From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id B34416B004A for ; Wed, 10 Nov 2010 16:04:20 -0500 (EST) Date: Wed, 10 Nov 2010 13:04:07 -0800 From: Andrew Morton Subject: Re: [PATCH 2/2] clean up set_page_dirty() Message-Id: <20101110130407.f6228a10.akpm@linux-foundation.org> In-Reply-To: <1289379628-14044-2-git-send-email-lliubbo@gmail.com> References: <1289379628-14044-1-git-send-email-lliubbo@gmail.com> <1289379628-14044-2-git-send-email-lliubbo@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Bob Liu Cc: fengguang.wu@intel.com, linux-mm@kvack.org, kenchen@google.com List-ID: On Wed, 10 Nov 2010 17:00:28 +0800 Bob Liu wrote: > Use TestSetPageDirty() to clean up set_page_dirty(). > > Signed-off-by: Bob Liu > --- > mm/page-writeback.c | 7 ++----- > 1 files changed, 2 insertions(+), 5 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index e8f5f06..da86224 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -1268,11 +1268,8 @@ int set_page_dirty(struct page *page) > #endif > return (*spd)(page); > } > - if (!PageDirty(page)) { > - if (!TestSetPageDirty(page)) > - return 1; > - } > - return 0; > + > + return !TestSetPageDirty(page); > } > EXPORT_SYMBOL(set_page_dirty); This just undoes the optimisation. We could do - if (!TestSetPageDirty(page)) - return 1; + return !TestSetPageDirty(page); I suppose. Or even return (!TestSetPageDirty(page) ^ 1); if we're feeling stupid, and if TestSetPageDirty() reliably returns 1/0, and if that really is superior (by eliminating a test-n-branch). -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org