From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756685AbcDLKMk (ORCPT ); Tue, 12 Apr 2016 06:12:40 -0400 Received: from outbound-smtp12.blacknight.com ([46.22.139.17]:45601 "EHLO outbound-smtp12.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756196AbcDLKMj (ORCPT ); Tue, 12 Apr 2016 06:12:39 -0400 From: Mel Gorman To: Andrew Morton Cc: Vlastimil Babka , Linux-MM , LKML , Mel Gorman Subject: [PATCH 01/24] mm, page_alloc: Only check PageCompound for high-order pages Date: Tue, 12 Apr 2016 11:12:02 +0100 Message-Id: <1460455945-29644-2-git-send-email-mgorman@techsingularity.net> X-Mailer: git-send-email 2.6.4 In-Reply-To: <1460455945-29644-1-git-send-email-mgorman@techsingularity.net> References: <1460455945-29644-1-git-send-email-mgorman@techsingularity.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org order-0 pages by definition cannot be compound so avoid the check in the fast path for those pages. Signed-off-by: Mel Gorman --- mm/page_alloc.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 59de90d5d3a3..5d205bcfe10d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1024,24 +1024,33 @@ void __meminit reserve_bootmem_region(unsigned long start, unsigned long end) static bool free_pages_prepare(struct page *page, unsigned int order) { - bool compound = PageCompound(page); - int i, bad = 0; + int bad = 0; VM_BUG_ON_PAGE(PageTail(page), page); - VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); trace_mm_page_free(page, order); kmemcheck_free_shadow(page, order); kasan_free_pages(page, order); + /* + * Check tail pages before head page information is cleared to + * avoid checking PageCompound for order-0 pages. + */ + if (order) { + bool compound = PageCompound(page); + int i; + + VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); + + for (i = 1; i < (1 << order); i++) { + if (compound) + bad += free_tail_pages_check(page, page + i); + bad += free_pages_check(page + i); + } + } if (PageAnon(page)) page->mapping = NULL; bad += free_pages_check(page); - for (i = 1; i < (1 << order); i++) { - if (compound) - bad += free_tail_pages_check(page, page + i); - bad += free_pages_check(page + i); - } if (bad) return false; -- 2.6.4