Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757385AbbBELuJ (ORCPT ); Thu, 5 Feb 2015 06:50:09 -0500 Received: from ipmail04.adl6.internode.on.net ([150.101.137.141]:55989 "EHLO ipmail04.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757337AbbBELuI (ORCPT ); Thu, 5 Feb 2015 06:50:08 -0500 X-Greylist: delayed 303 seconds by postgrey-1.27 at vger.kernel.org; Thu, 05 Feb 2015 06:50:07 EST X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AqYNAA9X01R5LHOVPGdsb2JhbABagwZSWYIyrU0BAQEBAQEGkkGFawQCAoEkRAEBAQEBBgEBAQE4O4QNAQU6HCMQCAMOCgklDwUlAwcaE4gsDtVtAQEBBwIBGwQYhWyJdAeEKQWSZIVZijuIMIQkKjEBgkEBAQE Date: Thu, 5 Feb 2015 22:45:00 +1100 From: Dave Chinner To: Oleg Drokin Cc: Steven Whitehouse , cluster-devel@redhat.com, Linux Kernel Mailing List , linux-mm@kvack.org Subject: Re: [PATCH] gfs2: use __vmalloc GFP_NOFS for fs-related allocations. Message-ID: <20150205114459.GI12722@dastard> References: <1422849594-15677-1-git-send-email-green@linuxhacker.ru> <20150202053708.GG4251@dastard> <20150202081115.GI4251@dastard> <54CF51C5.5050801@redhat.com> <20150203223350.GP6282@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1213 Lines: 30 On Wed, Feb 04, 2015 at 02:13:29AM -0500, Oleg Drokin wrote: > Hello! > > On Feb 3, 2015, at 5:33 PM, Dave Chinner wrote: > >> I also wonder if vmalloc is still very slow? That was the case some > >> time ago when I noticed a problem in directory access times in gfs2, > >> which made us change to use kmalloc with a vmalloc fallback in the > >> first place, > > Another of the "myths" about vmalloc. The speed and scalability of > > vmap/vmalloc is a long solved problem - Nick Piggin fixed the worst > > of those problems 5-6 years ago - see the rewrite from 2008 that > > started with commit db64fe0 ("mm: rewrite vmap layer").... > > This actually might be less true than one would hope. At least somewhat > recent studies by LLNL (https://jira.hpdd.intel.com/browse/LU-4008) > show that there's huge contention on vmlist_lock, so if you have vmalloc vmlist_lock and the list it protected went away in 3.10. Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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/