From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B255A38F920 for ; Thu, 10 Sep 2026 23:07:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789081639; cv=none; b=EZkLFiE9dO6S0CEA2DbZ/vQIt5Hcm3Mph6lBgqHOB1ta5He4eED6k4HwroDSNGmB8IoX254S8ljD+pv3pQEBq57zv5QKV6xSpTb0g3EWZC0rIIFi9EjOTTOGbpMjW1QrfuiPT620JvYbRZHGkLoFq853RclEVPJ3qu/dUBl0YP0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789081639; c=relaxed/simple; bh=HxBqCzlqqnQ1WOKc9BHlNb9vsRD4SYsaXm0GbIJf1B4=; h=Date:To:From:Subject:Message-Id; b=F5hwSOiewKE5YOjnq428bh097Vo9Bvi74diY24rVdpzI2Fu+O5y3J+ng5w1hrc5ULdowCQlYKcbl+O8l+9FwuY4wtw7IVuziQUHCxXYCeEzqHDt/StBlW+SX9d6ae+0gbtlrudiS5gg4GR0Owgfohf8tSJXrzkOsvcig46+2fHw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=XDEGX8iE; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="XDEGX8iE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 871D71F00893; Thu, 10 Sep 2026 23:07:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789081637; bh=4NnfmgE99W24z3lb4PU1GkqhfoR2OX7dhNIuE5oijOA=; h=Date:To:From:Subject; b=XDEGX8iEcNrFmQN9nNzYNL0OOVg/Q0rKYTeU14ZW3g8nEIPsEEwzewvbexj1vTHBs NJPnhLpy6NTILLBvqI8W/D0rzAODSOYsZJ/ff3TH6BY4u1cwp6OMJ3yUNoAnjEg/hL kPGOpRUp0hPVcmHF1PddTRT2Nrr18EyEYUYzAIyY= Date: Thu, 10 Sep 2026 16:07:17 -0700 To: mm-commits@vger.kernel.org,songmuchun@bytedance.com,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] powerpc-mm-switch-device-dax-to-shared-tail-vmemmap-pages.patch removed from -mm tree Message-Id: <20260910230717.871D71F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: powerpc/mm: switch device DAX to shared tail vmemmap pages has been removed from the -mm tree. Its filename was powerpc-mm-switch-device-dax-to-shared-tail-vmemmap-pages.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Muchun Song Subject: powerpc/mm: switch device DAX to shared tail vmemmap pages Date: Tue, 8 Sep 2026 11:03:32 +0800 The powerpc radix compound vmemmap population path still finds a reusable tail page by walking the vmemmap page tables. Switch it to the common vmemmap_shared_tail_page() helper instead, so it can use the shared vmemmap page directly to simplify the code. This removes the powerpc-specific tail-page lookup and its fallback path and aligns the device DAX vmemmap optimization path with HugeTLB. Link: https://lore.kernel.org/20260908030335.96549-9-songmuchun@bytedance.com Signed-off-by: Muchun Song Cc: David Hildenbrand Cc: Jonathan Corbet Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Qi Zheng Cc: Randy Dunlap Signed-off-by: Andrew Morton --- arch/powerpc/mm/book3s64/radix_pgtable.c | 80 ++------------------- 1 file changed, 9 insertions(+), 71 deletions(-) --- a/arch/powerpc/mm/book3s64/radix_pgtable.c~powerpc-mm-switch-device-dax-to-shared-tail-vmemmap-pages +++ a/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -1250,59 +1251,6 @@ static pte_t * __meminit radix__vmemmap_ return pte; } -static pte_t * __meminit vmemmap_compound_tail_page(unsigned long addr, - unsigned long pfn_offset, int node) -{ - pgd_t *pgd; - p4d_t *p4d; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - unsigned long map_addr; - - /* the second vmemmap page which we use for duplication */ - map_addr = addr - pfn_offset * sizeof(struct page) + PAGE_SIZE; - pgd = pgd_offset_k(map_addr); - p4d = p4d_offset(pgd, map_addr); - pud = vmemmap_pud_alloc(p4d, node, map_addr); - if (!pud) - return NULL; - pmd = vmemmap_pmd_alloc(pud, node, map_addr); - if (!pmd) - return NULL; - if (pmd_leaf(*pmd)) - /* - * The second page is mapped as a hugepage due to a