Re: [Xen-devel] [PATCH RESEND v7] libxl: vnuma topology configuration parser and doc

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Thu, Aug 21, 2014 at 01:10:29AM -0400, Elena Ufimtseva wrote:
> Parses vnuma topoplogy number of nodes and memory
> ranges. If not defined, initializes vnuma with
> only one node and default topology. This one node covers
> all domain memory and all vcpus assigned to it.

.. snip..
> +/*
> + * init vNUMA to "zero config" with one node and all other
> + * topology parameters set to default.
> + */
> +static int vnuma_default_config(libxl_domain_build_info *b_info)
> +{
> +    b_info->vnodes = 1;
> +    /* all memory goes to this one vnode, as well as vcpus. */
> +    if (!(b_info->vnuma_mem = (uint64_t *)calloc(b_info->vnodes,
> +                                sizeof(*b_info->vnuma_mem))))
> +        goto bad_vnumazerocfg;
> +
> +    if (!(b_info->vnuma_vcpumap = (unsigned int *)calloc(b_info->max_vcpus,
> +                                sizeof(*b_info->vnuma_vcpumap))))
> +        goto bad_vnumazerocfg;
> +
> +    if (!(b_info->vdistance = (unsigned int *)calloc(b_info->vnodes *
> +                                b_info->vnodes, sizeof(*b_info->vdistance))))
> +        goto bad_vnumazerocfg;
> +
> +    if (!(b_info->vnuma_vnodemap = (unsigned int *)calloc(b_info->vnodes,
> +                                sizeof(*b_info->vnuma_vnodemap))))
> +        goto bad_vnumazerocfg;
> +
> +    b_info->vnuma_mem[0] = b_info->max_memkb >> 10;
> +
> +    /* all vcpus assigned to this vnode. */
> +    vcputovnode_default(b_info->vnuma_vcpumap, b_info->vnodes,
> +                        b_info->max_vcpus);
> +
> +    /* default vdistance is 10. */
> +    vdistance_set(b_info->vdistance, b_info->vnodes, 10, 10);
> +
> +    /* VNUMA_NO_NODE for vnode_to_pnode. */
> +    vnuma_vnodemap_default(b_info->vnuma_vnodemap, b_info->vnodes);
> +
> +    /*
> +     * will be placed to some physical nodes defined by automatic
> +     * numa placement or VNUMA_NO_NODE will not request exact node.
> +     */
> +    libxl_defbool_set(&b_info->vnuma_autoplacement, true);
> +    return 0;
> +
> + bad_vnumazerocfg:

I know that the caller ends up calling free_vnuma_info if this fails,
but my impression is that we should do it here, as in:

        free_vnuma_info(&b_info);

However it is up to the maintainer (Ian) to weigh in which way
he would like it done.

> +    return -1;
> +}
> +
> +static void free_vnuma_info(libxl_domain_build_info *b_info)
> +{
> +    free(b_info->vnuma_mem);
> +    free(b_info->vdistance);
> +    free(b_info->vnuma_vcpumap);
> +    free(b_info->vnuma_vnodemap);

I think you need to set
        b_info->vnuma_mem = NULL;
        b_info->vdistance = NULL;
        ..

and so on. This is more of future proofing the code in case somebody
in the future adds this inadvertly:

 if (b_info->vnuma_mem) .. blah

without first checking for 'if (b_info->vnodes)'.

It has tripped me in the Linux kernel with the 'unbind' and 'bind' on
SysFs with drivers forgetting to set their internal states to NULL
and we crash.

> +    b_info->vnodes = 0;
> +}
> +
> +static int parse_vnuma_mem(XLU_Config *config,
> +                            libxl_domain_build_info **b_info)
> +{
> +    libxl_domain_build_info *dst;
> +    XLU_ConfigList *vnumamemcfg;
> +    int nr_vnuma_regions, i;
> +    unsigned long long vnuma_memparsed = 0;
> +    unsigned long ul;
> +    const char *buf;
> +
> +    dst = *b_info;
> +    if (!xlu_cfg_get_list(config, "vnuma_mem",
> +                          &vnumamemcfg, &nr_vnuma_regions, 0)) {
> +
> +        if (nr_vnuma_regions != dst->vnodes) {
> +            fprintf(stderr, "Number of numa regions (vnumamem = %d) is \
> +                    incorrect (should be %d).\n", nr_vnuma_regions,
> +                    dst->vnodes);
> +            goto bad_vnuma_mem;
> +        }
> +
> +        dst->vnuma_mem = calloc(dst->vnodes,
> +                                 sizeof(*dst->vnuma_mem));
> +        if (dst->vnuma_mem == NULL) {
> +            fprintf(stderr, "Unable to allocate memory for vnuma ranges.\n");
> +            goto bad_vnuma_mem;
> +        }
> +
> +        char *ep;

I am surprised the compiler didn't throw a fit!

