Using "-mem-prealloc" option for a large guest leads to higher guest start-up and migration time. This is because with "-mem-prealloc" option qemu tries to map every guest page (create address translations), and make sure the pages are available during runtime. virsh/libvirt by default, seems to use "-mem-prealloc" option in case the guest is configured to use huge pages. The patch tries to map all guest pages simultaneously by spawning multiple threads. Currently limiting the change to QEMU library functions on POSIX compliant host only, as we are not sure if the problem exists on win32. Below are some stats with "-mem-prealloc" option for guest configured to use huge pages. ------------------------------------------------------------------------ Idle Guest | Start-up time | Migration time ------------------------------------------------------------------------ Guest stats with 2M HugePage usage - single threaded (existing code) ------------------------------------------------------------------------ 64 Core - 4TB | 54m11.796s | 75m43.843s 64 Core - 1TB | 8m56.576s | 14m29.049s 64 Core - 256GB | 2m11.245s | 3m26.598s ------------------------------------------------------------------------ Guest stats with 2M HugePage usage - map guest pages using 8 threads ------------------------------------------------------------------------ 64 Core - 4TB | 5m1.027s | 34m10.565s 64 Core - 1TB | 1m10.366s | 8m28.188s 64 Core - 256GB | 0m19.040s | 2m10.148s ----------------------------------------------------------------------- Guest stats with 2M HugePage usage - map guest pages using 16 threads ----------------------------------------------------------------------- 64 Core - 4TB | 1m58.970s | 31m43.400s 64 Core - 1TB | 0m39.885s | 7m55.289s 64 Core - 256GB | 0m11.960s | 2m0.135s ----------------------------------------------------------------------- Changed in v2: - modify number of memset threads spawned to min(smp_cpus, 16). - removed 64GB memory restriction for spawning memset threads. Changed in v3: - limit number of threads spawned based on min(sysconf(_SC_NPROCESSORS_ONLN), 16, smp_cpus) - implement memset thread specific siglongjmp in SIGBUS signal_handler. Changed in v4 - remove sigsetjmp/siglongjmp and SIGBUS unblock/block for main thread as main thread no longer touches any pages. - simplify code my returning memset_thread_failed status from touch_all_pages. Signed-off-by: Jitendra Kolhe <jitendra.kolhe@hpe.com> Message-Id: <1487907103-32350-1-git-send-email-jitendra.kolhe@hpe.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
428 lines
12 KiB
C
428 lines
12 KiB
C
/*
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* QEMU Host Memory Backend
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*
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* Copyright (C) 2013-2014 Red Hat Inc
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*
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* Authors:
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* Igor Mammedov <imammedo@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "sysemu/hostmem.h"
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#include "hw/boards.h"
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#include "qapi/error.h"
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#include "qapi/visitor.h"
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#include "qapi-types.h"
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#include "qapi-visit.h"
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#include "qemu/config-file.h"
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#include "qom/object_interfaces.h"
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#ifdef CONFIG_NUMA
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#include <numaif.h>
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QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
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QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
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QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
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QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
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#endif
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static void
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host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
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void *opaque, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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uint64_t value = backend->size;
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visit_type_size(v, name, &value, errp);
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}
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static void
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host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
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void *opaque, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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Error *local_err = NULL;
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uint64_t value;
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if (memory_region_size(&backend->mr)) {
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error_setg(&local_err, "cannot change property value");
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goto out;
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}
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visit_type_size(v, name, &value, &local_err);
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if (local_err) {
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goto out;
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}
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if (!value) {
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error_setg(&local_err, "Property '%s.%s' doesn't take value '%"
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PRIu64 "'", object_get_typename(obj), name, value);
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goto out;
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}
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backend->size = value;
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out:
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error_propagate(errp, local_err);
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}
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static uint16List **host_memory_append_node(uint16List **node,
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unsigned long value)
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{
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*node = g_malloc0(sizeof(**node));
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(*node)->value = value;
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return &(*node)->next;
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}
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static void
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host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
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void *opaque, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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uint16List *host_nodes = NULL;
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uint16List **node = &host_nodes;
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unsigned long value;
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value = find_first_bit(backend->host_nodes, MAX_NODES);
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node = host_memory_append_node(node, value);
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if (value == MAX_NODES) {
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goto out;
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}
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do {
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value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
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if (value == MAX_NODES) {
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break;
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}
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node = host_memory_append_node(node, value);
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} while (true);
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out:
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visit_type_uint16List(v, name, &host_nodes, errp);
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}
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static void
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host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
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void *opaque, Error **errp)
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{
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#ifdef CONFIG_NUMA
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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uint16List *l = NULL;
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visit_type_uint16List(v, name, &l, errp);
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while (l) {
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bitmap_set(backend->host_nodes, l->value, 1);
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l = l->next;
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}
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#else
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error_setg(errp, "NUMA node binding are not supported by this QEMU");
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#endif
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}
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static int
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host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->policy;
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}
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static void
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host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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backend->policy = policy;
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#ifndef CONFIG_NUMA
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if (policy != HOST_MEM_POLICY_DEFAULT) {
