On Wed, Oct 21, 2015 at 9:21 AM, Leon Romanovsky <leon@xxxxxxx> wrote:
> From: Leon Romanovsky <leonro@xxxxxxxxxxxx>
>
> The remove_keys() logic is performed as garbage collection task. Such
> task is intended to be run when no other active processes are running.
>
> The need_resched() will return TRUE if there are user tasks to be
> activated in near future.
>
> In such case, we don't execute remove_keys() and postpone
> the garbage collection work to try to run in next cycle,
> in order to free CPU resources to other tasks.
>
> The possible pseudo-code to trigger such scenario:
> 1. Allocate a lot of MR to fill the cache above the limit.
> 2. Wait a small amount of time "to calm" the system.
> 3. Start CPU extensive operations on multi-node cluster.
> 4. Expect performance degradation during MR cache shrink operation.
>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
> Signed-off-by: Eli Cohen <eli@xxxxxxxxxxxx>
> ---
>
> diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
> index 54a15b5..45ce00e 100644
> --- a/drivers/infiniband/hw/mlx5/mr.c
> +++ b/drivers/infiniband/hw/mlx5/mr.c
> @@ -381,7 +381,19 @@
> }
> }
> } else if (ent->cur > 2 * ent->limit) {
> - if (!someone_adding(cache) &&
> + /*
> + * The remove_keys() logic is performed as garbage collection
> + * task. Such task is intended to be run when no other active
> + * processes are running.
> + *
> + * The need_resched() will return TRUE if there are user tasks
> + * to be activated in near future.
> + *
> + * In such case, we don't execute remove_keys() and postpone
> + * the garbage collection work to try to run in next cycle,
> + * in order to free CPU resources to other tasks.
> + */
> + if (!need_resched() && !someone_adding(cache) &&
> time_after(jiffies, cache->last_add + 300 * HZ)) {
> remove_keys(dev, i, 1);
> if (ent->cur > ent->limit)
Hi Doug,
Is it possible to take this patch before RoCE patches are coming?
This is a small change in mlx5 driver which gives us significant performance
improvement.
Thanks.
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