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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 08AD4C433E0 for ; Tue, 2 Jun 2020 16:18:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB7FB20757 for ; Tue, 2 Jun 2020 16:18:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591114697; bh=GOxWZFW5p0R4Mb6m/Bo6zAMohTrK5btdVpKdH3RUxMQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=P3OOzl/eDB7ffxxwwp+z1B+XMyuNJBqn/+GDrzL/2N6dVUL4gGK/3UBFja3mIbTSz eOTE/ESuOsbZk+1aEFWtsnK+i9vrY4DeLioXbwzT5DpSutMfts8hTOnobTpMp0V5B7 e7JCvUvEITtjJDNIKBiItftkrRL2PRdMGwOUuh8o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728202AbgFBQSR (ORCPT ); Tue, 2 Jun 2020 12:18:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726380AbgFBQSQ (ORCPT ); Tue, 2 Jun 2020 12:18:16 -0400 Received: from mail-qv1-xf41.google.com (mail-qv1-xf41.google.com [IPv6:2607:f8b0:4864:20::f41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96CC6C05BD1E for ; Tue, 2 Jun 2020 09:18:16 -0700 (PDT) Received: by mail-qv1-xf41.google.com with SMTP id z9so2026792qvi.12 for ; Tue, 02 Jun 2020 09:18:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=QnnRV7rBYpuwTlzjoMcd++pjDHDWrMhQw3hcrAJQ594=; b=WQ4N3HzBq/erSPg6m3Gl82qjtrEH5qF97Lji6xhOP72AObalMv/O288C0sPNfQTocB vNB8wtxVDBaAELiXdol6Yzsyw2XpL0AcHLSP9U23UyX+JeZo9q8Xt+vIcBKwAPR8qN/2 pfy2h7CjmAgjQJvo3OlVrObeAJ47qL9z/YBbTB34icAwtzBD+3Rt0j6rFREReFh6VfFx UnMWFWDtMJDUINbmMtTk9lBLa2Jm6OyH0OnlTysovnPKwiroqkZjemCAJoCsZ92MSbZR +uCehcEpTpSLUZ+IuLDBhd/OpMe/hd0oF+p5h2HSw2aK98+54J9C1qZEp/kQKWN4krzP wDJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=QnnRV7rBYpuwTlzjoMcd++pjDHDWrMhQw3hcrAJQ594=; b=HXxQKc/fvDgkVB1kaxQK/z/2JltYDpAO1s6N1Y5DqLH4ItlLqVX2dU8I91v7cD8tfF wgTQRUyMhwLGgX1BSEvwbN7C4FDEPmZlzo1SciHRv3PWAX8yKZetT63d59W3moaD6NFP CpLbHb0ag4DSMdieZ2BJxLszgB9TPm9SaLsUHFm1l1opr/V3oFQukq0J8SovEc6sWC6w W3aySL3aV8lmN+jeFUDQ9FqspG8UYgc/VlRHMGt+whSEaVPogIkt1eQ02j1oBYDpTevx oLyXMF0L7eYqSmyD5+iwY4lQ/CahqIxf7F6hZErHpOwQR2H7n/VBu9xCB6PpyDYt2p2I bQrA== X-Gm-Message-State: AOAM532mGRX2kQ+turrtx6YrpirceY1g80l8PUr9gjGCoHvpQDc/QgrI BBDfrnAoatnvXrZUBgriplMl3t6M X-Google-Smtp-Source: ABdhPJz1tkuCl3kLGoHvwv/meSx/T7pJg17HVSVIPLSMKQYAO9rdqY9DfiZRNnyxu5br9F64kGrJwg== X-Received: by 2002:a05:6214:9ce:: with SMTP id dp14mr25520546qvb.216.1591114695623; Tue, 02 Jun 2020 09:18:15 -0700 (PDT) Received: from localhost ([199.96.181.106]) by smtp.gmail.com with ESMTPSA id 63sm2726578qkm.82.2020.06.02.09.18.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2020 09:18:15 -0700 (PDT) Date: Tue, 2 Jun 2020 12:18:14 -0400 From: Tejun Heo To: Lai Jiangshan Cc: Lai Jiangshan , LKML Subject: Re: [PATCH 4/4] workqueue: slash half memory usage in 32bit system Message-ID: <20200602161814.GI31548@mtj.thefacebook.com> References: <20200601084442.8284-1-laijs@linux.alibaba.com> <20200601084442.8284-5-laijs@linux.alibaba.com> <20200601150723.GA31548@mtj.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, Jun 02, 2020 at 08:08:10AM +0800, Lai Jiangshan wrote: > It is not noticable from the "free" command. > By counting the number of allocated pwq (mainly percpu pwq), > it saves 20k in my simple kvm guest (4cpu). > I guess it highly various in different boxes with various > kernel modules loaded. Hmm... I find it difficult to judge in any direction. 32 bit machines are smaller and have less of everything - including CPUs and workqueues themselves, so while changing configuration for 32bit systems would reduce memory usage the impact isn't gonna be that big either and I have no data supporting whether the reduction is gonna help or hurt. Thanks. -- tejun