From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f172.google.com (mail-ig0-f172.google.com [209.85.213.172]) by kanga.kvack.org (Postfix) with ESMTP id A0DAF6B0032 for ; Fri, 27 Mar 2015 07:11:47 -0400 (EDT) Received: by igbud6 with SMTP id ud6so17068661igb.1 for ; Fri, 27 Mar 2015 04:11:47 -0700 (PDT) Received: from resqmta-ch2-09v.sys.comcast.net (resqmta-ch2-09v.sys.comcast.net. [2001:558:fe21:29:69:252:207:41]) by mx.google.com with ESMTPS id 41si1453024ioq.94.2015.03.27.04.11.46 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Fri, 27 Mar 2015 04:11:46 -0700 (PDT) Date: Fri, 27 Mar 2015 06:11:44 -0500 (CDT) From: Christoph Lameter Subject: Re: [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work In-Reply-To: <20150327093023.GA32047@worktop.ger.corp.intel.com> Message-ID: References: <359c926bc85cdf79650e39f2344c2083002545bb.1427347966.git.viresh.kumar@linaro.org> <20150326131822.fce6609efdd85b89ceb3f61c@linux-foundation.org> <20150327091613.GE27490@worktop.programming.kicks-ass.net> <20150327093023.GA32047@worktop.ger.corp.intel.com> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Viresh Kumar , Andrew Morton , hannes@cmpxchg.org, Linaro Kernel Mailman List , Linux Kernel Mailing List , vinmenon@codeaurora.org, shashim@codeaurora.org, Michal Hocko , mgorman@suse.de, dave@stgolabs.net, koct9i@gmail.com, Linux Memory Management List , Suresh Siddha , Thomas Gleixner On Fri, 27 Mar 2015, Peter Zijlstra wrote: > > We could align the base on 8 bytes to gain an extra bit in the pointer > > and use that bit to indicate the running state. Then these sites can > > spin on that bit while we can change the actual base pointer. > > Even though tvec_base has ____cacheline_aligned stuck on, most are > allocated using kzalloc_node() which does not actually respect that but > already guarantees a minimum u64 alignment, so I think we can use that > third bit without too much magic. Create a new slab cache for this purpose that does the proper aligning? -- 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