From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 88A3C84D04 for ; Wed, 7 Aug 2024 14:39:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723041577; cv=none; b=CyLncKAO5hmAsbP2tmPeawG6FCDKB0sHdFedq9Yl86GBIZia0AvowzJ8mrGIxSmnHxsMt3cHAK2NUjoK1SFxQ939rVgOKq0YoYPT4j+RNYJyHysbZPW3Zx0Tdbtszkah5irx586AaS8dXAll3/sjalXKkx1RGzsNnASHbfBZaZY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723041577; c=relaxed/simple; bh=AuD1e/htfG1lFR9kSdMvIEtoeOyeABqQKaB/QtDE2F8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=EAQGQIr/2LzkuQFzsu6fRQrlsokR3yXZWLtCSzKQvlK9/NifkQgYQqH3dSnBZn27CgDrFSE9dA+fRIBkSbS9VaRIr1MVzcXPVjcbdLLeo7aybBKNp55IbqQ/IsLpsZHxosjTRf/q3o3DnytyFBjuMJIPyJVQAHB5F3WGu/9BXzg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--cmllamas.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=xl6duz5M; arc=none smtp.client-ip=209.85.210.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--cmllamas.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="xl6duz5M" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-70eb4de4eb9so1911538b3a.2 for ; Wed, 07 Aug 2024 07:39:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1723041576; x=1723646376; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=26uLUGt1PbHjw3R3dD99uteqgjJ71bdj6keYRqjuSeo=; b=xl6duz5MIKSbbkUrFT/cd6sTwK25ZYwWq75wbDbcuUH6IQs0qdBKUQQyXhDjH1otd4 UnvShibEA3kicEQLFSKwQVRZYefcfp+OdRvK+JvDpbp7lJUiDRmw39r8eHSzIRcwVSJt 4XBsPlQXKC4Jod5l9adDefdkxuJdZCVAFKoamRDObiBNwmEsWKjTX7IBNUePDUkoOaLI z7iRNU7VsJv4cSxOoM6s/eBxra4RvyqoYEI9wWzdFX0Hx++EZ7SoPs97DfY6k/LadAXy Z2U4GR8WujkH+7ZEu0ZDmFx+SLI27pcPtTI8feDpIjezk09ngHg3h4KC1JGehPIw+f54 3m4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723041576; x=1723646376; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=26uLUGt1PbHjw3R3dD99uteqgjJ71bdj6keYRqjuSeo=; b=HBmPFRFPLzanjkfgFgo9kBRVY4qaCBFzHBKOUWtnW+i+ewYKlXPIZJp77bCmNKvffn hnfrKjUE37Fz/rIlp1lWCkSHhhiqx6VKhty/k1rAwP+mkgkvDdVQbbKCuLpQBdo6lb2p a8TNmUVoezJ7tfxFhI4p9SttpJLje0/jQAH+wU6bqHWXeDASVKUDn0DUF/NAlzM+oUjA scfExbKgktICPAk6Xq1EDUDV37+fwCdFJ1EXG1HBXVYtF5/Q+op3EfOrz3h1lHSd+B/1 3UukcE0b9HpKBZ7ppokaUstc906B7gr61Q7MFufk7DYJCzHK6FpyZ/vUFzSlZAWbO+WY t0ZQ== X-Gm-Message-State: AOJu0Yw7uUGzhoLCZI4WTSyzj/ltkmwXhCpjNz88NznukXE45xzalDDz N+L5NsKy6JGSwfQ+SnG15uAatZ2gA7DWjhNKjoZkhmDCaWHG7PEiKOV9QsM7GAIa2+QcPWVIBNQ gGQZjm85y2A== X-Google-Smtp-Source: AGHT+IEZMcCt1x+PG1vtH8TF7MugLb9TpmzKqwXDpbLZ8DPfCHSERoPeDJ86A+OyXAQiHcK24I8oxCxpxP4D/A== X-Received: from xllamas.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5070]) (user=cmllamas job=sendgmr) by 2002:a05:6a00:6f0b:b0:710:4d1c:9ee0 with SMTP id d2e1a72fcca58-7106d0861efmr343810b3a.4.1723041575752; Wed, 07 Aug 2024 07:39:35 -0700 (PDT) Date: Wed, 7 Aug 2024 14:39:19 +0000 In-Reply-To: <20240807143922.919604-1-cmllamas@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240807143922.919604-1-cmllamas@google.com> X-Mailer: git-send-email 2.46.0.rc2.264.g509ed76dc8-goog Message-ID: <20240807143922.919604-4-cmllamas@google.com> Subject: [PATCH v2 3/3] lockdep: document MAX_LOCKDEP_CHAIN_HLOCKS calculation From: Carlos Llamas To: Peter Zijlstra , Ingo Molnar , Will Deacon Cc: linux-kernel@vger.kernel.org, kernel-team@android.com, Andrew Morton , Carlos Llamas , Waiman Long , Huang Ying , "J. R. Okajima" , Boqun Feng Content-Type: text/plain; charset="UTF-8" Define a macro AVG_LOCKDEP_CHAIN_DEPTH to document the magic number '5' used in the calculation of MAX_LOCKDEP_CHAIN_HLOCKS. The number represents the estimated average depth (number of locks held) of a lock chain. The calculation of MAX_LOCKDEP_CHAIN_HLOCKS was first added in commit 443cd507ce7f ("lockdep: add lock_class information to lock_chain and output it"). Suggested-by: Waiman Long Cc: Huang Ying Cc: J. R. Okajima Cc: Peter Zijlstra Cc: Boqun Feng Cc: Ingo Molnar Cc: Will Deacon Signed-off-by: Carlos Llamas --- v2: switched the comment for a macro as suggested by Waiman Long. kernel/locking/lockdep_internals.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index bbe9000260d0..20f9ef58d3d0 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -119,7 +119,8 @@ static const unsigned long LOCKF_USED_IN_IRQ_READ = #define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS) -#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5) +#define AVG_LOCKDEP_CHAIN_DEPTH 5 +#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS * AVG_LOCKDEP_CHAIN_DEPTH) extern struct lock_chain lock_chains[]; -- 2.46.0.rc2.264.g509ed76dc8-goog