host_memory_backend_memory_complete(UserCreatable *uc, Error **errp) { HostMemoryBackend *backend = MEMORY_BACKEND(uc); HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc); Error *local_err = NULL; void *ptr; uint64_t sz; if (bc->alloc) { bc->alloc(backend, &local_err); if (local_err) { goto out; } ptr = memory_region_get_ram_ptr(&backend->mr); sz = memory_region_size(&backend->mr); if (backend->merge) { qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE); } if (!backend->dump) { qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP); } #ifdef CONFIG_NUMA unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES); /* lastbit == MAX_NODES means maxnode = 0 */ unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1); /* ensure policy won't be ignored in case memory is preallocated * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so * this doesn't catch hugepage case. */ unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE; /* check for invalid host-nodes and policies and give more verbose * error messages than mbind(). */ if (maxnode && backend->policy == MPOL_DEFAULT) { error_setg(errp, "host-nodes must be empty for policy default," " or you should explicitly specify a policy other" " than default"); return; } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) { error_setg(errp, "host-nodes must be set for policy %s", HostMemPolicy_lookup[backend->policy]); return; } /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1 * as argument to mbind() due to an old Linux bug (feature?) which * cuts off the last specified node. This means backend->host_nodes * must have MAX_NODES+1 bits available. */ assert(sizeof(backend->host_nodes) >= BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long)); assert(maxnode <= MAX_NODES); if (mbind(ptr, sz, backend->policy, maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) { if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) { error_setg_errno(errp, errno, "cannot bind memory to host NUMA nodes"); return; } } #endif /* Preallocate memory after the NUMA policy has been instantiated. * This is necessary to guarantee memory is allocated with * specified NUMA policy in place. */ if (backend->prealloc) { os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz, &local_err); if (local_err) { goto out; } } } out: error_propagate(errp, local_err); }