From patchwork Tue Oct 13 23:51:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11836331 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 257C8921 for ; Tue, 13 Oct 2020 23:51:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D95C521D7A for ; Tue, 13 Oct 2020 23:51:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="NrGNXfYe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D95C521D7A 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 805306B00AE; Tue, 13 Oct 2020 19:51:44 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 7669A6B00AF; Tue, 13 Oct 2020 19:51:44 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E3E06B00B0; Tue, 13 Oct 2020 19:51:44 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0138.hostedemail.com [216.40.44.138]) by kanga.kvack.org (Postfix) with ESMTP id 28D336B00AE for ; Tue, 13 Oct 2020 19:51:44 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id BB6B782499B9 for ; Tue, 13 Oct 2020 23:51:43 +0000 (UTC) X-FDA: 77368552086.20.boy88_2f02d8227207 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 9EC47180C07A3 for ; Tue, 13 Oct 2020 23:51:43 +0000 (UTC) X-Spam-Summary: 1,0,0,8059dea2d4b2ccee,d41d8cd98f00b204,akpm@linux-foundation.org,,RULES_HIT:41:355:379:800:960:967:973:988:989:1260:1345:1359:1381:1431:1437:1535:1544:1605:1711:1730:1747:1777:1792:2393:2525:2553:2559:2563:2682:2685:2693:2859:2902:2918:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3865:3867:3868:3870:3871:3872:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4250:4321:4605:5007:6261:6653:6737:7514:7576:7875:7903:8957:9010:9025:9545:10004:11026:11232:11473:11658:11914:12043:12048:12291:12296:12297:12438:12517:12519:12555:12679:12683:12986:13146:13230:13846:14096:14181:14721:21063:21080:21324:21433:21451:21627:21939:21990:30054:30064:30090,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-62.2.0.100 64.100.201.201;04ygcebxskcmbi1zeewa55c7wanxpycw44ckdputop6eqztpxbpr6fs3f8d7o4f.ft9a9ra41x5bmeqc4f9ahi7da54tzxm77643mp8anpd3edabtbsfzgcaeogt48q.h-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,D omainCac X-HE-Tag: boy88_2f02d8227207 X-Filterd-Recvd-Size: 5616 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Tue, 13 Oct 2020 23:51:43 +0000 (UTC) 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 E79D821D7B; Tue, 13 Oct 2020 23:51:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633102; bh=EhWnWsayRlrHqkP6dxl0ISwqXMFPoVuEHlN49BV7eZk=; h=Date:From:To:Subject:In-Reply-To:From; b=NrGNXfYeKg7F6op77cBUaXid+TwAFqW67e7Jdth//e2SKN455rZ7NWEPP4vnKonwr euXEqvrhV/24sUAnw1mKXCDizRtnfl0gaFmBkOhSWAne5x/VOp7aYcQ2s2drjDSo6S gejstPwwiyyylabEkOkMJ34tfSlkdYZaX7EtEd+g= Date: Tue, 13 Oct 2020 16:51:41 -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 061/181] mm: add find_lock_head Message-ID: <20201013235141.5Wzerxsbz%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 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 find_lock_head Add a new FGP_HEAD flag which avoids calling find_subpage() and add a convenience wrapper for it. Link: https://lkml.kernel.org/r/20200910183318.20139-9-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Alexey Dobriyan Cc: Chris Wilson Cc: Huang Ying Cc: Hugh Dickins Cc: Jani Nikula Cc: Johannes Weiner Cc: Matthew Auld Cc: William Kucharski Signed-off-by: Andrew Morton --- include/linux/pagemap.h | 32 ++++++++++++++++++++++++++------ mm/filemap.c | 9 ++++++--- 2 files changed, 32 insertions(+), 9 deletions(-) --- a/include/linux/pagemap.h~mm-add-find_lock_head +++ a/include/linux/pagemap.h @@ -279,6 +279,7 @@ pgoff_t page_cache_prev_miss(struct addr #define FGP_NOFS 0x00000010 #define FGP_NOWAIT 0x00000020 #define FGP_FOR_MMAP 0x00000040 +#define FGP_HEAD 0x00000080 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset, int fgp_flags, gfp_t cache_gfp_mask); @@ -310,18 +311,37 @@ static inline struct page *find_get_page * @mapping: the address_space to search * @offset: the page index * - * Looks up the page cache slot at @mapping & @offset. If there is a + * Looks up the page cache entry at @mapping & @offset. If there is a * page cache page, it is returned locked and with an increased * refcount. * - * Otherwise, %NULL is returned. - * - * find_lock_page() may sleep. + * Context: May sleep. + * Return: A struct page or %NULL if there is no page in the cache for this + * index. */ static inline struct page *find_lock_page(struct address_space *mapping, - pgoff_t offset) + pgoff_t index) +{ + return pagecache_get_page(mapping, index, FGP_LOCK, 0); +} + +/** + * find_lock_head - Locate, pin and lock a pagecache page. + * @mapping: The address_space to search. + * @offset: The page index. + * + * Looks up the page cache entry at @mapping & @offset. If there is a + * page cache page, its head page is returned locked and with an increased + * refcount. + * + * Context: May sleep. + * Return: A struct page which is !PageTail, or %NULL if there is no page + * in the cache for this index. + */ +static inline struct page *find_lock_head(struct address_space *mapping, + pgoff_t index) { - return pagecache_get_page(mapping, offset, FGP_LOCK, 0); + return pagecache_get_page(mapping, index, FGP_LOCK | FGP_HEAD, 0); } /** --- a/mm/filemap.c~mm-add-find_lock_head +++ a/mm/filemap.c @@ -1737,6 +1737,8 @@ repeat: * * * %FGP_ACCESSED - The page will be marked accessed. * * %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_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. @@ -1765,7 +1767,6 @@ repeat: page = NULL; if (!page) goto no_page; - page = find_subpage(page, index); if (fgp_flags & FGP_LOCK) { if (fgp_flags & FGP_NOWAIT) { @@ -1778,12 +1779,12 @@ repeat: } /* Has the page been truncated? */ - if (unlikely(compound_head(page)->mapping != mapping)) { + if (unlikely(page->mapping != mapping)) { unlock_page(page); put_page(page); goto repeat; } - VM_BUG_ON_PAGE(page->index != index, page); + VM_BUG_ON_PAGE(!thp_contains(page, index), page); } if (fgp_flags & FGP_ACCESSED) @@ -1793,6 +1794,8 @@ repeat: if (page_is_idle(page)) clear_page_idle(page); } + if (!(fgp_flags & FGP_HEAD)) + page = find_subpage(page, index); no_page: if (!page && (fgp_flags & FGP_CREAT)) {