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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEE29C43615 for ; Tue, 21 Aug 2018 12:58:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 89765214C4 for ; Tue, 21 Aug 2018 12:58:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89765214C4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techadventures.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727589AbeHUQSx (ORCPT ); Tue, 21 Aug 2018 12:18:53 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:40052 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727159AbeHUQSw (ORCPT ); Tue, 21 Aug 2018 12:18:52 -0400 Received: by mail-wr1-f65.google.com with SMTP id n2-v6so5306569wrw.7 for ; Tue, 21 Aug 2018 05:58:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=oJeTZCFZ6Vc724C5uEYbt7sNJqz7l1QoeZkwSeK1ZDQ=; b=LbvUfxAOOkCoKSEeZjh8oKWCQXjU3PDUif1LqXQdk3fHSXFci5YR/B1hR+KpCk9nsG NelIwREKfBCcjLdaTExCeHYjn10PvKUyZyk+3XZEVXwI9p72Ic76YUf+IXv24goeK+ev rp86UFUtqJBdc3snL6oycCQOuvo7i+YLL3WjEJ6jJwlSFE3H+MjbyjvDybWes1AmBls7 LqjeXXM/UUQocPND61CEvFwyqkrcOqVG/39ywkiLS4CPq4mKsTyl/O0iW4gdBORUWNJv GJfuVDX03ttyA2pN/EeM6EvNMCN6viuT6/XaVtcflQ0jwCDOC2i3uAQQlIrQXHHTrgdN BceQ== X-Gm-Message-State: APzg51BZrwALorWFiVWvx85nMms2GkxIdvQe7XzjsMP6MpmpueV0Evfb gDAev0qVAWPEIk2DFNe/frA= X-Google-Smtp-Source: ANB0VdYIAsOhmGhYZBQvWRX474wkfVyBb2cPKHfQ6/GSDYaXcfsevA1sFQWugnKsbtqkO6Y8FQT8SQ== X-Received: by 2002:adf:a11c:: with SMTP id o28-v6mr11236890wro.169.1534856328037; Tue, 21 Aug 2018 05:58:48 -0700 (PDT) Received: from techadventures.net (techadventures.net. [62.201.165.239]) by smtp.gmail.com with ESMTPSA id g6-v6sm2370606wmf.16.2018.08.21.05.58.47 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 21 Aug 2018 05:58:47 -0700 (PDT) Received: by techadventures.net (Postfix, from userid 1000) id BBA911249C5; Tue, 21 Aug 2018 14:58:46 +0200 (CEST) Date: Tue, 21 Aug 2018 14:58:46 +0200 From: Oscar Salvador To: Michal Hocko Cc: Andrew Morton , tglx@linutronix.de, joe@perches.com, arnd@arndb.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Oscar Salvador Subject: Re: [PATCH] mm: Fix comment for NODEMASK_ALLOC Message-ID: <20180821125846.GB9489@techadventures.net> References: <20180820085516.9687-1-osalvador@techadventures.net> <20180820142440.1f9ccbebefc5d617c881b41e@linux-foundation.org> <20180821121734.GA29735@dhcp22.suse.cz> <20180821123024.GA9489@techadventures.net> <20180821125156.GB29735@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180821125156.GB29735@dhcp22.suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 21, 2018 at 02:51:56PM +0200, Michal Hocko wrote: > On Tue 21-08-18 14:30:24, Oscar Salvador wrote: > > On Tue, Aug 21, 2018 at 02:17:34PM +0200, Michal Hocko wrote: > > > We do have CONFIG_NODES_SHIFT=10 in our SLES kernels for quite some > > > time (around SLE11-SP3 AFAICS). > > > > > > Anyway, isn't NODES_ALLOC over engineered a bit? Does actually even do > > > larger than 1024 NUMA nodes? This would be 128B and from a quick glance > > > it seems that none of those functions are called in deep stacks. I > > > haven't gone through all of them but a patch which checks them all and > > > removes NODES_ALLOC would be quite nice IMHO. > > > > No, maximum we can get is 1024 NUMA nodes. > > I checked this when writing another patch [1], and since having gone > > through all archs Kconfigs, CONFIG_NODES_SHIFT=10 is the limit. > > > > NODEMASK_ALLOC gets only called from: > > > > - unregister_mem_sect_under_nodes() (not anymore after [1]) > > - __nr_hugepages_store_common (This does not seem to have a deep stack, we could use a normal nodemask_t) > > > > But is also used for NODEMASK_SCRATCH (mainly used for mempolicy): > > mempolicy code should be a shallow stack as well. Mostly the syscall > entry. Ok, then I could give it a try and see if we can get rid of NODEMASK_ALLOC in there as well. -- Oscar Salvador SUSE L3