From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-216.mta1.migadu.com [95.215.58.216]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DF33C43785C for ; Tue, 22 Sep 2026 12:48:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.216 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790081326; cv=none; b=U32oTo935vYSnFwch8adkpE4O1HR3t1BcuDuY5HspLPez7KOzdcjgO+ULHpzRj8ElTJooLi9HonDVHHHAZ55t4NmA7RB/qHiw5/OBg1zjWQboW4kx7hnMCODSH8RU71ZvI9zL+1Y6ZfSXBLJtJ4GGzu4TYxjTjDGNSqlQcIUXAA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790081326; c=relaxed/simple; bh=wzEk4sVRhnKEVhasilKpOv1uZCDcHlKB164cBBTlxVg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ob6gBirfAXGh3/K92CxH1jK2VyKLL9NpmF7LYP4OgciTD/n4RihFfy3y6HX9b5Ez08Y5corF62762+gUIjJC9PonUCDbVR/IRNk77g/4KOMf+0jW3E2VVvQ8q2ImvaX0lhxHlRVQUZapM2+tYI9sdzcrg/QVwrOq6xWYKnx39Yk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ScIUg1yc; arc=none smtp.client-ip=95.215.58.216 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ScIUg1yc" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=wzEk4sVRhnKEVhasilKpOv1uZCDcHlKB164cBBTlxVg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790081321; v=1; x=1790686121; b=ScIUg1ycfRo/nD9Kja2lpXBYOE6RWOnBn+P75dYa43XguSRz+XP4POoPKz98trp/QpBrVHe0 zYBLxubVICiMqLMjFPjAd8/d0I2Q0/pPjmrpGpCzkFzVGKY3i+okkxseYrGdTH8OxuOdB74euNu ZMqgqTHrc4MUktsCQy/swjYU= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 5ef79b9281d7277d; Tue, 22 Sep 2026 12:48:41 +0000 X-Mizu-Trace-ID: 5ef79b9281d7277d X-Migadu-Flow: FLOW_OUT Message-ID: Date: Tue, 22 Sep 2026 13:48:33 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RESEND v7 04/29] powerpc: mm: add PMD swap-exclusive helpers To: "David Hildenbrand (Arm)" , Andrew Morton , chrisl@kernel.org, kasong@tencent.com, ljs@kernel.org, ziy@nvidia.com, linux-mm@kvack.org Cc: ying.huang@linux.alibaba.com, Baoquan He , willy@infradead.org, youngjun.park@lge.com, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, alex@ghiti.fr, kas@kernel.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, Nico Pache , "Liam R. Howlett" , ryan.roberts@arm.com, Vlastimil Babka , lance.yang@linux.dev, linux-kernel@vger.kernel.org, nphamcs@gmail.com, shikemeng@huaweicloud.com, yosry@kernel.org, qi.zheng@linux.dev, luizcap@redhat.com, kernel-team@meta.com, Madhavan Srinivasan References: <20260914122950.3283997-1-usama.arif@linux.dev> <20260914122950.3283997-5-usama.arif@linux.dev> <47ccd5ce-2301-4ddd-881c-d57cb82b562c@kernel.org> Content-Language: en-US From: Usama Arif In-Reply-To: <47ccd5ce-2301-4ddd-881c-d57cb82b562c@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 18/09/2026 22:22, David Hildenbrand (Arm) wrote: > On 9/14/26 14:27, Usama Arif wrote: >> A later patch keeps a PMD-mapped anonymous THP mapped by a PMD across the >> swap round-trip, so PG_anon_exclusive now has to survive in a swap PMD and >> not just in a swap PTE. >> >> book3s64 builds a swap PMD by running the PTE encoding over pmd_pte(), so >> the PMD helpers use the same _PAGE_SWP_EXCLUSIVE bit. It is also the only >> powerpc variant that selects ARCH_HAS_PMD_SOFTLEAVES, via PPC_THP. >> >> Cc: Madhavan Srinivasan >> Signed-off-by: Usama Arif >> --- >> arch/powerpc/include/asm/book3s/64/pgtable.h | 17 +++++++++++++++++ >> 1 file changed, 17 insertions(+) >> >> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h >> index dff8790a047db..28943ef3c1c80 100644 >> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h >> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h >> @@ -699,6 +699,23 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte) >> return __pte_raw(pte_raw(pte) & cpu_to_be64(~_PAGE_SWP_EXCLUSIVE)); >> } >> >> +#ifdef CONFIG_ARCH_HAS_PMD_SOFTLEAVES >> +static inline pmd_t pmd_swp_mkexclusive(pmd_t pmd) >> +{ >> + return __pmd_raw(pmd_raw(pmd) | cpu_to_be64(_PAGE_SWP_EXCLUSIVE)); >> +} >> + >> +static inline bool pmd_swp_exclusive(pmd_t pmd) >> +{ >> + return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_SWP_EXCLUSIVE)); >> +} >> + >> +static inline pmd_t pmd_swp_clear_exclusive(pmd_t pmd) >> +{ >> + return __pmd_raw(pmd_raw(pmd) & cpu_to_be64(~_PAGE_SWP_EXCLUSIVE)); >> +} >> +#endif > > This should likely go below the pmd_swp_mksoft_dirty() handling block? > > For softdirty it's e.g., > > #define pmd_swp_mksoft_dirty(pmd) pte_pmd(pte_swp_mksoft_dirty(pmd_pte(pmd))) > > > Why can't we follow a similar model here? > I had just copied from pte_swp_mkexclusive()/pte_swp_exclusive()/pte_swp_clear_exclusive(). I will do this in the following revision for this patch: diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index dff8790a047db..458c85cebfa65 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -1060,6 +1060,12 @@ static inline pte_t *pmdp_ptep(pmd_t *pmd) #endif #endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */ +#ifdef CONFIG_ARCH_HAS_PMD_SOFTLEAVES +#define pmd_swp_mkexclusive(pmd) pte_pmd(pte_swp_mkexclusive(pmd_pte(pmd))) +#define pmd_swp_exclusive(pmd) pte_swp_exclusive(pmd_pte(pmd)) +#define pmd_swp_clear_exclusive(pmd) pte_pmd(pte_swp_clear_exclusive(pmd_pte(pmd))) +#endif + #ifdef CONFIG_ARCH_HAS_PTE_PROTNONE static inline int pmd_protnone(pmd_t pmd) {