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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 7613EC0044C for ; Mon, 5 Nov 2018 05:16:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F3A920685 for ; Mon, 5 Nov 2018 05:16:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F3A920685 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com 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 S1729167AbeKEOeF (ORCPT ); Mon, 5 Nov 2018 09:34:05 -0500 Received: from mga07.intel.com ([134.134.136.100]:25411 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728918AbeKEOeF (ORCPT ); Mon, 5 Nov 2018 09:34:05 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Nov 2018 21:16:15 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,466,1534834800"; d="scan'208";a="103430333" Received: from yhuang-dev.sh.intel.com (HELO yhuang-dev) ([10.239.13.27]) by fmsmga004.fm.intel.com with ESMTP; 04 Nov 2018 21:16:09 -0800 From: "Huang\, Ying" To: Vasily Averin Cc: , Andrew Morton , , Aaron Lu Subject: Re: [PATCH 1/2] mm: use kvzalloc for swap_info_struct allocation References: <37b60523-d085-71e9-fef9-80b90bfcef18@virtuozzo.com> <87wopsbb5v.fsf@yhuang-dev.intel.com> Date: Mon, 05 Nov 2018 13:16:09 +0800 In-Reply-To: (Vasily Averin's message of "Mon, 5 Nov 2018 07:59:13 +0300") Message-ID: <878t28ayue.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Vasily Averin writes: > On 11/5/18 3:50 AM, Huang, Ying wrote: >> Vasily Averin writes: >> >>> commit a2468cc9bfdf ("swap: choose swap device according to numa node") >>> increased size of swap_info_struct up to 44 Kbytes, now it requires >>> 4th order page. >> >> Why swap_info_struct could be so large? Because MAX_NUMNODES could be >> thousands so that 'avail_lists' field could be tens KB? If so, I think >> it's fair to use kvzalloc(). Can you add one line comment? Because >> struct swap_info_struct is quite small in default configuration. > > I was incorrect not 44Kb but 40kb should be here. > We have found CONFIG_NODES_SHIFT=10 in new RHEL7 update 6 kernel, > default ubuntu kernels have the same setting too. > > crash> struct swap_info_struct -o > struct swap_info_struct { > [0] unsigned long flags; > [8] short prio; > ... > [140] spinlock_t lock; > [144] struct plist_node list; > [184] struct plist_node avail_lists[1024]; <<<< here > [41144] struct swap_cluster_info *cluster_info; > [41152] struct swap_cluster_list free_clusters; > ... > [41224] spinlock_t cont_lock; > } > SIZE: 41232 > > struct swap_info_struct { > ... > RH_KABI_EXTEND(struct plist_node avail_lists[MAX_NUMNODES]) /* entry in swap_avail_head */ > ... > } > > #define MAX_NUMNODES (1 << NODES_SHIFT) > > #ifdef CONFIG_NODES_SHIFT > #define NODES_SHIFT CONFIG_NODES_SHIFT > #else > #define NODES_SHIFT 0 > #endif > > /boot/config-4.15.0-38-generic:CONFIG_NODES_SHIFT=10 I see. So this is a more practical issue than my original imagination. But for default config, I mean $ make defconfig And it turns out, CONFIG_NODES_SHIFT=6 Best Regards, Huang, Ying