From patchwork Fri Jun 19 21:56:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ralph Campbell X-Patchwork-Id: 11615215 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5A6EA913 for ; Fri, 19 Jun 2020 21:58:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4233B22211 for ; Fri, 19 Jun 2020 21:58:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="NIxcE9Fd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728308AbgFSV6V (ORCPT ); Fri, 19 Jun 2020 17:58:21 -0400 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:2228 "EHLO hqnvemgate26.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728269AbgFSV5I (ORCPT ); Fri, 19 Jun 2020 17:57:08 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 19 Jun 2020 14:56:54 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 19 Jun 2020 14:57:07 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 19 Jun 2020 14:57:07 -0700 Received: from HQMAIL105.nvidia.com (172.20.187.12) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 19 Jun 2020 21:56:59 +0000 Received: from hqnvemgw03.nvidia.com (10.124.88.68) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Fri, 19 Jun 2020 21:56:59 +0000 Received: from rcampbell-dev.nvidia.com (Not Verified[10.110.48.66]) by hqnvemgw03.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Fri, 19 Jun 2020 14:56:59 -0700 From: Ralph Campbell To: , , , , CC: Jerome Glisse , John Hubbard , Christoph Hellwig , Jason Gunthorpe , "Ben Skeggs" , Andrew Morton , Shuah Khan , Ralph Campbell Subject: [PATCH 12/16] mm/hmm: optimize migrate_vma_setup() for holes Date: Fri, 19 Jun 2020 14:56:45 -0700 Message-ID: <20200619215649.32297-13-rcampbell@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200619215649.32297-1-rcampbell@nvidia.com> References: <20200619215649.32297-1-rcampbell@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1592603814; bh=axo1qROEDM7hJwmmu8OcpvGAO/8DiPu78Ea49fo3JP8=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; b=NIxcE9Fdl7sawaTciO5YlsjyXWpVEzFy0PbON2Sjk/IyFNSrBJ3Z0/rsrrAxkjrPQ Gf9NZudc7Nbt8Zl7jnG+RRXt4NWhRcV1pDwSpZrAuJLTXo3sCmo+0KRW4p1KpP1C2O IGlJdkSh1pbgcUuFPE/eHS9ARNZCW+Vct1T3yR8P47uoaS0F8MUoGYnVrVSCAeuAAL Wa0mn3fQfKu6brwDG1bL1YBu9wmXB2HDxw8Ozxh5DG7e9SaU/k/qtMIomYAX5KoRsN dROV2rrac8AawgKXAEL67b2guP7Gye49n/ClaiscMGrEh5ewh1ZOYWwMOdfQ2WKXZS jeiLsbDR/xcHw== Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org When migrating system memory to device private memory, if the source address range is a valid VMA range and there is no memory or a zero page, the source PFN array is marked as valid but with no PFN. This lets the device driver allocate private memory and clear it, then insert the new device private struct page into the CPU's page tables when migrate_vma_pages() is called. migrate_vma_pages() only inserts the new page if the VMA is an anonymous range. There is no point in telling the device driver to allocate device private memory and then throwing it away. Instead, mark the source PFN array entries as not migrating to avoid this overhead. Signed-off-by: Ralph Campbell --- mm/migrate.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 24535281cea3..87c52e0ee580 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2178,9 +2178,13 @@ static int migrate_vma_collect_hole(unsigned long start, { struct migrate_vma *migrate = walk->private; unsigned long addr; + unsigned long flags; + + /* Only allow populating anonymous memory */ + flags = vma_is_anonymous(walk->vma) ? MIGRATE_PFN_MIGRATE : 0; for (addr = start; addr < end; addr += PAGE_SIZE) { - migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE; + migrate->src[migrate->npages] = flags; migrate->dst[migrate->npages] = 0; migrate->npages++; migrate->cpages++; @@ -2748,7 +2752,7 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, pte_t *ptep; /* Only allow populating anonymous memory */ - if (!vma_is_anonymous(vma)) + if (WARN_ON_ONCE(!vma_is_anonymous(vma))) goto abort; pgdp = pgd_offset(mm, addr);