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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,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 02E4BC43219 for ; Thu, 2 May 2019 09:48:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC2742089E for ; Thu, 2 May 2019 09:48:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556790500; bh=izrYoKTU4xWJRGopNdBEVJaICGTT0gZCvv2SqjNIn1o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=PXogCUCtg4YEAxDIB+5J1utS20nmby3w5osGR013pEM972HGHwGeBu/pmzINcPJvp DJNUpNO2g9nkKjS9Kw9IxEl4TdeTLVWqYiMM8vmTz+Q57vzR1XGQglYGNrO60A8ZTz NkQN5aEPkKAwXfKXMjP6GtKVDE5UNA3QlXaJvAAk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726300AbfEBJsT (ORCPT ); Thu, 2 May 2019 05:48:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:55400 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbfEBJsT (ORCPT ); Thu, 2 May 2019 05:48:19 -0400 Received: from linux-8ccs (ip5f5ade58.dynamic.kabel-deutschland.de [95.90.222.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 588B9206DF; Thu, 2 May 2019 09:48:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556790498; bh=izrYoKTU4xWJRGopNdBEVJaICGTT0gZCvv2SqjNIn1o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mdbUWmrvxijmiVfMWUtjlXpscQSHqZq3GqPkGTrtp/+KqsIObnFELpvpwmTv/CnJ+ cmY2ZrmaBiSGD+K6OTlqONxIwG5WrXGPdtzr5Xzd12Udohl86b+i485k1rJlVozc6s MBCFvdBCyeTe40o1Oo0306A1eN8xf2KQxLeVIbcg= Date: Thu, 2 May 2019 11:48:14 +0200 From: Jessica Yu To: Prarit Bhargava Cc: linux-kernel@vger.kernel.org, Heiko Carstens , David Arcari Subject: Re: [PATCH v3] kernel/module: Reschedule while waiting for modules to finish loading Message-ID: <20190502094813.GA6690@linux-8ccs> References: <20190430222207.3002-1-prarit@redhat.com> <90e18809-2b70-52d8-00b3-9c16768db9ad@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <90e18809-2b70-52d8-00b3-9c16768db9ad@redhat.com> X-OS: Linux linux-8ccs 5.1.0-rc1-lp150.12.28-default+ x86_64 User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +++ Prarit Bhargava [01/05/19 17:26 -0400]: > > >On 4/30/19 6:22 PM, Prarit Bhargava wrote: >> On a s390 z14 LAR with 2 cpus about stalls about 3% of the time while >> loading the s390_trng.ko module. >> >> Add a reschedule point to the loop that waits for modules to complete >> loading. >> >> v3: cleanup Fixes line. > >Jessica, even with this additional patch there appears to be some other issues >in the module code that are causing significant delays in boot up on large >systems. Is this limited to only s390? Or are you seeing this on other arches as well? And is it limited to specific modules (like s390_trng)? >Please revert these fixes from linux-next & modules-next. I apologize for the >extra work but I think it is for the best until I come up with a more complete & >better tested patch. Sure, then I will revert this patch and the other one as well ("modules: Only return -EEXIST for modules that have finished loading"). >FWIW, the logic in the original patch is correct. It's just that there's, as >Heiko discovered, some poor scheduling, etc., that is impacting the module >loading code after these changes. I am really curious to see what these performance regressions look like :/ Please update us when you find out more. >Again, my apologies, No problem! Thanks again. Jessica