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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7A5F1C98315 for ; Thu, 24 Sep 2026 07:58:33 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4hr5ms4vqyz30TL; Thu, 24 Sep 2026 17:58:21 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2607:f8b0:4864:39::11" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1790236701; cv=none; b=Ao4EoVv7UAzTr3KTj49DoMI8tPgg1075xEUjT2izKVEPfmKVjdrSwrSU4rv3HS8Ybpyvt1rGshx8u9G2pZ2l3sn49EErk7aqdrPbkBU0Eq0T8E1sgsZ5NdFU2dW4rGk4ONPzb7ncxsWFLzJnQDvu3/VTzRMhLjZJx7R1xu7BmgEQdtLAJUYuaRkgazhaysGL2/mtGTXzFCitKv/fNXQO8LHTTcz05msofSQZnFVzp+2Z0QH4gvX3L7hynfG1uzXohUMj2FZDTiJcF/SyB9Wm5MF1EKRTq6O7GpoWsYI5qQkj+fsz5s2SuGIszPwkkXKbqpEGDSvzQD5jYRsOUaIh/w== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1790236701; c=relaxed/relaxed; bh=Mwg8qfU0YRGSE8UK0HBy9iZTs3Sk7OFpk3Nxuz+XYco=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QAY513uv9WZ4LeyVGL0oAQai2I3DXGLbw0XaLz+o5s37bQVUiqk9Ocqw9sk8YFQeVOjnddooKzt2aMXfNoDrRRmC3s9FSSzcHFYoJFEVuby6rKH6Nffl5eEPWWGcGrJNvfyygb6ngCO2T3DdJq4LXC9EzaoDpwhvJvjZVFkWL9gkcH3iyuu8asM8wnwP1b5b07ftDxWGz2yspHCGo39O4Jq3DtxoIFLLInGTzavaWlJTW7u6vE7/NYNHfypkysK2LMVyPB+10dtllP/hBedGB2c+vhAvRuMjjunW8HeCQXxZGsZzTUUET18YXlgHSZd2NLF3ahjUOjscC/PpNdO9Zg== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com; dkim=pass (2048-bit key; unprotected) header.d=bytedance.com header.i=@bytedance.com header.a=rsa-sha256 header.s=google header.b=Q8aED7nZ; dkim-atps=neutral; spf=pass (client-ip=2607:f8b0:4864:39::11; helo=mail-pj2-x11.google.com; envelope-from=songmuchun@bytedance.com; receiver=lists.ozlabs.org) smtp.mailfrom=bytedance.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=bytedance.com header.i=@bytedance.com header.a=rsa-sha256 header.s=google header.b=Q8aED7nZ; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=bytedance.com (client-ip=2607:f8b0:4864:39::11; helo=mail-pj2-x11.google.com; envelope-from=songmuchun@bytedance.com; receiver=lists.ozlabs.org) Received: from mail-pj2-x11.google.com (mail-pj2-x11.google.com [IPv6:2607:f8b0:4864:39::11]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4hr5mr5sx3z30T9 for ; Thu, 24 Sep 2026 17:58:20 +1000 (AEST) Received: by mail-pj2-x11.google.com with SMTP id 98e67ed59e1d1-398a1676000so1072344a91.2 for ; Thu, 24 Sep 2026 00:58:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1790236698; x=1790841498; darn=lists.ozlabs.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Mwg8qfU0YRGSE8UK0HBy9iZTs3Sk7OFpk3Nxuz+XYco=; b=Q8aED7nZLEywCzc4P3uQhlpUbsvVw2otzQxD/eSvASAsbvvXbBvhzICGlwknJFIc2I RHppa2IisiD8aB7RFYm8xPtchyS34B8uXfZmAxWCJXBUz7H3aXMhOtlsPMd3jDnniAvq tUTFZOnrCE+LyjHjGFl5A6x9pu4NPT15bpdD47i5AWbKAoMLGWPiqQCg+NGMa9BlFoR1 +PaHZAx120Dxn0goNeRQF3GgdZ3TNrvEd1bdmMFukaDXapMIW+84csledB+88NFD48Si 4y9KafVS+QY/PEU9OYhnNJP+d11u5YrAyC57j2DWi2Y4FPmf1VN8L+5AY4ZlG+M8F6kH 2XSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790236698; x=1790841498; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=Mwg8qfU0YRGSE8UK0HBy9iZTs3Sk7OFpk3Nxuz+XYco=; b=rk1B9pg866W/zS2HJ7xWYLu9im93SC2476fwKtNHlhOIeCB2VZQKWvfS886ZKiY6vw 4ZWx3JpZ+9aTWBUHjCRuiIXUQ4EN+wX9OEZMpK/mf4iU/EsQTy9328iLHy1gg5BEWEy+ VjVBgv1PQrfyDFnUppCZdNkEhnrXmPPavuPSsLdNJ27m3BSOnilhdPnfy0LTfygRLdOo 7JQ6oncZ32k2Nx0zS9yFg3h7S8qZP1AnJ25x8gWCTCkBU5ikMM1jheu+zLdYifvGJgtE