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 B8B7E34F492 for ; Thu, 25 Jun 2026 02:57:34 +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=1782356256; cv=none; b=IkbJDXwG821k4eFqxDNhrHvGE9B/J31SroMIt/jZcJ8qwCvJT6SNzDchfP5qivbdb7KwzhTI1zXkZZ6ZSa8sDjDUarxwIhDbxQqXFG6IfoGtJSw3H/hGIPWz7mknj1NnGT5UhM1ebcQA/6YvND8EB6rOEPGpTEAD0PW68CYPMNU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782356256; c=relaxed/simple; bh=xT/NiZUX84dsLNaE1P608vftMpmv4WVDgg7mYyfdbfQ=; h=Date:To:From:Subject:Message-Id; b=c8ydWGDHm2kQ1OTOlB4CKvAp5Sg0hGuI8vnngt5bdpLY4gjNpgm8lnp92rM4wjrJ6P65Ekopm0BFtaqgEojaIdronxTILhHUCEidw91f3B7+xFV6Os/bIyXJarYr3rkKTgjhSGkVucYH3OHqtdT3T0gbVdBOOJZd4Uc8ku46wZk= 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=jlQe6UDX; 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="jlQe6UDX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8429A1F000E9; Thu, 25 Jun 2026 02:57:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1782356254; bh=BOknUndDYNn+lS82wL9+Z7L+NI67Qeb8mzlCNk9h9OI=; h=Date:To:From:Subject; b=jlQe6UDXees0LanrUC4bpsd4upm3IpKCqr9Q9kWKwMdiRkhhjZV5yKBQSxtCa7MIm Cll7CF2cJ/hZd+U/dLXqzPMlzYf4VARaFtIPJKc0IYW+byDI8rHQX0AUCMo3YXvzs2 baRaYeNHYxNfNwWFRSK1v+M4uRrFxAjuNHFMsS9M= Date: Wed, 24 Jun 2026 19:57:34 -0700 To: mm-commits@vger.kernel.org,xueyuan.chen21@gmail.com,will@kernel.org,urezki@gmail.com,ryan.roberts@arm.com,rppt@kernel.org,jiangwenxiaomi@gmail.com,jiangwen6@xiaomi.com,dev.jain@arm.com,david@kernel.org,catalin.marinas@arm.com,anshuman.khandual@arm.com,ajd@linux.ibm.com,baohua@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-vmalloc-map-contiguous-pages-in-batches-for-vmap-if-possible.patch added to mm-new branch Message-Id: <20260625025734.8429A1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/vmalloc: map contiguous pages in batches for vmap() if possible has been added to the -mm mm-new branch. Its filename is mm-vmalloc-map-contiguous-pages-in-batches-for-vmap-if-possible.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-map-contiguous-pages-in-batches-for-vmap-if-possible.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: "Barry Song (Xiaomi)" Subject: mm/vmalloc: map contiguous pages in batches for vmap() if possible Date: Thu, 18 Jun 2026 16:47:25 +0800 In many cases, the pages passed to vmap() may include high-order pages. For example, the systemheap often allocates pages in descending order: order 8, then 4, then 0. Currently, vmap() iterates over every page individually—even pages inside a high-order block are handled one by one. This patch detects physically contiguous pages (regardless of whether they are compound or non-compound) by scanning with num_pages_contiguous(), and maps them as a single contiguous block whenever possible. The mapping order is determined by taking the minimum of the contiguous page count and the pfn alignment, allowing graceful degradation when pfn alignment is less than the contiguous range. Pages with the same page_shift are coalesced and mapped via vmap_pages_range_noflush_walk() to avoid page table rewalk. As users typically allocate memory in descending orders (e.g. 8 → 4 → 0), once an order-0 page is encountered, we stop scanning for contiguous pages since subsequent pages are likely order-0 as well. Link: https://lore.kernel.org/20260618084726.1070022-6-jiangwen6@xiaomi.com Signed-off-by: Barry Song (Xiaomi) Co-developed-by: Dev Jain Signed-off-by: Dev Jain Signed-off-by: Wen Jiang Tested-by: Xueyuan Chen Cc: Andrew Donnellan Cc: Anshuman Khandual Cc: Catalin Marinas Cc: David Hildenbrand Cc: Mike Rapoport Cc: Ryan Roberts Cc: Uladzislau Rezki Cc: Wen Jiang Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/vmalloc.