From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8AAE7C982D2 for ; Thu, 17 Sep 2026 18:12:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8C2A26B0093; Thu, 17 Sep 2026 14:12:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8933B6B0095; Thu, 17 Sep 2026 14:12:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7D00C6B0096; Thu, 17 Sep 2026 14:12:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 648A86B0093 for ; Thu, 17 Sep 2026 14:12:20 -0400 (EDT) Received: from smtpin17.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 0B359A048D for ; Thu, 17 Sep 2026 18:12:20 +0000 (UTC) X-FDA: 85224048840.17.C72862B Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf30.hostedemail.com (Postfix) with ESMTP id 3DE1380006 for ; Thu, 17 Sep 2026 18:12:18 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=mCMXQQCu; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf30.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789668738; b=EYnGS1tq6VhJGXFclKbk1fPgjh9ThDMPORTVNdJuVV5PL1/586+q1I+s9+DE8hg8P8099L SeFWQFtD97N/6ebx6W1DDNua+VP387YOVUZjBQGUnxoYnWq8lLnZjRcVwXmvvqbvFvuk+o ScKKkylXnAi4XVXR+xMqS5iuDJIR/Uc= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=mCMXQQCu; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf30.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789668738; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=vqyQgMFAJVi2Td/IFUmuzFBF1bi1YpyEHAojG3GW2qw=; b=KZYdRR3HSGnsn9Ja+9pPhl2360prqrYFFCOrA+sbTHKK64bxwwJYG/1o16VarKgapdgf/d yz/EjS9y2P46mTPMJN5RU+DNuhgRRvwrfsoBDozT0yqfZ71n5FAztb72OY17HXYsYN1Dx2 +nICF93zgG3iKwQfin1orNWeAs8iUSU= 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 A6D8D1596; Thu, 17 Sep 2026 11:12:13 -0700 (PDT) Received: from [10.57.7.135] (unknown [10.57.7.135]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EB6E23F86F; Thu, 17 Sep 2026 11:12:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789668737; bh=JRotaeYUDA8OKw6fWgN1iioU01GNC1YxBAHOCuSkCcg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=mCMXQQCuXWXGh8CqhS0W7cwhE2pXGdXIab/vrQATUL3/XaFJNt8Xf3XcEukOlMYCK ugh3zQSksUsKim10k1OD4vF/PrNn0SbUDLvpZ5GQyazWmyouKJGKG5+oDmjP89b8Rg 7/ZY9aaQUsSH+CtdxVNQuZgcibuXfkywZeR0hrNM= Message-ID: <19b00695-9f99-4d21-9592-13fad31f85e7@arm.com> Date: Thu, 17 Sep 2026 20:12:07 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 4/6] mm/vmalloc: make set_area_direct_map HUGE_VMAP friendly To: "Mike Rapoport (Microsoft)" , Andrew Morton Cc: =?UTF-8?Q?Adrian_Barna=C5=9B?= , Albert Ou , Alexander Gordeev , Alexandre Ghiti , Andy Lutomirski , Borislav Petkov , Brendan Jackman , Catalin Marinas , Christian Borntraeger , Dave Hansen , David Hildenbrand , Gerald Schaefer , Heiko Carstens , Huacai Chen , Ingo Molnar , Len Brown , Palmer Dabbelt , Paul Walmsley , Pavel Machek , Peter Zijlstra , "H. Peter Anvin" , "Rafael J. Wysocki" , Ryan Roberts , Sven Schnelle , Thomas Gleixner , Uladzislau Rezki , Vasily Gorbik , WANG Xuerui , Will Deacon , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, loongarch@lists.linux.dev References: <20260903-execmem-set-vm-perms-v0-2-v3-0-949b64a9f755@kernel.org> <20260903-execmem-set-vm-perms-v0-2-v3-4-949b64a9f755@kernel.org> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: <20260903-execmem-set-vm-perms-v0-2-v3-4-949b64a9f755@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 3DE1380006 X-Stat-Signature: uuc9de8toa74b4kpta3fudoqgbk3xsom X-HE-Tag: 1789668738-137133 X-HE-Meta: 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 gJEtD79W RdPtlY+GK7SPEOusthXNqYsOVqED2NiFq5iz2H2Xhf9NupiZkwguenZMCPaMC1ygM0vrALYP4QETc6RMC8a65j1ZnZx8FMR5eK4A+Qs9Fx4/FqVYx6H2ZD/NkNUsR41xfX3mELFN6tel/zZKG7v4EM5BJR88Xs1DI+MB6jNXMYExWImsCyxYJzlxb+M3laXy4bMPxO6eqeJQAlmzn1ul/+T9fJptFXyWfZfRhGAPp8gU2BTG+8aldSgcNbRfIYj3h6C59m691JxjYkep2ef1lDayv/mbBQ1eDl/CLA94BALBpYB656wiN4uZElLzpwVcEREfpkTobRw6Gv3/BAEtGwGLNOJftY0aQiL86u0gurmGpaYA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 03/09/2026 11:28, Mike Rapoport (Microsoft) wrote: > set_area_direct_map() always updates direct map alias permissions in > single page increments. > > For HUGE_VMAP areas it's suboptimal. Not only the loop in > set_area_direct_map() needlessly has more iterations (e.g times 512 on > x86), but it also causes fragmentation of the direct map that could be > avoided for the HUGE_VMAP areas populated with large pages. > > All pages in an area are always of the same order: either same-order > large pages when VM_ALLOW_HUGE_VMAP is set and all huge pages were > successfully allocated, or order-0 page when VM_ALLOW_HUGE_VMAP is > cleared or when huge pages allocation fails and fallback path is taken. > > Instead of updating the direct map permissions for every order-0 page in > an area, use the area's page_order as the loop increment and update the > large pages in one call to set_direct_map_{invalid,default}_noflush(). > > Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Kevin Brodsky > --- > mm/vmalloc.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 5506b180f5c27..6ed6c160abed7 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3367,12 +3367,15 @@ static inline void set_area_direct_map(const struct vm_struct *area, > int (*set_direct_map)(struct page *page, > unsigned int nr)) > { > - unsigned long i; > + unsigned int nr = (1U << vm_area_page_order(area)); > + > + for (unsigned long i = 0; i < area->nr_pages; i += nr) { > + if (page_address(area->pages[i])) { > + int err = set_direct_map(area->pages[i], nr); > > - /* HUGE_VMALLOC passes small pages to set_direct_map */ > - for (i = 0; i < area->nr_pages; i++) > - if (page_address(area->pages[i])) > - set_direct_map(area->pages[i], 1); > + WARN_ON_ONCE(err); > + } > + } > } > > /* >