From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vk0-f71.google.com (mail-vk0-f71.google.com [209.85.213.71]) by kanga.kvack.org (Postfix) with ESMTP id BA8506B0003 for ; Thu, 8 Feb 2018 08:33:56 -0500 (EST) Received: by mail-vk0-f71.google.com with SMTP id o202so2283494vkd.23 for ; Thu, 08 Feb 2018 05:33:56 -0800 (PST) Received: from userp2120.oracle.com (userp2120.oracle.com. [156.151.31.85]) by mx.google.com with ESMTPS id f1si838503uae.366.2018.02.08.05.33.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 08 Feb 2018 05:33:55 -0800 (PST) Subject: Re: [LSF/MM TOPIC] lru_lock scalability References: <2a16be43-0757-d342-abfb-d4d043922da9@oracle.com> <20180201094431.GA20742@bombadil.infradead.org> <20180202170003.GA16840@bombadil.infradead.org> <20180206153359.GA31089@bombadil.infradead.org> From: Daniel Jordan Message-ID: Date: Thu, 8 Feb 2018 08:33:56 -0500 MIME-Version: 1.0 In-Reply-To: <20180206153359.GA31089@bombadil.infradead.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, steven.sistare@oracle.com, pasha.tatashin@oracle.com, yossi.lev@oracle.com, Dave.Dice@oracle.com, akpm@linux-foundation.org, mhocko@kernel.org, ldufour@linux.vnet.ibm.com, dave@stgolabs.net, khandual@linux.vnet.ibm.com, ak@linux.intel.com, mgorman@suse.de, Peter Zijlstra On 02/06/2018 10:33 AM, Matthew Wilcox wrote: > static inline void xas_maybe_lock_irq(struct xa_state *xas, void *entry) > { > if (entry) { > rcu_read_lock(); > xas_start(&xas); > if (!xas_bounds(&xas)) > return; > } Trying to understand what's going on here. xas_bounds isn't in your latest two XArray branches (xarray-4.16 or xarray-2018-01-09). Isn't it checking whether 'entry' falls inside the currently allocated range of the XArray? So that it should tell us whether a new xa_node needs to be allocated for 'entry'? If that's true, I guess it should take 'entry' as well as '&xas'. Daniel -- 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