From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71]) by kanga.kvack.org (Postfix) with ESMTP id 896A16B0008 for ; Mon, 5 Mar 2018 14:20:12 -0500 (EST) Received: by mail-pl0-f71.google.com with SMTP id n12-v6so8464792pls.12 for ; Mon, 05 Mar 2018 11:20:12 -0800 (PST) Received: from mga04.intel.com (mga04.intel.com. [192.55.52.120]) by mx.google.com with ESMTPS id s190si8717429pgc.510.2018.03.05.11.20.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Mar 2018 11:20:11 -0800 (PST) Subject: Re: [PATCH v12 02/11] mm, swap: Add infrastructure for saving page metadata on swap References: From: Dave Hansen Message-ID: <0d77dc3c-1454-a689-a0fb-f07e8973c29e@linux.intel.com> Date: Mon, 5 Mar 2018 11:20:09 -0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Khalid Aziz , akpm@linux-foundation.org, davem@davemloft.net, arnd@arndb.de Cc: kirill.shutemov@linux.intel.com, mhocko@suse.com, ross.zwisler@linux.intel.com, dave.jiang@intel.com, mgorman@techsingularity.net, willy@infradead.org, hughd@google.com, minchan@kernel.org, hannes@cmpxchg.org, shli@fb.com, mingo@kernel.org, jglisse@redhat.com, me@tobin.cc, anthony.yznaga@oracle.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, sparclinux@vger.kernel.org, Khalid Aziz On 02/21/2018 09:15 AM, Khalid Aziz wrote: > If a processor supports special metadata for a page, for example ADI > version tags on SPARC M7, this metadata must be saved when the page is > swapped out. The same metadata must be restored when the page is swapped > back in. This patch adds two new architecture specific functions - > arch_do_swap_page() to be called when a page is swapped in, and > arch_unmap_one() to be called when a page is being unmapped for swap > out. These architecture hooks allow page metadata to be saved if the > architecture supports it. I still think silently squishing cacheline-level hardware data into page-level software data structures is dangerous. But, you seem rather determined to do it this way. I don't think this will _hurt_ anyone else, though other than needlessly cluttering up the code. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org