From patchwork Wed Jun 10 20:13:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 11598775 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 E291F92A for ; Wed, 10 Jun 2020 20:18:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C68AD207F9 for ; Wed, 10 Jun 2020 20:18:24 +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="LZhl8Xoq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728174AbgFJUSH (ORCPT ); Wed, 10 Jun 2020 16:18:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730516AbgFJUNr (ORCPT ); Wed, 10 Jun 2020 16:13:47 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A62D9C08C5C2; Wed, 10 Jun 2020 13:13:47 -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=J/UeCwTdxdvssMS23HfBywrddunudah3jTHxFdDluWw=; b=LZhl8XoqWmoxoe4oiI7dUinI5V U776oT0ROF8uRC9JNB/LJXhTM+4p3TiyRvjzsIpCYCyO3a68xtitko/SBbg+ZVmx5GhngKvg9teOe WdyM9DdbiWNiNitspHxiYl9Nnk76ZbMXbemycCOEyXCj0YGes58HTegT39DkLVzMaCjRFXStIJ5kG CCvcIZMcZ+8zG/h8Ltb42ivV8fr2o3mwB1mfvj4o/3/wV0RG+WfDKZzyxnfPYIYRbsnTLZiVYQP3i bDBLGubh523Oi32hOAU2iXSukuT2B54nfqXae++cWaFptGmzzUymDbzAPIFUGkPFbaJp3uSHJUErK qj72UUNw==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jj76Z-0003TO-EQ; Wed, 10 Jun 2020 20:13:47 +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 v6 06/51] mm: Store compound_nr as well as compound_order Date: Wed, 10 Jun 2020 13:13:00 -0700 Message-Id: <20200610201345.13273-7-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200610201345.13273-1-willy@infradead.org> References: <20200610201345.13273-1-willy@infradead.org> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: "Matthew Wilcox (Oracle)" This removes a few instructions from functions which need to know how many pages are in a compound page. The storage used is either page->mapping on 64-bit or page->index on 32-bit. Both of these are fine to overlay on tail pages. Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/mm.h | 5 ++++- include/linux/mm_types.h | 1 + mm/page_alloc.c | 5 +++-- 3 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index dc7b87310c10..af0305ad090f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -911,12 +911,15 @@ static inline int compound_pincount(struct page *page) static inline void set_compound_order(struct page *page, unsigned int order) { page[1].compound_order = order; + page[1].compound_nr = 1U << order; } /* Returns the number of pages in this potentially compound page. */ static inline unsigned long compound_nr(struct page *page) { - return 1UL << compound_order(page); + if (!PageHead(page)) + return 1; + return page[1].compound_nr; } /* Returns the number of bytes in this potentially compound page. */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 64ede5f150dc..561ed987ab44 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -134,6 +134,7 @@ struct page { unsigned char compound_dtor; unsigned char compound_order; atomic_t compound_mapcount; + unsigned int compound_nr; /* 1 << compound_order */ }; struct { /* Second tail page of compound page */ unsigned long _compound_pad_1; /* compound_head */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 727751219003..3fb61ef4c3a4 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -673,8 +673,6 @@ void prep_compound_page(struct page *page, unsigned int order) int i; int nr_pages = 1 << order; - set_compound_page_dtor(page, COMPOUND_PAGE_DTOR); - set_compound_order(page, order); __SetPageHead(page); for (i = 1; i < nr_pages; i++) { struct page *p = page + i; @@ -682,6 +680,9 @@ void prep_compound_page(struct page *page, unsigned int order) p->mapping = TAIL_MAPPING; set_compound_head(p, page); } + + set_compound_page_dtor(page, COMPOUND_PAGE_DTOR); + set_compound_order(page, order); atomic_set(compound_mapcount_ptr(page), -1); if (hpage_pincount_available(page)) atomic_set(compound_pincount_ptr(page), 0);