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| author | David Hildenbrand | 2022-10-14 15:47:19 +0200 |
|---|---|---|
| committer | David Hildenbrand | 2022-10-27 11:01:03 +0200 |
| commit | e6816458624813de4a31f89096a620b410e1c2b8 (patch) | |
| tree | 327eb49230110c949e5443ebae4d1fd64336acf8 /backends | |
| parent | util: Make qemu_prealloc_mem() optionally consume a ThreadContext (diff) | |
| download | qemu-e6816458624813de4a31f89096a620b410e1c2b8.tar.gz qemu-e6816458624813de4a31f89096a620b410e1c2b8.tar.xz qemu-e6816458624813de4a31f89096a620b410e1c2b8.zip | |
hostmem: Allow for specifying a ThreadContext for preallocation
Let's allow for specifying a thread context via the "prealloc-context"
property. When set, preallcoation threads will be crated via the
thread context -- inheriting the same CPU affinity as the thread
context.
Pinning preallcoation threads to CPUs can heavily increase performance
in NUMA setups, because, preallocation from a CPU close to the target
NUMA node(s) is faster then preallocation from a CPU further remote,
simply because of memory bandwidth for initializing memory with zeroes.
This is especially relevant for very large VMs backed by huge/gigantic
pages, whereby preallocation is mandatory.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <20221014134720.168738-7-david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Diffstat (limited to 'backends')
| -rw-r--r-- | backends/hostmem.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/backends/hostmem.c b/backends/hostmem.c index 76f0394490..8640294c10 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -232,8 +232,8 @@ static void host_memory_backend_set_prealloc(Object *obj, bool value, void *ptr = memory_region_get_ram_ptr(&backend->mr); uint64_t sz = memory_region_size(&backend->mr); - qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, NULL, - &local_err); + qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, + backend->prealloc_context, &local_err); if (local_err) { error_propagate(errp, local_err); return; @@ -385,7 +385,8 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp) */ if (backend->prealloc) { qemu_prealloc_mem(memory_region_get_fd(&backend->mr), ptr, sz, - backend->prealloc_threads, NULL, &local_err); + backend->prealloc_threads, + backend->prealloc_context, &local_err); if (local_err) { goto out; } @@ -493,6 +494,11 @@ host_memory_backend_class_init(ObjectClass *oc, void *data) NULL, NULL); object_class_property_set_description(oc, "prealloc-threads", "Number of CPU threads to use for prealloc"); + object_class_property_add_link(oc, "prealloc-context", + TYPE_THREAD_CONTEXT, offsetof(HostMemoryBackend, prealloc_context), + object_property_allow_set_link, OBJ_PROP_LINK_STRONG); + object_class_property_set_description(oc, "prealloc-context", + "Context to use for creating CPU threads for preallocation"); object_class_property_add(oc, "size", "int", host_memory_backend_get_size, host_memory_backend_set_size, |