[lustre-devel] [PATCH v3 13/26] staging: lustre: libcfs: use int type for CPT identification.

[NeilBrown]

On Sun, Jun 24 2018, James Simmons wrote:

> From: Dmitry Eremin <dmitry.eremin at intel.com>
>
> Use int type for CPT identification to match the linux kernel
> CPU identification.

Can someone site evidence for "int" being the dominant choice for CPU
identification in the kernel?
I looked in cpumask.h and found plenty of "unsigned int".
I also found

Commit: 9b130ad5bb82 ("treewide: make "nr_cpu_ids" unsigned")

which makes nr_cpu_ids unsigned.

So I'm dropping this patch for now as the justification is not
convincing.

If there is a real case to be made, please resubmit.

Thanks,
NeilBrown



>
> Signed-off-by: Dmitry Eremin <dmitry.eremin at intel.com>
> WC-bug-id: https://jira.whamcloud.com/browse/LU-8703
> Reviewed-on: https://review.whamcloud.com/23304
> Reviewed-by: James Simmons <uja.ornl at yahoo.com>
> Reviewed-by: Doug Oucharek <dougso at me.com>
> Reviewed-by: Oleg Drokin <green at whamcloud.com>
> Signed-off-by: James Simmons <jsimmons at infradead.org>
> ---
>  drivers/staging/lustre/include/linux/libcfs/libcfs_cpu.h |  8 ++++----
>  drivers/staging/lustre/lnet/libcfs/libcfs_cpu.c          | 14 +++++++-------
>  2 files changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/staging/lustre/include/linux/libcfs/libcfs_cpu.h b/drivers/staging/lustre/include/linux/libcfs/libcfs_cpu.h
> index 9dbb0b1..2bb2140 100644
> --- a/drivers/staging/lustre/include/linux/libcfs/libcfs_cpu.h
> +++ b/drivers/staging/lustre/include/linux/libcfs/libcfs_cpu.h
> @@ -89,18 +89,18 @@ struct cfs_cpu_partition {
>  	/* NUMA distance between CPTs */
>  	unsigned int			*cpt_distance;
>  	/* spread rotor for NUMA allocator */
> -	unsigned int			cpt_spread_rotor;
> +	int				cpt_spread_rotor;
>  };
>  
>  
>  /** descriptor for CPU partitions */
>  struct cfs_cpt_table {
>  	/* spread rotor for NUMA allocator */
> -	unsigned int			ctb_spread_rotor;
> +	int				ctb_spread_rotor;
>  	/* maximum NUMA distance between all nodes in table */
>  	unsigned int			ctb_distance;
>  	/* # of CPU partitions */
> -	unsigned int			ctb_nparts;
> +	int				ctb_nparts;
>  	/* partitions tables */
>  	struct cfs_cpu_partition	*ctb_parts;
>  	/* shadow HW CPU to CPU partition ID */
> @@ -355,7 +355,7 @@ static inline void cfs_cpu_fini(void)
>  /**
>   * create a cfs_cpt_table with \a ncpt number of partitions
>   */
> -struct cfs_cpt_table *cfs_cpt_table_alloc(unsigned int ncpt);
> +struct cfs_cpt_table *cfs_cpt_table_alloc(int ncpt);
>  
>  /*
>   * allocate per-cpu-partition data, returned value is an array of pointers,
> diff --git a/drivers/staging/lustre/lnet/libcfs/libcfs_cpu.c b/drivers/staging/lustre/lnet/libcfs/libcfs_cpu.c
> index aaab7cb..8f7de59 100644
> --- a/drivers/staging/lustre/lnet/libcfs/libcfs_cpu.c
> +++ b/drivers/staging/lustre/lnet/libcfs/libcfs_cpu.c
> @@ -73,7 +73,7 @@
>  module_param(cpu_pattern, charp, 0444);
>  MODULE_PARM_DESC(cpu_pattern, "CPU partitions pattern");
>  
> -struct cfs_cpt_table *cfs_cpt_table_alloc(unsigned int ncpt)
> +struct cfs_cpt_table *cfs_cpt_table_alloc(int ncpt)
>  {
>  	struct cfs_cpt_table *cptab;
>  	int i;
> @@ -788,13 +788,13 @@ static int cfs_cpt_choose_ncpus(struct cfs_cpt_table *cptab, int cpt,
>  	return rc;
>  }
>  
> -#define CPT_WEIGHT_MIN  4u
> +#define CPT_WEIGHT_MIN 4
>  
> -static unsigned int cfs_cpt_num_estimate(void)
> +static int cfs_cpt_num_estimate(void)
>  {
> -	unsigned int nnode = num_online_nodes();
> -	unsigned int ncpu = num_online_cpus();
> -	unsigned int ncpt;
> +	int nnode = num_online_nodes();
> +	int ncpu = num_online_cpus();
> +	int ncpt;
>  
>  	if (ncpu <= CPT_WEIGHT_MIN) {
>  		ncpt = 1;
> @@ -824,7 +824,7 @@ static unsigned int cfs_cpt_num_estimate(void)
>  	/* config many CPU partitions on 32-bit system could consume
>  	 * too much memory
>  	 */
> -	ncpt = min(2U, ncpt);
> +	ncpt = min(2, ncpt);
>  #endif
>  	while (ncpu % ncpt)
>  		ncpt--; /* worst case is 1 */
> -- 
> 1.8.3.1
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