Re: [PATCH] libxenlight: implement libxl_set_memory_target

[Andres Lagar-Cavilla <andres@lagarcavilla.com>]

Hi,
couple of comments:
- PV domains without videoram won't be able to use this
- Further, doesn't the PV domain build function need to use 
target_memkb? (That's my read of what xend does at least)
- Finally, LIBXL_MAXMEM_CONSTANT looks like an "evil constant we should 
avoid". Where did it come from?
Andres
> Hi all,
> this patch adds a target_memkb parameter to libxl_domain_build_info to
> set the target memory for the VM at build time and a new function
> called libxl_set_memory_target to dynamically modify the memory target
> of a VM at run time.
> Finally a new command "mem-set" is added to xl that calls directly
> libxl_set_memory_target.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>
> ---
>
> diff -r fe3c8ba27d2f tools/libxl/libxl.c
> --- a/tools/libxl/libxl.c	Tue Dec 08 17:02:15 2009 +0000
> +++ b/tools/libxl/libxl.c	Tue Dec 08 17:14:35 2009 +0000
> @@ -935,6 +935,7 @@
>      memset(&b_info, 0x00, sizeof(libxl_domain_build_info));
>      b_info.max_vcpus = 1;
>      b_info.max_memkb = 32 * 1024;
> +    b_info.target_memkb = b_info.max_memkb;
>      b_info.kernel = "/usr/lib/xen/boot/ioemu-stubdom.gz";
>      b_info.u.pv.cmdline = libxl_sprintf(ctx, " -d %d", info->domid);
>      b_info.u.pv.ramdisk = "";
> @@ -2264,6 +2265,7 @@
>      b_info->vpt_align = -1;
>      b_info->max_vcpus = 1;
>      b_info->max_memkb = 32 * 1024;
> +    b_info->target_memkb = b_info->max_memkb;
>      if (c_info->hvm) {
>          b_info->shadow_memkb = libxl_get_required_shadow_memory(b_info->max_memkb, b_info->max_vcpus);
>          b_info->video_memkb = 8 * 1024;
> @@ -2356,4 +2358,22 @@
>          console->build_state = state;
>  }
>  
> +int libxl_set_memory_target(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb)
> +{
> +    int rc = 0;
> +    uint32_t videoram;
> +    char *videoram_s = NULL;
> +    char *dompath = libxl_xs_get_dompath(ctx, domid);
>  
> +    videoram_s = libxl_xs_read(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/videoram", dompath));
> +    if (!videoram_s)
> +        return -1;
> +    videoram = atoi(videoram_s);
> +
> +    libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/target", dompath), "%lu", target_memkb);
> +    if ((rc = xc_domain_setmaxmem(ctx->xch, domid, target_memkb + LIBXL_MAXMEM_CONSTANT)) != 0) return rc;
> +    rc = xc_domain_memory_set_pod_target(ctx->xch, domid, (target_memkb - videoram) / 4, NULL, NULL, NULL);
> +    return rc;
> +}
> +
> +
> diff -r fe3c8ba27d2f tools/libxl/libxl.h
> --- a/tools/libxl/libxl.h	Tue Dec 08 17:02:15 2009 +0000
> +++ b/tools/libxl/libxl.h	Tue Dec 08 17:14:35 2009 +0000
> @@ -66,6 +66,7 @@
>      int max_vcpus;
>      int cur_vcpus;
>      uint32_t max_memkb;
> +    uint32_t target_memkb;
>      uint32_t video_memkb;
>      uint32_t shadow_memkb;
>      const char *kernel;
> @@ -305,6 +306,8 @@
>  int libxl_domain_pause(struct libxl_ctx *ctx, uint32_t domid);
>  int libxl_domain_unpause(struct libxl_ctx *ctx, uint32_t domid);
>  
> +int libxl_set_memory_target(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb);
> +
>  int libxl_console_attach(struct libxl_ctx *ctx, uint32_t domid, int cons_num);
>  
>  struct libxl_dominfo * libxl_domain_list(struct libxl_ctx *ctx, int *nb_domain);
> diff -r fe3c8ba27d2f tools/libxl/libxl_dom.c
> --- a/tools/libxl/libxl_dom.c	Tue Dec 08 17:02:15 2009 +0000
> +++ b/tools/libxl/libxl_dom.c	Tue Dec 08 17:14:35 2009 +0000
> @@ -52,7 +52,7 @@
>      if (info->vpt_align != -1)
>          xc_set_hvm_param(ctx->xch, domid, HVM_PARAM_VPT_ALIGN, (unsigned long) info->vpt_align);
>      xc_domain_max_vcpus(ctx->xch, domid, info->max_vcpus);
> -    xc_domain_setmaxmem(ctx->xch, domid, info->max_memkb + info->video_memkb);
> +    xc_domain_setmaxmem(ctx->xch, domid, info->target_memkb + LIBXL_MAXMEM_CONSTANT);
>      xc_domain_set_memmap_limit(ctx->xch, domid, 
>              (info->hvm) ? info->max_memkb : 
>              (info->max_memkb + info->u.pv.slack_memkb));
> @@ -81,7 +81,9 @@
>      ents[0] = "memory/static-max";
>      ents[1] = libxl_sprintf(ctx, "%d", info->max_memkb);
>      ents[2] = "memory/target";
> -    ents[3] = libxl_sprintf(ctx, "%d", info->max_memkb); /* PROBABLY WRONG */
> +    ents[3] = libxl_sprintf(ctx, "%d", info->target_memkb);
> +    ents[2] = "memory/videoram";
> +    ents[3] = libxl_sprintf(ctx, "%d", info->video_memkb);
