Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 6 Jul 2023 12:45:14 -0700 (PDT)
From:   Hugh Dickins <hughd@google.com>
To:     Gerald Schaefer <gerald.schaefer@linux.ibm.com>
cc:     Hugh Dickins <hughd@google.com>, Jason Gunthorpe <jgg@ziepe.ca>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Mike Rapoport <rppt@kernel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        David Hildenbrand <david@redhat.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Qi Zheng <zhengqi.arch@bytedance.com>,
        Yang Shi <shy828301@gmail.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Peter Xu <peterx@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Will Deacon <will@kernel.org>, Yu Zhao <yuzhao@google.com>,
        Alistair Popple <apopple@nvidia.com>,
        Ralph Campbell <rcampbell@nvidia.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Steven Price <steven.price@arm.com>,
        SeongJae Park <sj@kernel.org>,
        Lorenzo Stoakes <lstoakes@gmail.com>,
        Huang Ying <ying.huang@intel.com>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Zack Rusin <zackr@vmware.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Pasha Tatashin <pasha.tatashin@soleen.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Minchan Kim <minchan@kernel.org>,
        Christoph Hellwig <hch@infradead.org>,
        Song Liu <song@kernel.org>,
        Thomas Hellstrom <thomas.hellstrom@linux.intel.com>,
        Russell King <linux@armlinux.org.uk>,
        "David S. Miller" <davem@davemloft.net>,
        Michael Ellerman <mpe@ellerman.id.au>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Jann Horn <jannh@google.com>,
        Vishal Moola <vishal.moola@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        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: <20230706170213.2ea63606@thinkpad-T15>
Message-ID: <b454cfb1-85dc-743f-8f0-30d7e3d4376@google.com>
References: <54cb04f-3762-987f-8294-91dafd8ebfb0@google.com> <a722dbec-bd9e-1213-1edd-53cd547aa4f@google.com> <20230628211624.531cdc58@thinkpad-T15> <cd7c2851-1440-7220-6c53-16b343b1474@google.com> <ZJ2hsM5Tn+yUZ5ZV@ziepe.ca> <20230629175645.7654d0a8@thinkpad-T15>
 <edaa96f-80c1-1252-acbb-71c4f045b035@google.com> <7bef5695-fa4a-7215-7e9d-d4a83161c7ab@google.com> <20230704171905.1263478f@thinkpad-T15> <e678affb-5eee-a055-7af1-1d29a965663b@google.com> <20230705145516.7d9d554d@thinkpad-T15> <1014735-ecc4-b4bc-3ae7-48a4328ed149@google.com>
 <20230706170213.2ea63606@thinkpad-T15>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Precedence: bulk

On Thu, 6 Jul 2023, Gerald Schaefer wrote:
> 
> Since none of my remarks on the comments seem valid or strictly necessary
> any more, and I also could not find functional issues, I think you can add
> this patch as new version for 07/12. And I can now give you this:
> 
> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>

Great, thanks a lot Gerald.
The one change I'm making to it is then this merged in:

--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -455,6 +455,11 @@ void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable)
 	page = virt_to_page(pgtable);
 	SetPageActive(page);
 	page_table_free(mm, (unsigned long *)pgtable);
+	/*
+	 * page_table_free() does not do the pgste gmap_unlink() which
+	 * page_table_free_rcu() does: warn us if pgste ever reaches here.
+	 */
+	WARN_ON_ONCE(mm_alloc_pgste(mm));
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */