From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id 6CFB9831F4 for ; Mon, 22 May 2017 05:29:16 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id g143so24593185wme.13 for ; Mon, 22 May 2017 02:29:16 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id v7si10450536wmv.91.2017.05.22.02.29.14 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 22 May 2017 02:29:15 -0700 (PDT) Date: Mon, 22 May 2017 11:29:10 +0200 From: Michal Hocko Subject: Re: [v4 1/1] mm: Adaptive hash table scaling Message-ID: <20170522092910.GD8509@dhcp22.suse.cz> References: <1495300013-653283-1-git-send-email-pasha.tatashin@oracle.com> <1495300013-653283-2-git-send-email-pasha.tatashin@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1495300013-653283-2-git-send-email-pasha.tatashin@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Pavel Tatashin Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Sat 20-05-17 13:06:53, Pavel Tatashin wrote: [...] > /* > + * Adaptive scale is meant to reduce sizes of hash tables on large memory > + * machines. As memory size is increased the scale is also increased but at > + * slower pace. Starting from ADAPT_SCALE_BASE (64G), every time memory > + * quadruples the scale is increased by one, which means the size of hash table > + * only doubles, instead of quadrupling as well. > + */ > +#define ADAPT_SCALE_BASE (64ull << 30) I have only noticed this email today because my incoming emails stopped syncing since Friday. But this is _definitely_ not the right approachh. 64G for 32b systems is _way_ off. We have only ~1G for the kernel. I've already proposed scaling up to 32M for 32b systems and Andi seems to be suggesting the same. So can we fold or apply the following instead? ---