From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8197A303A37 for ; Mon, 29 Jun 2026 06:47:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782715637; cv=none; b=Z62hqEqRGQTC4JIfrxlplHR5J4xCuKW1+NBiQadT0tuo6Skh1Y2bnTEwymH9JmNP9WLnJYmo0VwExgzkXT7E/sPHNckQ+9iqf0L5faJWvOB7Qecf4VE9Dz/8NMmAPKJsKv3xQWYLZnBlEjReEPUFuAU38DNMOReKkCIBN9NmNI4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782715637; c=relaxed/simple; bh=wG+BKRCh7EswG1NnBEIJLxPGzB+YZ6gQORqGiFpNlxk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=d+E6Yo2K3PXLbITgOfdvJs47KrkYaxwK1DRhQg9PvSCi/E13eh26aLQk9BbJKQ8g+r13gLn2N1jMkkze79tmms3iscvIasD990LF7rJUli9KdHINdHQVXNIJrig/RfQkyOheQrRu3Bbhn6e9whYSpJ0qJPYWCt5LWbJu0iW7N1A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=L1ipuc6p; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="L1ipuc6p" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2002E176B; Sun, 28 Jun 2026 23:47:10 -0700 (PDT) Received: from [10.164.19.15] (unknown [10.164.19.15]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3C1F03F85F; Sun, 28 Jun 2026 23:47:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782715634; bh=wG+BKRCh7EswG1NnBEIJLxPGzB+YZ6gQORqGiFpNlxk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=L1ipuc6pUg//TJm2iPvJ8j4e8NZzKbVkfx4X1O65glkyl1Z6AzAdvwnb9H9muTdJO yIY6NujGnMcYEdyOgxBHRN6ZdFko2nQQ03RgGjxLf8sfQD0J/IMOFAieH7m5C84m1a DYnT2j6Lc7v4DOn1UajCixH0dkmX1SKs8MWOtFHM= Message-ID: Date: Mon, 29 Jun 2026 12:17:07 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 6/6] mm/vmalloc: align vm_area so vmap() can batch mappings To: Wen Jiang , 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, 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, shanghaoqiang@xiaomi.com References: <20260618084726.1070022-1-jiangwen6@xiaomi.com> <20260618084726.1070022-7-jiangwen6@xiaomi.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20260618084726.1070022-7-jiangwen6@xiaomi.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 18/06/26 2:17 pm, Wen Jiang wrote: > From: "Barry Song (Xiaomi)" > > Try to align the vmap virtual address to PMD_SHIFT or a > larger PTE mapping size hinted by the architecture, so > contiguous pages can be batch-mapped when setting PMD or > PTE entries. > > Add __get_vm_area_node_aligned_caller() as a wrapper over > __get_vm_area_node() to simplify repeated calls with fixed > arguments. > > Signed-off-by: Barry Song (Xiaomi) > Signed-off-by: Wen Jiang > Tested-by: Xueyuan Chen > --- > mm/vmalloc.c | 37 ++++++++++++++++++++++++++++++++++++- > 1 file changed, 36 insertions(+), 1 deletion(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index fffb885cb2158..bc9fa93e2bdc6 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3628,6 +3628,41 @@ static int vmap_batched(unsigned long addr, unsigned long end, > return err; > } > > +static struct vm_struct *__get_vm_area_node_aligned_caller(unsigned long size, > + unsigned long align, unsigned long flags, const void *caller) There are 3 similar functions below __get_vm_area_node: they are __get_vm_area_caller, get_vm_area and get_vm_area_caller. You can put this one just below them. > +{ > + return __get_vm_area_node(size, align, PAGE_SHIFT, flags, > + VMALLOC_START, VMALLOC_END, > + NUMA_NO_NODE, GFP_KERNEL, caller); > +} > + > +static struct vm_struct *vmap_get_aligned_vm_area(unsigned long size, > + unsigned long flags, const void *caller) > +{ > + struct vm_struct *vm_area; > + unsigned int shift; > + > + /* Try PMD alignment for large sizes */ This comment feels excessive. Can remove it. > + if (size >= PMD_SIZE) { Need an arch_vmap_pmd_supported() check here. > + vm_area = __get_vm_area_node_aligned_caller(size, PMD_SIZE, > + flags, caller); > + if (vm_area) > + return vm_area; > + } > + > + /* Try CONT_PTE alignment */ Comment feels excessive, and again no need to mention arm64 specific stuff here. Just remove it. > + shift = arch_vmap_pte_supported_shift(size); > + if (shift > PAGE_SHIFT) { > + vm_area = __get_vm_area_node_aligned_caller(size, 1UL << shift, > + flags, caller); > + if (vm_area) > + return vm_area; > + } > + > + /* Fall back to page alignment */ This comment can also be dropped, but I am fine either way. > + return __get_vm_area_node_aligned_caller(size, PAGE_SIZE, flags, caller); > +} > + > /** > * vmap - map an array of pages into virtually contiguous space > * @pages: array of page pointers > @@ -3666,7 +3701,7 @@ void *vmap(struct page **pages, unsigned int count, > return NULL; > > size = (unsigned long)count << PAGE_SHIFT; > - area = get_vm_area_caller(size, flags, __builtin_return_address(0)); > + area = vmap_get_aligned_vm_area(size, flags, __builtin_return_address(0)); So the effect is that now we search for an aligned vm_struct unconditionally. Better to mention in the commit message that we do not expect any significant overhead for this. > if (!area) > return NULL; >