xCD2R6oWL4erjTyuPkqnXfPZ4AWpYbuY15EfH9lgwSPlwSz5C7nnp8plIdCDfs7l4yrq h+vg== X-Forwarded-Encrypted: i=1; AKwUvBzv0DcT8GT1TM1/PJH4tKX92nArE0jsx51DeDEYHsURitMvaJavaUMTrKYs0A809kxC61X/Xis0nWJDupQ=@lists.ozlabs.org X-Gm-Message-State: AFuF++lZAZjAMwF10fcybF9HovXiOcHjN+++CtbKBE40qsydY9ZgpjHB shNLU6a1hFY+843eo2e/xA57JU5qI5kxtQWI1w+i9bEL2VWjwORH3CNSmIVQ8jePao0= X-Gm-Gg: AYBFou1H6hVOY+biHx4qOyu+IKkA4XnA4v389iGJHt4ZCc4vo5GPTKAtMJCOoACrmwR XrBIlETa/RIZVTHhObhZSqQZQ8+r0KnD6xeiGntCPDI5Afb+YLo28qRjeisncAi3J5L1cQ5Fgzq oTJG0nWejzSOUdqoeo0b2Eilvzx6tWHrhAMstSSP1nihUOd0rYbxCKlLS4a7vdUITbw0FaNjnex QygdRkZTBn7BxZIset+7Bg+KkuBk3KCbC1sdB93bJDP4J8lq8SK9nsOMoEqLwTV4XTQVsMIqc5G qoES0wigIeOvTSYUfeDYSoEMR0aie2OSlSwk2pr7hWiTX9auylId+Qj95qbGdP93ew/KYqqyTWX JmmgFmF64R925cHc9zv2YwC/qj56t+k39cecWFsgJwC7vuUozeWdkb5Q3vfAUT1rCqGzNy2XYr8 Dxsql0H+kOkW1RYFoHvB5mK7sHxLBSYfcNosbxsHHqlOjLwL7g0APJ2lrvdmKR/ZXcAtJbOMPVp AKj0RTSjybVa7Vxcmlh X-Received: by 2002:a17:90b:4e8f:b0:39e:4c80:f67c with SMTP id 98e67ed59e1d1-3a09875f8f6mr1584809a91.27.1790236698392; Thu, 24 Sep 2026 00:58:18 -0700 (PDT) Received: from n232-176-004.byted.org ([36.110.163.97]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3a0972eec92sm3575622a91.7.2026.09.24.00.58.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Sep 2026 00:58:17 -0700 (PDT) From: Muchun Song To: Madhavan Srinivasan , Mike Rapoport , Andrew Morton , David Hildenbrand Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Qi Zheng , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Muchun Song , muchun.song@linux.dev Subject: [PATCH v2 3/6] mm/sparse-vmemmap: drop Device DAX-specific population path Date: Thu, 24 Sep 2026 15:52:56 +0800 Message-ID: <20260924075259.2013039-4-songmuchun@bytedance.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260924075259.2013039-1-songmuchun@bytedance.com> References: <20260924075259.2013039-1-songmuchun@bytedance.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The common vmemmap path selects the shared page for optimized mappings itself, so Device DAX no longer needs vmemmap_populate_compound_pages() to find a shared tail page and pass its backing PFN through the generic population helpers. Remove the Device DAX-specific population path and let section memmap population always use vmemmap_populate(). The powerpc retains an architecture-specific compound-page implementation, so select it directly from radix__vmemmap_populate() for optimizable sections. Signed-off-by: Muchun Song Acked-by: Qi Zheng --- v2: - Collect Acked-by from Qi Zheng --- arch/powerpc/mm/book3s64/radix_pgtable.c | 3 + mm/mm_init.c | 2 +- mm/sparse-vmemmap.c | 71 +----------------------- 3 files changed, 5 insertions(+), 71 deletions(-) diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c index 9ca28e4a610a..cb72d9ccf747 100644 --- a/arch/powerpc/mm/book3s64/radix_pgtable.c +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -1122,7 +1122,10 @@ int __meminit radix__vmemmap_populate(unsigned long start, unsigned long end, in pud_t *pud; pmd_t *pmd; pte_t *pte; + unsigned long pfn = page_to_pfn((struct page *)start); + if (section_vmemmap_optimizable(__pfn_to_section(pfn))) + return vmemmap_populate_compound_pages(pfn, start, end, node, NULL); /* * If altmap is present, Make sure we align the start vmemmap addr * to PAGE_SIZE so that we calculate the