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error_setg(errp, "NUMA policies are not supported by this QEMU");
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}
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#endif
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}
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static bool host_memory_backend_get_merge(Object *obj, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->merge;
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}
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static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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if (!memory_region_size(&backend->mr)) {
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backend->merge = value;
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return;
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}
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if (value != backend->merge) {
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void *ptr = memory_region_get_ram_ptr(&backend->mr);
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uint64_t sz = memory_region_size(&backend->mr);
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qemu_madvise(ptr, sz,
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value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
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backend->merge = value;
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}
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}
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static bool host_memory_backend_get_dump(Object *obj, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->dump;
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}
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static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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if (!memory_region_size(&backend->mr)) {
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backend->dump = value;
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return;
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}
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if (value != backend->dump) {
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void *ptr = memory_region_get_ram_ptr(&backend->mr);
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uint64_t sz = memory_region_size(&backend->mr);
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qemu_madvise(ptr, sz,
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value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
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backend->dump = value;
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}
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}
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static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->prealloc || backend->force_prealloc;
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}
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static void host_memory_backend_set_prealloc(Object *obj, bool value,
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Error **errp)
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{
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Error *local_err = NULL;
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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if (backend->force_prealloc) {
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if (value) {
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error_setg(errp,
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"remove -mem-prealloc to use the prealloc property");
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return;
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}
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}
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if (!memory_region_size(&backend->mr)) {
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backend->prealloc = value;
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return;
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}
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if (value && !backend->prealloc) {
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int fd = memory_region_get_fd(&backend->mr);
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void *ptr = memory_region_get_ram_ptr(&backend->mr);
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uint64_t sz = memory_region_size(&backend->mr);
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os_mem_prealloc(fd, ptr, sz, smp_cpus, &local_err);
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if (local_err) {
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error_propagate(errp, local_err);
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return;
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}
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backend->prealloc = true;
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}
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}
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static void host_memory_backend_init(Object *obj)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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MachineState *machine = MACHINE(qdev_get_machine());
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backend->merge = machine_mem_merge(machine);
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backend->dump = machine_dump_guest_core(machine);
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backend->prealloc = mem_prealloc;
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}
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MemoryRegion *
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host_memory_backend_get_memory(HostMemoryBackend *backend, Error **errp)
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{
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return memory_region_size(&backend->mr) ? &backend->mr : NULL;
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}
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void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
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{
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backend->is_mapped = mapped;
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}
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bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
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{
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return backend->is_mapped;
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}
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static void
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host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(uc);
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HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
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Error *local_err = NULL;
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void *ptr;
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uint64_t sz;
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if (bc->alloc) {
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bc->alloc(backend, &local_err);
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if (local_err) {
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goto out;
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}
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ptr = memory_region_get_ram_ptr(&backend->mr);
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sz = memory_region_size(&backend->mr);
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if (backend->merge) {
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qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
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}
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if (!backend->dump) {
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qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
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}
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#ifdef CONFIG_NUMA
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unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
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/* lastbit == MAX_NODES means maxnode = 0 */
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unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
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/* ensure policy won't be ignored in case memory is preallocated
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* before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
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* this doesn't catch hugepage case. */
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unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
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/* check for invalid host-nodes and policies and give more verbose
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* error messages than mbind(). */
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if (maxnode && backend->policy == MPOL_DEFAULT) {
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error_setg(errp, "host-nodes must be empty for policy default,"
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" or you should explicitly specify a policy other"
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" than default");
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return;
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} else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
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error_setg(errp, "host-nodes must be set for policy %s",
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HostMemPolicy_lookup[backend->policy]);
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return;
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}
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/* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
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* as argument to mbind() due to an old Linux bug (feature?) which
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* cuts off the last specified node. This means backend->host_nodes
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* must have MAX_NODES+1 bits available.
