Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933638AbcKOPxR convert rfc822-to-8bit (ORCPT ); Tue, 15 Nov 2016 10:53:17 -0500 Received: from lhrrgout.huawei.com ([194.213.3.17]:4154 "EHLO lhrrgout.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754170AbcKOPxL (ORCPT ); Tue, 15 Nov 2016 10:53:11 -0500 From: Salil Mehta To: Leon Romanovsky CC: "dledford@redhat.com" , "Huwei (Xavier)" , oulijun , "mehta.salil.lnk@gmail.com" , "linux-rdma@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Linuxarm , "Zhangping (ZP)" Subject: RE: [PATCH for-next 03/11] IB/hns: Optimize the logic of allocating memory using APIs Thread-Topic: [PATCH for-next 03/11] IB/hns: Optimize the logic of allocating memory using APIs Thread-Index: AQHSNrnWOaTLjEdgR062ss5CfO0xkKDQRlQAgAnzTlA= Date: Tue, 15 Nov 2016 15:52:46 +0000 Message-ID: References: <20161104163633.141880-1-salil.mehta@huawei.com> <20161104163633.141880-4-salil.mehta@huawei.com> <20161109072130.GH27883@leon.nu> In-Reply-To: <20161109072130.GH27883@leon.nu> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.203.181.153] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090204.582B2F5A.0021,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 220623f7be5393e8ba51fede4e61d896 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2450 Lines: 62 > -----Original Message----- > From: Leon Romanovsky [mailto:leon@kernel.org] > Sent: Wednesday, November 09, 2016 7:22 AM > To: Salil Mehta > Cc: dledford@redhat.com; Huwei (Xavier); oulijun; > mehta.salil.lnk@gmail.com; linux-rdma@vger.kernel.org; > netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Linuxarm; > Zhangping (ZP) > Subject: Re: [PATCH for-next 03/11] IB/hns: Optimize the logic of > allocating memory using APIs > > On Fri, Nov 04, 2016 at 04:36:25PM +0000, Salil Mehta wrote: > > From: "Wei Hu (Xavier)" > > > > This patch modified the logic of allocating memory using APIs in > > hns RoCE driver. We used kcalloc instead of kmalloc_array and > > bitmap_zero. And When kcalloc failed, call vzalloc to alloc > > memory. > > > > Signed-off-by: Wei Hu (Xavier) > > Signed-off-by: Ping Zhang > > Signed-off-by: Salil Mehta > > --- > > drivers/infiniband/hw/hns/hns_roce_mr.c | 15 ++++++++------- > > 1 file changed, 8 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/infiniband/hw/hns/hns_roce_mr.c > b/drivers/infiniband/hw/hns/hns_roce_mr.c > > index fb87883..d3dfb5f 100644 > > --- a/drivers/infiniband/hw/hns/hns_roce_mr.c > > +++ b/drivers/infiniband/hw/hns/hns_roce_mr.c > > @@ -137,11 +137,12 @@ static int hns_roce_buddy_init(struct > hns_roce_buddy *buddy, int max_order) > > > > for (i = 0; i <= buddy->max_order; ++i) { > > s = BITS_TO_LONGS(1 << (buddy->max_order - i)); > > - buddy->bits[i] = kmalloc_array(s, sizeof(long), > GFP_KERNEL); > > - if (!buddy->bits[i]) > > - goto err_out_free; > > - > > - bitmap_zero(buddy->bits[i], 1 << (buddy->max_order - i)); > > + buddy->bits[i] = kcalloc(s, sizeof(long), GFP_KERNEL); > > + if (!buddy->bits[i]) { > > + buddy->bits[i] = vzalloc(s * sizeof(long)); > > I wonder, why don't you use directly vzalloc instead of kcalloc > fallback? As we know we will have physical contiguous pages if the kcalloc call succeeds. This will give us a chance to have better performance over the allocations which are just virtually contiguous through the function vzalloc(). Therefore, later has only been used as a fallback when our memory request cannot be entertained through kcalloc. Are you suggesting that there will not be much performance penalty if we use just vzalloc ? > > > + if (!buddy->bits[i]) > > + goto err_out_free; > > + } > > }