From patchwork Thu Jul 23 22:30:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ralph Campbell X-Patchwork-Id: 11681725 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 EB4366C1 for ; Thu, 23 Jul 2020 22:31:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBF0B20792 for ; Thu, 23 Jul 2020 22:31:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728008AbgGWWbB convert rfc822-to-8bit (ORCPT ); Thu, 23 Jul 2020 18:31:01 -0400 Received: from hqnvemgate25.nvidia.com ([216.228.121.64]:13903 "EHLO hqnvemgate25.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727876AbgGWWaw (ORCPT ); Thu, 23 Jul 2020 18:30:52 -0400 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 23 Jul 2020 15:29:48 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Thu, 23 Jul 2020 15:30:51 -0700 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Thu, 23 Jul 2020 15:30:51 -0700 Received: from HQMAIL111.nvidia.com (172.20.187.18) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 23 Jul 2020 22:30:42 +0000 Received: from rnnvemgw01.nvidia.com (10.128.109.123) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Thu, 23 Jul 2020 22:30:42 +0000 Received: from rcampbell-dev.nvidia.com (Not Verified[10.110.48.66]) by rnnvemgw01.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Thu, 23 Jul 2020 15:30:42 -0700 From: Ralph Campbell To: , , , , , CC: Jerome Glisse , John Hubbard , Christoph Hellwig , Jason Gunthorpe , "Andrew Morton" , Shuah Khan , "Ben Skeggs" , Bharata B Rao , "Ralph Campbell" Subject: [PATCH v4 6/6] mm/migrate: remove range invalidation in migrate_vma_pages() Date: Thu, 23 Jul 2020 15:30:04 -0700 Message-ID: <20200723223004.9586-7-rcampbell@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200723223004.9586-1-rcampbell@nvidia.com> References: <20200723223004.9586-1-rcampbell@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org When migrating the special zero page, migrate_vma_pages() calls mmu_notifier_invalidate_range_start() before replacing the zero page PFN in the CPU page tables. This is unnecessary since the range was invalidated in migrate_vma_setup() and the page table entry is checked to be sure it hasn't changed between migrate_vma_setup() and migrate_vma_pages(). Therefore, remove the redundant invalidation. DKIM-Signature: v aa-sha256; claxed/relaxed; didia.com; s; t95543388; bhqnSzc0udfc4m+P6cziRmRJk5XEGcgDU5ImloLrCuE hPGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; byLVqKU1Kxf67Qz9TIZ2f1lAaP7YxvFgCZR8v0Vw1fwq7aUbMbgfzcF0bd6+XzG6 ZHtBRMp/Zu/ZLGRxP6lBqZo4wHMHbuW3fXOvPCrYTD5YsCCLv+Ao4RmreWyec2wBTk uBo3ZylCHJ0ckD85BcjQQxpXyY99cBsvIomZw9wzg6QGm7Ksbq6d+UKSkb0L04d6v8 fiRvvLNq3kCbPzrifaBTj3klQcVcKXz34km0XUoRQlSaftlq4BJWopBPX8U7gQtstO OvA7Al9t87sCpKjSnqjE7N1jThU0KzjPrCxJiEHq/0Vf4sqeUA42bOkc+bk/CV1ZSF n9jm36j4kRTUg Signed-off-by: Ralph Campbell --- mm/migrate.c | 20 -------------------- 1 file changed, 20 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 96e1f41a991e..36076ba2f51a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2877,9 +2877,7 @@ void migrate_vma_pages(struct migrate_vma *migrate) { const unsigned long npages = migrate->npages; const unsigned long start = migrate->start; - struct mmu_notifier_range range; unsigned long addr, i; - bool notified = false; for (i = 0, addr = start; i < npages; addr += PAGE_SIZE, i++) { struct page *newpage = migrate_pfn_to_page(migrate->dst[i]); @@ -2895,16 +2893,6 @@ void migrate_vma_pages(struct migrate_vma *migrate) if (!page) { if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE)) continue; - if (!notified) { - notified = true; - - mmu_notifier_range_init(&range, - MMU_NOTIFY_CLEAR, 0, - NULL, - migrate->vma->vm_mm, - addr, migrate->end); - mmu_notifier_invalidate_range_start(&range); - } migrate_vma_insert_page(migrate, addr, newpage, &migrate->src[i], &migrate->dst[i]); @@ -2937,14 +2925,6 @@ void migrate_vma_pages(struct migrate_vma *migrate) if (r != MIGRATEPAGE_SUCCESS) migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; } - - /* - * No need to double call mmu_notifier->invalidate_range() callback as - * the above ptep_clear_flush_notify() inside migrate_vma_insert_page() - * did already call it. - */ - if (notified) - mmu_notifier_invalidate_range_only_end(&range); } EXPORT_SYMBOL(migrate_vma_pages);