehkvghrnhgvlhdrohhrghdprhgtphhtthhopegsohhq uhhnrdhfvghnghesghhmrghilhdrtghomhdprhgtphhtthhopehlohhnghhmrghnsehrvg guhhgrthdrtghomhdprhgtphhtthhopehnrghthhgrnheskhgvrhhnvghlrdhorhhgpdhr tghpthhtohepnhhitghkrdguvghsrghulhhnihgvrhhsodhlkhhmlhesghhmrghilhdrtg homhdprhgtphhtthhopehmohhrsghosehgohhoghhlvgdrtghomh X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 6 May 2025 00:20:57 -0400 (EDT) From: Boqun Feng To: Ingo Molnar , Peter Zijlstra Cc: Ingo Molnar , Will Deacon , Boqun Feng , Waiman Long , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH 3/3] locking/lockdep: Add # of dynamic keys stat to /proc/lockdep_stats Date: Mon, 5 May 2025 21:20:49 -0700 Message-Id: <20250506042049.50060-4-boqun.feng@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20250506042049.50060-1-boqun.feng@gmail.com> References: <20250506042049.50060-1-boqun.feng@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Waiman Long There have been recent reports about running out of lockdep keys (MAX_LOCKDEP_KEYS too low!). One possible reason is that too many dynamic keys have been registered. A possible culprit is the lockdep_register_key() call in qdisc_alloc() of net/sched/sch_generic.c. Currently, there is no way to find out how many dynamic keys have been registered. Add such a stat to the /proc/lockdep_stats to get better clarity. Signed-off-by: Waiman Long Signed-off-by: Boqun Feng Link: https://lore.kernel.org/r/20250425001155.775458-1-longman@redhat.com --- kernel/locking/lockdep.c | 3 +++ kernel/locking/lockdep_internals.h | 1 + kernel/locking/lockdep_proc.c | 2 ++ 3 files changed, 6 insertions(+) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 58883c8375d1..e7166ff64681 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -219,6 +219,7 @@ static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_= ENTRIES); static struct hlist_head lock_keys_hash[KEYHASH_SIZE]; unsigned long nr_lock_classes; unsigned long nr_zapped_classes; +unsigned long nr_dynamic_keys; unsigned long max_lock_class_idx; struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS); @@ -1238,6 +1239,7 @@ void lockdep_register_key(struct lock_class_key *key) goto out_unlock; } hlist_add_head_rcu(&key->hash_entry, hash_head); + nr_dynamic_keys++; out_unlock: graph_unlock(); restore_irqs: @@ -6606,6 +6608,7 @@ void lockdep_unregister_key(struct lock_class_key *ke= y) pf =3D get_pending_free(); __lockdep_free_key_range(pf, key, 1); need_callback =3D prepare_call_rcu_zapped(pf); + nr_dynamic_keys--; } lockdep_unlock(); raw_local_irq_restore(flags); diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_in= ternals.h index 20f9ef58d3d0..82156caf77d1 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -138,6 +138,7 @@ extern unsigned long nr_lock_classes; extern unsigned long nr_zapped_classes; extern unsigned long nr_zapped_lock_chains; extern unsigned long nr_list_entries; +extern unsigned long nr_dynamic_keys; long lockdep_next_lockchain(long i); unsigned long lock_chain_count(void); extern unsigned long nr_stack_trace_entries; diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 6db0f43fc4df..b52c07c4707c 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -286,6 +286,8 @@ static int lockdep_stats_show(struct seq_file *m, void = *v) #endif seq_printf(m, " lock-classes: %11lu [max: %lu]\n", nr_lock_classes, MAX_LOCKDEP_KEYS); + seq_printf(m, " dynamic-keys: %11lu\n", + nr_dynamic_keys); seq_printf(m, " direct dependencies: %11lu [max: %lu]\n", nr_list_entries, MAX_LOCKDEP_ENTRIES); seq_printf(m, " indirect dependencies: %11lu\n", --=20 2.39.5 (Apple Git-154)