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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F883C0015E for ; Thu, 29 Jun 2023 05:08:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EA9CD8D0003; Thu, 29 Jun 2023 01:08:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E334F8D0001; Thu, 29 Jun 2023 01:08:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CAE2E8D0003; Thu, 29 Jun 2023 01:08:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id BAB428D0001 for ; Thu, 29 Jun 2023 01:08:22 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 8654A160BF1 for ; Thu, 29 Jun 2023 05:08:22 +0000 (UTC) X-FDA: 80954604444.22.973EA27 Received: from mail-yb1-f172.google.com (mail-yb1-f172.google.com [209.85.219.172]) by imf09.hostedemail.com (Postfix) with ESMTP id BBCEE14000C for ; Thu, 29 Jun 2023 05:08:20 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=google.com header.s=20221208 header.b=SH61IoWs; spf=pass (imf09.hostedemail.com: domain of hughd@google.com designates 209.85.219.172 as permitted sender) smtp.mailfrom=hughd@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1688015300; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=zFm7aP76Kl3qxn7n2tNVkuwpkcso4qVmefkLtKFqRbs=; b=HBuF/bq3Cv3WwyffEUQzIPG3FARN4p4osHzJc7uMV0u3f1+aIUuX7k2f4dTq0wxxUK4uig 0IlvsuTGBxSP4KOFXoqCwXsf28VZM/ZTzE5MBZm9721P+5YoQ86ZQNogMgIrYn8F0gXmjq +7Mw0SPhDVM9wpjApPL+0lsXXaEprT4= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=google.com header.s=20221208 header.b=SH61IoWs; spf=pass (imf09.hostedemail.com: domain of hughd@google.com designates 209.85.219.172 as permitted sender) smtp.mailfrom=hughd@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1688015300; a=rsa-sha256; cv=none; b=l38/dAHGostWzo2FE9+1ervtAHOX2ygZBd5kcsBnGi/Ynqrf3ICmDM/Jwo7qg72HBGeuSv sDZyCK2K2bgo+Ys7kyuC3dm+gMoYfRXblvLHKVE3Lx/vULPdwmGYf9kkJyG3L8+1Q1eRZ7 WN+dA3JG4fiPxooJ1GQn7TfVGml0RQM= Received: by mail-yb1-f172.google.com with SMTP id 3f1490d57ef6-c17534f4c63so284011276.0 for ; Wed, 28 Jun 2023 22:08:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1688015300; x=1690607300; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to; bh=zFm7aP76Kl3qxn7n2tNVkuwpkcso4qVmefkLtKFqRbs=; b=SH61IoWshgo0/pKjl3ljDej2EI0+DSaPIoPH0EnGJIbXtfIIjKOXzIBV7zaurn/u2O NzEik2ic/sSNSVVbeZ/UgymQtK7K6oY5QRG/wzVH8poLJ32013nMh89etey0qcHiO54m 9VJ8ecSgnyFVz892TYk34hIsLIVdE3C863sWe4PpKLL17z0rdk//QH8zHLezplf5zecn CMt8pQ6lO/N91/4KfIatcw4X88/dCSpVTpYW/IpvL+vwGOTzzDciFmwrt9muCsAvhi7d WOqlfS0Kym0VC+rHJLQVRUIX2a29Zo7bJvGsOEaU1uowBUKaMzsYZ9yHhLs0KJAe7PQ3 Eu7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688015300; x=1690607300; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=zFm7aP76Kl3qxn7n2tNVkuwpkcso4qVmefkLtKFqRbs=; b=brs7/gACFDuvSroAeExEC57u4/SQxDgiFHJZGyNEubIkDjBd8vPz2Qgtl4ZBk7K+e0 WYqIt7F7KqMnjIPe9kYJ0lvgSbs2epP/Ri0D/2dGgPuu9kGQHviY1KhPL+zIaF0cs+VD f0ag2uLUNKkD2hSlkOYgANyv5xoXV1MJ3zWsfi3X0WtracFMY91v9t0PhHt02xYaQeoG xf63RIA8omg7ucIv2GNNY2ZOmdwcqK4S1RUSY5KuxwEqKWGRfwV7Fl/T7O1Am17cXwHB PBVnPp0b9nU98v+7zeuOK6xEoaRwpVoDgjrDx+ixfPhZ8sf2msMkf1qip+csAZOBr4Qf tLqA== X-Gm-Message-State: