From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17])
	by smtp.lore.kernel.org (Postfix) with ESMTP id 8D4CBC43219
	for <linux-mm@archiver.kernel.org>; Wed, 15 Dec 2021 16:01:49 +0000 (UTC)
Received: by kanga.kvack.org (Postfix)
	id E08026B0071; Wed, 15 Dec 2021 10:23:17 -0500 (EST)
Received: by kanga.kvack.org (Postfix, from userid 40)
	id DB7E46B0073; Wed, 15 Dec 2021 10:23:17 -0500 (EST)
X-Delivered-To: int-list-linux-mm@kvack.org
Received: by kanga.kvack.org (Postfix, from userid 63042)
	id CCD376B0074; Wed, 15 Dec 2021 10:23:17 -0500 (EST)
X-Delivered-To: linux-mm@kvack.org
Received: from forelay.hostedemail.com (smtprelay0235.hostedemail.com [216.40.44.235])
	by kanga.kvack.org (Postfix) with ESMTP id BE95C6B0071
	for <linux-mm@kvack.org>; Wed, 15 Dec 2021 10:23:17 -0500 (EST)
Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251])
	by forelay01.hostedemail.com (Postfix) with ESMTP id 70EB5180EB6E0
	for <linux-mm@kvack.org>; Wed, 15 Dec 2021 15:23:07 +0000 (UTC)
X-FDA: 78920396814.14.F46C2FC
Received: from gentwo.de (gentwo.de [161.97.139.209])
	by imf01.hostedemail.com (Postfix) with ESMTP id 93AE840017
	for <linux-mm@kvack.org>; Wed, 15 Dec 2021 15:23:02 +0000 (UTC)
Received: by gentwo.de (Postfix, from userid 1001)
	id DF8EDB0023A; Wed, 15 Dec 2021 16:23:04 +0100 (CET)
Received: from localhost (localhost [127.0.0.1])
	by gentwo.de (Postfix) with ESMTP id DE388B0006D;
	Wed, 15 Dec 2021 16:23:04 +0100 (CET)
Date: Wed, 15 Dec 2021 16:23:04 +0100 (CET)
From: Christoph Lameter <cl@gentwo.org>
X-X-Sender: cl@gentwo.de
To: Vlastimil Babka <vbabka@suse.cz>
cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>, Matthew Wilcox <willy@infradead.org>, 
    Christoph Lameter <cl@gentwo.de>, 
    Linux Memory Management List <linux-mm@kvack.org>, 
    LKML <linux-kernel@vger.kernel.org>, Pekka Enberg <penberg@kernel.org>, 
    David Rientjes <rientjes@google.com>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, 
    Andrew Morton <akpm@linux-foundation.org>
Subject: Re: Do we really need SLOB nowdays?
In-Reply-To: <54c6fff8-8c79-463b-a359-96e37bd13674@suse.cz>
Message-ID: <alpine.DEB.2.22.394.2112151621300.434315@gentwo.de>
References: <20211017133618.GA7989@kvm.asia-northeast3-a.c.our-ratio-313919.internal> <20211017135708.GA8442@kvm.asia-northeast3-a.c.our-ratio-313919.internal> <YWw1n6y/AGED14HD@casper.infradead.org> <CAB=+i9Tor-tmZuB8YjATT_rv68nnF2W_TvMvyGp55AGaSyKynw@mail.gmail.com>
 <alpine.DEB.2.22.394.2110251016260.3145@gentwo.de> <20211028100414.GA2928@kvm.asia-northeast3-a.c.our-ratio-313919.internal> <YXqSoo+b9RTclW/2@casper.infradead.org> <20211210110835.GA632811@odroid> <alpine.DEB.2.22.394.2112101305500.290446@gentwo.de>
 <cbfaeb40-13c7-15b6-177d-07b3f3c4a0a9@suse.cz> <20211215062904.GA1150813@odroid> <54c6fff8-8c79-463b-a359-96e37bd13674@suse.cz>
User-Agent: Alpine 2.22 (DEB 394 2020-01-19)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
X-Rspamd-Queue-Id: 93AE840017
X-Stat-Signature: peazakh1bxncakjaw6df5zhinkssyg8m
Authentication-Results: imf01.hostedemail.com;
	dkim=none;
	dmarc=none;
	spf=none (imf01.hostedemail.com: domain of cl@gentwo.org has no SPF policy when checking 161.97.139.209) smtp.mailfrom=cl@gentwo.org
X-Rspamd-Server: rspam11
X-HE-Tag: 1639581782-948809
X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4
Sender: owner-linux-mm@kvack.org
Precedence: bulk
X-Loop: owner-majordomo@kvack.org
List-ID: <linux-mm.kvack.org>

On Wed, 15 Dec 2021, Vlastimil Babka wrote:

> > SLOB:
> >
> > 	Memory required to boot: 6950K
> >
> > 		Slab:                368 kB
> >
> > SLUB:
> > 	Memory required to boot: 6800K
> >
> > 		Slab:                552 kB
> >
> > SLUB with slab merging:
> >
> > 		Slab:                536 kB
>
> 168kB different on a system with less than 8MB memory looks rather
> significant to me to simply delete SLOB, I'm afraid.

This looks more like a bug/difference in SLAB accounting of SLOB.

How could SLOB require more memory to boot but use less SLAB memory?

This looks to me like a significant reason enough to remove SLOB since
SLUB works with less memory than SLOB.