Re: [PATCH] xl: add memory allocation logic for numa platform

[Juergen Gross <juergen.gross@ts.fujitsu.com>]

Hi,

On 08/09/2011 06:55 AM, Zhang, Yang Z wrote:
> For numa platform, we need to allocate memory for guest on which guest cpu reside. This patch add
> this feature for xl. Just use the simple algorithm to select the best node.

You are ignoring cpupools. This could result in pinning vcpus to
physical cpus not available for the domU.
An easy solution would be to skip numa optimization if cpupools are
active (see comment below).

> diff -r 0f36c2eec2e1 tools/libxl/libxl.c
> --- a/tools/libxl/libxl.c       Thu Jul 28 15:40:54 2011 +0100
> +++ b/tools/libxl/libxl.c       Tue Aug 09 12:46:18 2011 +0800
> @@ -2236,6 +2236,109 @@
>       return ERROR_FAIL;
>   }
>
> +static inline void set_bit(int nr, volatile void *addr)
> +{
> +    asm volatile (
> +      "btsl %1,%0"
> +       : "=m" (ADDR)
> +       : "Ir" (nr), "m" (ADDR) : "memory");
> +}
> +
> +int libxl_get_numainfo(libxl_ctx *ctx, libxl_numainfo_t *numainfo)
> +{
> +    xc_numainfo_t ninfo = { 0 };
> +    libxl_physinfo physinfo = { 0 };
> +    libxl_topologyinfo topoinfo;
> +    int i,  max_nodes, max_cpus, node;
> +    libxl_nodeinfo_t *nodeinfo;
> +    DECLARE_HYPERCALL_BUFFER(xc_node_to_memsize_t, node_memsize);
> +    DECLARE_HYPERCALL_BUFFER(xc_node_to_memfree_t, node_memfree);
> +
> +    if (libxl_get_physinfo(ctx,&physinfo))
> +        goto out;
> +
> +    max_cpus = physinfo.max_cpu_id + 1;
> +    max_nodes = NUMA_NO_NODE + 1;
> +    numainfo->max_cpus = max_cpus;
> +
> +    numainfo->cpu_to_node = calloc(max_cpus, sizeof (unsigned long));
> +    if (numainfo->cpu_to_node == NULL)
> +        goto out;
> +
> +    numainfo->nodeinfo = (char *)calloc(max_nodes, sizeof(libxl_nodeinfo_t));
> +    if (numainfo->nodeinfo == NULL)
> +        goto out;
> +
> +    nodeinfo = (libxl_nodeinfo_t *)numainfo->nodeinfo;
> +    node_memsize = xc_hypercall_buffer_alloc(ctx->xch, node_memsize, sizeof(*node_memsize) * max_nodes);
> +    if ( node_memsize == NULL )
> +        goto out;
> +    node_memfree = xc_hypercall_buffer_alloc(ctx->xch, node_memfree, sizeof(*node_memfree) * max_nodes);
> +    if ( node_memfree == NULL )
> +        goto out;
> +
> +    set_xen_guest_handle(ninfo.node_to_memsize, node_memsize);
> +    set_xen_guest_handle(ninfo.node_to_memfree, node_memfree);
> +    ninfo.max_node_index = max_nodes - 1;
> +
> +    if ( xc_numainfo(ctx->xch,&ninfo) != 0 )
> +        goto out;
> +
> +    max_nodes = ninfo.max_node_index + 1;
> +    numainfo->max_nodes = max_nodes;
> +
> +    if (libxl_get_topologyinfo(ctx,&topoinfo))
> +        goto out;
> +
> +    for ( i = 0; i<= max_nodes; i++ ) {
> +        if (node_memsize[i] != INVALID_MEM_NODE) {
> +            nodeinfo[i].online = 1;
> +            nodeinfo[i].cpumap = malloc(BITS_TO_LONGS(max_cpus) * sizeof (unsigned long));
> +            bzero(nodeinfo[i].cpumap, BITS_TO_LONGS(max_cpus) * sizeof (unsigned long));
> +
> +            /* Total Memory */
> +            nodeinfo[i].total_memkb = node_memsize[i]>>  10; /* KB */
> +
> +            /* Free Memory */
> +            nodeinfo[i].free_memkb = node_memfree[i]>>  10; /* KB */
> +        } else
> +            nodeinfo[i].online = 0;
> +    }
> +
> +    for (i = 0; i<  max_cpus; i++)
> +        if (topoinfo.coremap.array[i] != LIBXL_CPUARRAY_INVALID_ENTRY) {
> +            node = topoinfo.nodemap.array[i];
> +            set_bit(i, nodeinfo[node].cpumap);
> +            numainfo->cpu_to_node[i] = node;
> +        }
> +    libxl_topologyinfo_destroy(&topoinfo);
> +
> +    xc_hypercall_buffer_free(ctx->xch, node_memsize);
> +    xc_hypercall_buffer_free(ctx->xch, node_memfree);
> +    return 0;
> +
> +out:
> +    if (numainfo->cpu_to_node)
> +        free(numainfo->cpu_to_node);
> +    if (numainfo->nodeinfo);
> +        free(numainfo->nodeinfo);
> +    xc_hypercall_buffer_free(ctx->xch, node_memsize);
> +    xc_hypercall_buffer_free(ctx->xch, node_memfree);
> +    return ERROR_FAIL;
> +}
> +
> +void libxl_free_numainfo(libxl_numainfo_t *numainfo)
