From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f50.google.com (mail-qv1-f50.google.com [209.85.219.50]) (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 B3306154BEF for ; Wed, 27 Mar 2024 23:26:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711581987; cv=none; b=RobIGAHC/+hz2H8kzm5awrpottV0KbFsVd/3v5FpgEKajXEnAf95vJ/vIPwPSSCqH7xaMRKqimuNouPXLlv2ALt1v4hcHp98QcDafkdEonkwApMtlSwvkkqTTfkBYBODGmsY0khUMj6kCWPZFF5nOkPrYE3QV0rSNjyInKnZReg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711581987; c=relaxed/simple; bh=+oCABmCPcwsGI+OhvQ5+d6UIKy/f+/yNNpmYX+NieJY=; h=Date:Message-ID:MIME-Version:Content-Type:Content-Disposition: From:To:Cc:Subject:References:In-Reply-To; b=kmIrQ4wjbteiy3E+hpfg2N2s5VxBW9VkFpzfQqazVlXYWm/3v53tMQZpjkq74WP/oqMaOCaB+VOazHI55hemrXLR8IBntUpELBkhlmJwW5lw5a8u8hA1EdM1mbFgOGUs0j38ilmN55YYaYHSYUBM/A5Zfaab9keTL4Wf/eCDhno= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=paul-moore.com; spf=pass smtp.mailfrom=paul-moore.com; dkim=pass (2048-bit key) header.d=paul-moore.com header.i=@paul-moore.com header.b=JQNepPW7; arc=none smtp.client-ip=209.85.219.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=paul-moore.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=paul-moore.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=paul-moore.com header.i=@paul-moore.com header.b="JQNepPW7" Received: by mail-qv1-f50.google.com with SMTP id 6a1803df08f44-696147fb5a7so3849836d6.0 for ; Wed, 27 Mar 2024 16:26:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore.com; s=google; t=1711581984; x=1712186784; darn=vger.kernel.org; h=in-reply-to:references:subject:cc:to:from:content-transfer-encoding :content-disposition:mime-version:message-id:date:from:to:cc:subject :date:message-id:reply-to; bh=gqkZ3v0W1Swr1887NZEacpasAkv1jS/mgA7NWhO8GpI=; b=JQNepPW7vDsJNSH4p6RKkvKnojO92Puk+tn77PZ/YicU8UM83rG7TsxDxxOngz8duk 01BVL6WBSklDqX5YXvFGVf2UiRN6K4jXvj1kDtkY50TkVb0R4/jOIk0J6J2uqT3oKq1w hCLA0mFrjvAGs6Mim2c7z7npV0Higph9DQBWrCuL2LclpmT3QzB0KUmbkY8WJf4bAOBd mcaAafqyJQ9CucEfnRBZ3s4kqr1OBuGVQREBuf3J77lmcHaeb0cHbLQXLRTixTBHG2dm 69WMayd8/yxSYgpz9nztuDGAYHWzY2l5yL+vWMJwR9oJRk3bJc4QHGUg8FLBARXsNqdm FsaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711581984; x=1712186784; h=in-reply-to:references:subject:cc:to:from:content-transfer-encoding :content-disposition:mime-version:message-id:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=gqkZ3v0W1Swr1887NZEacpasAkv1jS/mgA7NWhO8GpI=; b=Fm0zNqg7PTNSWoi1b1vYfpJNkghIbow2t+5ZV15ZPHdU9DmCjX48Dh7vdcx+ULwH6V BkmO1L7TU0LFZXfnLBSyhO/fOkosldpqbWzXrTATjY75Xp10rewbaFDUqwj7TpWbqPhv SOI6Ed93GcYUzYX0vs/x3bbt9dk4PH+QDJgtc2vAb+Ngda384BgBps9rKs1/f68y8LuF ChEFcTUClNP3JRc0uxk3xyO6aKFqGfv0Zsxv5Zx1ZHSLkQF7WSdY44vk5IF4d14wCE0r 0V+xV3xUeI52BqtzZg42t4DymunTzjS9p8JHv4q417anoBBRiz4Z92LcRfUIITuijNw/ Okjg== X-Forwarded-Encrypted: i=1; AJvYcCWncBOEs2SYP5uhLqPUPHazAWPUqtTtTmyf+LM8nifLn5A3NZjw+ETKegB222JpNhsTV216qidVw7a2lW7TOCbsIhkTy6yOZVhm586h X-Gm-Message-State: AOJu0YxGaqDVNbSYKlgwQqVkfS8bc0p6ugUbDUscVHlNT79zambeFx7T gBJ6d9RMpdsCILOQAdISTnyXNZh8dA2ZfaJJmPoXpE0gEZP4Bt3yuHLxSgSiCw== X-Google-Smtp-Source: AGHT+IGHHtvVIRpffHHM8Wdp7ieP8QGpfN/LOSUG5hir/HCGtrR8F2jvWgTd2q8lMFIIPMJ0RMrQMA== X-Received: by 2002:a0c:8e01:0:b0:696:a7f3:92fd with SMTP id v1-20020a0c8e01000000b00696a7f392fdmr935941qvb.65.1711581984604; Wed, 27 Mar 2024 16:26:24 -0700 (PDT) Received: from localhost ([70.22.175.108]) by smtp.gmail.com with ESMTPSA id me18-20020a0562145d1200b00696a03c6bc0sm90410qvb.7.2024.03.27.16.26.