From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f175.google.com (mail-pf0-f175.google.com [209.85.192.175]) by kanga.kvack.org (Postfix) with ESMTP id 531376B0005 for ; Tue, 26 Jan 2016 23:46:14 -0500 (EST) Received: by mail-pf0-f175.google.com with SMTP id q63so113847410pfb.1 for ; Tue, 26 Jan 2016 20:46:14 -0800 (PST) Received: from lgeamrelo11.lge.com (LGEAMRELO11.lge.com. [156.147.23.51]) by mx.google.com with ESMTPS id r6si6650841pap.212.2016.01.26.20.46.13 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 26 Jan 2016 20:46:13 -0800 (PST) Date: Wed, 27 Jan 2016 13:46:14 +0900 From: Joonsoo Kim Subject: Re: [PATCH 00/16] mm/slab: introduce new freed objects management way, OBJFREELIST_SLAB Message-ID: <20160127044614.GA8326@js1304-P5Q-DELUXE> References: <1452749069-15334-1-git-send-email-iamjoonsoo.kim@lge.com> <20160126204013.a065301b.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160126204013.a065301b.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Jesper Dangaard Brouer , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, Jan 26, 2016 at 08:40:13PM -0800, Andrew Morton wrote: > On Thu, 14 Jan 2016 14:24:13 +0900 Joonsoo Kim wrote: > > > This patchset implements new freed object management way, that is, > > OBJFREELIST_SLAB. Purpose of it is to reduce memory overhead in SLAB. > > > > SLAB needs a array to manage freed objects in a slab. If there is > > leftover after objects are packed into a slab, we can use it as > > a management array, and, in this case, there is no memory waste. > > But, in the other cases, we need to allocate extra memory for > > a management array or utilize dedicated internal memory in a slab for it. > > Both cases causes memory waste so it's not good. > > > > With this patchset, freed object itself can be used for a management > > array. So, memory waste could be reduced. Detailed idea and numbers > > are described in last patch's commit description. Please refer it. > > > > In fact, I tested another idea implementing OBJFREELIST_SLAB with > > extendable linked array through another freed object. It can remove > > memory waste completely but it causes more computational overhead > > in critical lock path and it seems that overhead outweigh benefit. > > So, this patchset doesn't include it. I will attach prototype just for > > a reference. > > It appears that this patchset is perhaps due a couple of touchups from > Christoph's comments. I'll grab it as-is as I want to get an mmotm > into linux-next tomorrow then vanish for a few days. Hello, Andrew. Could you add just one small fix below to 16/16 "mm/slab: introduce new slab management type, OBJFREELIST_SLAB"? Thanks. ------------>8-------------