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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 08C81C83004 for ; Wed, 29 Apr 2020 13:41:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD454206D6 for ; Wed, 29 Apr 2020 13:41:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="DtXWrjwc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728628AbgD2NlM (ORCPT ); Wed, 29 Apr 2020 09:41:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727077AbgD2NhB (ORCPT ); Wed, 29 Apr 2020 09:37:01 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E357AC09B054; Wed, 29 Apr 2020 06:36:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=7CmfqOJK6S19EckditoMkvWvGLDrCQNnv0HgEdn9l3o=; b=DtXWrjwccPuY+GQBBQ67oO8Rk9 4MsYFoEsxJaT+XuKLfigNfQvaAGeyc941g4/O1qVdXQhGxuHIV/t8StKWw3VYS/fQyPV99C9gk/AV hfoig8Yye9pi54kgWiAYPvHg6Ecyvy3YNCNvdoc6xUJ6LD+dE9897vBfH7ICBeMSEhBL6wd7M/NS9 S1taO1QBsfsDN9bTmmsykfBKgAGoUHDMQhQpKSbYyF3JxUJVeMoKl2J5woH0/G4HCLdI0YmyHmQod Ul6AqLNuxoKaPzae9zBdz3DLHu93mBAArADWQSeTbnjpAmfTZCQOtBvz8AduEppKkLGZ1BB1I5wnB FqppMCKw==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jTmtX-0005w9-O8; Wed, 29 Apr 2020 13:36:59 +0000 From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 18/25] mm: Allow large pages to be added to the page cache Date: Wed, 29 Apr 2020 06:36:50 -0700 Message-Id: <20200429133657.22632-19-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200429133657.22632-1-willy@infradead.org> References: <20200429133657.22632-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Matthew Wilcox (Oracle)" We return -EEXIST if there are any non-shadow entries in the page cache in the range covered by the large page. If there are multiple shadow entries in the range, we set *shadowp to one of them (currently the one at the highest index). If that turns out to be the wrong answer, we can implement something more complex. This is mostly modelled after the equivalent function in the shmem code. Signed-off-by: Matthew Wilcox (Oracle) --- mm/filemap.c | 46 +++++++++++++++++++++++++++++++++------------- 1 file changed, 33 insertions(+), 13 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 9abba062973a..842afee3d066 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -834,6 +834,7 @@ static int __add_to_page_cache_locked(struct page *page, int huge = PageHuge(page); struct mem_cgroup *memcg; int error; + unsigned int nr = 1; void *old; VM_BUG_ON_PAGE(!PageLocked(page), page); @@ -845,31 +846,50 @@ static int __add_to_page_cache_locked(struct page *page, gfp_mask, &memcg, false); if (error) return error; + xas_set_order(&xas, offset, thp_order(page)); + nr = hpage_nr_pages(page); } - get_page(page); + page_ref_add(page, nr); page->mapping = mapping; page->index = offset; do { + unsigned long exceptional = 0; + unsigned int i = 0; + xas_lock_irq(&xas); - old = xas_load(&xas); - if (old && !xa_is_value(old)) - xas_set_err(&xas, -EEXIST); - xas_store(&xas, page); + xas_for_each_conflict(&xas, old) { + if (!xa_is_value(old)) { + xas_set_err(&xas, -EEXIST); + break; + } + exceptional++; + if (shadowp) + *shadowp = old; + } + xas_create_range(&xas); if (xas_error(&xas)) goto unlock; - if (xa_is_value(old)) { - mapping->nrexceptional--; - if (shadowp) - *shadowp = old; +next: + xas_store(&xas, page); + if (++i < nr) { + xas_next(&xas); + goto next; } - mapping->nrpages++; + mapping->nrexceptional -= exceptional; + mapping->nrpages += nr; /* hugetlb pages do not participate in page cache accounting */ - if (!huge) - __inc_node_page_state(page, NR_FILE_PAGES); + if (!huge) { + __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, + nr); + if (nr > 1) { + __inc_node_page_state(page, NR_FILE_THPS); + filemap_nr_thps_inc(mapping); + } + } unlock: xas_unlock_irq(&xas); } while (xas_nomem(&xas, gfp_mask & GFP_RECLAIM_MASK)); @@ -886,7 +906,7 @@ static int __add_to_page_cache_locked(struct page *page, /* Leave page->index set: truncation relies upon it */ if (!huge) mem_cgroup_cancel_charge(page, memcg, false); - put_page(page); + page_ref_sub(page, nr); return xas_error(&xas); } ALLOW_ERROR_INJECTION(__add_to_page_cache_locked, ERRNO); -- 2.26.2