From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f182.google.com (mail-pl1-f182.google.com [209.85.214.182]) (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 E60AC3A05CC for ; Fri, 22 May 2026 05:32:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779427938; cv=none; b=ZrE3QgsyVVeMrI6K+7VwI7+Afj8FctO13dnPWpnLtSErQdKXfa8xfOePxFQ4Kr4MAmwvwoC+Zufsqv377DmGl00J/y7hQjPDgVnhhWJpzmDVxQChEiXzmGTLy+IM6UgjnCKEzxX//54mb90eV5ENDHQlNowEGmQyOMQWwpNa3Gw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779427938; c=relaxed/simple; bh=LdsND3STYh4BypV9GZjw0LQICsDiKifD84zvHA/3J20=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=G+i60wvZ3dDbgiVWO4ya1FVxV43qnW64YpVggszfqUAjU7chPkM6V4v8Aa4qX0XCObJYg7Hxk3egdnvHPiOjqTA0ZMqcnk5X5wlV4iff8/iUWlvSd7uihUfcRcQS+WuQhpEH7AixwZOjJ8QIgb/st/9bzA2Bq6ScN+/+YXdzoSM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=sxDecJi8; arc=none smtp.client-ip=209.85.214.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sxDecJi8" Received: by mail-pl1-f182.google.com with SMTP id d9443c01a7336-2bd2c147abaso41751195ad.3 for ; Thu, 21 May 2026 22:32:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1779427936; x=1780032736; darn=vger.kernel.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; bh=G4nDVPNvDGaaEdnxQatYVMpRpD4mqtQtLPJNe5AMUKI=; b=sxDecJi8HwsR/C09FxppDBBwOkKjqqHRInHNxYDaXbDwY1n+dBebOmzFusgGQ0bVox WURxIPHvvOLQLdwo8Q+gDt0V/lcFjZ4ylgryvL/t9cWY1xwJtRAi0vpefb0AmqUNw5Ww NnGC6lB8vsWQdXQK2+cVVzKK5nTjisPEqtL5dHPhYt3jb15s0/0hQnk7f/R96QwaNdRR 9DOAgWnC9qydbv84FHEv2uM1544QOrwN4XESFzBPMCHCKsoEgmVtjGCQJBb7h5l1aw5g hbPxCg3M2j8+2rFlsErM3RKqbILd49RILxmjRViu2fjIXrp2KNyNaEGoldyhCwy8BAu+ QLJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779427936; x=1780032736; 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; bh=G4nDVPNvDGaaEdnxQatYVMpRpD4mqtQtLPJNe5AMUKI=; b=WEMmPD4YTP0WqWLoPhX7y+7qW0mjITj4KDEvuhqMozZQ1gUhWgI5kEUAgPCMTuORWm NZJmZvpme6ZTinVF3Z47fS6bXllod0dDjJcFLCKnmnkhVdm4FeKccFaF5DTHxsYnJE+B E3IQ9cANsISdKX/MwHty+kI2x4LrhfD37BnNKb6rA8BuhQRaHjTT7TLn0c8flmMPDIKk W+n7WIjCb7VOYjs0+M5CwSowUAjdF9C4dkX+hoyF6DxOAKKkYp7XCeXV8ZnvMnYsWsTO RG/1mWpQlLbt5oLz7gG/rgIvKJGXA/QD/Ygjw2CDyvE3oje7IbAj0tT8cH68YTv9O5Dw JD5A== X-Forwarded-Encrypted: i=1; AFNElJ+3xIE63T9Q85kEkoeBLd1yWc9MwSbhmt58yHwQ7mFXo/wR/+Alq9H6zPUnEcN1ZKHtbEW0NH06HGUwrxo=@vger.kernel.org X-Gm-Message-State: AOJu0YxlmJJqWBx7LdulZo93ZNllVnjGn7Q7cpW0UF4pngjlz527/yq9 Rc2uderCzKnnY2L+eNh5++OUMwswi6uGbk9+mtFW5FxjGupcA+N50B0o X-Gm-Gg: Acq92OE3k8gK6L/l21wGDpyE85JhsUSlDmRlQIylMySGZVUydt6wxkfhcyP76dq3kTG G9lIQL9GRwiYMA8iW7wuQNMf/29n3WltxoI4XsTmv5S0jnW+kW62m6GMvU7j31vQFCnfxT9Foa0 7x8c9FGT+4/fRzvoI6Fg/xiAOnPrHtpgFuL2SudzwVuARrmVQB3UOqu6FuRKlfKj0z8eG2YgvRL uDPK4g/mP8CCnuAYMmr03EMFgKFt3mHwh9Tqu9mNywU/12Go52boU0+Fi6JnkFgL6UkhqVWxgbp z4z2f+F9EaXxXlTNe8nkUgJLq7+f14gL2lJXi9fAVMfDoTRRuB4+zWfEaeVXzQjBvyA1CD8bTVo IGwCQ+2Gd6eV2nh9L5ftQSEcnmAkBqG11Wvib6NZa2NvWj/Ul8eNHeYh8kaogjD/vRC0TcxuZCi xjgnBrBHQgF5MWMP+XV17KuzopeXyvOn7ZpHJP3Dz5Bg/Ypf4wxoX5UqCiYek0EQ== X-Received: by 2002:a17:903:2c04:b0:2b4:61cc:37a8 with SMTP id d9443c01a7336-2beb037a5ebmr22161795ad.17.1779427936265; Thu, 21 May 2026 22:32:16 -0700 (PDT) Received: from mi-OptiPlex-7060.mioffice.cn ([43.224.245.234]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2beb56d68adsm4782665ad.32.2026.05.21.22.32.