> +{
> +    int i;
> +    libxl_nodeinfo_t *nodeinfo = (libxl_nodeinfo_t *)numainfo->nodeinfo;
> +
> +    for(i = 0; i<  numainfo->max_nodes; i++)
> +        if(nodeinfo[i].cpumap)
> +            free(nodeinfo[i].cpumap);
> +    free(numainfo->cpu_to_node);
> +    free(numainfo->nodeinfo);
> +}
> +
>   const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
>   {
>       union {
> diff -r 0f36c2eec2e1 tools/libxl/libxl.h
> --- a/tools/libxl/libxl.h       Thu Jul 28 15:40:54 2011 +0100
> +++ b/tools/libxl/libxl.h       Tue Aug 09 12:46:18 2011 +0800
> @@ -459,6 +459,16 @@
>
>   int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo *physinfo);
>   int libxl_get_topologyinfo(libxl_ctx *ctx, libxl_topologyinfo *info);
> +
> +#define NUMA_NO_NODE    0xFF
> +#define INVALID_MEM_NODE     0ul
> +#define BITS_PER_LONG (sizeof(unsigned long) * 8)
> +#define BITS_TO_LONGS(bits) (((bits)+BITS_PER_LONG-1)/BITS_PER_LONG)
> +#define ADDR (*(volatile long *) addr)
> +
> +int libxl_get_numainfo(libxl_ctx *ctx, libxl_numainfo_t *numainfo);
> +void libxl_free_numainfo(libxl_numainfo_t *numainfo);
> +
>   libxl_vcpuinfo *libxl_list_vcpu(libxl_ctx *ctx, uint32_t domid,
>                                          int *nb_vcpu, int *nrcpus);
>   int libxl_set_vcpuaffinity(libxl_ctx *ctx, uint32_t domid, uint32_t vcpuid,
> diff -r 0f36c2eec2e1 tools/libxl/libxl.idl
> --- a/tools/libxl/libxl.idl     Thu Jul 28 15:40:54 2011 +0100
> +++ b/tools/libxl/libxl.idl     Tue Aug 09 12:46:18 2011 +0800
> @@ -366,6 +366,19 @@
>       ("socketmap", libxl_cpuarray, False, "cpu to socket map"),
>       ("nodemap", libxl_cpuarray,   False, "cpu to node map"),
>       ])
> +libxl_nodeinfo = Struct("nodeinfo_t", [
> +    ("free_memkb", uint32),
> +    ("total_memkb", uint32),
> +    ("candidate", uint32),
> +    ("online", uint32),
> +    ("cpumap", string),
> +    ])
> +libxl_numainfo = Struct("numainfo_t", [
> +    ("nodeinfo", string),
> +    ("max_nodes", uint32),
> +    ("cpu_to_node", string),
> +    ("max_cpus", uint32),
> +    ])
>
>   libxl_sched_credit = Struct("sched_credit", [
>       ("weight", integer),
> diff -r 0f36c2eec2e1 tools/libxl/libxl_create.c
> --- a/tools/libxl/libxl_create.c        Thu Jul 28 15:40:54 2011 +0100
> +++ b/tools/libxl/libxl_create.c        Tue Aug 09 12:46:18 2011 +0800
> @@ -159,6 +159,86 @@
>       return 0;
>   }
>
> +static int find_best_node(libxl_ctx *ctx, libxl_numainfo_t *numainfo)
> +{
> +    int nr_doms, i, j, nr_vcpu, nrcpus, best_node, pcpu, node_id;
> +    unsigned long max_nodes = numainfo->max_nodes;
> +    unsigned long *nodeload;
> +    libxl_dominfo *dominfo;
> +    libxl_vcpuinfo *vcpuinfo;
> +    libxl_nodeinfo_t *nodeinfo = (libxl_nodeinfo_t *)numainfo->nodeinfo;
> +
> +    nodeload = malloc(max_nodes * sizeof(*nodeload));
> +    bzero(nodeload, max_nodes * sizeof(*nodeload));
> +
> +    if (!(dominfo = libxl_list_domain(ctx,&nr_doms)))
> +        goto out;
> +
> +    for (i = 0; i<  nr_doms; i++) {
> +        vcpuinfo = libxl_list_vcpu(ctx, dominfo[i].domid,&nr_vcpu,&nrcpus);
> +        if (!vcpuinfo)
> +            goto out;
> +        for (j = 0; j<  nr_vcpu; j++) {
> +            if (!vcpuinfo[j].online)
> +                continue;
> +            pcpu = vcpuinfo[j].cpu;
> +            node_id = numainfo->cpu_to_node[pcpu];
> +            if (nodeinfo[node_id].candidate)
> +                nodeload[node_id]++;
> +            else
> +                nodeload[node_id] += 8;
> +        }
> +        free(vcpuinfo);
> +    }
> +    best_node = 0;
> +    for (i = 1; i<  max_nodes; i++)
> +        if(nodeinfo[i].candidate&&  nodeinfo[i].online
> +&&  nodeload[i]<  nodeload[best_node])
> +            best_node = i;
> +
> +    return best_node;
> +out:
> +    if (dominfo)
> +        free(dominfo);
> +    return -1;
> +}
> +
> +static int libxl_node_select(libxl_ctx *ctx, libxl_domain_build_info *b_info, uint32_t domid)
> +{
> +    unsigned long i, best_node;
> +    unsigned long needmem = b_info->max_memkb;
> +    libxl_numainfo_t numainfo ={ 0 };
> +    libxl_nodeinfo_t *nodeinfo;

