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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 92E6AC43457 for ; Tue, 13 Oct 2020 23:51:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 582D821D7A for ; Tue, 13 Oct 2020 23:51:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633080; bh=NfHANz71e0zeMCmDscWvHhVHhtKECDL8lHMS0tn1Id8=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=Nbs1Bu21VXuaoeOOr52jQwm0goN9X50vQvjbU1LDetWplKCmZ2Od5JCOVcKOdNn1c ZeHxT12sCGwY4kRng3/G+8FcOV1wGCy7W7+puaPliStHgTdm2n0+nsXyhwlFTU6pFv P6VoBLZ3zZ6mlWIZGlhy12JcGni/vyO6kjO5R6FA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730416AbgJMXvT (ORCPT ); Tue, 13 Oct 2020 19:51:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:36054 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730412AbgJMXvT (ORCPT ); Tue, 13 Oct 2020 19:51:19 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1888B21D81; Tue, 13 Oct 2020 23:51:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633078; bh=NfHANz71e0zeMCmDscWvHhVHhtKECDL8lHMS0tn1Id8=; h=Date:From:To:Subject:In-Reply-To:From; b=bKNlXd91ghb54Cprs0352HAdFVnRHuGBYWxlF0SqY6O4G47SfFG//TXKf9ka8DaB7 jWO5plQvMljmkjPjeGauD4xIevJa6b5JeJjdXUr3IO7AW0hpTII0B1oiBLTHb8sI4O LQwXs68un1X3rn3zCormc7al3KClg6WKcxClFqFs= Date: Tue, 13 Oct 2020 16:51:17 -0700 From: Andrew Morton To: adobriyan@gmail.com, akpm@linux-foundation.org, chris@chris-wilson.co.uk, hannes@cmpxchg.org, hughd@google.com, jani.nikula@linux.intel.com, linux-mm@kvack.org, matthew.auld@intel.com, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, ying.huang@intel.com Subject: [patch 054/181] mm: factor find_get_incore_page out of mincore_page Message-ID: <20201013235117.BCOZHNo0D%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: "Matthew Wilcox (Oracle)" Subject: mm: factor find_get_incore_page out of mincore_page Patch series "Return head pages from find_*_entry", v2. This patch series started out as part of the THP patch set, but it has some nice effects along the way and it seems worth splitting it out and submitting separately. Currently find_get_entry() and find_lock_entry() return the page corresponding to the requested index, but the first thing most callers do is find the head page, which we just threw away. As part of auditing all the callers, I found some misuses of the APIs and some plain inefficiencies that I've fixed. The diffstat is unflattering, but I added more kernel-doc and a new wrapper. This patch (of 8); Provide this functionality from the swap cache. It's useful for more than just mincore(). Link: https://lkml.kernel.org/r/20200910183318.20139-1-willy@infradead.org Link: https://lkml.kernel.org/r/20200910183318.20139-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Hugh Dickins Cc: William Kucharski Cc: Jani Nikula Cc: Alexey Dobriyan Cc: Johannes Weiner Cc: Chris Wilson Cc: Matthew Auld Cc: Huang Ying Signed-off-by: Andrew Morton --- include/linux/swap.h | 7 +++++++ mm/mincore.c | 28 ++-------------------------- mm/swap_state.c | 32 ++++++++++++++++++++++++++++++++ 3 files changed, 41 insertions(+), 26 deletions(-) --- a/include/linux/swap.h~mm-factor-find_get_incore_page-out-of-mincore_page +++ a/include/linux/swap.h @@ -427,6 +427,7 @@ extern void free_pages_and_swap_cache(st extern struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma, unsigned long addr); +struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index); extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, struct vm_area_struct *vma, unsigned long addr, bool do_poll); @@ -570,6 +571,12 @@ static inline struct page *lookup_swap_c return NULL; } +static inline +struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index) +{ + return find_get_page(mapping, index); +} + static inline int add_to_swap(struct page *page) { return 0; --- a/mm/mincore.c~mm-factor-find_get_incore_page-out-of-mincore_page +++ a/mm/mincore.c @@ -48,7 +48,7 @@ static int mincore_hugetlb(pte_t *pte, u * and is up to date; i.e. that no page-in operation would be required * at this time if an application were to map and access this page. */ -static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff) +static unsigned char mincore_page(struct address_space *mapping, pgoff_t index) { unsigned char present = 0; struct page *page; @@ -59,31 +59,7 @@ static unsigned char mincore_page(struct * any other file mapping (ie. marked !present and faulted in with * tmpfs's .fault). So swapped out tmpfs mappings are tested here. */ -#ifdef CONFIG_SWAP - if (shmem_mapping(mapping)) { - page = find_get_entry(mapping, pgoff); - /* - * shmem/tmpfs may return swap: account for swapcache - * page too. - */ - if (xa_is_value(page)) { - swp_entry_t swp = radix_to_swp_entry(page); - struct swap_info_struct *si; - - /* Prevent swap device to being swapoff under us */ - si = get_swap_device(swp); - if (si) { - page = find_get_page(swap_address_space(swp), - swp_offset(swp)); - put_swap_device(si); - } else - page = NULL; - } - } else - page = find_get_page(mapping, pgoff); -#else - page = find_get_page(mapping, pgoff); -#endif + page = find_get_incore_page(mapping, index); if (page) { present = PageUptodate(page); put_page(page); --- a/mm/swap_state.c~mm-factor-find_get_incore_page-out-of-mincore_page +++ a/mm/swap_state.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "internal.h" /* @@ -414,6 +415,37 @@ struct page *lookup_swap_cache(swp_entry return page; } +/** + * find_get_incore_page - Find and get a page from the page or swap caches. + * @mapping: The address_space to search. + * @index: The page cache index. + * + * This differs from find_get_page() in that it will also look for the + * page in the swap cache. + * + * Return: The found page or %NULL. + */ +struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index) +{ + swp_entry_t swp; + struct swap_info_struct *si; + struct page *page = find_get_entry(mapping, index); + + if (!xa_is_value(page)) + return page; + if (!shmem_mapping(mapping)) + return NULL; + + swp = radix_to_swp_entry(page); + /* Prevent swapoff from happening to us */ + si = get_swap_device(swp); + if (!si) + return NULL; + page = find_get_page(swap_address_space(swp), swp_offset(swp)); + put_swap_device(si); + return page; +} + struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, struct vm_area_struct *vma, unsigned long addr, bool *new_page_allocated) _