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 4F494C79FA1 for ; Tue, 8 Sep 2026 09:59:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3CB5A6B00A2; Tue, 8 Sep 2026 05:59:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 37AD56B00A3; Tue, 8 Sep 2026 05:59:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 245CC6B00A4; Tue, 8 Sep 2026 05:59:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id F3A7C6B00A2 for ; Tue, 8 Sep 2026 05:59:32 -0400 (EDT) Received: from smtpin01.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 75D1D404ED for ; Tue, 8 Sep 2026 09:59:32 +0000 (UTC) X-FDA: 85190147784.01.CC4C041 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf13.hostedemail.com (Postfix) with ESMTP id 660E220004 for ; Tue, 8 Sep 2026 09:59:30 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=YR0UOmZK; spf=pass (imf13.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788861570; b=VncV9FPGbvISs+Kk/2QllzU574sVGi9FhxnM1LSs9UFU0azPQhtXipD8++/GYLqXG8IaLd Cc4jPUgi9798FPE/IPi6TYgu6ef2TALXfsXDXU+tR2TxjJLB11kOUnHInYHpUulOy/QBJ6 zHLyNCqA1g3d8JQG2ccJAgkhKQs5K/Y= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788861570; 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=CHEe090zxcvX/G2IQLHQp9iXm/EoC7Qx7nHJQJ/rGtQ=; b=Dd87u6wQRQaH1bKv9K26XFakpuDWn/FB/qx5uOo+MRDD65jYNIpjpxZeSoANsEYugIVdNq d1NsOO99QpeIYFlrmo1UyZYALjbagSu17ef/HTUod3wRbGT/Q0Z0IU51wSicyyoovHPLFk HmVbR4MuJlslEZ/5baw/rCE0ZIZdyBg= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=YR0UOmZK; spf=pass (imf13.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com; dmarc=pass (policy=none) header.from=arm.com 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 7E6391476; Tue, 8 Sep 2026 02:59:25 -0700 (PDT) Received: from [10.164.19.55] (unknown [10.164.19.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8CBC43F7B4; Tue, 8 Sep 2026 02:59:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788861569; bh=a/a9VuH1Pbu7fuqb4EF439JhWu4OMvquSWkjlVGi4tM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=YR0UOmZKFbfAJ3SQSDswiFS+rXAWEo6USejgl07yJMtcUVzwUvoX92dfUQwwVpdX5 EaS2HlcY5AR9bV7tQg2bFaeizuNwDp69wiztfvHe7QfBZ8M2HAbZx4+U2VfjisKvus ye1W5JquN+zfg/oiJuWT9J+cxec8MSXZ7ZVkbbDw= Message-ID: <88b48587-1f3e-479b-ae9b-67aa643e2acb@arm.com> Date: Tue, 8 Sep 2026 15:29:16 +0530 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> Content-Language: en-US From: Dev Jain 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: rspam07 X-Rspamd-Queue-Id: 660E220004 X-Stat-Signature: o3xpnoibk7gxhjwcia3t8hqpmhyn7zhb X-HE-Tag: 1788861570-617018 X-HE-Meta: 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 nwyvCdfs THvgDdfLz7UHAJDleXY91fFyBizNPa33LJolQwIgsE8RYCDS0jAK3Weuiihoh05AT44run5oBK+7Ll8GMBeNrUb29cwrtWPpK3/pkX29XQmTeERMSGA+2qxaZNcK1Z2y0xOl33N1BzUpQI33RN98QY4m7eyK6IBv/aPwLe4z7Q1jNnb6AXaTB8tPBvepzV1qaK41L4xPiykJFZ72IBYsGG4UzuEqbWYaxfqx18YyFwa7QWPzM22kQkRVHAlIlL539krrbp0nBJry32Fhpgoi73lfXThrxWQxqiZT5n3LgHhPWPaLuJjqwBWNeQDGVsmAKwLsHEFPH7jkLWUeYI5u4lp4glr7zi8UCuChQwAAFecZD3yY= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 03/09/26 2:58 pm, 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. Correct, this would also help us on arm64 once we have ROX caches. > > 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) > --- LGTM: Reviewed-by: Dev Jain > 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); > + } > + } > } > > /* >