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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C13DEB64DD for ; Tue, 27 Jun 2023 08:09:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231134AbjF0IJj (ORCPT ); Tue, 27 Jun 2023 04:09:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51916 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229740AbjF0IJi (ORCPT ); Tue, 27 Jun 2023 04:09:38 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id ACF931FC7; Tue, 27 Jun 2023 01:09:37 -0700 (PDT) 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 7400B2F4; Tue, 27 Jun 2023 01:10:21 -0700 (PDT) Received: from [10.57.76.16] (unknown [10.57.76.16]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 780303F663; Tue, 27 Jun 2023 01:09:33 -0700 (PDT) Message-ID: Date: Tue, 27 Jun 2023 09:09:31 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v1 04/10] mm: Implement folio_add_new_anon_rmap_range() To: Yu Zhao Cc: Andrew Morton , "Matthew Wilcox (Oracle)" , "Kirill A. Shutemov" , Yin Fengwei , David Hildenbrand , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-s390@vger.kernel.org References: <20230626171430.3167004-1-ryan.roberts@arm.com> <20230626171430.3167004-5-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-ia64@vger.kernel.org On 27/06/2023 08:08, Yu Zhao wrote: > On Mon, Jun 26, 2023 at 11:14 AM Ryan Roberts wrote: >> >> Like folio_add_new_anon_rmap() but batch-rmaps a range of pages >> belonging to a folio, for effciency savings. All pages are accounted as >> small pages. >> >> Signed-off-by: Ryan Roberts >> --- >> include/linux/rmap.h | 2 ++ >> mm/rmap.c | 43 +++++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 45 insertions(+) >> >> diff --git a/include/linux/rmap.h b/include/linux/rmap.h >> index a3825ce81102..15433a3d0cbf 100644 >> --- a/include/linux/rmap.h >> +++ b/include/linux/rmap.h >> @@ -196,6 +196,8 @@ void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, >> unsigned long address); >> void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *, >> unsigned long address); >> +void folio_add_new_anon_rmap_range(struct folio *folio, struct page *page, >> + int nr, struct vm_area_struct *vma, unsigned long address); > > We should update folio_add_new_anon_rmap() to support large() && > !folio_test_pmd_mappable() folios instead. > > I double checked all places currently using folio_add_new_anon_rmap(), > and as expected, none actually allocates large() && > !folio_test_pmd_mappable() and maps it one by one, which makes the > cases simpler, i.e., > if (!large()) > // the existing basepage case > else if (!folio_test_pmd_mappable()) > // our new case > else > // the existing THP case I don't have a strong opinion either way. Happy to go with this suggestion. But the reason I did it as a new function was because I was following the pattern in [1] which adds a new folio_add_file_rmap_range() function. [1] https://lore.kernel.org/linux-mm/20230315051444.3229621-35-willy@infradead.org/ > >> void page_add_file_rmap(struct page *, struct vm_area_struct *, >> bool compound); >> void folio_add_file_rmap_range(struct folio *, struct page *, unsigned int nr, >> diff --git a/mm/rmap.c b/mm/rmap.c >> index 1d8369549424..4050bcea7ae7 100644 >> --- a/mm/rmap.c >> +++ b/mm/rmap.c >> @@ -1305,6 +1305,49 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma, >> __page_set_anon_rmap(folio, &folio->page, vma, address, 1); >> } >> >> +/** >> + * folio_add_new_anon_rmap_range - Add mapping to a set of pages within a new >> + * anonymous potentially large folio. >> + * @folio: The folio containing the pages to be mapped >> + * @page: First page in the folio to be mapped >> + * @nr: Number of pages to be mapped >> + * @vma: the vm area in which the mapping is added >> + * @address: the user virtual address of the first page to be mapped >> + * >> + * Like folio_add_new_anon_rmap() but batch-maps a range of pages within a folio >> + * using non-THP accounting. Like folio_add_new_anon_rmap(), the inc-and-test is >> + * bypassed and the folio does not have to be locked. All pages in the folio are >> + * individually accounted. >> + * >> + * As the folio is new, it's assumed to be mapped exclusively by a single >> + * process. >> + */ >> +void folio_add_new_anon_rmap_range(struct folio *folio, struct page *page, >> + int nr, struct vm_area_struct *vma, unsigned long address) >> +{ >> + int i; >> + >> + VM_BUG_ON_VMA(address < vma->vm_start || >> + address + (nr << PAGE_SHIFT) > vma->vm_end, vma); > > BTW, VM_BUG_ON* shouldn't be used in new code: > Documentation/process/coding-style.rst Thanks, sorry about that. Was copy-pasting from folio_add_new_anon_rmap().