From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f178.google.com (mail-pd0-f178.google.com [209.85.192.178]) by kanga.kvack.org (Postfix) with ESMTP id 3E7666B0038 for ; Thu, 16 Apr 2015 03:19:39 -0400 (EDT) Received: by pdbnk13 with SMTP id nk13so82120647pdb.0 for ; Thu, 16 Apr 2015 00:19:38 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id ht8si10850115pdb.99.2015.04.16.00.19.38 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Apr 2015 00:19:38 -0700 (PDT) Date: Thu, 16 Apr 2015 00:25:01 -0700 From: Andrew Morton 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> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Linux-MM , Robin Holt , Nathan Zimmer , Daniel Rahn , Davidlohr Bueso , Dave Hansen , Tom Vaden , Scott Norton , LKML 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, 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