From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f69.google.com (mail-oi0-f69.google.com [209.85.218.69]) by kanga.kvack.org (Postfix) with ESMTP id 7F66C830F1 for ; Mon, 29 Aug 2016 10:49:12 -0400 (EDT) Received: by mail-oi0-f69.google.com with SMTP id u191so485599339oie.3 for ; Mon, 29 Aug 2016 07:49:12 -0700 (PDT) Received: from resqmta-po-02v.sys.comcast.net (resqmta-po-02v.sys.comcast.net. [2001:558:fe16:19:96:114:154:161]) by mx.google.com with ESMTPS id m195si14322805itm.123.2016.08.29.07.49.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 29 Aug 2016 07:49:11 -0700 (PDT) Date: Mon, 29 Aug 2016 09:49:09 -0500 (CDT) From: Christoph Lameter Subject: Re: what is the purpose of SLAB and SLUB In-Reply-To: <20160829134458.GD2968@dhcp22.suse.cz> Message-ID: References: <1471458050-29622-1-git-send-email-aruna.ramakrishna@oracle.com> <20160818115218.GJ30162@dhcp22.suse.cz> <20160823021303.GB17039@js1304-P5Q-DELUXE> <20160823153807.GN23577@dhcp22.suse.cz> <20160824082057.GT2693@suse.de> <20160825100707.GU2693@suse.de> <87h9a71clo.fsf@tassilo.jf.intel.com> <20160829134458.GD2968@dhcp22.suse.cz> Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andi Kleen , Mel Gorman , Joonsoo Kim , Aruna Ramakrishna , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mike Kravetz , Pekka Enberg , David Rientjes , Andrew Morton , Jiri Slaby On Mon, 29 Aug 2016, Michal Hocko wrote: > Compaction can certainly help and the more we are proactive in that > direction the better. Vlastimil has already done a first step in that > direction and we a have a dedicated kcompactd kernel thread for that > purpose. But I guess what Mel had in mind is the latency of higher > order pages which is inherently higher with the current page allocator > no matter how well the compaction works. There are other changes, mostly > for the fast path, needed to make higher order pages less of a second > citizen. Compaction needs to be able to move many more types of kernel objects out of the way. I think if the callbacks that were merged for the migration of CMA pages are made usable for slab allocations then we may make some progress there. This would require the creator of a slab cache to specify functions that allow the migration of an object. Would require additional subsystem specific code. But doing that for inodes and dentries could be very benficial for compaction. -- 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