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[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 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org 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