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Mar 2024 16:26:24 -0700 (PDT) Date: Wed, 27 Mar 2024 19:26:23 -0400 Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit From: Paul Moore To: =?UTF-8?q?Christian=20G=C3=B6ttsche?= , selinux@vger.kernel.org Cc: Stephen Smalley , Ondrej Mosnacek , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] selinux: improve symtab string hashing References: <20240315181414.649045-1-cgzones@googlemail.com> In-Reply-To: <20240315181414.649045-1-cgzones@googlemail.com> On Mar 15, 2024 =?UTF-8?q?Christian=20G=C3=B6ttsche?= wrote: > > The number of buckets is calculated by performing a binary AND against > the mask of the hash table, which is one less than its size (which is a > power of two). This leads to all top bits being discarded, requiring > for short or similar inputs a hash function with a good avalanche > effect. > > Use djb2a: > > # current > common prefixes: 7 entries and 5/8 buckets used, longest chain length 2, sum of chain length^2 11 > classes: 134 entries and 100/256 buckets used, longest chain length 5, sum of chain length^2 234 > roles: 15 entries and 6/16 buckets used, longest chain length 5, sum of chain length^2 57 > types: 4448 entries and 3016/8192 buckets used, longest chain length 41, sum of chain length^2 14922 > users: 7 entries and 3/8 buckets used, longest chain length 3, sum of chain length^2 17 > bools: 306 entries and 221/512 buckets used, longest chain length 4, sum of chain length^2 524 > levels: 1 entries and 1/1 buckets used, longest chain length 1, sum of chain length^2 1 > categories: 1024 entries and 400/1024 buckets used, longest chain length 4, sum of chain length^2 2740 > > # patch > common prefixes: 7 entries and 5/8 buckets used, longest chain length 2, sum of chain length^2 11 > classes: 134 entries and 101/256 buckets used, longest chain length 3, sum of chain length^2 210 > roles: 15 entries and 9/16 buckets used, longest chain length 3, sum of chain length^2 31 > types: 4448 entries and 3459/8192 buckets used, longest chain length 5, sum of chain length^2 6778 > users: 7 entries and 5/8 buckets used, longest chain length 3, sum of chain length^2 13 > bools: 306 entries and 236/512 buckets used, longest chain length 5, sum of chain length^2 470 > levels: 1 entries and 1/1 buckets used, longest chain length 1, sum of chain length^2 1 > categories: 1024 entries and 518/1024 buckets used, longest chain length 7, sum of chain length^2 2992 > > Signed-off-by: Christian Göttsche > --- > v2: > add licensing note > --- > security/selinux/ss/symtab.c | 22 +++++++++++----------- > 1 file changed, 11 insertions(+), 11 deletions(-) Merged into selinux/dev, thanks. -- paul-moore.com