From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx151.postini.com [74.125.245.151]) by kanga.kvack.org (Postfix) with SMTP id 32B456B0031 for ; Wed, 31 Jul 2013 04:20:31 -0400 (EDT) Date: Wed, 31 Jul 2013 10:20:29 +0200 From: Michal Hocko Subject: Re: [PATCH 4/4] memcg: reduce function dereference Message-ID: <20130731082029.GH30514@dhcp22.suse.cz> References: <1375255885-10648-1-git-send-email-h.huangqiang@huawei.com> <1375255885-10648-5-git-send-email-h.huangqiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1375255885-10648-5-git-send-email-h.huangqiang@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: Qiang Huang Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, handai.szj@taobao.com, lizefan@huawei.com, nishimura@mxp.nes.nec.co.jp, akpm@linux-foundation.org, jeff.liu@oracle.com On Wed 31-07-13 15:31:25, Qiang Huang wrote: > This function dereferences res far too often, so optimize it. > > Signed-off-by: Sha Zhengju > Signed-off-by: Qiang Huang Reviewed-by: Michal Hocko > --- > kernel/res_counter.c | 19 +++++++++++-------- > 1 file changed, 11 insertions(+), 8 deletions(-) > > diff --git a/kernel/res_counter.c b/kernel/res_counter.c > index 085d3ae..4aa8a30 100644 > --- a/kernel/res_counter.c > +++ b/kernel/res_counter.c > @@ -178,27 +178,30 @@ u64 res_counter_read_u64(struct res_counter *counter, int member) > #endif > > int res_counter_memparse_write_strategy(const char *buf, > - unsigned long long *res) > + unsigned long long *resp) > { > char *end; > + unsigned long long res; > > /* return RES_COUNTER_MAX(unlimited) if "-1" is specified */ > if (*buf == '-') { > - *res = simple_strtoull(buf + 1, &end, 10); > - if (*res != 1 || *end != '\0') > + res = simple_strtoull(buf + 1, &end, 10); > + if (res != 1 || *end != '\0') > return -EINVAL; > - *res = RES_COUNTER_MAX; > + *resp = RES_COUNTER_MAX; > return 0; > } > > - *res = memparse(buf, &end); > + res = memparse(buf, &end); > if (*end != '\0') > return -EINVAL; > > - if (PAGE_ALIGN(*res) >= *res) > - *res = PAGE_ALIGN(*res); > + if (PAGE_ALIGN(res) >= res) > + res = PAGE_ALIGN(res); > else > - *res = RES_COUNTER_MAX; > + res = RES_COUNTER_MAX; > + > + *resp = res; > > return 0; > } > -- > 1.8.3 > > -- Michal Hocko SUSE Labs -- 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