> -----Original Message----- > From: Leon Romanovsky [mailto:l...@kernel.org] > Sent: Wednesday, November 09, 2016 7:22 AM > To: Salil Mehta > Cc: dledf...@redhat.com; Huwei (Xavier); oulijun; > mehta.salil....@gmail.com; linux-r...@vger.kernel.org; > netdev@vger.kernel.org; linux-ker...@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)" <xavier.hu...@huawei.com> > > > > 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) <xavier.hu...@huawei.com> > > Signed-off-by: Ping Zhang <zhangpi...@huawei.com> > > Signed-off-by: Salil Mehta <salil.me...@huawei.com> > > --- > > 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; > > + } > > }
