Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757048AbbDPHTp (ORCPT ); Thu, 16 Apr 2015 03:19:45 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60790 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756497AbbDPHTi (ORCPT ); Thu, 16 Apr 2015 03:19:38 -0400 Date: Thu, 16 Apr 2015 00:25:01 -0700 From: Andrew Morton To: Mel Gorman Cc: Linux-MM , Robin Holt , Nathan Zimmer , Daniel Rahn , Davidlohr Bueso , Dave Hansen , Tom Vaden , Scott Norton , LKML Subject: Re: [RFC PATCH 0/14] Parallel memory initialisation Message-Id: <20150416002501.e9615db6.akpm@linux-foundation.org> In-Reply-To: <1428920226-18147-1-git-send-email-mgorman@suse.de> References: <1428920226-18147-1-git-send-email-mgorman@suse.de> X-Mailer: Sylpheed 2.7.1 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1557 Lines: 33 On Mon, 13 Apr 2015 11:16:52 +0100 Mel Gorman wrote: > Memory initialisation I wish we didn't call this "memory initialization". Because memory initialization is memset(), and that isn't what we're doing here. Installation? Bringup? > had been identified as one of the reasons why large > machines take a long time to boot. Patches were posted a long time ago > that attempted to move deferred initialisation into the page allocator > paths. This was rejected on the grounds it should not be necessary to hurt > the fast paths to parallelise initialisation. This series reuses much of > the work from that time but defers the initialisation of memory to kswapd > so that one thread per node initialises memory local to that node. The > issue is that on the machines I tested with, memory initialisation was not > a major contributor to boot times. I'm posting the RFC to both review the > series and see if it actually helps users of very large machines. > > ... > > 15 files changed, 507 insertions(+), 98 deletions(-) Sadface at how large and complex this is. I'd hoped the way we were going to do this was by bringing up a bit of memory to get booted up, then later on we just fake a bunch of memory hot-add operations. So the new code would be pretty small and quite high-level. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/