From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5818C433EF for ; Fri, 18 Feb 2022 16:10:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237530AbiBRQKz convert rfc822-to-8bit (ORCPT ); Fri, 18 Feb 2022 11:10:55 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:48112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237518AbiBRQKu (ORCPT ); Fri, 18 Feb 2022 11:10:50 -0500 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B7D6313C9FD for ; Fri, 18 Feb 2022 08:10:33 -0800 (PST) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-56-O3XU_dwdNqmADcxbKhNOfQ-1; Fri, 18 Feb 2022 16:10:31 +0000 X-MC-Unique: O3XU_dwdNqmADcxbKhNOfQ-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.28; Fri, 18 Feb 2022 16:10:28 +0000 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.028; Fri, 18 Feb 2022 16:10:28 +0000 From: David Laight To: 'Hyeonggon Yoo' <42.hyeyoo@gmail.com>, Vlastimil Babka CC: Christoph Lameter , Matthew Wilcox , Christoph Lameter , Linux Memory Management List , LKML , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton Subject: RE: Do we really need SLOB nowdays? Thread-Topic: Do we really need SLOB nowdays? Thread-Index: AQHYJLAyvH6iV8tqykeD7oCpMSL3UayZeSGA Date: Fri, 18 Feb 2022 16:10:28 +0000 Message-ID: <7829ee15074448d5a7cec1a0e3c352d4@AcuMS.aculab.com> References: <20211028100414.GA2928@kvm.asia-northeast3-a.c.our-ratio-313919.internal> <20211210110835.GA632811@odroid> <20211215062904.GA1150813@odroid> <54c6fff8-8c79-463b-a359-96e37bd13674@suse.cz> In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hyeonggon Yoo > Sent: 18 February 2022 10:13 ... > I think SLUB can be memory-efficient as SLOB. > Is SLOB (Address-Ordered next^Wfirst fit) stronger to fragmentation than SLUB? Dunno, but I had to patch the vxworks malloc to use 'best fit' because 'first fit' based on a fifo free list was really horrid. I can't imagine an address ordered 'first fit' really being that much better. There are probably a lot more allocs and frees than the kernel used to have. Also isn't the performance of a 'first fit' going to get horrid when there are a lot of small items on the free list. Does SLUB split pages into 3s and 5s (on cache lime boundaries) as well as powers of 2? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)