From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 3 May 2018 09:43:27 +0200 From: Michal Hocko Subject: Re: [PATCH] include/linux/gfp.h: use unsigned int in gfp_zone Message-ID: <20180503074327.GA4535@dhcp22.suse.cz> References: <1525319098-91429-1-git-send-email-yehs1@lenovo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1525319098-91429-1-git-send-email-yehs1@lenovo.com> Sender: linux-kernel-owner@vger.kernel.org To: Huaisheng Ye Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, vbabka@suse.cz, mgorman@techsingularity.net, alexander.levin@verizon.com, colyli@suse.de, chengnt@lenovo.com List-ID: On Thu 03-05-18 11:44:58, Huaisheng Ye wrote: > Suggest using unsigned int instead of int for bit within gfp_zone. > > The value of bit comes from flags, which's type is gfp_t. And it > indicates the number of bits in the right shift for GFP_ZONE_TABLE. > > Signed-off-by: Huaisheng Ye The patch looks OK but it misses the most important piece of information. Why this is worth changing. Does it lead to a better code? Silence a warning or... > --- > include/linux/gfp.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > index 1a4582b..21551fc 100644 > --- a/include/linux/gfp.h > +++ b/include/linux/gfp.h > @@ -401,7 +401,7 @@ static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags) > static inline enum zone_type gfp_zone(gfp_t flags) > { > enum zone_type z; > - int bit = (__force int) (flags & GFP_ZONEMASK); > + unsigned int bit = (__force unsigned int) (flags & GFP_ZONEMASK); > > z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) & > ((1 << GFP_ZONES_SHIFT) - 1); > -- > 1.8.3.1 > -- Michal Hocko SUSE Labs