Re: [XEN RFC PATCH 12/40] xen/x86: Move numa_initmem_init to common

[Julien Grall <julien@xen.org>]

Hi Wei,

On 11/08/2021 11:23, Wei Chen wrote:
> This function can be reused by Arm device tree based
> NUMA support. So we move it from x86 to common, as well
> as its related variables and functions:
> setup_node_bootmem, numa_init_array and numa_emulation.
> 
> As numa_initmem_init has been moved to common, _memnodemap
> is not used cross files. We can restore _memnodemap to
> static.

As we discussed on a previous patch, we should try to avoid this kind of 
dance. I can help to find a split that would achieve that.

> 
> Signed-off-by: Wei Chen <wei.chen@arm.com>
> ---
>   xen/arch/x86/numa.c         | 118 ----------------------------------
>   xen/common/numa.c           | 122 +++++++++++++++++++++++++++++++++++-
>   xen/include/asm-x86/numa.h  |   5 --
>   xen/include/asm-x86/setup.h |   1 -
>   xen/include/xen/numa.h      |   8 ++-
>   5 files changed, 128 insertions(+), 126 deletions(-)
> 
> diff --git a/xen/arch/x86/numa.c b/xen/arch/x86/numa.c
> index f2626b3968..6908738305 100644
> --- a/xen/arch/x86/numa.c
> +++ b/xen/arch/x86/numa.c
> @@ -38,7 +38,6 @@ nodeid_t apicid_to_node[MAX_LOCAL_APIC] = {
>   
>   nodemask_t __read_mostly node_online_map = { { [0] = 1UL } };
>   
> -bool numa_off;
>   s8 acpi_numa = 0;
>   
>   int srat_disabled(void)
> @@ -46,123 +45,6 @@ int srat_disabled(void)
>       return numa_off || acpi_numa < 0;
>   }
>   
> -/* initialize NODE_DATA given nodeid and start/end */
> -void __init setup_node_bootmem(nodeid_t nodeid, u64 start, u64 end)
> -{
> -    unsigned long start_pfn, end_pfn;
> -
> -    start_pfn = start >> PAGE_SHIFT;
> -    end_pfn = end >> PAGE_SHIFT;
> -
> -    NODE_DATA(nodeid)->node_start_pfn = start_pfn;
> -    NODE_DATA(nodeid)->node_spanned_pages = end_pfn - start_pfn;
> -
> -    node_set_online(nodeid);
> -}
> -
> -void __init numa_init_array(void)
> -{
> -    int rr, i;
> -
> -    /* There are unfortunately some poorly designed mainboards around
> -       that only connect memory to a single CPU. This breaks the 1:1 cpu->node
> -       mapping. To avoid this fill in the mapping for all possible
> -       CPUs, as the number of CPUs is not known yet.
> -       We round robin the existing nodes. */
> -    rr = first_node(node_online_map);
> -    for ( i = 0; i < nr_cpu_ids; i++ )
> -    {
> -        if ( cpu_to_node[i] != NUMA_NO_NODE )
> -            continue;
> -        numa_set_node(i, rr);
> -        rr = cycle_node(rr, node_online_map);
> -    }
> -}
> -
> -#ifdef CONFIG_NUMA_EMU
> -static int numa_fake __initdata = 0;
> -
> -/* Numa emulation */
> -static int __init numa_emulation(u64 start_pfn, u64 end_pfn)
> -{
> -    int i;
> -    struct node nodes[MAX_NUMNODES];
