From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f200.google.com (mail-yw0-f200.google.com [209.85.161.200]) by kanga.kvack.org (Postfix) with ESMTP id 91B716B007E for ; Fri, 6 May 2016 11:04:04 -0400 (EDT) Received: by mail-yw0-f200.google.com with SMTP id v81so271319570ywa.1 for ; Fri, 06 May 2016 08:04:04 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id m128si9770170qkd.253.2016.05.06.08.04.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 06 May 2016 08:04:03 -0700 (PDT) From: Andrea Arcangeli Subject: [PATCH 2/3] mm: thp: microoptimize compound_mapcount() Date: Fri, 6 May 2016 17:03:59 +0200 Message-Id: <1462547040-1737-3-git-send-email-aarcange@redhat.com> In-Reply-To: <1462547040-1737-1-git-send-email-aarcange@redhat.com> References: <1462547040-1737-1-git-send-email-aarcange@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Alex Williamson , "Kirill A. Shutemov" compound_mapcount() is only called after PageCompound() has already been checked by the caller, so there's no point to check it again. Gcc may optimize it away too because it's inline but this will remove the runtime check for sure and add it'll add an assert instead. Signed-off-by: Andrea Arcangeli --- include/linux/mm.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 263f229..726ba80 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -471,8 +471,7 @@ static inline atomic_t *compound_mapcount_ptr(struct page *page) static inline int compound_mapcount(struct page *page) { - if (!PageCompound(page)) - return 0; + VM_BUG_ON_PAGE(!PageCompound(page), page); page = compound_head(page); return atomic_read(compound_mapcount_ptr(page)) + 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