[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <a26f1947-58fc-48c4-a8f3-4fe2a274afa6@nvidia.com>
Date: Sun, 26 May 2024 18:23:44 +0300
From: Shay Drori <shayd@...dia.com>
To: Anand Khoje <anand.a.khoje@...cle.com>, <linux-rdma@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <moshe@...dia.com>
CC: <rama.nichanamatlu@...cle.com>, <manjunath.b.patil@...cle.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH 1/1] RDMA/mlx5: Release CPU for other processes in
mlx5_free_cmd_msg()
Hi Anand.
First, the correct Mailing list for this patch is
netdev@...r.kernel.org, please send there the next version.
On 22/05/2024 6:32, Anand Khoje wrote:
> In non FLR context, at times CX-5 requests release of ~8 million device pages.
> This needs humongous number of cmd mailboxes, which to be released once
> the pages are reclaimed. Release of humongous number of cmd mailboxes
> consuming cpu time running into many secs, with non preemptable kernels
> is leading to critical process starving on that cpu’s RQ. To alleviate
> this, this patch relinquishes cpu periodically but conditionally.
>
> Orabug: 36275016
this doesn't seem relevant
>
> Signed-off-by: Anand Khoje <anand.a.khoje@...cle.com>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> index 9c21bce..9fbf25d 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> @@ -1336,16 +1336,23 @@ static struct mlx5_cmd_msg *mlx5_alloc_cmd_msg(struct mlx5_core_dev *dev,
> return ERR_PTR(err);
> }
>
> +#define RESCHED_MSEC 2
What if you add cond_resched() on every iteration of the loop ? Does it
take much more time to finish 8 Million pages or same ?
If it does matter, maybe 2 ms is too high freq ? 20 ms ? 200 ms ?
Thanks
> static void mlx5_free_cmd_msg(struct mlx5_core_dev *dev,
> struct mlx5_cmd_msg *msg)
> {
> struct mlx5_cmd_mailbox *head = msg->next;
> struct mlx5_cmd_mailbox *next;
> + unsigned long start_time = jiffies;
>
> while (head) {
> next = head->next;
> free_cmd_box(dev, head);
> head = next;
> + if (time_after(jiffies, start_time + msecs_to_jiffies(RESCHED_MSEC))) {
> + mlx5_core_warn_rl(dev, "Spent more than %d msecs, yielding CPU\n", RESCHED_MSEC);
> + cond_resched();
> + start_time = jiffies;
> + }
> }
> kfree(msg);
> }
Powered by blists - more mailing lists