You should add something like this here:

libxl_cpupoolinfo *poolinfo;
int n_pools;

poolinfo = libxl_list_cpupool(ctx, &n_pools);
for (i = 0; i < n_pools; i++) {
     libxl_cpupoolinfo_destroy(poolinfo + i);
}
if (n_pools > 1) {
     printf("cpupools are being used - skip numa optimization.\n");
     return 0;
}

> +
> +    if (libxl_get_numainfo(ctx,&numainfo)) {
> +        fprintf(stderr, "libxl_get_topologyinfo failed.\n");
> +        return -1;
> +    }
> +
> +    if (numainfo.max_nodes<  2) {
> +        printf("max_nodes = %d\n", numainfo.max_nodes);
> +        return 0;
> +        }
> +
> +    nodeinfo = (libxl_nodeinfo_t *)numainfo.nodeinfo;
> +
> +    for (i = 0; i<  numainfo.max_nodes; i++)
> +        if (nodeinfo[i].free_memkb>  needmem)
> +            nodeinfo[i].candidate = 1;
> +
> +    best_node = find_best_node(ctx,&numainfo);
> +    if (best_node == -1) {
> +        libxl_numainfo_t_destroy(&numainfo);
> +        return -1;
> +    }
> +
> +    for (i = 0; i<  b_info->max_vcpus; i++)
> +        xc_vcpu_setaffinity(ctx->xch, domid, i, (uint8_t *)(nodeinfo[best_node].cpumap));
> +
> +    libxl_numainfo_t_destroy(&numainfo);
> +    return 0;
> +}
> +
>   int libxl__domain_build(libxl__gc *gc,
>                           libxl_domain_build_info *info,
>                           libxl_device_model_info *dm_info,
> @@ -168,11 +248,15 @@
>       char **vments = NULL, **localents = NULL;
>       struct timeval start_time;
>       int i, ret;
> +    libxl_ctx *ctx = libxl__gc_owner(gc);
>
>       ret = libxl__build_pre(gc, domid, info, state);
>       if (ret)
>           goto out;
>
> +   if (libxl_node_select(ctx, info, domid))
> +       printf("Cannot find best node, using defaul algorithm\n");
> +
>       gettimeofday(&start_time, NULL);
>
>       switch (info->type) {

Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
PDG ES&S SWE OS6                       Telephone: +49 (0) 89 3222 2967
Fujitsu Technology Solutions              e-mail: juergen.gross@ts.fujitsu.com
Domagkstr. 28                           Internet: ts.fujitsu.com
D-80807 Muenchen                 Company details: ts.fujitsu.com/imprint.html