From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0C61C5DF62 for ; Wed, 6 Nov 2019 08:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9CB87206A3 for ; Wed, 6 Nov 2019 08:00:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nrz8ddPk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730194AbfKFIAl (ORCPT ); Wed, 6 Nov 2019 03:00:41 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:46305 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729878AbfKFIAl (ORCPT ); Wed, 6 Nov 2019 03:00:41 -0500 Received: by mail-pf1-f195.google.com with SMTP id 193so16938167pfc.13 for ; Wed, 06 Nov 2019 00:00:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=KuPVTVr4RYweQb+V3z56bkXkHnz53CjmsEHwNcAKPBA=; b=nrz8ddPkTcWqz4wbBXtX1ZVpAU55IYE7RYAUO6y5C3CA9bYv9NQ8EB6N1Mn1prJBdm pa/1N+2ErAAwWwcSLAH4+Q5E5BmC5oJAt7vBdKoFtZR68Yta1/Heo4pwtfPJPiQHopbV DzMsrrf+pPTLtHT3c01UvZaB/ryskTUdorhm1B4BVr2UJAVKMKpU7qsxdfBsLD6ZFI/U /MMZf4JIrpIM5EX9rHOoiKD+pZ/e5W9ZvGrVwN0RqQO1ycKkEYQFCiMyKyRVAnDajHCZ QOZ6XVv8FLfc9WDguFYQFgjQcObPl3WSnGX1rtXe6ZjMlnmOv5SNhfngzgzqyEw2Wknx nPpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=KuPVTVr4RYweQb+V3z56bkXkHnz53CjmsEHwNcAKPBA=; b=i3SV9YhU3KHmKa0VJR6NK85HsKhm1fxCuHtqAM2b4Az+oZoJXMtmpXnMX/wkAC+HPY cutRFtmyNjYWKO+A7Dxypq20foZ6lVzk8S8JczGb0ssYKHW1rb/nt18uqPC1rqcy6Xnm IELaKkFm1W0ZbMvVg9p/noBZmaRtQBx6joX1Q0frOjnGWhEIvie+2VbA8CipZfx317YR Da8+ESXY2fjuV8ucz2TqnSf9222+WeEWOvZTHg2wK9aIqcW7w3MWMioIWlyxXlR/9m+b bCU8u5SGzJML2xkVfrGUEthB5qq3koLk7C2n7/HDlXwww2fQcpOk9qOD+RgW+vHYaItK IzGQ== X-Gm-Message-State: APjAAAUvzZnYPXDoxO0hStdeKDTETSLsgibl6xAaIJCBK9qQtSy5HGx4 LCvrnh98G22hSaeuA6m+vS0= X-Google-Smtp-Source: APXvYqy6WTKqy9mtM9teFAhh5LwP4xmTEivvABPHoP3S/DIO3JEoUN6rh0CwbHefPFSoxTmIK/fKCA== X-Received: by 2002:a62:108:: with SMTP id 8mr1688106pfb.53.1573027240908; Wed, 06 Nov 2019 00:00:40 -0800 (PST) Received: from localhost ([2401:fa00:8f:203:250d:e71d:5a0a:9afe]) by smtp.gmail.com with ESMTPSA id 13sm24968289pgq.72.2019.11.06.00.00.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Nov 2019 00:00:39 -0800 (PST) Date: Wed, 6 Nov 2019 17:00:37 +0900 From: Sergey Senozhatsky To: "Joel Fernandes (Google)" Cc: linux-kernel@vger.kernel.org, Ioannis Ilkos , minchan@google.com, primiano@google.com, fmayer@google.com, hjd@google.com, joaodias@google.com, joelaf@google.com, lalitm@google.com, rslawik@google.com, sspatil@google.com, timmurray@google.com, Andrew Morton , Andy Shevchenko , Changbin Du , Ingo Molnar , Joe Perches , Kees Cook , linux-mm@kvack.org, Michal Hocko , Petr Mladek , "Rafael J. Wysocki" , Sakari Ailus , Sergey Senozhatsky , Stephen Rothwell , Steven Rostedt Subject: Re: [PATCH] rss_stat: Add support to detect RSS updates of external mm Message-ID: <20191106080037.GA59367@google.com> References: <20191106024452.81923-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191106024452.81923-1-joel@joelfernandes.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (19/11/05 21:44), Joel Fernandes (Google) wrote: [..] > +++ b/lib/vsprintf.c > @@ -761,11 +761,34 @@ static int __init initialize_ptr_random(void) > early_initcall(initialize_ptr_random); > > /* Maps a pointer to a 32 bit unique identifier. */ > +int ptr_to_hashval(const void *ptr, unsigned long *hashval_out) > +{ > + const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)"; > + unsigned long hashval; > + > + if (static_branch_unlikely(¬_filled_random_ptr_key)) > + return -EAGAIN; > + > +#ifdef CONFIG_64BIT > + hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key); > + /* > + * Mask off the first 32 bits, this makes explicit that we have > + * modified the address (and 32 bits is plenty for a unique ID). > + */ > + hashval = hashval & 0xffffffff; > +#else > + hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key); > +#endif > + *hashval_out = hashval; > + return 0; > +} Maybe we want to move this thing to more generic code - lib/siphash.c - since it's going to have several users. -ss