From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f173.google.com (mail-pg1-f173.google.com [209.85.215.173]) (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 CD9D73BB101 for ; Thu, 9 Jul 2026 07:38:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783582743; cv=none; b=kyLOyW2yRPb2h3lWMKn/7dE6TQH2yvRZVWje2RNYw9/SxhV4g1VbM7Fb+EFn+BaT9rd0lvNVDs6Stit+NC/CtatS3M29ahco7Lbdjn7ATDiAfxrRx3QWLagqQxv1fdnXXuUs9xHqXbE8P3unSPRMXsJ0r/zqvWOvBPZvlhSvufU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783582743; c=relaxed/simple; bh=T1yDXxIwaJViN0ouQGQdGGb8WsXDgcHLgWyXUtT4e1o=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=GRYsjhOrKS/nWZ8NR35443ieljaoxR6dnZAYhjSRZzfEEq2S9giaij4RMjvRPOJfNgnsnKTPJDuTKfWzZrFFBQDJ8Ym37tmR+611B0N7I2NEEQpGarPRqtPVKroTGXX92STJt4IuWvmVrR7n4IZWICuYewY2xuj+y3ML/KUYJtM= 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=YW6h/Iol; arc=none smtp.client-ip=209.85.215.173 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="YW6h/Iol" Received: by mail-pg1-f173.google.com with SMTP id 41be03b00d2f7-c95d0a54ea5so1125097a12.0 for ; Thu, 09 Jul 2026 00:38:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1783582737; x=1784187537; 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:content-type; bh=Fk2AnNyTURv/eSeaFRjqsjfwR0678HcFAycOaxoU8q0=; b=YW6h/IoliIC8beKBfluv/lVvTsWePME9Cz7RVhV6dzRoiHhulnVMYfAYB7hScFoKns DB80RwbGFoUXI6MVxn7tMpbzLs08zpMV+RbqSlkE3WfazvjvBV8TnMv01U2Dp63nza+X oBmEhdDZ6tLgHI/S/nXbrKXlMCZggiJn4c3OI79tk0+Qm8Vw1FGhAJAaSCUhlYiJzOjD 8/TlaT3hX6LOvfBD2fBog/z1zLq7jhGkZ1BCb1sEszNWvcxMAlaY6n/MvvFcRdfwFkEB LfaTLuxOwx3cXvmpa011rI631PD+LsbzqwTVLurzC57w24cNAuwht6BURdykwqbTeG2/ HIfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783582737; x=1784187537; 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=Fk2AnNyTURv/eSeaFRjqsjfwR0678HcFAycOaxoU8q0=; b=QtDZJyPW6xTLdU1a7miVE1eG/M2/yCd8MUO1PWBseakRh4u2pwatQkElL+KxMqUlKo xAggQ33lfUn6vvUhCRniJZinFTKB66wc1oKXg6VMRH+7SRdTfM8M7hxxz3ve/yiYnSxN yXvAr1AFbvh80NdHyUfKFiAfR+kkxrBtkU2o5w2M3CzlQMTyjVGwH33c7lc1XHJZ2OSC pPTVItAX/fzz/pqBEIzPC5p+X0davSDSQlb/WcJrb5xiDb3ozMfSAh7eQvV9u1MylKhF xJqMTvbhdii9ggsqvjo2boDecyJciLmxQNButcIGPEtzF0bdQfoXgPdaBZ25iZl8vj6S Su1A== X-Forwarded-Encrypted: i=1; AHgh+RoNvfzVEvBxYxGdLEtgSSu3VAu+tZe4S9+dWFJ5/OQunyQLKtQMJpLBI/NLS6pOUUuE/uwLCQQH3BGCDdU=@vger.kernel.org X-Gm-Message-State: AOJu0YytVkoLqkqjSpbLhH7hk5OSC6UDuvAiIC63KEl9GEGGH3RpYzik vkjOWsdRL6Helb9wjxS9TjPd/tQvOVWjslm0xdOlK/qN6VcMGc4nYRMH X-Gm-Gg: AfdE7cnphidhGa7p23Hx6O/Obt2MiXEPsQoHbCWWMA1TQWSdpGzu0u3a+5sAd5AdMwj R+EhHvNyoFy/MfGSPJvp832+Q1ZqYJr3LcmS1U0wIpReMORk2cv69gFqAVzRVo/yapTEjW3HMPg 1r1BuSbzvSEYecVaEdV+rMthsGPiw98lKsW/ze3hDl2AfL8tsy/HaSDlX74qrO27k12MjIAzJkP 7IHZLg+zq+X1knbhxC3pzyqEqFb7cHdrnbLpMSAc0PpFBOEkvydnDzzHnoBlCF9iiG09aVAxcB/ 74QpluKFQtumkMvEM0BKplEN7KIkemfaMQoRk+DWFgEjWyLuNcn18XqLZFXjcKJHLjHv4FLqRz3 0io5/Dm3+3PZg7m+vCFP4fTnX7c2bSrPDoMgJjjX7sFJvBaM/nf+o4tTKM/yZ6Wc5JccvllDnUL deMsOh760vffipyc51meDuY8yZ+6A0sMFq1MI= X-Received: by 2002:a05:6a20:7486:b0:3b3:26aa:5455 with SMTP id adf61e73a8af0-3c0bc8c42e6mr7909704637.13.1783582737175; Thu, 09 Jul 2026 00:38:57 -0700 (PDT) Received: from mi-OptiPlex-7060.mioffice.cn ([43.224.245.234]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-ca5b3162a49sm3334902a12.15.2026.07.09.00.38.