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 2A1DAC79FA1 for ; Tue, 8 Sep 2026 11:12:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DA3586B008A; Tue, 8 Sep 2026 07:12:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D546B6B008C; Tue, 8 Sep 2026 07:12:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C46766B0092; Tue, 8 Sep 2026 07:12:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id A23546B008A for ; Tue, 8 Sep 2026 07:12:30 -0400 (EDT) Received: from smtpin01.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 26FB01404D8 for ; Tue, 8 Sep 2026 11:12:30 +0000 (UTC) X-FDA: 85190331660.01.B38A7C8 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf29.hostedemail.com (Postfix) with ESMTP id 6051012000B for ; Tue, 8 Sep 2026 11:12:28 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=j0YvJw5X; spf=pass (imf29.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788865948; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=+8zEZzYXKDWjMscmRriONU7KthgG+ikNsFsSCx8Kl7U=; b=he84eCAhnQC3IqVxWVAHb0InElbe7bXje7KfMmbpUlibc//tqHHyP/5aUWc46b58xF3G0p gN0HszpD7007WV0xRMtOJLitxYaolENT4O9yIkPq3nQQuMVIZ0ewLLoRijRqpKh/mbLdyi tsI0U3H9pWfHOAjPG0AREVrOUpvTKvk= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788865948; b=N3yKq0LWeVcgBqksFqCAiNaJykcnZ8PAuUtgma9oHN7jKTbRIRMec9+CYKLpvUsk992MRA vuFUKwPYias0tkNpCIIesjP+67zbtXWrNCw6jQMoT5WJVyID24/Xa7H18fEi3Vkh/spT6+ p3cM0QMVBkkMP2hh0qvk7uejTNrtcR8= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=j0YvJw5X; spf=pass (imf29.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 7FC6D412D4; Tue, 8 Sep 2026 11:12:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CCEF1F00A3A; Tue, 8 Sep 2026 11:12:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788865947; bh=+8zEZzYXKDWjMscmRriONU7KthgG+ikNsFsSCx8Kl7U=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=j0YvJw5XRabkDRwY07U/Nr51yNYPwxCyv+z3STNN3DvhiZbQ2LLliKVdQxWj7ppq+ zv9BhrPbhWQJAVescoenFKCBK8dIe4FnLE41q0oGajg4NKGEFMqenvTN8qGcT5KALG fQMcuKC+7NJE6h1JkAWJGjRFe7kuNrWWBJi63S3F7fZ6YaNOkz2UdfAh8vmFC5EXcp bHxMCUACQA7hH4tJIGFFrWqfN8HNtsfKVFr7W/ZxLarzhz8HriGsNqqucFmQRW8PiZ axL0F5cVKdHUSq7uODecJDsNjdMRPzRgNMNU9BLViewX8ONteqjFxwoO/2vXDW+IOk Uivt3hlM1NCZw== Date: Tue, 8 Sep 2026 14:12:12 +0300 From: Mike Rapoport To: "David Hildenbrand (Arm)" Cc: Andrew Morton , Adrian =?utf-8?Q?Barna=C5=9B?= , Albert Ou , Alexander Gordeev , Alexandre Ghiti , Andy Lutomirski , Borislav Petkov , Brendan Jackman , Catalin Marinas , Christian Borntraeger , Dave Hansen , 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 Subject: Re: [PATCH v3 4/6] mm/vmalloc: make set_area_direct_map HUGE_VMAP friendly Message-ID: 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> <2b0f5877-e71a-4824-adeb-5af2dd8b0269@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2b0f5877-e71a-4824-adeb-5af2dd8b0269@kernel.org> X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: 1m516pgms6mb1stkmb4sz3rpsrbp8x4o X-Rspamd-Queue-Id: 6051012000B X-HE-Tag: 1788865948-553000 X-HE-Meta: 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 SQS+WEie R9qrmwALG+f1UJFW/LvQa7zsqXhAA5BgEFj+PvH+dzg2zR1edJV34ThO8lrBeLsXXyQxeEy6iVfzbwJnfEEtVoj4uTuiRlzp3vKyh+chWc3++AWF/D2wNLI2oGDJld1WqP2xDcAgW2u7amyDfu1vVM05eayq40efR91T9u6gIa1UZLWSjbFI7P1scDYGMavxIER6FIEk/fCXusp7a+nwa35g09P2tlDkK/B/NNNRbK5XPBANJSDwSynOWADqY+GBCRAELmvv+6lRa51drUlawcnXPf3bsF2EN8eSwy/rJPG+ue9V73igx9eqHrQ55vp1cSPOZD4Gs7W/nHRQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 08, 2026 at 12:41:48PM +0200, David Hildenbrand (Arm) wrote: > On 9/3/26 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) > > --- > > 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); > > Do we really expect some pages to have a directmap and others not? Every page in the area can be allocated separately and __vmalloc_area_node() has if (!(gfp_mask & (GFP_DMA | GFP_DMA32))) gfp_mask |= __GFP_HIGHMEM; so generally speaking yes :) > -- > Cheers, > > David -- Sincerely yours, Mike.