Re: [Xen-devel] [PATCH v3] Xen: Spread boot time page scrubbing across all available CPU's

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Konrad,

This patch will break ARM build (see below).

On 04/11/2014 07:08 PM, Konrad Rzeszutek Wilk wrote:
> +void __init smp_scrub_heap_pages(void *data)
> +{
> +    unsigned long mfn, start, end;
> +    struct page_info *pg;
> +    struct scrub_region *r;
> +    unsigned int temp_cpu, node, cpu_idx = 0;
> +    unsigned int cpu = smp_processor_id();
> +
> +    if ( data )
> +        r = data;
> +    else {

else
{

> +        node = cpu_to_node(cpu);
> +        if ( node == NUMA_NO_NODE )
> +            return;
> +        r = &region[node];
> +    }
> +    ASSERT(r != NULL);
> +
> +    /* Determine the current CPU's index into CPU's linked to this node*/
> +    for_each_cpu ( temp_cpu, &r->cpu )
> +    {
> +        if ( cpu == temp_cpu )
> +            break;
> +        cpu_idx++;
> +    }
> +
> +    /* Calculate the starting mfn for this CPU's memory block */
> +    start = r->start + (r->per_cpu_sz * cpu_idx) + r->offset;
> +
> +    /* Calculate the end mfn into this CPU's memory block for this iteration 
> */
> +    if ( r->offset + chunk_size > r->per_cpu_sz ) {

if ( ... )
{

[..]

>  void __init scrub_heap_pages(void)
>  {
> -    unsigned long mfn;
> -    struct page_info *pg;
> +    cpumask_t node_cpus, temp_cpus, all_worker_cpus = {{ 0 }};
> +    unsigned int i, j, cpu, sibling;
> +    unsigned long offset, max_per_cpu_sz = 0;
> +    unsigned long start, end;
> +    unsigned long rem = 0;
>  
>      if ( !opt_bootscrub )
>          return;
>  
> -    printk("Scrubbing Free RAM: ");
> +    /* Scrub block size */
> +    chunk_size = opt_bootscrub_chunk >> PAGE_SHIFT;
> +    if ( chunk_size == 0 )
> +        chunk_size = 1;
>  
> -    for ( mfn = first_valid_mfn; mfn < max_page; mfn++ )
> +    /* Round #0 - figure out amounts and which CPUs to use */
> +    for_each_online_node ( i )
>      {
> +        /* Calculate Node memory start and end address */
> +        start = max(node_start_pfn(i), first_valid_mfn);

node_start_pfn doesn't exists on ARM.
As we don't yet support NUMA, you will have to add a dummy #define in
asm-arm/numa.h which will return the correct value.

> +        end = min(node_start_pfn(i) + node_spanned_pages(i), max_page);
> +        /* CPUs that are online and on this node (if none, that it is OK */
> +        cpumask_and(&node_cpus, &node_to_cpumask(i), &cpu_online_map);
> +        cpumask_copy(&temp_cpus, &node_cpus);
> +        /* Rip out threads. */
> +        for_each_cpu ( j, &temp_cpus )
> +        {
> +            cpu = 0;
> +            for_each_cpu(sibling, per_cpu(cpu_sibling_mask, j)) {

for_each_cpu( ... )
{

> +                if (cpu++ == 0) /* Skip 1st CPU - the core */

if ( ... )

> +                    continue;
> +                cpumask_clear_cpu(sibling, &node_cpus);
> +            }
> +        }
> +        cpumask_or(&all_worker_cpus, &all_worker_cpus, &node_cpus);
> +        if ( cpumask_empty(&node_cpus) ) { /* No CPUs on this node. */

if ( ... )
{

Regards,

-- 
Julien Grall

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