nearby request. - * Force our mapping to page size without deduplication - */ - return NULL; - pte = vmemmap_pte_alloc(pmd, node, map_addr); - if (!pte) - return NULL; - /* - * Check if there exist a mapping to the left - */ - if (pte_none(*pte)) { - /* - * Populate the head page vmemmap page. - * It can fall in different pmd, hence - * vmemmap_populate_address() - */ - pte = radix__vmemmap_populate_address(map_addr - PAGE_SIZE, node, NULL, NULL); - if (!pte) - return NULL; - /* - * Populate the tail pages vmemmap page - */ - pte = radix__vmemmap_pte_populate(pmd, map_addr, node, NULL, NULL); - if (!pte) - return NULL; - vmemmap_verify(pte, node, map_addr, map_addr + PAGE_SIZE); - return pte; - } - return pte; -} - int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, unsigned long start, unsigned long end, int node, @@ -1320,6 +1268,12 @@ int __meminit vmemmap_populate_compound_ pud_t *pud; pmd_t *pmd; pte_t *pte; + struct page *tail_page; + unsigned int order = pfn_to_section_order(start_pfn); + + tail_page = vmemmap_shared_tail_page(order, device_zone(node)); + if (!tail_page) + return -ENOMEM; for (addr = start; addr < end; addr = next) { @@ -1349,10 +1303,9 @@ int __meminit vmemmap_populate_compound_ next = addr + PAGE_SIZE; continue; } else { - unsigned long nr_pages = pgmap_vmemmap_nr(pgmap); + unsigned long nr_pages = 1UL << order; unsigned long addr_pfn = page_to_pfn((struct page *)addr); unsigned long pfn_offset = addr_pfn - ALIGN_DOWN(addr_pfn, nr_pages); - pte_t *tail_page_pte; /* * if the address is aligned to huge page size it is the @@ -1377,23 +1330,8 @@ int __meminit vmemmap_populate_compound_ next = addr + 2 * PAGE_SIZE; continue; } - /* - * get the 2nd mapping details - * Also create it if that doesn't exist - */ - tail_page_pte = vmemmap_compound_tail_page(addr, pfn_offset, node); - if (!tail_page_pte) { - - pte = radix__vmemmap_pte_populate(pmd, addr, node, NULL, NULL); - if (!pte) - return -ENOMEM; - vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); - - next = addr + PAGE_SIZE; - continue; - } - pte = radix__vmemmap_pte_populate(pmd, addr, node, NULL, pte_page(*tail_page_pte)); + pte = radix__vmemmap_pte_populate(pmd, addr, node, NULL, tail_page); if (!pte) return -ENOMEM; vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); _ Patches currently in -mm which might be from songmuchun@bytedance.com are mm-sparse-relax-struct-mem_section-size-constraints.patch mm-sparse-vmemmap-rename-hvo-order-macros.patch mm-mm_init-skip-initializing-shared-vmemmap-tail-pages.patch mm-sparse-vmemmap-initialize-shared-tail-vmemmap-pages-on-allocation.patch mm-sparse-vmemmap-support-section-based-vmemmap-accounting.patch mm-mm_init-factor-out-pfn_to_zone.patch mm-sparse-vmemmap-move-helpers-ahead-of-future-callers.patch mm-sparse-vmemmap-support-section-based-vmemmap-optimization.patch mm-sparse-initialize-memory-sections-earlier.patch mm-hugetlb-switch-hugetlb-to-section-based-vmemmap-optimization.patch mm-sparse-vmemmap-remove-sparsemem_vmemmap_preinit-support.patch mm-sparse-inline-usemap-allocation-into-sparse_init_nid.patch mm-sparse-remove-section_map_size.patch mm-hugetlb-remove-huge_bootmem_hvo.patch mm-hugetlb-remove-huge_bootmem_cma.patch mm-hugetlb-localize-struct-huge_bootmem_page.patch mm-hugetlb-localize-huge_bootmem_zones_valid.patch mm-sparse-vmemmap-drop-the-extra-tail-page-from-device-dax-reservation.patch mm-sparse-vmemmap-drop-unused-section_nr_vmemmap_pages-arguments.patch documentation-mm-update-dax-vmemmap-deduplication-docs.patch