[lustre-devel] [PATCH v3 23/26] staging: lustre: ptlrpc: use current CPU instead of hardcoded 0

[NeilBrown]

On Sun, Jun 24 2018, James Simmons wrote:

> From: Dmitry Eremin <dmitry.eremin at intel.com>
>
> fix crash if CPU 0 disabled.
>
> Signed-off-by: Dmitry Eremin <dmitry.eremin at intel.com>
> WC-bug-id: https://jira.whamcloud.com/browse/LU-8710
> Reviewed-on: https://review.whamcloud.com/23305
> Reviewed-by: Doug Oucharek <dougso at me.com>
> Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
> Signed-off-by: James Simmons <jsimmons at infradead.org>
> ---
>  drivers/staging/lustre/lustre/ptlrpc/service.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/ptlrpc/service.c b/drivers/staging/lustre/lustre/ptlrpc/service.c
> index 3fd8c74..8e74a45 100644
> --- a/drivers/staging/lustre/lustre/ptlrpc/service.c
> +++ b/drivers/staging/lustre/lustre/ptlrpc/service.c
> @@ -421,7 +421,7 @@ static void ptlrpc_at_timer(struct timer_list *t)
>  		 * there are.
>  		 */
>  		/* weight is # of HTs */
> -		if (cpumask_weight(topology_sibling_cpumask(0)) > 1) {
> +		if (cpumask_weight(topology_sibling_cpumask(smp_processor_id())) > 1) {

This pops a warning for me:
[ 1877.516799] BUG: using smp_processor_id() in preemptible [00000000] code: mount.lustre/14077

I'll change it to disable preemption, both here and below.

Thanks,
NeilBrown


>  			/* depress thread factor for hyper-thread */
>  			factor = factor - (factor >> 1) + (factor >> 3);
>  		}
> @@ -2221,15 +2221,16 @@ static int ptlrpc_hr_main(void *arg)
>  	struct ptlrpc_hr_thread	*hrt = arg;
>  	struct ptlrpc_hr_partition *hrp = hrt->hrt_partition;
>  	LIST_HEAD(replies);
> -	char threadname[20];
>  	int rc;
>  
> -	snprintf(threadname, sizeof(threadname), "ptlrpc_hr%02d_%03d",
> -		 hrp->hrp_cpt, hrt->hrt_id);
>  	unshare_fs_struct();
>  
>  	rc = cfs_cpt_bind(ptlrpc_hr.hr_cpt_table, hrp->hrp_cpt);
>  	if (rc != 0) {
> +		char threadname[20];
> +
> +		snprintf(threadname, sizeof(threadname), "ptlrpc_hr%02d_%03d",
> +			 hrp->hrp_cpt, hrt->hrt_id);
>  		CWARN("Failed to bind %s on CPT %d of CPT table %p: rc = %d\n",
>  		      threadname, hrp->hrp_cpt, ptlrpc_hr.hr_cpt_table, rc);
>  	}
> @@ -2528,7 +2529,7 @@ int ptlrpc_hr_init(void)
>  
>  	init_waitqueue_head(&ptlrpc_hr.hr_waitq);
>  
> -	weight = cpumask_weight(topology_sibling_cpumask(0));
> +	weight = cpumask_weight(topology_sibling_cpumask(smp_processor_id()));
>  
>  	cfs_percpt_for_each(hrp, i, ptlrpc_hr.hr_partitions) {
>  		hrp->hrp_cpt = i;
> -- 
> 1.8.3.1
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