From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 46EF36B0266 for ; Sat, 16 Dec 2017 11:44:44 -0500 (EST) Received: by mail-pf0-f198.google.com with SMTP id j26so9964049pff.8 for ; Sat, 16 Dec 2017 08:44:44 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id o2si6205549pge.198.2017.12.16.08.44.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 16 Dec 2017 08:44:42 -0800 (PST) From: Matthew Wilcox Subject: [PATCH 6/8] mm: Store compound_dtor / compound_order as bytes Date: Sat, 16 Dec 2017 08:44:23 -0800 Message-Id: <20171216164425.8703-7-willy@infradead.org> In-Reply-To: <20171216164425.8703-1-willy@infradead.org> References: <20171216164425.8703-1-willy@infradead.org> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: "Kirill A. Shutemov" , Christoph Lameter , Matthew Wilcox From: Matthew Wilcox Neither of these values get even close to 256; compound_dtor is currently at a maximum of 3, and compound_order can't be over 64. No machine has inefficient access to bytes since EV5, and while those are still supported, we don't optimise for them any more. Signed-off-by: Matthew Wilcox --- include/linux/mm_types.h | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5521c9799c50..1a3ba1f1605d 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -136,19 +136,8 @@ struct page { unsigned long compound_head; /* If bit zero is set */ /* First tail page only */ -#ifdef CONFIG_64BIT - /* - * On 64 bit system we have enough space in struct page - * to encode compound_dtor and compound_order with - * unsigned int. It can help compiler generate better or - * smaller code on some archtectures. - */ - unsigned int compound_dtor; - unsigned int compound_order; -#else - unsigned short int compound_dtor; - unsigned short int compound_order; -#endif + unsigned char compound_dtor; + unsigned char compound_order; }; #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS -- 2.15.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org