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 27576C88E56 for ; Sun, 13 Sep 2026 08:40:49 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4hjMDv22Z9z30Lw; Sun, 13 Sep 2026 18:40:47 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2607:f8b0:4864:3b::10" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1789288847; cv=none; b=CYHewVbcJBf2ANmwXf/h0Z+P8/L4YZmxKiNqdkP64oNR9NGFBeq1NNliclmtFXoZOrCPKewwROvL0rPPb+Wn9v4IFPvpsDhoV1y9SBJVRr+e3EOki+xEPFW1xGt7es2L9psn3bn6x7MKdNO6j8ENn1noEPlOtAeA2cUqOi7DjI4p98Kvp7M/XrbxLJz4h5ZHSbOteItsDJPj+iIDzEHMv5gHWekc6o/3e/VO6pJNrhv78niUx8yzbdYrS1w/teonU85efIFo70FQH+22SdkYeuodt+sIUsUzwtRgp/jmXrhR8TMcCiTCsALOuk4xu55Fp9a0vn8EVReik8wmKt14JA== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1789288847; c=relaxed/relaxed; bh=ML0t01Bj4qeBUEzdqhHtr19Sc8eC1B+HcCN0p8hsXSo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d692DXVMuy2imKMP43DlNO9IGs3c+7Hzq1x6JILqsyGCl+AhYoefRxLYg4fj9Y0xsZmyyVS9r9SpIU6YDo+CDYtgamiK6DwAFD9fRwyAcvdDDFtIJDhH1x6gnyBCWV8zf1SV3P2frvP9pBemATtD2yYxiRfGfrbhoYLMf++h4MPxpPuUIc8i3m6pEvpDe7pahFYHIh1TKWZ+PrKCPkDeaDdmKURoQgM2iFUlXMs6nL7LiA+ZkTJRn5o/2x/ZTIoe/L8qgHu7CbErcmQ8Y2Y8xzlAGHFCZMERW+WgiTsc/Ms/5oUADSP7GGJnqljFbXLP5KaR6srBsjkcYB7awX3C5g== 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=PvxIxpjN; dkim-atps=neutral; spf=pass (client-ip=2607:f8b0:4864:3b::10; helo=mail-pz2-x10.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=PvxIxpjN; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=bytedance.com (client-ip=2607:f8b0:4864:3b::10; helo=mail-pz2-x10.google.com; envelope-from=songmuchun@bytedance.com; receiver=lists.ozlabs.org) Received: from mail-pz2-x10.google.com (mail-pz2-x10.google.com [IPv6:2607:f8b0:4864:3b::10]) (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 4hjMDt3sGXz2xkr for ; Sun, 13 Sep 2026 18:40:46 +1000 (AEST) Received: by mail-pz2-x10.google.com with SMTP id d2e1a72fcca58-85469e25400so816394b3a.0 for ; Sun, 13 Sep 2026 01:40:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1789288844; x=1789893644; 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=ML0t01Bj4qeBUEzdqhHtr19Sc8eC1B+HcCN0p8hsXSo=; b=PvxIxpjNqNkSv/uaU+vJR9bZebFnGF4Z9FsyfDyjFPO5ZJ4CzXh7unuI20uKzb797A KswhEIwi1jXKxqKVU8Dl46AUEwsDduziwDzsQI4/S8WDlFbOjH+DVZBrO3977SQ/LPvn IU4PIhiMp3P83OJaq8hm1ya5HxiUTiGEPJ4hNQYJVWu6qHFSigersKYcWD42hFZvT/rP trDd+heK2H228UHrqfWj5ZyxLoEnScrJsrk7CHDcNZp8WdK33DClVml0ofwtRSTM/TiQ GpXnRdpqVpRku09ys1meD2+SRZAMF2/GU0RAvfH5UwjboSY6dizQRH4qmfuTd71KSW2M WIqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1789288844; x=1789893644; 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=ML0t01Bj4qeBUEzdqhHtr19Sc8eC1B+HcCN0p8hsXSo=; b=qxtTIbn6taCVvcJDdlGxzCv81TMREq7hvseJ8kqivf7owjOH3dhxnAUrv8BGgoGRAx Iv8snqBCl3YnA9Ok20v2FhSnzF59BF0jHjLCkZ4zOcfLSbL7s0b7WX4vSPA+3vtSmoy+ zAM7ipp603KO4/66B0vibXwzNdoKocXXciAv1JYi0XtJPkvkwiLDFo9T+rsaqugXYYtN EZaQHNeneruxFcwixX7IE8mYF167BzsFRBl5D1qezVm/X6aiSlZ61RqNxjwNYUSEBu9t nN6uc36v1m8dlzT6m8vfdDlnFkFI+n5vbhg0Z9ccWwf/eEg/M/7uvdUDl5RjzhckwVP/ 4jHQ== X-Forwarded-Encrypted: i=1; AKwUvBwCsVw3hJuPRKX5+0/aK4+H++WwE/o5KlguEWSFMt5osA1J8O+zNbJmE8TZDnBZYAjMiL9nlMeK3WKV5lM=@lists.ozlabs.org X-Gm-Message-State: AFuF++nPTBEUI6Mbt8k3uveZBgvvhMvve8gQjR3YeP3+Nphc4aGoYg3b YoqbZpfIqrUW72EzeX8eL5kcsRfdPMHBL+3lRMdqeTmQI1nDkOzvFZjgPWlaSZr5/VE= X-Gm-Gg: AYBFou0PmQQVzE/BMJZ3hmxHyNcrUaO9zH5/kkVhKhNQnhWFvaisGvy+HptXhG0b2FQ bDKhZPC9krksa7jbQ6c3RkEZjkZEAa9prWTR1D3HtyZLglBWlFfgTbO2ntbKVgzbcM0CN4K4FsL X+f9e8d2V9eT2IS+UNK7L+H2rGNPO8ZEkxUxqMWPXmGm0GRAGX1qGGM5qSws7pAxyv+qgsNPBrc 0/ZOJ3x4YCAb8MBecPBt6RNZJMEUvZqEcwCU+L69wXHUov0RrFVmYma515lMuv+lgJDK0A1ugBS TAMa4SWPTI1JES8iTJHQfCUpdpa+TainvZGreHchsgdStXsy/662wzWDjcLkj/93WhaqCkAXgJx 1WtWb4RL+t8saSq6dVK0gj9viaduRTMIBue115zeY2DbHFVu5chM9a99TiRrAyrzrg3P0bFxaug z5JMZjsNIGc1bo5RdB+Ic8EclDBhz97gCmc2YftVCHGkkbSgen/EXYDLpeK6seOMSmRmrI2UvtL ng95Ue5SzRCBT8gGTC8cQMBIDk= X-Received: by 2002:a05:6a00:8c6:b0:845:e440:d0ca with SMTP id d2e1a72fcca58-86b2fe25315mr17990526b3a.8.1789288844473; Sun, 13 Sep 2026 01:40:44 -0700 (PDT) Received: from G6L4RL2QG9 ([2409:8a00:1832:cf0:5137:990:100e:cc7e]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-86b29cbb0d3sm3070531b3a.42.2026.09.13.01.40.35 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sun, 13 Sep 2026 01:40:44 -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 3/6] mm/sparse-vmemmap: drop Device DAX-specific population path Date: Sun, 13 Sep 2026 16:37:31 +0800 Message-ID: <20260913083734.86802-4-songmuchun@bytedance.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260913083734.86802-1-songmuchun@bytedance.com> References: <20260913083734.86802-1-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 --- 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 e83821768c12..028f844c90f5 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -454,71 +454,6 @@ 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) @@ -531,11 +466,7 @@ 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