> -    u64 sz = ((end_pfn - start_pfn)<<PAGE_SHIFT) / numa_fake;
> -
> -    /* Kludge needed for the hash function */
> -    if ( hweight64(sz) > 1 )
> -    {
> -        u64 x = 1;
> -        while ( (x << 1) < sz )
> -            x <<= 1;
> -        if ( x < sz/2 )
> -            printk(KERN_ERR "Numa emulation unbalanced. Complain to maintainer\n");
> -        sz = x;
> -    }
> -
> -    memset(&nodes,0,sizeof(nodes));
> -    for ( i = 0; i < numa_fake; i++ )
> -    {
> -        nodes[i].start = (start_pfn<<PAGE_SHIFT) + i*sz;
> -        if ( i == numa_fake - 1 )
> -            sz = (end_pfn<<PAGE_SHIFT) - nodes[i].start;
> -        nodes[i].end = nodes[i].start + sz;
> -        printk(KERN_INFO "Faking node %d at %"PRIx64"-%"PRIx64" (%"PRIu64"MB)\n",
> -               i,
> -               nodes[i].start, nodes[i].end,
> -               (nodes[i].end - nodes[i].start) >> 20);
> -        node_set_online(i);
> -    }
> -    memnode_shift = compute_hash_shift(nodes, numa_fake, NULL);
> -    if ( memnode_shift < 0 )
> -    {
> -        memnode_shift = 0;
> -        printk(KERN_ERR "No NUMA hash function found. Emulation disabled.\n");
> -        return -1;
> -    }
> -    for_each_online_node ( i )
> -        setup_node_bootmem(i, nodes[i].start, nodes[i].end);
> -    numa_init_array();
> -
> -    return 0;
> -}
> -#endif
> -
> -void __init numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn)
> -{
> -    int i;
> -
> -#ifdef CONFIG_NUMA_EMU
> -    if ( numa_fake && !numa_emulation(start_pfn, end_pfn) )
> -        return;
> -#endif
> -
> -#ifdef CONFIG_ACPI_NUMA
> -    if ( !numa_off && !acpi_scan_nodes((u64)start_pfn << PAGE_SHIFT,
> -         (u64)end_pfn << PAGE_SHIFT) )
> -        return;
> -#endif
> -
> -    printk(KERN_INFO "%s\n",
> -           numa_off ? "NUMA turned off" : "No NUMA configuration found");
> -
> -    printk(KERN_INFO "Faking a node at %016"PRIx64"-%016"PRIx64"\n",
> -           (u64)start_pfn << PAGE_SHIFT,
> -           (u64)end_pfn << PAGE_SHIFT);
> -    /* setup dummy node covering all memory */
> -    memnode_shift = BITS_PER_LONG - 1;
> -    memnodemap = _memnodemap;
> -    memnodemapsize = ARRAY_SIZE(_memnodemap);
> -
> -    nodes_clear(node_online_map);
> -    node_set_online(0);
> -    for ( i = 0; i < nr_cpu_ids; i++ )
> -        numa_set_node(i, 0);
> -    cpumask_copy(&node_to_cpumask[0], cpumask_of(0));
> -    setup_node_bootmem(0, (u64)start_pfn << PAGE_SHIFT,
> -                    (u64)end_pfn << PAGE_SHIFT);
> -}
> -
>   void numa_set_node(int cpu, nodeid_t node)
>   {
>       cpu_to_node[cpu] = node;
> diff --git a/xen/common/numa.c b/xen/common/numa.c
> index 1facc8fe2b..26c0006d04 100644
> --- a/xen/common/numa.c
> +++ b/xen/common/numa.c
> @@ -14,12 +14,13 @@
>   #include <xen/smp.h>
>   #include <xen/pfn.h>
>   #include <xen/sched.h>