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 May 2026 22:32:15 -0700 (PDT) From: Wen Jiang To: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, urezki@gmail.com Cc: baohua@kernel.org, Xueyuan.chen21@gmail.com, dev.jain@arm.com, rppt@kernel.org, david@kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, ajd@linux.ibm.com, linux-kernel@vger.kernel.org, jiangwen6@xiaomi.com Subject: [PATCH v3 5/6] mm/vmalloc: map contiguous pages in batches for vmap() if possible Date: Fri, 22 May 2026 13:31:45 +0800 Message-Id: <20260522053146.83209-6-jiangwenxiaomi@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260522053146.83209-1-jiangwenxiaomi@gmail.com> References: <20260522053146.83209-1-jiangwenxiaomi@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: "Barry Song (Xiaomi)" 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 first page's pfn must be aligned to the mapping order for the batched mapping to be used. 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. 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 --- mm/vmalloc.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 80 insertions(+), 2 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index deb764abc0571..50642246f4d40 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3542,6 +3542,84 @@ void vunmap(const void *addr) } EXPORT_SYMBOL(vunmap); +static inline int get_vmap_batch_order(struct page **pages, + unsigned int max_steps, unsigned int idx) +{ + unsigned int nr_contig; + int order; + + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP) || + ioremap_max_page_shift == PAGE_SHIFT) + return 0; + + nr_contig = num_pages_contiguous(&pages[idx], max_steps); + if (nr_contig < 2) + return 0; + + order = fls(nr_contig) - 1; + + if (arch_vmap_pte_supported_shift(PAGE_SIZE << order) == PAGE_SHIFT) + return 0; + + /* Ensure the first page's pfn is aligned to the order */ + if (!IS_ALIGNED(page_to_pfn(pages[idx]), 1 << order)) + 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, count - i, i); + + if (!i) + prev_shift = shift; + + if (shift != prev_shift) { + err = vmap_pages_range_noflush_walk(map_addr, addr, + prot, pages + idx, + min(prev_shift, PMD_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, min(prev_shift, PMD_SHIFT)); + +out: + flush_cache_vmap(start, end); + return err; +} + /** * vmap - map an array of pages into virtually contiguous space * @pages: array of page pointers @@ -3585,8 +3663,8 @@ void *vmap(struct page **pages, unsigned int count, 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; } -- 2.34.1