This is usually done at the start of the function or the '{ }' block.
Please move it there.
> +        /*
> +         * Will parse only nr_vnodes times, even if we have more/less 
> regions.
> +         * Take care of it later if less or discard if too many regions.
> +         */
> +        for (i = 0; i < dst->vnodes; i++) {
> +            buf = xlu_cfg_get_listitem(vnumamemcfg, i);
> +            if (!buf) {
> +                fprintf(stderr,
> +                        "xl: Unable to get element %d in vnuma memory 
> list.\n", i);

You also need to free dst->vnuma_mem before you do the 'goto'.

> +                goto bad_vnuma_mem;
> +            }
> +
> +            ul = strtoul(buf, &ep, 10);
> +            if (ep == buf) {
> +                fprintf(stderr, "xl: Invalid argument parsing vnumamem: 
> %s.\n", buf);

Ditto.
> +                goto bad_vnuma_mem;
> +            }
> +
> +            /* 32Mb is a min size for a node, taken from Linux */

I thought it was 64? Or perhaps I forgot it? Could you give a pointer to
where this was defined in Linux? Say (taken from Linux - see 
arch/x86/blahbla/bla.c).

> +            if (ul >= UINT32_MAX || ul < MIN_VNODE_SIZE) {
> +                fprintf(stderr, "xl: vnuma memory %lu is not within %u - %u 
> range.\n",
> +                        ul, MIN_VNODE_SIZE, UINT32_MAX);

        free(dst->vnuma_mem);

before you jump. Or you can have in the bad_vnuma_mem:
        free(dst->vnuma_mem);
        dst->vnuma_mem = NULL;

> +                goto bad_vnuma_mem;
> +            }
> +
> +            /* memory in MBytes */
> +            dst->vnuma_mem[i] = ul;
> +        }
> +
> +        /* Total memory for vNUMA parsed to verify */
> +        for (i = 0; i < nr_vnuma_regions; i++)
> +            vnuma_memparsed = vnuma_memparsed + (dst->vnuma_mem[i]);
> +
> +        /* Amount of memory for vnodes same as total? */
> +        if ((vnuma_memparsed << 10) != (dst->max_memkb)) {
> +            fprintf(stderr, "xl: vnuma memory is not the same as domain \
> +                    memory size.\n");
> +            goto bad_vnuma_mem;

Again, either free it or the label is responsible for it.
> +        }
> +    } else {
> +        dst->vnuma_mem = calloc(dst->vnodes,
> +                                      sizeof(*dst->vnuma_mem));
> +        if (dst->vnuma_mem == NULL) {
> +            fprintf(stderr, "Unable to allocate memory for vnuma ranges.\n");
> +            goto bad_vnuma_mem;
> +        }
> +
> +        fprintf(stderr, "WARNING: vNUMA memory ranges were not 
> specified.\n");
> +        fprintf(stderr, "Using default equal vnode memory size %lu Kbytes \
> +                to cover %lu Kbytes.\n",
> +                dst->max_memkb / dst->vnodes, dst->max_memkb);
> +
> +        if (split_vnumamem(dst) < 0) {
> +            fprintf(stderr, "Could not split vnuma memory into equal 
> chunks.\n");

Guess what I am going to say :-)

