From patchwork Fri Feb 26 01:15:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12105351 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F072C433DB for ; Fri, 26 Feb 2021 01:15:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 08B2264EEB for ; Fri, 26 Feb 2021 01:15:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 08B2264EEB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9140A6B006E; Thu, 25 Feb 2021 20:15:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E8B08D0002; Thu, 25 Feb 2021 20:15:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7FDDC6B0072; Thu, 25 Feb 2021 20:15:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0166.hostedemail.com [216.40.44.166]) by kanga.kvack.org (Postfix) with ESMTP id 69E286B006E for ; Thu, 25 Feb 2021 20:15:39 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 27B29183F8689 for ; Fri, 26 Feb 2021 01:15:39 +0000 (UTC) X-FDA: 77858651598.25.4F0BBAB Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf07.hostedemail.com (Postfix) with ESMTP id 0CEE8A0009D3 for ; Fri, 26 Feb 2021 01:15:37 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 51D5764EDC; Fri, 26 Feb 2021 01:15:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614302137; bh=8lZ4OC8zIErX0CHe+/2dPFmBWQNT9SRfeJzRSD3whOE=; h=Date:From:To:Subject:In-Reply-To:From; b=wvCo83N6l5mQeDyiectWWh7g2M+rbmajehkNqnJolGu60Anqyf71lZMIGdxsP7q5u zM5NFSqt2J0W70M/83wB+WLfCRo6eTr6Fubor1U2oycGdZjNje9M2jZNuEdx0aGfMX VduCuVoUke7U5B7BLm+AZw4YYzDScMX9l5UAmLBg= Date: Thu, 25 Feb 2021 17:15:36 -0800 From: Andrew Morton To: akpm@linux-foundation.org, dchinner@redhat.com, hannes@cmpxchg.org, hch@lst.de, hughd@google.com, jack@suse.cz, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, yang.shi@linux.alibaba.com Subject: [patch 004/118] mm: add FGP_ENTRY Message-ID: <20210226011536.YFTPl8PHT%akpm@linux-foundation.org> In-Reply-To: <20210225171452.713967e96554bb6a53e44a19@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 0CEE8A0009D3 X-Stat-Signature: 9pw9aeb63do4e4b76h81oymhnwzzmwnc Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf07; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614302137-33704 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: "Matthew Wilcox (Oracle)" Subject: mm: add FGP_ENTRY The functionality of find_lock_entry() and find_get_entry() can be provided by pagecache_get_page(), which lets us delete find_lock_entry() and make find_get_entry() static. Link: https://lkml.kernel.org/r/20201112212641.27837-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Cc: Dave Chinner Cc: Hugh Dickins Cc: Jan Kara Cc: Johannes Weiner Cc: Kirill A. Shutemov Cc: William Kucharski Cc: Yang Shi Signed-off-by: Andrew Morton --- include/linux/pagemap.h | 1 mm/filemap.c | 44 ++++++-------------------------------- mm/internal.h | 3 -- mm/shmem.c | 3 +- mm/swap_state.c | 3 +- 5 files changed, 13 insertions(+), 41 deletions(-) --- a/include/linux/pagemap.h~mm-add-fgp_entry +++ a/include/linux/pagemap.h @@ -315,6 +315,7 @@ pgoff_t page_cache_prev_miss(struct addr #define FGP_NOWAIT 0x00000020 #define FGP_FOR_MMAP 0x00000040 #define FGP_HEAD 0x00000080 +#define FGP_ENTRY 0x00000100 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset, int fgp_flags, gfp_t cache_gfp_mask); --- a/mm/filemap.c~mm-add-fgp_entry +++ a/mm/filemap.c @@ -1658,7 +1658,7 @@ pgoff_t page_cache_prev_miss(struct addr } EXPORT_SYMBOL(page_cache_prev_miss); -/** +/* * find_get_entry - find and get a page cache entry * @mapping: the address_space to search * @index: The page cache index. @@ -1671,7 +1671,7 @@ EXPORT_SYMBOL(page_cache_prev_miss); * * Return: The head page or shadow entry, %NULL if nothing is found. */ -struct page *find_get_entry(struct address_space *mapping, pgoff_t index) +static struct page *find_get_entry(struct address_space *mapping, pgoff_t index) { XA_STATE(xas, &mapping->i_pages, index); struct page *page; @@ -1708,39 +1708,6 @@ out: } /** - * find_lock_entry - Locate and lock a page cache entry. - * @mapping: The address_space to search. - * @index: The page cache index. - * - * Looks up the page at @mapping & @index. If there is a page in the - * cache, the head page is returned locked and with an increased refcount. - * - * If the slot holds a shadow entry of a previously evicted page, or a - * swap entry from shmem/tmpfs, it is returned. - * - * Context: May sleep. - * Return: The head page or shadow entry, %NULL if nothing is found. - */ -struct page *find_lock_entry(struct address_space *mapping, pgoff_t index) -{ - struct page *page; - -repeat: - page = find_get_entry(mapping, index); - if (page && !xa_is_value(page)) { - lock_page(page); - /* Has the page been truncated? */ - if (unlikely(page->mapping != mapping)) { - unlock_page(page); - put_page(page); - goto repeat; - } - VM_BUG_ON_PAGE(!thp_contains(page, index), page); - } - return page; -} - -/** * pagecache_get_page - Find and get a reference to a page. * @mapping: The address_space to search. * @index: The page index. @@ -1755,6 +1722,8 @@ repeat: * * %FGP_LOCK - The page is returned locked. * * %FGP_HEAD - If the page is present and a THP, return the head page * rather than the exact page specified by the index. + * * %FGP_ENTRY - If there is a shadow / swap / DAX entry, return it + * instead of allocating a new page to replace it. * * %FGP_CREAT - If no page is present then a new page is allocated using * @gfp_mask and added to the page cache and the VM's LRU list. * The page is returned locked and with an increased refcount. @@ -1779,8 +1748,11 @@ struct page *pagecache_get_page(struct a repeat: page = find_get_entry(mapping, index); - if (xa_is_value(page)) + if (xa_is_value(page)) { + if (fgp_flags & FGP_ENTRY) + return page; page = NULL; + } if (!page) goto no_page; --- a/mm/internal.h~mm-add-fgp_entry +++ a/mm/internal.h @@ -60,9 +60,6 @@ static inline void force_page_cache_read force_page_cache_ra(&ractl, &file->f_ra, nr_to_read); } -struct page *find_get_entry(struct address_space *mapping, pgoff_t index); -struct page *find_lock_entry(struct address_space *mapping, pgoff_t index); - /** * page_evictable - test whether a page is evictable * @page: the page to test --- a/mm/shmem.c~mm-add-fgp_entry +++ a/mm/shmem.c @@ -1812,7 +1812,8 @@ repeat: sbinfo = SHMEM_SB(inode->i_sb); charge_mm = vma ? vma->vm_mm : current->mm; - page = find_lock_entry(mapping, index); + page = pagecache_get_page(mapping, index, + FGP_ENTRY | FGP_HEAD | FGP_LOCK, 0); if (xa_is_value(page)) { error = shmem_swapin_page(inode, index, &page, sgp, gfp, vma, fault_type); --- a/mm/swap_state.c~mm-add-fgp_entry +++ a/mm/swap_state.c @@ -403,7 +403,8 @@ struct page *find_get_incore_page(struct { swp_entry_t swp; struct swap_info_struct *si; - struct page *page = find_get_entry(mapping, index); + struct page *page = pagecache_get_page(mapping, index, + FGP_ENTRY | FGP_HEAD, 0); if (!page) return page;