From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4821057F.8090706@cn.fujitsu.com> Date: Wed, 07 May 2008 09:27:27 +0800 From: Li Zefan MIME-Version: 1.0 Subject: Re: [PATCH] mm/page_alloc.c: fix a typo References: <4820272C.4060009@cn.fujitsu.com> <482027E4.6030300@cn.fujitsu.com> <482029E7.6070308@cn.fujitsu.com> <20080506071943.46641c26.akpm@linux-foundation.org> In-Reply-To: <20080506071943.46641c26.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: clameter@sgi.com, LKML , "linux-mm@kvack.org" List-ID: Andrew Morton wrote: > On Tue, 06 May 2008 17:50:31 +0800 Li Zefan wrote: > >> Li Zefan wrote: >>> --- >> Signed-off-by: Li Zefan >> --- >> >> Sorry for the noise, but the signed-off was eaten. :( >> Maybe I should leave a blank line before the signed-off. >> >> --- >> >> mm/page_alloc.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index bdd5c43..d0ba10d 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -303,7 +303,7 @@ static void destroy_compound_page(struct page *page, unsigned long order) >> for (i = 1; i < nr_pages; i++) { >> struct page *p = page + i; >> >> - if (unlikely(!PageTail(p) | >> + if (unlikely(!PageTail(p) || >> (p->first_page != page))) >> bad_page(page); >> __ClearPageTail(p); > > I have a vague memory that the "|" was deliberate. Most of the time, > "!PageTail" will be false so most of the time we won't take the first !PageTail will be true if nothing bad happened, corrected me if I'm wrong: static void prep_compound_page(struct page *page, unsigned long order) { ... for (i = 1; i < nr_pages; i++) { struct page *p = page + i; __SetPageTail(p); p->first_page = page; } } > branch so it's probably worth omitting it and always doing the pointer > comparison. > > It's a somewhat dopey trick and shouldn't have been done without a comment. > > otoh maybe it was a typo. > > -- 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