From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Wei Hu (Xavier)" Subject: Re: [PATCH rdma-next 2/5] RDMA/hns: Modify uar allocation algorithm to avoid bitmap exhaust Date: Wed, 23 May 2018 14:49:35 +0800 Message-ID: <5B050EFF.4040908@huawei.com> References: <1526544173-106587-1-git-send-email-xavier.huwei@huawei.com> <1526544173-106587-3-git-send-email-xavier.huwei@huawei.com> <20180523060515.GD2933@mtr-leonro.mtl.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180523060515.GD2933@mtr-leonro.mtl.com> Sender: linux-kernel-owner@vger.kernel.org To: Leon Romanovsky Cc: dledford@redhat.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, xavier.huwei@tom.com, lijun_nudt@163.com List-Id: linux-rdma@vger.kernel.org On 2018/5/23 14:05, Leon Romanovsky wrote: > On Thu, May 17, 2018 at 04:02:50PM +0800, Wei Hu (Xavier) wrote: >> This patch modified uar allocation algorithm in hns_roce_uar_alloc >> function to avoid bitmap exhaust. >> >> Signed-off-by: Wei Hu (Xavier) >> --- >> drivers/infiniband/hw/hns/hns_roce_device.h | 1 + >> drivers/infiniband/hw/hns/hns_roce_pd.c | 10 ++++++---- >> 2 files changed, 7 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h b/drivers/infiniband/hw/hns/hns_roce_device.h >> index 53c2f1b..412297d4 100644 >> --- a/drivers/infiniband/hw/hns/hns_roce_device.h >> +++ b/drivers/infiniband/hw/hns/hns_roce_device.h >> @@ -214,6 +214,7 @@ enum { >> struct hns_roce_uar { >> u64 pfn; >> unsigned long index; >> + unsigned long logic_idx; >> }; >> >> struct hns_roce_ucontext { >> diff --git a/drivers/infiniband/hw/hns/hns_roce_pd.c b/drivers/infiniband/hw/hns/hns_roce_pd.c >> index 4b41e04..b9f2c87 100644 >> --- a/drivers/infiniband/hw/hns/hns_roce_pd.c >> +++ b/drivers/infiniband/hw/hns/hns_roce_pd.c >> @@ -107,13 +107,15 @@ int hns_roce_uar_alloc(struct hns_roce_dev *hr_dev, struct hns_roce_uar *uar) >> int ret = 0; >> >> /* Using bitmap to manager UAR index */ >> - ret = hns_roce_bitmap_alloc(&hr_dev->uar_table.bitmap, &uar->index); >> + ret = hns_roce_bitmap_alloc(&hr_dev->uar_table.bitmap, &uar->logic_idx); >> if (ret == -1) >> return -ENOMEM; >> >> - if (uar->index > 0) >> - uar->index = (uar->index - 1) % >> + if (uar->logic_idx > 0 && hr_dev->caps.phy_num_uars > 1) >> + uar->index = (uar->logic_idx - 1) % >> (hr_dev->caps.phy_num_uars - 1) + 1; >> + else >> + uar->index = 0; >> > Sorry, but maybe I didn't understand this change fully, but logic_idx is > not initialized at all and one of two (needs to check your uar > allocation): the logic_idx is always zero -> index will be zero too, > or logic_idx is random variable -> index will be random too. > > What did you want to do? > Hi, Leon The prototype of hns_roce_bitmap_alloc as belows: int hns_roce_bitmap_alloc(struct hns_roce_bitmap *bitmap, unsigned long *obj); In this statement, we evaluate uar->logic_idx. ret = hns_roce_bitmap_alloc(&hr_dev->uar_table.bitmap, &uar->logic_idx); In hip06, hr_dev->caps.phy_num_uars equals 8, if (uar->logic_idx > 0) uar-> index = 0; else uar-> index =(uar->logic_idx - 1) % (hr_dev->caps.phy_num_uars - 1) + 1; In hip08, hr_dev->caps.phy_num_uars equals 1, uar-> index = 0; Regards Wei Hu >> if (!dev_is_pci(hr_dev->dev)) { >> res = platform_get_resource(hr_dev->pdev, IORESOURCE_MEM, 0); >> @@ -132,7 +134,7 @@ int hns_roce_uar_alloc(struct hns_roce_dev *hr_dev, struct hns_roce_uar *uar) >> >> void hns_roce_uar_free(struct hns_roce_dev *hr_dev, struct hns_roce_uar *uar) >> { >> - hns_roce_bitmap_free(&hr_dev->uar_table.bitmap, uar->index, >> + hns_roce_bitmap_free(&hr_dev->uar_table.bitmap, uar->logic_idx, >> BITMAP_NO_RR); >> } >> >> -- >> 1.9.1 >>