> +            goto bad_vnuma_mem;
> +        }
> +    }
> +    return 0;
> +
> + bad_vnuma_mem:
> +    return -1;
> +}
> +
> +static int parse_vnuma_distance(XLU_Config *config,
> +                                libxl_domain_build_info **b_info)
> +{
> +    libxl_domain_build_info *dst;
> +    XLU_ConfigList *vdistancecfg;
> +    int nr_vdist;
> +
> +    dst = *b_info;
> +    dst->vdistance = calloc(dst->vnodes * dst->vnodes,
> +                               sizeof(*dst->vdistance));
> +    if (dst->vdistance == NULL)
> +        goto bad_distance;
> +
> +    if (!xlu_cfg_get_list(config, "vdistance", &vdistancecfg, &nr_vdist, 0)) 
> {
> +        int d1, d2, i;
> +        /*
> +         * First value is the same node distance, the second as the
> +         * rest of distances. The following is required right now to
> +         * avoid non-symmetrical distance table as it may break latest 
> kernel.
> +         * TODO: Better way to analyze extended distance table, possibly
> +         * OS specific.
> +         */
> +
> +        for (i = 0; i < nr_vdist; i++) {
> +            d1 = get_list_item_uint(vdistancecfg, i);
> +        }
> +
> +        d1 = get_list_item_uint(vdistancecfg, 0);
> +        if (dst->vnodes > 1)
> +           d2 = get_list_item_uint(vdistancecfg, 1);
> +        else
> +           d2 = d1;
> +
> +        if (d1 >= 0 && d2 >= 0) {
> +            if (d1 < d2)
> +                fprintf(stderr, "WARNING: vnuma distance d1 < d2, %u < 
> %u\n", d1, d2);
> +            vdistance_set(dst->vdistance, dst->vnodes, d1, d2);
> +        } else {
> +            fprintf(stderr, "WARNING: vnuma distance values are 
> incorrect.\n");
> +            goto bad_distance;

free dst->vdistance first.

> +        }
> +    } else {
> +        fprintf(stderr, "Could not parse vnuma distances.\n");
> +        vdistance_set(dst->vdistance, dst->vnodes, 10, 20);
> +    }
> +    return 0;
> +
> + bad_distance:
> +    return -1;
> +}
> +
> +static int parse_vnuma_vcpumap(XLU_Config *config,
> +                                libxl_domain_build_info **b_info)
> +{
> +    libxl_domain_build_info *dst;
> +    XLU_ConfigList *vcpumap;
> +    int nr_vcpumap, i;
> +
> +    dst = *b_info;
> +    dst->vnuma_vcpumap = (unsigned int *)calloc(dst->max_vcpus,
> +                                     sizeof(*dst->vnuma_vcpumap));
> +    if (dst->vnuma_vcpumap == NULL)
> +        goto bad_vcpumap;
> +
> +    if (!xlu_cfg_get_list(config, "vnuma_vcpumap",
> +                          &vcpumap, &nr_vcpumap, 0)) {
> +        if (nr_vcpumap == dst->max_vcpus) {
> +            unsigned int  vnode, vcpumask = 0, vmask;

An newline here please.

> +            vmask = ~(~0 << nr_vcpumap);
> +            for (i = 0; i < nr_vcpumap; i++) {
> +                vnode = get_list_item_uint(vcpumap, i);
> +                if (vnode >= 0 && vnode < dst->vnodes) {
> +                    vcpumask  |= (1 << i);

There is an extra space there.

> +                    dst->vnuma_vcpumap[i] = vnode;
> +                }
> +            }
> +
> +            /* Did it covered all vnodes in the vcpu mask? */
> +            if ( !(((vmask & vcpumask) + 1) == (1 << nr_vcpumap)) ) {
> +                fprintf(stderr, "WARNING: Not all vnodes were covered \
> +                        in numa_cpumask.\n");

Either free it here or the label has to clear it.

> +                goto bad_vcpumap;
> +            }
> +        } else {
> +            fprintf(stderr, "WARNING:  Bad vnuma_vcpumap.\n");
> +            goto bad_vcpumap;
> +        }
> +    }
> +    else
> +        vcputovnode_default(dst->vnuma_vcpumap,
> +                            dst->vnodes,
> +                            dst->max_vcpus);
> +    return 0;
> +
> + bad_vcpumap:
> +    return -1;
> +}
> +
> +static int parse_vnuma_vnodemap(XLU_Config *config,
> +                                libxl_domain_build_info **b_info)
> +{
> +    libxl_domain_build_info *dst;
> +    XLU_ConfigList *vnodemap;
> +    int nr_vnodemap, i;
> +
> +    dst = *b_info;
> +
> +    /* There is mapping to NUMA physical nodes? */
> +    dst->vnuma_vnodemap = (unsigned int *)calloc(dst->vnodes,
> +                                    sizeof(*dst->vnuma_vnodemap));
> +    if (dst->vnuma_vnodemap == NULL)
> +        goto bad_vnodemap;
> +    if (!xlu_cfg_get_list(config, "vnuma_vnodemap",&vnodemap,
> +                                            &nr_vnodemap, 0)) {

something is off. It doesn't need to be so far off. The &nr_vnodemap
can be aligned with the first parameter.
> +        /*
> +        * If not specified or incorred, will be defined

s/incorred/incorrect/

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