From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792788797; b=X3oHeGbsl1+i7TBGAtTsbC8N7QJhwbPxLkCu77+rJZFLot066KkEH9lSs6d0Iw7P8xiZ QP/UV93fYLH0SjEJPiCI0le8HYbqId/9r7zS+5Taax0tJcubnNEcK5Neq2muS5PlylrT9 3o+smE4GUBjPeHsUR07VKzVV6TkcyqcEvJNuRF303H+LW/QzDCDURyqOCJ0Hik5Cykj6d OPsTTD7itV1RkL9+7JVf4RlzS3SSPznBT4O6aZ+ab7TJA4BM7H9K2TYdkw9zrBr7JxAds qp+G8jPPzg3GU1D3pJYmP9rkWJ7zhR+wBX1+JTxgeW1ddL8H2WnK80HU89litk4Bqtg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792788797; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:Content-Language:Autocrypt:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=0buMQQINV0ZMT10UHG2uFH0Ptzl8aD3BfO7547k5kqY=; b=zX6NFEhmTWvGJcCoSs16DzEtq9uqntiEOfnWgRDLMvIYunnFi4edSdtuDs4cBQPWW+9l 34VALkM+Mz2jCGcPwEIJv1rk+gJBJEJWPiyGds0zP1UElNrk4gXG+zjP/FZ9OJB7zcfk7 5VhS62eJeorCvnLOhH1NlEZUn598DeCZPbNpMo8J+CYKh4jzdP2A0ngeK6+ZygcJsEN/I WpXQzUY/rPEpUc188406TqHCWNeanoDx1FXqfAlIC2VDUqHFdcjz48bggTJSci00KUTye d6QZsPcNNnj0HeZ83AOLts7/wRDE/IiPxSFR5wDBPCICohypqgxDNRrXhwnpzf4hivg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DUU81bAs; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 886C7606A31B; Fri, 23 Oct 2026 20:53:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DUU81bAs Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15DEB1F01825; Fri, 23 Oct 2026 20:53:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792788797; bh=0buMQQINV0ZMT10UHG2uFH0Ptzl8aD3BfO7547k5kqY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=DUU81bAsRlByMerKC6j8ENrXC1/LZaH6l/iyH813lPlUNnkhTUzRJZ7FS62aiyRtg nk18HnfoiLhgD/7nubtqFeBFg8UJPicbpbNVP1OiMueX/sFnkIptckyLCdt3yShdok fOmBsw0eNvATOPhavkFKgnshJ/cF4t2QGt4/goRkbHFXKSC+j6Sz1i4YTDQJs9StRI 1k3eNBpmp7vjOP9O8hXMfiWhngOVx6UgHOW2RsbPmrG4kzH/Q6tDPkOrw8CuZMcYSY 99iKODVHyysJalk31n5BoLCcDBQ+AfAMuQGn2jzvcF1E+IB7wVuvrRF9fA4u8i4QYX WRBqUM0rLtOlw== Message-ID: <409079fe-ab52-4389-9fe0-d7246eb27bad@kernel.org> Date: Fri, 23 Oct 2026 22:53:09 +0200 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 4/4] mm: pass the number of PTEs to move_pte() To: Imre Kaloz , "David S. Miller" , Andreas Larsson Cc: "Matthew Wilcox (Oracle)" , "Mike Rapoport (IBM)" , Andrew Morton , "Liam R. Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn , Pedro Falcato , Suren Baghdasaryan , Michal Hocko , sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <2bc50d2a6829b49ee909e5bb943244859661a40b.1792609488.git.kaloz@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <2bc50d2a6829b49ee909e5bb943244859661a40b.1792609488.git.kaloz@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/22/26 01:33, Imre Kaloz wrote: > Since commit f822a9a81a31 ("mm: optimize mremap() by PTE batching"), > move_ptes() moves a batch of PTEs mapping consecutive pages of a folio > at a time, but calls move_pte() once per batch with the first PTE > only. sparc64, the only architecture that overrides move_pte(), flushes > from the D-cache the page that PTE maps when the move changes its > colour, so the other pages of a batch would keep lines of the old > colour. This cannot happen today only because sparc64 has no > pte_batch_hint(), and mremap_folio_pte_batch() then never batches. > > Pass nr_ptes to move_pte(), as get_and_clear_ptes() takes it. The > generic version ignores it, and sparc64 flushes every page of the > batch. > > Signed-off-by: Imre Kaloz > --- > arch/sparc/include/asm/pgtable_64.h | 16 +++++++++------- > include/linux/pgtable.h | 2 +- > mm/mremap.c | 2 +- > 3 files changed, 11 insertions(+), 9 deletions(-) > > diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h > index 1430489b9ac5..9ca787b3cbfe 100644 > --- a/arch/sparc/include/asm/pgtable_64.h > +++ b/arch/sparc/include/asm/pgtable_64.h > @@ -946,21 +946,23 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr, > set_pte_at((mm), (addr), (ptep), __pte(0UL)) > > #ifdef DCACHE_ALIASING_POSSIBLE > -/* This flushes only the page the PTE maps, so it relies on move_ptes() > - * calling it for one PTE at a time, which the default pte_batch_hint() > - * guarantees. > +/* The nr PTEs map consecutive pages of one folio and all move by the > + * same offset, so either every page of the batch aliases or none does. > */ > #define __HAVE_ARCH_MOVE_PTE > -#define move_pte(pte, old_addr, new_addr) \ > +#define move_pte(pte, old_addr, new_addr, nr) \ > ({ \ > pte_t newpte = (pte); \ > if (tlb_type != hypervisor && pte_present(pte)) { \ > unsigned long this_pfn = pte_pfn(pte); \ > + unsigned int i; \ > \ > if (pfn_valid(this_pfn) && \ > - (((old_addr) ^ (new_addr)) & (1 << 13))) \ > - flush_dcache_page_all(current->mm, \ > - pfn_to_page(this_pfn)); \ > + (((old_addr) ^ (new_addr)) & (1 << 13))) { \ > + for (i = 0; i < (nr); i++) \ > + flush_dcache_page_all(current->mm, \ > + pfn_to_page(this_pfn + i)); \ > + } \ > } \ > newpte; \ > }) > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h > index 8c093c119e5a..b58c0e98994e 100644 > --- a/include/linux/pgtable.h > +++ b/include/linux/pgtable.h > @@ -1471,7 +1471,7 @@ static inline void arch_swap_restore(swp_entry_t entry, struct folio *folio) > #endif > > #ifndef __HAVE_ARCH_MOVE_PTE > -#define move_pte(pte, old_addr, new_addr) (pte) > +#define move_pte(pte, old_addr, new_addr, nr) (pte) > #endif > > #ifndef pte_accessible > diff --git a/mm/mremap.c b/mm/mremap.c > index e8df5cdb0ac9..7fcae7f0082d 100644 > --- a/mm/mremap.c > +++ b/mm/mremap.c > @@ -289,7 +289,7 @@ static int move_ptes(struct pagetable_move_control *pmc, > force_flush = true; > } > pte = get_and_clear_ptes(mm, old_addr, old_ptep, nr_ptes); > - pte = move_pte(pte, old_addr, new_addr); > + pte = move_pte(pte, old_addr, new_addr, nr_ptes); > pte = move_soft_dirty_pte(pte); > > if (need_clear_uffd_wp && pte_is_uffd_wp_marker(pte)) I hate move_pte() so much. And I hate sparc64 for requiring it. ;) Is there some way we can avoid this helper-that-shouldn't-exist-but-someone-hacked-it-in entirely? If it makes sparc64 slightly slower #dontcare. -- Cheers, David