>      ents[4] = "domid";
>      ents[5] = libxl_sprintf(ctx, "%d", domid);
>      ents[6] = "store/port";
> @@ -145,7 +147,7 @@
>  {
>      int ret;
>  
> -    ret = xc_hvm_build(ctx->xch, domid, info->max_memkb / 1024, info->kernel);
> +    ret = xc_hvm_build_target_mem(ctx->xch, domid, (info->max_memkb - info->video_memkb) / 1024, (info->target_memkb - info->video_memkb) / 1024, info->kernel);
>      if (ret) {
>          XL_LOG_ERRNOVAL(ctx, XL_LOG_ERROR, ret, "hvm building failed");
>          return ERROR_FAIL;
> diff -r fe3c8ba27d2f tools/libxl/libxl_internal.h
> --- a/tools/libxl/libxl_internal.h	Tue Dec 08 17:02:15 2009 +0000
> +++ b/tools/libxl/libxl_internal.h	Tue Dec 08 17:14:35 2009 +0000
> @@ -31,6 +31,7 @@
>  #define LIBXL_DEVICE_MODEL_START_TIMEOUT 10
>  #define LIBXL_XENCONSOLE_LIMIT 1048576
>  #define LIBXL_XENCONSOLE_PROTOCOL "vt100"
> +#define LIBXL_MAXMEM_CONSTANT (1 * 1024 * 1024)
>  #define QEMU_SIGNATURE "QemuDeviceModelRecord"
>  
>  #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
> diff -r fe3c8ba27d2f tools/libxl/xl.c
> --- a/tools/libxl/xl.c	Tue Dec 08 17:02:15 2009 +0000
> +++ b/tools/libxl/xl.c	Tue Dec 08 17:14:35 2009 +0000
> @@ -85,6 +85,7 @@
>      printf("vpt_align: %d\n", b_info->vpt_align);
>      printf("max_vcpus: %d\n", b_info->max_vcpus);
>      printf("max_memkb: %d\n", b_info->max_memkb);
> +    printf("target_memkb: %d\n", b_info->target_memkb);
>      printf("kernel: %s\n", b_info->kernel);
>      printf("hvm: %d\n", b_info->hvm);
>  
> @@ -283,8 +284,10 @@
>      if (config_lookup_int (&config, "vcpus", &l) == CONFIG_TRUE)
>          b_info->max_vcpus = l;
>  
> -    if (config_lookup_int (&config, "memory", &l) == CONFIG_TRUE)
> +    if (config_lookup_int (&config, "memory", &l) == CONFIG_TRUE) {
>          b_info->max_memkb = l * 1024;
> +        b_info->target_memkb = b_info->max_memkb;
> +    }
>  
>      if (config_lookup_int (&config, "shadow_memory", &l) == CONFIG_TRUE)
>          b_info->shadow_memkb = l * 1024;
> @@ -756,6 +759,7 @@
>          printf(" restore                       restore a domain from a saved state\n\n");
>          printf(" cd-insert                     insert a cdrom into a guest's cd drive\n\n");
>          printf(" cd-eject                      eject a cdrom from a guest's cd drive\n\n");
> +        printf(" mem-set                       set the current memory usage for a domain\n\n");
>      } else if(!strcmp(command, "create")) {
>          printf("Usage: xl create <ConfigFile> [options] [vars]\n\n");
>          printf("Create a domain based on <ConfigFile>.\n\n");
> @@ -804,7 +808,52 @@
>      } else if (!strcmp(command, "cd-eject")) {
>          printf("Usage: xl cd-eject <Domain> <VirtualDevice>\n\n");
>          printf("Eject a cdrom from a guest's cd drive.\n\n");
> +    } else if (!strcmp(command, "mem-set")) {
> +        printf("Usage: xl mem-set <Domain> <MemKB>\n\n");
> +        printf("Set the current memory usage for a domain.\n\n");
>      }
> +}
> +
> +void set_memory_target(char *p, char *mem)
> +{
> +    struct libxl_ctx ctx;
> +    uint32_t domid;
> +
> +    libxl_ctx_init(&ctx);
> +    libxl_ctx_set_log(&ctx, log_callback, NULL);
> +
> +    if (libxl_param_to_domid(&ctx, p, &domid) < 0) {
> +        fprintf(stderr, "%s is an invalid domain identifier\n", p);
> +        exit(2);
> +    }
> +    libxl_set_memory_target(&ctx, domid, atoi(mem));
> +}
> +
> +int main_memset(int argc, char **argv)
> +{
> +    int opt = 0;
> +    char *p = NULL, *mem;
> +
> +    while ((opt = getopt(argc, argv, "h:")) != -1) {
> +        switch (opt) {
> +        case 'h':
> +            help("mem-set");
> +            exit(0);
> +        default:
> +            fprintf(stderr, "option not supported\n");
> +            break;
> +        }
> +    }
> +    if (optind >= argc - 1) {
> +        help("mem-set");
> +        exit(2);
> +    }
> +
> +    p = argv[optind];
> +    mem = argv[optind + 1];
> +
> +    set_memory_target(p, mem);
> +    exit(0);
>  }
>  
>  void console(char *p, int cons_num)
> @@ -1436,6 +1485,8 @@
>          main_cd_insert(argc - 1, argv + 1);
>      } else if (!strcmp(argv[1], "cd-eject")) {
>          main_cd_eject(argc - 1, argv + 1);
> +    } else if (!strcmp(argv[1], "mem-set")) {
> +        main_memset(argc - 1, argv + 1);
>      } else if (!strcmp(argv[1], "help")) {
>          if (argc > 2)
>              help(argv[2]);
>
>
>
>