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*/
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assert(sizeof(backend->host_nodes) >=
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BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
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assert(maxnode <= MAX_NODES);
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if (mbind(ptr, sz, backend->policy,
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maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
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if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
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error_setg_errno(errp, errno,
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"cannot bind memory to host NUMA nodes");
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return;
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}
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}
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#endif
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/* Preallocate memory after the NUMA policy has been instantiated.
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* This is necessary to guarantee memory is allocated with
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* specified NUMA policy in place.
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*/
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if (backend->prealloc) {
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os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
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smp_cpus, &local_err);
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if (local_err) {
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goto out;
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}
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}
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}
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out:
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error_propagate(errp, local_err);
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}
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static bool
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host_memory_backend_can_be_deleted(UserCreatable *uc, Error **errp)
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{
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if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
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return false;
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} else {
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return true;
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}
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}
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static char *get_id(Object *o, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(o);
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return g_strdup(backend->id);
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}
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static void set_id(Object *o, const char *str, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(o);
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if (backend->id) {
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error_setg(errp, "cannot change property value");
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return;
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}
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backend->id = g_strdup(str);
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}
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static void
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host_memory_backend_class_init(ObjectClass *oc, void *data)
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{
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UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
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ucc->complete = host_memory_backend_memory_complete;
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ucc->can_be_deleted = host_memory_backend_can_be_deleted;
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object_class_property_add_bool(oc, "merge",
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host_memory_backend_get_merge,
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host_memory_backend_set_merge, &error_abort);
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object_class_property_add_bool(oc, "dump",
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host_memory_backend_get_dump,
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host_memory_backend_set_dump, &error_abort);
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object_class_property_add_bool(oc, "prealloc",
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host_memory_backend_get_prealloc,
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host_memory_backend_set_prealloc, &error_abort);
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object_class_property_add(oc, "size", "int",
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host_memory_backend_get_size,
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host_memory_backend_set_size,
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NULL, NULL, &error_abort);
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object_class_property_add(oc, "host-nodes", "int",
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host_memory_backend_get_host_nodes,
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host_memory_backend_set_host_nodes,
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NULL, NULL, &error_abort);
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object_class_property_add_enum(oc, "policy", "HostMemPolicy",
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HostMemPolicy_lookup,
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host_memory_backend_get_policy,
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host_memory_backend_set_policy, &error_abort);
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object_class_property_add_str(oc, "id", get_id, set_id, &error_abort);
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}
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static void host_memory_backend_finalize(Object *o)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(o);
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g_free(backend->id);
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}
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static const TypeInfo host_memory_backend_info = {
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.name = TYPE_MEMORY_BACKEND,
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.parent = TYPE_OBJECT,
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.abstract = true,
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.class_size = sizeof(HostMemoryBackendClass),
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.class_init = host_memory_backend_class_init,
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.instance_size = sizeof(HostMemoryBackend),
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.instance_init = host_memory_backend_init,
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.instance_finalize = host_memory_backend_finalize,
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.interfaces = (InterfaceInfo[]) {
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{ TYPE_USER_CREATABLE },
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{ }
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}
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};
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static void register_types(void)
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{
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type_register_static(&host_memory_backend_info);
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}
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type_init(register_types);
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