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jul 2026 00:38:56 -0700 (PDT) From: Wen Jiang X-Google-Original-From: Wen Jiang To: akpm@linux-foundation.org, catalin.marinas@arm.com, linux-mm@kvack.org, urezki@gmail.com, will@kernel.org Cc: Xueyuan.chen21@gmail.com, ajd@linux.ibm.com, anshuman.khandual@arm.com, david@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, rppt@kernel.org, ryan.roberts@arm.com, dev.jain@arm.com, "Barry Song (Xiaomi)" , Wen Jiang , Xueyuan Chen , Leo Yan Subject: [PATCH v6 4/6] mm/vmalloc: Extend page table walk to support larger page_shift sizes and eliminate page table rewalk Date: Thu, 9 Jul 2026 15:38:21 +0800 Message-Id: <20260709073823.6643-5-jiangwen6@xiaomi.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260709073823.6643-1-jiangwen6@xiaomi.com> References: <20260709073823.6643-1-jiangwen6@xiaomi.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Barry Song (Xiaomi)" vmap_pages_range_noflush_walk() (formerly vmap_small_pages_range_noflush()) provides a clean interface by taking struct page **pages and mapping them via direct PTE iteration. This avoids the page table rewalk seen when using vmap_range_noflush() for page_shift values other than PAGE_SHIFT. Extend it to support larger page_shift values, and add PMD- and contiguous-PTE mappings as well. Rename it to vmap_pages_range_noflush_walk() since it now handles more than just small pages. For vmalloc() allocations with VM_ALLOW_HUGE_VMAP, we no longer need to iterate over pages one by one via vmap_range_noflush(), which would otherwise lead to page table rewalk. The code is now unified with the PAGE_SHIFT case by simply calling vmap_pages_range_noflush_walk(). Signed-off-by: Barry Song (Xiaomi) Signed-off-by: Wen Jiang Tested-by: Xueyuan Chen Tested-by: Leo Yan Reviewed-by: Dev Jain --- mm/vmalloc.c | 81 ++++++++++++++++++++++++++++++---------------------- 1 file changed, 47 insertions(+), 34 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d7fef85b241c4..d2a4d649af549 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -125,7 +125,8 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, pte_t *pte; u64 pfn; struct page *page; - unsigned long size = PAGE_SIZE; + unsigned long size; + unsigned int steps; if (WARN_ON_ONCE(!PAGE_ALIGNED(end - addr))) return -EINVAL; @@ -147,8 +148,8 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, } size = vmap_set_ptes(pte, addr, end, pfn, prot, max_page_shift); - pfn += PFN_DOWN(size); - } while (pte += PFN_DOWN(size), addr += size, addr != end); + steps = PFN_DOWN(size); + } while (pte += steps, pfn += steps, addr += size, addr != end); lazy_mmu_mode_disable(); *mask |= PGTBL_PTE_MODIFIED; @@ -540,8 +541,10 @@ void vunmap_range(unsigned long addr, unsigned long end) static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, int *nr, - pgtbl_mod_mask *mask) + pgtbl_mod_mask *mask, unsigned int shift) { + unsigned long pfn, size; + unsigned int steps; int err = 0; pte_t *pte; @@ -572,9 +575,10 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr, break; } - set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); - (*nr)++; - } while (pte++, addr += PAGE_SIZE, addr != end); + pfn = page_to_pfn(page); + size = vmap_set_ptes(pte, addr, end, pfn, prot, shift); + steps = PFN_DOWN(size); + } while (pte += steps, *nr += steps, addr += size, addr != end); lazy_mmu_mode_disable(); *mask |= PGTBL_PTE_MODIFIED; @@ -584,7 +588,7 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr, static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, int *nr, - pgtbl_mod_mask *mask) + pgtbl_mod_mask *mask, unsigned int shift) { pmd_t *pmd; unsigned long next; @@ -594,7 +598,27 @@ static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr, return -ENOMEM; do { next = pmd_addr_end(addr, end); - if (vmap_pages_pte_range(pmd, addr, next, prot, pages, nr, mask)) + + if (shift >= PMD_SHIFT) { + struct page *page = pages[*nr]; + phys_addr_t phys_addr; + + if (WARN_ON(!page)) + return -ENOMEM; + if (WARN_ON(!pfn_valid(page_to_pfn(page)))) + return -EINVAL; + + phys_addr = page_to_phys(page); + + if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot, + shift)) { + *mask |= PGTBL_PMD_MODIFIED; + *nr += 1 << (PMD_SHIFT - PAGE_SHIFT); + continue; + } + } + + if (vmap_pages_pte_range(pmd, addr, next, prot, pages, nr, mask, shift)) return -ENOMEM; } while (pmd++, addr = next, addr != end); return 0; @@ -602,7 +626,7 @@ static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr, static int vmap_pages_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, int *nr, - pgtbl_mod_mask *mask) + pgtbl_mod_mask *mask, unsigned int shift) { pud_t *pud; unsigned long next; @@ -612,7 +636,7 @@ static int vmap_pages_pud_range(p4d_t *p4d, unsigned long addr, return -ENOMEM; do { next = pud_addr_end(addr, end); - if (vmap_pages_pmd_range(pud, addr, next, prot, pages, nr, mask)) + if (vmap_pages_pmd_range(pud, addr, next, prot, pages, nr, mask, shift)) return -ENOMEM; } while (pud++, addr = next, addr != end); return 0; @@ -620,7 +644,7 @@ static int vmap_pages_pud_range(p4d_t *p4d, unsigned long addr, static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, int *nr, - pgtbl_mod_mask *mask) + pgtbl_mod_mask *mask, unsigned int shift) { p4d_t *p4d; unsigned long next; @@ -630,14 +654,18 @@ static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr, return -ENOMEM; do { next = p4d_addr_end(addr, end); - if (vmap_pages_pud_range(p4d, addr, next, prot, pages, nr, mask)) + if (vmap_pages_pud_range(p4d, addr, next, prot, pages, nr, mask, shift)) return -ENOMEM; } while (p4d++, addr = next, addr != end); return 0; } -static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end, - pgprot_t prot, struct page **pages) +/* + * It can take an array of pages which are not all contiguous, but it + * may have contiguous chunks, as hinted by @shift. + */ +static int vmap_pages_range_noflush_walk(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages, unsigned int shift) { unsigned long start = addr; pgd_t *pgd; @@ -652,7 +680,7 @@ static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end, next = pgd_addr_end(addr, end); if (pgd_bad(*pgd)) mask |= PGTBL_PGD_MODIFIED; - err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask); + err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask, shift); if (err) break; } while (pgd++, addr = next, addr != end); @@ -675,27 +703,12 @@ static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end, int __vmap_pages_range_noflush(unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, unsigned int page_shift) { - unsigned int i, nr = (end - addr) >> PAGE_SHIFT; - WARN_ON(page_shift < PAGE_SHIFT); - if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC) || - page_shift == PAGE_SHIFT) - return vmap_small_pages_range_noflush(addr, end, prot, pages); - - for (i = 0; i < nr; i += 1U << (page_shift - PAGE_SHIFT)) { - int err; + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC)) + page_shift = PAGE_SHIFT; - err = vmap_range_noflush(addr, addr + (1UL << page_shift), - page_to_phys(pages[i]), prot, - page_shift); - if (err) - return err; - - addr += 1UL << page_shift; - } - - return 0; + return vmap_pages_range_noflush_walk(addr, end, prot, pages, page_shift); } int vmap_pages_range_noflush(unsigned long addr, unsigned long end, -- 2.34.1