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=-9.5 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=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 2E78DC433E0 for ; Fri, 29 May 2020 03:02:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 077C52075F for ; Fri, 29 May 2020 03:02:52 +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="kcPI2phi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389091AbgE2DCr (ORCPT ); Thu, 28 May 2020 23:02:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391656AbgE2C6g (ORCPT ); Thu, 28 May 2020 22:58:36 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF217C014D07; Thu, 28 May 2020 19:58:35 -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=/2fZQu8w66RARx8vOLpWsju1X69BaYw4U1H3jkF+yV0=; b=kcPI2philKd18Jgn0HN8dfP7jN HB8Fc9cJnCn/S8r2aN2OlISHcO/ex/bsIJ5HPJUCjnyGUVbE2ILQpxwztQ4ymcPFj6ssJ0NkKNhTZ k2PhAPNzm+ioYHhFgjXTGe3xA81E3YzSsayCF92SXU1Y2w+uclRKim0cx2yw7bKOlvMvhx6GkQ+tl cT8BgRD1uVzMBy/AzRYyjXCke1aTZ+Zbby1a/+TSjLVQmC+OCFX2JfSOCVLG31irEBr5dazT0yvxs pK/jFhZ7PKn7LtrfYD7C3Har+Hu+E6RRtZhG6PAMo+18B4rFn8YNScNSY4J4mSQsSPl2x83Hb7aja 09yF9/TA==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jeVE3-0008SD-Ea; Fri, 29 May 2020 02:58:27 +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 v5 23/39] mm: Allow large pages to be added to the page cache Date: Thu, 28 May 2020 19:58:08 -0700 Message-Id: <20200529025824.32296-24-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200529025824.32296-1-willy@infradead.org> References: <20200529025824.32296-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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 | 44 +++++++++++++++++++++++++++++++------------- 1 file changed, 31 insertions(+), 13 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 9abba062973a..437484d42b78 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 +846,48 @@ 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); + } unlock: xas_unlock_irq(&xas); } while (xas_nomem(&xas, gfp_mask & GFP_RECLAIM_MASK)); @@ -886,7 +904,7 @@ 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