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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68482C00528 for ; Mon, 7 Aug 2023 16:43:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231831AbjHGQns (ORCPT ); Mon, 7 Aug 2023 12:43:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231584AbjHGQnq (ORCPT ); Mon, 7 Aug 2023 12:43:46 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 908AB172A; Mon, 7 Aug 2023 09:43:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2AE3961F5F; Mon, 7 Aug 2023 16:43:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 28418C433C7; Mon, 7 Aug 2023 16:43:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1691426623; bh=mC/OCo8hq+diLms6Fsc67TK0qEWRyhhnzPlcu8trSb8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=COIfvsny16WgH9j0mtGIQ5SmK6mHXLjrjumtR4I2MUWJ7RfrVddCiXNFh/BglZOz9 VWXQaqTT0zXnwJnJI4lENI8tGb6YWhf+OseHCQvVMwywv4Ve/ZsCndA88YVv612EE0 Z03tnfzBhKg0C+zjBHnUBZfMsUjll1sJW5Jfvc2Q= Date: Mon, 7 Aug 2023 09:43:42 -0700 From: Andrew Morton To: "Yin, Fengwei" Cc: , , , , , , , , , , Subject: Re: [PATCH 0/2] don't use mapcount() to check large folio sharing Message-Id: <20230807094342.17199a897f51a298f20fda57@linux-foundation.org> In-Reply-To: <6dbf9f37-e4bf-656d-4121-789e2e6cfae2@intel.com> References: <20230728161356.1784568-1-fengwei.yin@intel.com> <20230728102405.7b456eb87fb46042fbce5e4b@linux-foundation.org> <29cd58c4-08d3-c03c-7232-15f85878934d@intel.com> <6dbf9f37-e4bf-656d-4121-789e2e6cfae2@intel.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 4 Aug 2023 15:14:53 +0800 "Yin, Fengwei" wrote: > Hi Andrew, > > On 8/2/2023 8:39 PM, Yin, Fengwei wrote: > > Hi Andrew, > > > > On 7/29/2023 1:24 AM, Andrew Morton wrote: > >> On Sat, 29 Jul 2023 00:13:54 +0800 Yin Fengwei wrote: > >> > >>> In madvise_cold_or_pageout_pte_range() and madvise_free_pte_range(), > >>> folio_mapcount() is used to check whether the folio is shared. But it's > >>> not correct as folio_mapcount() returns total mapcount of large folio. > >>> > >>> Use folio_estimated_sharers() here as the estimated number is enough. > >> > >> What are the user-visible runtime effects of these changes? > >> > >> (and please try to avoid using the same Subject: for different patches) > >> > > > > Can you hold on these patches to mm-unstable? I think we need to wait for > > David's work on folio_maybe_mapped_shared() and redo the fix base on that. > > Thanks and sorry for the noise. > Sorry for bothering you again for this patchset. > > Let me explain the situation here: > - The reason to hold on the patches to mm-unstable is that I don't want to > promote the fix in this patch (using folio_estimated_sharers()). The > correct way is waiting for folio_maybe_mapped_shared() from David. > > Merging these patches motivate using folio_estimated_sharers() in other > places. So once folio_maybe_mapped_shared() is ready, we need to replace > folio_estimated_sharers() with folio_maybe_mapped_shared(). > > - For this specific patches, if they are suitable for stable, we may want to > merge it (special for stable branch. I assume folio_maybe_mapped_shared() > may not be back ported to stable branch). > > So how do we deal with this situation? Thanks in advance. > I think I'll stage them for 6.5, with a cc:stable. I'll drop the current three patches. Please resend with a) different Subject:s for all patches and b) changelogs which fully describe the user-visible effects of the change. Thanks.