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 85 insertions(+), 2 deletions(-) --- a/mm/vmalloc.c~mm-vmalloc-map-contiguous-pages-in-batches-for-vmap-if-possible +++ a/mm/vmalloc.c @@ -3550,6 +3550,89 @@ void vunmap(const void *addr) } EXPORT_SYMBOL(vunmap); +static inline unsigned int vm_shift(pgprot_t prot, unsigned long size) +{ + if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE) + return PMD_SHIFT; + + return arch_vmap_pte_supported_shift(size); +} + +static inline int get_vmap_batch_order(struct page **pages, + pgprot_t prot, unsigned int max_steps, unsigned int idx) +{ + unsigned int nr_contig; + int order; + + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP)) + return 0; + + nr_contig = num_pages_contiguous(&pages[idx], max_steps); + if (nr_contig < 2) + return 0; + + order = ilog2(nr_contig); + + /* Limit order by pfn alignment */ + order = min_t(int, order, __ffs(page_to_pfn(pages[idx]))); + + if (vm_shift(prot, PAGE_SIZE << order) == PAGE_SHIFT) + return 0; + + return order; +} + +static int vmap_batched(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages) +{ + unsigned int count = (end - addr) >> PAGE_SHIFT; + unsigned int prev_shift = 0, idx = 0; + unsigned long start = addr, map_addr = addr; + int err; + + err = kmsan_vmap_pages_range_noflush(addr, end, prot, pages, + PAGE_SHIFT, GFP_KERNEL); + if (err) + goto out; + + for (unsigned int i = 0; i < count; ) { + unsigned int shift = PAGE_SHIFT + + get_vmap_batch_order(pages, prot, count - i, i); + + if (!i) + prev_shift = shift; + + if (shift != prev_shift) { + err = vmap_pages_range_noflush_walk(map_addr, addr, + prot, pages + idx, prev_shift); + if (err) + goto out; + prev_shift = shift; + map_addr = addr; + idx = i; + } + + /* + * Once small pages are encountered, the remaining pages + * are likely small as well. + */ + if (shift == PAGE_SHIFT) + break; + + addr += 1UL << shift; + i += 1U << (shift - PAGE_SHIFT); + } + + /* Remaining */ + if (map_addr < end) + err = vmap_pages_range_noflush_walk(map_addr, end, + prot, pages + idx, prev_shift); + +out: + flush_cache_vmap(start, end); + return err; +} + /** * vmap - map an array of pages into virtually contiguous space * @pages: array of page pointers @@ -3593,8 +3676,8 @@ void *vmap(struct page **pages, unsigned return NULL; addr = (unsigned long)area->addr; - if (vmap_pages_range(addr, addr + size, pgprot_nx(prot), - pages, PAGE_SHIFT) < 0) { + if (vmap_batched(addr, addr + size, pgprot_nx(prot), + pages) < 0) { vunmap(area->addr); return NULL; } _ Patches currently in -mm which might be from baohua@kernel.org are arm64-hugetlb-extend-batching-of-multiple-cont_pte-in-a-single-pte-setup.patch arm64-vmalloc-allow-arch_vmap_pte_range_map_size-to-batch-multiple-cont_pte.patch mm-vmalloc-extend-page-table-walk-to-support-larger-page_shift-sizes-and-eliminate-page-table-rewalk.patch mm-vmalloc-map-contiguous-pages-in-batches-for-vmap-if-possible.patch mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings.patch