Re: [PATCH] IB/mlx5: fall back to vmalloc for mlx5_ib_wq

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Wed, Aug 16, 2017 at 09:06:32PM +1000, Li Dongyang wrote:
> We observed multiple times on our Lustre OSS servers that when
> the system memory is fragmented, kmalloc() in create_kernel_qp()
> could fail order 4/5 allocations while we still have many free pages.
>
> Fall back to vmalloc to allow the operation to contine, also switch
> to kmalloc_array() from kmalloc().
>
> Signed-off-by: Li Dongyang <dongyang.li-FCV4sgi5zeUQrrorzV6ljw@public.gmane.org>
> ---
>  drivers/infiniband/hw/mlx5/qp.c  | 54 +++++++++++++++++++++++++++++-----------
>  drivers/infiniband/hw/mlx5/srq.c |  8 ++++--
>  2 files changed, 45 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
> index 0889ff367c86..e662fa5af5bb 100644
> --- a/drivers/infiniband/hw/mlx5/qp.c
> +++ b/drivers/infiniband/hw/mlx5/qp.c
> @@ -959,11 +959,35 @@ static int create_kernel_qp(struct mlx5_ib_dev *dev,
>  		goto err_free;
>  	}
>
> -	qp->sq.wrid = kmalloc(qp->sq.wqe_cnt * sizeof(*qp->sq.wrid), GFP_KERNEL);
> -	qp->sq.wr_data = kmalloc(qp->sq.wqe_cnt * sizeof(*qp->sq.wr_data), GFP_KERNEL);
> -	qp->rq.wrid = kmalloc(qp->rq.wqe_cnt * sizeof(*qp->rq.wrid), GFP_KERNEL);
> -	qp->sq.w_list = kmalloc(qp->sq.wqe_cnt * sizeof(*qp->sq.w_list), GFP_KERNEL);
> -	qp->sq.wqe_head = kmalloc(qp->sq.wqe_cnt * sizeof(*qp->sq.wqe_head), GFP_KERNEL);
> +	qp->sq.wrid = kmalloc_array(qp->sq.wqe_cnt, sizeof(*qp->sq.wrid),
> +				    GFP_KERNEL | __GFP_NOWARN);
> +	if (!qp->sq.wrid)
> +		qp->sq.wrid = __vmalloc(qp->sq.wqe_cnt * sizeof(*qp->sq.wrid),
> +					GFP_KERNEL, PAGE_KERNEL);

Please don't open code, the kvmalloc and kvmalloc_array functions.

Thanks for doing it.

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