AC+VfDzHxImJMIdG+SsRYz112zWwcT2foSMYZLiHeZT9ypNLtKZQyPoh wWA5tm0hkQfNMs8ZFw1wiWCKaw== X-Google-Smtp-Source: ACHHUZ7dmal1wUP2kBcbn8Y+5hPCsOTidCkpFmDgLcwfB+9Ewvv4+lKBVPvM/Ea71yfLSwxu543Ddg== X-Received: by 2002:a25:bc86:0:b0:c25:3076:ffdc with SMTP id e6-20020a25bc86000000b00c253076ffdcmr9008572ybk.1.1688015299744; Wed, 28 Jun 2023 22:08:19 -0700 (PDT) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id 66-20020a251545000000b00bcc0f2e4f05sm2365847ybv.59.2023.06.28.22.08.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Jun 2023 22:08:19 -0700 (PDT) Date: Wed, 28 Jun 2023 22:08:08 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Gerald Schaefer cc: Hugh Dickins , Andrew Morton , Vasily Gorbik , Mike Kravetz , Mike Rapoport , "Kirill A. Shutemov" , Matthew Wilcox , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Yang Shi , Mel Gorman , Peter Xu , Peter Zijlstra , Will Deacon , Yu Zhao , Alistair Popple , Ralph Campbell , Ira Weiny , Steven Price , SeongJae Park , Lorenzo Stoakes , Huang Ying , Naoya Horiguchi , Christophe Leroy , Zack Rusin , Jason Gunthorpe , Axel Rasmussen , Anshuman Khandual , Pasha Tatashin , Miaohe Lin , Minchan Kim , Christoph Hellwig , Song Liu , Thomas Hellstrom , Russell King , "David S. Miller" , Michael Ellerman , "Aneesh Kumar K.V" , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda , Alexander Gordeev , Jann Horn , Vishal Moola , Vlastimil Babka , linux-arm-kernel@lists.infradead.org, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 07/12] s390: add pte_free_defer() for pgtables sharing page In-Reply-To: <20230628211624.531cdc58@thinkpad-T15> Message-ID: References: <54cb04f-3762-987f-8294-91dafd8ebfb0@google.com> <20230628211624.531cdc58@thinkpad-T15> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: BBCEE14000C X-Rspam-User: X-Stat-Signature: rbdbf8xbiyqahyg1a36hdoye3yi3nduz X-Rspamd-Server: rspam01 X-HE-Tag: 1688015300-588408 X-HE-Meta: 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 OI+fWRti 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 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 Wed, 28 Jun 2023, Gerald Schaefer wrote: > > As discussed in the other thread, we would rather go with less complexity, > possibly switching to an approach w/o the list and fragment re-use in the > future. For now, as a first step in that direction, we can try with not > adding fragments back only for pte_free_defer(). Here is an adjusted > version of your patch, copying most of your pte_free_defer() logic and > also description, tested with LTP and all three of your patch series applied: Thanks, Gerald: I don't mind abandoning my 13/12 SLAB_TYPESAFE_BY_RCU patch (posted with fewer Cc's to the s390 list last week), and switching to your simpler who-cares-if-we-sometimes-don't-make-maximal-use-of-page patch. But I didn't get deep enough into it today to confirm it - and disappointed that you've found it necessary to play with pt_frag_refcount in addition to _refcount and HH bits. No real problem with that, but my instinct says it should be simpler. Tomorrow... Hugh