From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx200.postini.com [74.125.245.200]) by kanga.kvack.org (Postfix) with SMTP id EF38D6B0005 for ; Thu, 4 Apr 2013 23:48:15 -0400 (EDT) Received: by mail-pb0-f51.google.com with SMTP id rr4so1772803pbb.24 for ; Thu, 04 Apr 2013 20:48:15 -0700 (PDT) Message-ID: <515E4977.3040002@gmail.com> Date: Fri, 05 Apr 2013 11:48:07 +0800 From: Ric Mason MIME-Version: 1.0 Subject: Re: [PATCHv2, RFC 07/30] thp, mm: introduce mapping_can_have_hugepages() predicate References: <1363283435-7666-1-git-send-email-kirill.shutemov@linux.intel.com> <1363283435-7666-8-git-send-email-kirill.shutemov@linux.intel.com> <515E48D1.2090505@gmail.com> In-Reply-To: <515E48D1.2090505@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Andrea Arcangeli , Andrew Morton , Al Viro , Hugh Dickins , Wu Fengguang , Jan Kara , Mel Gorman , linux-mm@kvack.org, Andi Kleen , Matthew Wilcox , "Kirill A. Shutemov" , Hillf Danton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org On 04/05/2013 11:45 AM, Ric Mason wrote: > Hi Kirill, > On 03/15/2013 01:50 AM, Kirill A. Shutemov wrote: >> From: "Kirill A. Shutemov" >> >> Returns true if mapping can have huge pages. Just check for __GFP_COMP >> in gfp mask of the mapping for now. >> >> Signed-off-by: Kirill A. Shutemov >> --- >> include/linux/pagemap.h | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h >> index e3dea75..3521b0d 100644 >> --- a/include/linux/pagemap.h >> +++ b/include/linux/pagemap.h >> @@ -84,6 +84,16 @@ static inline void mapping_set_gfp_mask(struct >> address_space *m, gfp_t mask) >> (__force unsigned long)mask; >> } >> +static inline bool mapping_can_have_hugepages(struct address_space >> *m) >> +{ >> + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { >> + gfp_t gfp_mask = mapping_gfp_mask(m); >> + return !!(gfp_mask & __GFP_COMP); > > I always see !! in kernel, but why check directly instead of have !! > prefix? s/why/why not > >> + } >> + >> + return false; >> +} >> + >> /* >> * The page cache can done in larger chunks than >> * one page, because it allows for more efficient > -- 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