NIT: We tend to add a newline betwen <xen/...> headers and <asm/...> 
headers.

> +#include <asm/acpi.h>
>   
>   struct node_data node_data[MAX_NUMNODES];
>   
>   /* Mapping from pdx to node id */
>   int memnode_shift;
> -typeof(*memnodemap) _memnodemap[64];
> +static typeof(*memnodemap) _memnodemap[64];
>   unsigned long memnodemapsize;
>   u8 *memnodemap;
>   
> @@ -34,6 +35,8 @@ int num_node_memblks;
>   struct node node_memblk_range[NR_NODE_MEMBLKS];
>   nodeid_t memblk_nodeid[NR_NODE_MEMBLKS];
>   
> +bool numa_off;
> +
>   /*
>    * Given a shift value, try to populate memnodemap[]
>    * Returns :
> @@ -191,3 +194,120 @@ void numa_add_cpu(int cpu)
>   {
>       cpumask_set_cpu(cpu, &node_to_cpumask[cpu_to_node(cpu)]);
>   }
> +
> +/* initialize NODE_DATA given nodeid and start/end */
> +void __init setup_node_bootmem(nodeid_t nodeid, u64 start, u64 end)

 From an abstract PoV, start and end should be paddr_t. This should be 
done on a separate patch though.

> +{
> +    unsigned long start_pfn, end_pfn;
> +
> +    start_pfn = start >> PAGE_SHIFT;
> +    end_pfn = end >> PAGE_SHIFT;
> +
> +    NODE_DATA(nodeid)->node_start_pfn = start_pfn;
> +    NODE_DATA(nodeid)->node_spanned_pages = end_pfn - start_pfn;
> +
> +    node_set_online(nodeid);
> +}
> +
> +void __init numa_init_array(void)
> +{
> +    int rr, i;
> +
> +    /* There are unfortunately some poorly designed mainboards around
> +       that only connect memory to a single CPU. This breaks the 1:1 cpu->node
> +       mapping. To avoid this fill in the mapping for all possible
> +       CPUs, as the number of CPUs is not known yet.
> +       We round robin the existing nodes. */
> +    rr = first_node(node_online_map);
> +    for ( i = 0; i < nr_cpu_ids; i++ )
> +    {
> +        if ( cpu_to_node[i] != NUMA_NO_NODE )
> +            continue;
> +        numa_set_node(i, rr);
> +        rr = cycle_node(rr, node_online_map);
> +    }
> +}
> +
> +#ifdef CONFIG_NUMA_EMU
> +int numa_fake __initdata = 0;
> +
> +/* Numa emulation */
> +static int __init numa_emulation(u64 start_pfn, u64 end_pfn)

Here, this should be either "unsigned long" or ideally "mfn_t". 
Although, if you use "unsigned long", you will need to...

> +{
> +    int i;
> +    struct node nodes[MAX_NUMNODES];
> +    u64 sz = ((end_pfn - start_pfn)<<PAGE_SHIFT) / numa_fake;

... cast "(end_pfn - start_pfn)" to uin64_t or use pfn_to_paddr().

> +
> +    /* Kludge needed for the hash function */
> +    if ( hweight64(sz) > 1 )
> +    {
> +        u64 x = 1;
> +        while ( (x << 1) < sz )
> +            x <<= 1;
> +        if ( x < sz/2 )
> +            printk(KERN_ERR "Numa emulation unbalanced. Complain to maintainer\n");
> +        sz = x;
> +    }
> +
> +    memset(&nodes,0,sizeof(nodes));
> +    for ( i = 0; i < numa_fake; i++ )
> +    {
> +        nodes[i].start = (start_pfn<<PAGE_SHIFT) + i*sz;
> +        if ( i == numa_fake - 1 )
> +            sz = (end_pfn<<PAGE_SHIFT) - nodes[i].start;
> +        nodes[i].end = nodes[i].start + sz;
> +        printk(KERN_INFO "Faking node %d at %"PRIx64"-%"PRIx64" (%"PRIu64"MB)\n",
> +               i,
> +               nodes[i].start, nodes[i].end,
> +               (nodes[i].end - nodes[i].start) >> 20);
> +        node_set_online(i);
> +    }
> +    memnode_shift = compute_hash_shift(nodes, numa_fake, NULL);
> +    if ( memnode_shift < 0 )
> +    {
> +        memnode_shift = 0;
> +        printk(KERN_ERR "No NUMA hash function found. Emulation disabled.\n");
> +        return -1;
> +    }
> +    for_each_online_node ( i )
> +        setup_node_bootmem(i, nodes[i].start, nodes[i].end);
> +    numa_init_array();
> +
> +    return 0;
> +}
> +#endif
> +
> +void __init numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn)
> +{
> +    int i;
> +
> +#ifdef CONFIG_NUMA_EMU
> +    if ( numa_fake && !numa_emulation(start_pfn, end_pfn) )
> +        return;
> +#endif
> +
> +#ifdef CONFIG_ACPI_NUMA
> +    if ( !numa_off && !acpi_scan_nodes((u64)start_pfn << PAGE_SHIFT,
> +         (u64)end_pfn << PAGE_SHIFT) )

(u64)v << PAGE_SHIFT should be switched to use pfn_to_paddr() or 
mfn_to_paddr() if you decide to make start_pfn and end_pfn typesafe.