correct start_pfn in diff --git a/mm/mm_init.c b/mm/mm_init.c index 56bb4567a494..1650d6bc1211 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1046,7 +1046,7 @@ static void zone_device_page_init_from_template(struct page *page, * initialize is a lot smaller that the total amount of struct pages being * mapped. This is a paired / mild layering violation with explicit knowledge * of how the sparse_vmemmap internals handle compound pages in the lack - * of an altmap. See vmemmap_populate_compound_pages(). + * of an altmap. */ static inline unsigned long compound_nr_pages(unsigned long pfn, struct dev_pagemap *pgmap) diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index cdcc93714a9a..4aae22beca21 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -466,71 +466,6 @@ int __meminit vmemmap_populate_hugepages(unsigned long start, unsigned long end, return 0; } -#ifndef vmemmap_populate_compound_pages -/* - * For compound pages bigger than section size (e.g. x86 1G compound - * pages with 2M subsection size) fill the rest of sections as tail - * pages. - * - * Note that memremap_pages() resets @nr_range value and will increment - * it after each range successful onlining. Thus the value or @nr_range - * at section memmap populate corresponds to the in-progress range - * being onlined here. - */ -static bool __meminit reuse_compound_section(unsigned long start_pfn, - struct dev_pagemap *pgmap) -{ - unsigned long nr_pages = pgmap_vmemmap_nr(pgmap); - unsigned long offset = start_pfn - - PHYS_PFN(pgmap->ranges[pgmap->nr_range].start); - - return !IS_ALIGNED(offset, nr_pages) && nr_pages > PAGES_PER_SUBSECTION; -} - -static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, - unsigned long start, - unsigned long end, int node, - struct dev_pagemap *pgmap) -{ - unsigned long size, addr; - pte_t *pte; - int rc; - struct page *page; - unsigned int order = pfn_to_section_compound_order(start_pfn); - - page = vmemmap_shared_tail_page(order, device_zone(node)); - if (!page) - return -ENOMEM; - - if (reuse_compound_section(start_pfn, pgmap)) - return vmemmap_populate_range(start, end, node, NULL, - page_to_pfn(page)); - - size = min(end - start, (1UL << order) * sizeof(struct page)); - for (addr = start; addr < end; addr += size) { - unsigned long next, last = addr + size; - - /* Populate the head page vmemmap page */ - pte = vmemmap_populate_address(addr, node, NULL, -1); - if (!pte) - return -ENOMEM; - - /* - * Reuse the shared page for the rest of tail pages - * See layout diagram in Documentation/mm/vmemmap_dedup.rst - */ - next = addr + PAGE_SIZE; - rc = vmemmap_populate_range(next, last, node, NULL, - page_to_pfn(page)); - if (rc) - return -ENOMEM; - } - - return 0; -} - -#endif - struct page * __meminit __populate_section_memmap(unsigned long pfn, unsigned long nr_pages, int nid, struct vmem_altmap *altmap, struct dev_pagemap *pgmap) @@ -543,11 +478,7 @@ struct page * __meminit __populate_section_memmap(unsigned long pfn, !IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION))) return NULL; - if (pgmap && section_vmemmap_optimizable(__pfn_to_section(pfn))) - r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap); - else - r = vmemmap_populate(start, end, nid, altmap); - + r = vmemmap_populate(start, end, nid, altmap); if (r < 0) return NULL; -- 2.54.0