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=-4.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,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 3D635C433E1 for ; Fri, 31 Jul 2020 21:29:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F178322B42 for ; Fri, 31 Jul 2020 21:29:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Q1vafZGO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F178322B42 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 694288D005E; Fri, 31 Jul 2020 17:29:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 645308D000B; Fri, 31 Jul 2020 17:29:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 581B98D005E; Fri, 31 Jul 2020 17:29:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0050.hostedemail.com [216.40.44.50]) by kanga.kvack.org (Postfix) with ESMTP id 4017A8D000B for ; Fri, 31 Jul 2020 17:29:22 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id C92CD180AD81A for ; Fri, 31 Jul 2020 21:29:21 +0000 (UTC) X-FDA: 77099662122.27.cat34_121788426f87 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id 9A2E43D674 for ; Fri, 31 Jul 2020 21:29:21 +0000 (UTC) X-HE-Tag: cat34_121788426f87 X-Filterd-Recvd-Size: 2107 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Fri, 31 Jul 2020 21:29:21 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 E11572087C; Fri, 31 Jul 2020 21:29:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596230960; bh=ZLbhjQCA6Lr7WPMvsYnug+Z6zWPo3a5RksC7e/DM1fA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Q1vafZGOKmYfsr5pJBTDVcEEjUwbni9ZQ9kgigWtjQQpQodJ2WQuh0chgAAKqBz5Q 5s7pikAA9/q8ZMKsGa13LalkyHBux3OH0KlU/kFwgf3F0vSalf7cAC0h72fiyKGhzK pI/uGrmtvYemcBN36TA8mNVTcQjafUFR6dALa0+8= Date: Fri, 31 Jul 2020 14:29:19 -0700 From: Andrew Morton To: paulmck@kernel.org Cc: Matthew Wilcox , cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, hannes@cmpxchg.org, urezki@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: Raw spinlocks and memory allocation Message-Id: <20200731142919.36c4c741189426db0f8b8514@linux-foundation.org> In-Reply-To: <20200731212457.GS9247@paulmck-ThinkPad-P72> References: <20200730231205.GA11265@paulmck-ThinkPad-P72> <20200731133834.517fdfee99b7ed2239f576aa@linux-foundation.org> <20200731204855.GR9247@paulmck-ThinkPad-P72> <20200731205933.GT23808@casper.infradead.org> <20200731212457.GS9247@paulmck-ThinkPad-P72> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 9A2E43D674 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 31 Jul 2020 14:24:57 -0700 "Paul E. McKenney" wrote: > The reason for this restriction is that in -rt, the spin_lock(&zone->lock) > in rmqueue_bulk() can sleep. So if there is runtime overhead, this overhead could be restricted to -rt kernels with suitable ifdefs?