> +        return;
> +#endif
> +
> +    printk(KERN_INFO "%s\n",
> +           numa_off ? "NUMA turned off" : "No NUMA configuration found");
> +
> +    printk(KERN_INFO "Faking a node at %016"PRIx64"-%016"PRIx64"\n",
> +           (u64)start_pfn << PAGE_SHIFT,
> +           (u64)end_pfn << PAGE_SHIFT);

Same remark here. PRIx64 would also have to be switched to PRIpaddr.

> +    /* setup dummy node covering all memory */
> +    memnode_shift = BITS_PER_LONG - 1;
> +    memnodemap = _memnodemap;
> +    memnodemapsize = ARRAY_SIZE(_memnodemap);
> +
> +    nodes_clear(node_online_map);
> +    node_set_online(0);
> +    for ( i = 0; i < nr_cpu_ids; i++ )
> +        numa_set_node(i, 0);
> +    cpumask_copy(&node_to_cpumask[0], cpumask_of(0));
> +    setup_node_bootmem(0, (u64)start_pfn << PAGE_SHIFT,
> +                    (u64)end_pfn << PAGE_SHIFT);
> +}
> diff --git a/xen/include/asm-x86/numa.h b/xen/include/asm-x86/numa.h
> index e8a92ad9df..f8e4e15586 100644
> --- a/xen/include/asm-x86/numa.h
> +++ b/xen/include/asm-x86/numa.h
> @@ -21,16 +21,11 @@ extern nodeid_t pxm_to_node(unsigned int pxm);
>   
>   #define ZONE_ALIGN (1UL << (MAX_ORDER+PAGE_SHIFT))
>   
> -extern void numa_init_array(void);
> -extern bool numa_off;
> -
> -
>   extern int srat_disabled(void);
>   extern void numa_set_node(int cpu, nodeid_t node);
>   extern nodeid_t setup_node(unsigned int pxm);
>   extern void srat_detect_node(int cpu);
>   
> -extern void setup_node_bootmem(nodeid_t nodeid, u64 start, u64 end);
>   extern nodeid_t apicid_to_node[];
>   extern void init_cpu_to_node(void);
>   
> diff --git a/xen/include/asm-x86/setup.h b/xen/include/asm-x86/setup.h
> index 24be46115d..63838ba2d1 100644
> --- a/xen/include/asm-x86/setup.h
> +++ b/xen/include/asm-x86/setup.h
> @@ -17,7 +17,6 @@ void early_time_init(void);
>   
>   void set_nr_cpu_ids(unsigned int max_cpus);
>   
> -void numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn);
>   void arch_init_memory(void);
>   void subarch_init_memory(void);
>   
> diff --git a/xen/include/xen/numa.h b/xen/include/xen/numa.h
> index 67b79a73a3..258a5cb3db 100644
> --- a/xen/include/xen/numa.h
> +++ b/xen/include/xen/numa.h
> @@ -26,7 +26,6 @@
>   extern int memnode_shift;
>   extern unsigned long memnodemapsize;
>   extern u8 *memnodemap;
> -extern typeof(*memnodemap) _memnodemap[64];
>   
>   struct node_data {
>       unsigned long node_start_pfn;
> @@ -69,6 +68,13 @@ extern int conflicting_memblks(u64 start, u64 end);
>   extern void cutoff_node(int i, u64 start, u64 end);
>   extern int valid_numa_range(u64 start, u64 end, nodeid_t node);
>   
> +extern void numa_init_array(void);
> +extern void numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn);
> +extern bool numa_off;
> +extern int numa_fake;
> +
> +extern void setup_node_bootmem(nodeid_t nodeid, u64 start, u64 end);
> +
>   #endif /* CONFIG_NUMA */
>   
>   #endif /* _XEN_NUMA_H */
> 

Cheers,

-- 
Julien Grall