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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 345EDC11F69 for ; Thu, 1 Jul 2021 13:00:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1DA36613CE for ; Thu, 1 Jul 2021 13:00:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236626AbhGANDV (ORCPT ); Thu, 1 Jul 2021 09:03:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236630AbhGANCz (ORCPT ); Thu, 1 Jul 2021 09:02:55 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F63CC0611C1 for ; Thu, 1 Jul 2021 05:57:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=QRaGlVqQxKh9WQJkeW4dawAj001OxCCf88GK3Bqe4I4=; b=hxUEbXmA11V3cAoBt8+TuCIy7Q bQjoQGrS0GOkh7nTMlsWDCxuJXu4BdK7DOAj/0Jh3U/894aT3Ih19pOtVbc+jntu5/v4yXb6zN6o8 uVtOiV6tqmoOGJKoMR2agcXOclbxGPV5qzZy7eYl8o2gkSXl6VQ6kOgEgeEIXd27cSTeJy6e2MGop ltWtp8p82SmIwM4zjt5jjDelEJODajk3PheJJ2/9VsBLhpePhpn0VkPvtClESodvJit23Ntl79ca5 JmAqO/ovwDPQsO7goZFYMN9ZOWyF2JO3uu+OdZ/Eqk42H5rbM2Gd2QlnFj8V3d0j1WJ0NADcRama0 O0WQsWOg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1lywG1-006ZTc-7r; Thu, 01 Jul 2021 12:57:33 +0000 Date: Thu, 1 Jul 2021 13:57:29 +0100 From: Matthew Wilcox To: Anshuman Khandual Cc: linux-mm@kvack.org, akpm@linux-foundation.org, Vlastimil Babka , Randy Dunlap , linux-kernel@vger.kernel.org Subject: Re: [PATCH V2] mm/thp: Make ALLOC_SPLIT_PTLOCKS dependent on USE_SPLIT_PTE_PTLOCKS Message-ID: References: <1621409586-5555-1-git-send-email-anshuman.khandual@arm.com> <9d1ce685-e0fd-febd-5ff2-179f7fa6e3fa@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9d1ce685-e0fd-febd-5ff2-179f7fa6e3fa@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 01, 2021 at 10:51:27AM +0530, Anshuman Khandual wrote: > > > On 5/20/21 4:47 PM, Matthew Wilcox wrote: > > On Wed, May 19, 2021 at 01:03:06PM +0530, Anshuman Khandual wrote: > >> Split ptlocks need not be defined and allocated unless they are being used. > >> ALLOC_SPLIT_PTLOCKS is inherently dependent on USE_SPLIT_PTE_PTLOCKS. This > >> just makes it explicit and clear. While here drop the spinlock_t element > >> from the struct page when USE_SPLIT_PTE_PTLOCKS is not enabled. > > > > I didn't spot this email yesterday. I'm not a fan. Isn't struct page > > already complicated enough without adding another ifdef to it? Surely > > there's a better way than this. > > This discussion thread just got dropped off the radar, sorry about it. > None of the spinlock_t elements are required unless split ptlocks are > in use. I understand your concern regarding yet another #ifdef in the > struct page definition. But this change is simple and minimal. Do you > have any other particular alternative in mind which I could explore ? Do nothing? I don't understand what problem you're trying to solve.