From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 12 May 2007 11:11:00 -0700 From: Andrew Morton Subject: Re: [PATCH 1/2] scalable rw_mutex Message-Id: <20070512111100.86ae13f6.akpm@linux-foundation.org> In-Reply-To: <20070512110624.9ac3aa44.akpm@linux-foundation.org> References: <20070511131541.992688403@chello.nl> <20070511132321.895740140@chello.nl> <20070511093108.495feb70.akpm@linux-foundation.org> <20070511110522.ed459635.akpm@linux-foundation.org> <20070512110624.9ac3aa44.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen , Christoph Lameter , Peter Zijlstra , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Oleg Nesterov , Ingo Molnar , Thomas Gleixner , Nick Piggin List-ID: On Sat, 12 May 2007 11:06:24 -0700 Andrew Morton wrote: > We could put a cpumask in percpu_counter, initialise it to > cpu_possible_map. Then, those callsites which have hotplug notifiers can > call into new percpu_counter functions which clear and set bits in that > cpumask and which drain percpu_counter.counts[cpu] into > percpu_counter.count. > > And percpu_counter_sum() gets taught to do for_each_cpu_mask(fbc->cpumask). Perhaps we could have a single cpu hotplug notifier in the percpu_counter library. Add register/deregister functions to the percpu_counter API so that all percpu_counters in the machine can be linked together. One _could_ just register and deregister the counters in percpu_counter_init() and percpu_counter_destroy(), but perhaps that wouldn't suit all callers, dunno. -- 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