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-rw-r--r--backends/hostmem.c4
-rw-r--r--exec.c2
-rw-r--r--include/qemu/osdep.h3
-rw-r--r--util/oslib-posix.c108
-rw-r--r--util/oslib-win32.c3
5 files changed, 94 insertions, 26 deletions
diff --git a/backends/hostmem.c b/backends/hostmem.c
index 7f5de70..162c218 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -224,7 +224,7 @@ 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);
- os_mem_prealloc(fd, ptr, sz, &local_err);
+ os_mem_prealloc(fd, ptr, sz, smp_cpus, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
@@ -328,7 +328,7 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
*/
if (backend->prealloc) {
os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
- &local_err);
+ smp_cpus, &local_err);
if (local_err) {
goto out;
}
diff --git a/exec.c b/exec.c
index aabb035..68135a9 100644
--- a/exec.c
+++ b/exec.c
@@ -1467,7 +1467,7 @@ static void *file_ram_alloc(RAMBlock *block,
}
if (mem_prealloc) {
- os_mem_prealloc(fd, area, memory, errp);
+ os_mem_prealloc(fd, area, memory, smp_cpus, errp);
if (errp && *errp) {
goto error;
}
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index af37195..122ff06 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -438,7 +438,8 @@ unsigned long qemu_getauxval(unsigned long type);
void qemu_set_tty_echo(int fd, bool echo);
-void os_mem_prealloc(int fd, char *area, size_t sz, Error **errp);
+void os_mem_prealloc(int fd, char *area, size_t sz, int smp_cpus,
+ Error **errp);
int qemu_read_password(char *buf, int buf_size);
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index cd686aa..956f66a 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -55,6 +55,21 @@
#include "qemu/error-report.h"
#endif
+#define MAX_MEM_PREALLOC_THREAD_COUNT (MIN(sysconf(_SC_NPROCESSORS_ONLN), 16))
+
+struct MemsetThread {
+ char *addr;
+ uint64_t numpages;
+ uint64_t hpagesize;
+ QemuThread pgthread;
+ sigjmp_buf env;
+};
+typedef struct MemsetThread MemsetThread;
+
+static MemsetThread *memset_thread;
+static int memset_num_threads;
+static bool memset_thread_failed;
+
int qemu_get_thread_id(void)
{
#if defined(__linux__)
@@ -316,18 +331,83 @@ char *qemu_get_exec_dir(void)
return g_strdup(exec_dir);
}
-static sigjmp_buf sigjump;
-
static void sigbus_handler(int signal)
{
- siglongjmp(sigjump, 1);
+ int i;
+ if (memset_thread) {
+ for (i = 0; i < memset_num_threads; i++) {
+ if (qemu_thread_is_self(&memset_thread[i].pgthread)) {
+ siglongjmp(memset_thread[i].env, 1);
+ }
+ }
+ }
+}
+
+static void *do_touch_pages(void *arg)
+{
+ MemsetThread *memset_args = (MemsetThread *)arg;
+ char *addr = memset_args->addr;
+ uint64_t numpages = memset_args->numpages;
+ uint64_t hpagesize = memset_args->hpagesize;
+ sigset_t set, oldset;
+ int i = 0;
+
+ /* unblock SIGBUS */
+ sigemptyset(&set);
+ sigaddset(&set, SIGBUS);
+ pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
+
+ if (sigsetjmp(memset_args->env, 1)) {
+ memset_thread_failed = true;
+ } else {
+ for (i = 0; i < numpages; i++) {
+ memset(addr, 0, 1);
+ addr += hpagesize;
+ }
+ }
+ pthread_sigmask(SIG_SETMASK, &oldset, NULL);
+ return NULL;
+}
+
+static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
+ int smp_cpus)
+{
+ uint64_t numpages_per_thread, size_per_thread;
+ char *addr = area;
+ int i = 0;
+
+ memset_thread_failed = false;
+ memset_num_threads = MIN(smp_cpus, MAX_MEM_PREALLOC_THREAD_COUNT);
+ memset_thread = g_new0(MemsetThread, memset_num_threads);
+ numpages_per_thread = (numpages / memset_num_threads);
+ size_per_thread = (hpagesize * numpages_per_thread);
+ for (i = 0; i < memset_num_threads; i++) {
+ memset_thread[i].addr = addr;
+ memset_thread[i].numpages = (i == (memset_num_threads - 1)) ?
+ numpages : numpages_per_thread;
+ memset_thread[i].hpagesize = hpagesize;
+ qemu_thread_create(&memset_thread[i].pgthread, "touch_pages",
+ do_touch_pages, &memset_thread[i],
+ QEMU_THREAD_JOINABLE);
+ addr += size_per_thread;
+ numpages -= numpages_per_thread;
+ }
+ for (i = 0; i < memset_num_threads; i++) {
+ qemu_thread_join(&memset_thread[i].pgthread);
+ }
+ g_free(memset_thread);
+ memset_thread = NULL;
+
+ return memset_thread_failed;
}
-void os_mem_prealloc(int fd, char *area, size_t memory, Error **errp)
+void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
+ Error **errp)
{
int ret;
struct sigaction act, oldact;
- sigset_t set, oldset;
+ size_t hpagesize = qemu_fd_getpagesize(fd);
+ size_t numpages = DIV_ROUND_UP(memory, hpagesize);
memset(&act, 0, sizeof(act));
act.sa_handler = &sigbus_handler;
@@ -340,23 +420,10 @@ void os_mem_prealloc(int fd, char *area, size_t memory, Error **errp)
return;
}
- /* unblock SIGBUS */
- sigemptyset(&set);
- sigaddset(&set, SIGBUS);
- pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
-
- if (sigsetjmp(sigjump, 1)) {
+ /* touch pages simultaneously */
+ if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) {
error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
"pages available to allocate guest RAM\n");
- } else {
- int i;
- size_t hpagesize = qemu_fd_getpagesize(fd);
- size_t numpages = DIV_ROUND_UP(memory, hpagesize);
-
- /* MAP_POPULATE silently ignores failures */
- for (i = 0; i < numpages; i++) {
- memset(area + (hpagesize * i), 0, 1);
- }
}
ret = sigaction(SIGBUS, &oldact, NULL);
@@ -365,7 +432,6 @@ void os_mem_prealloc(int fd, char *area, size_t memory, Error **errp)
perror("os_mem_prealloc: failed to reinstall signal handler");
exit(1);
}
- pthread_sigmask(SIG_SETMASK, &oldset, NULL);
}
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index 0b1890f..80e4668 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -541,7 +541,8 @@ int getpagesize(void)
return system_info.dwPageSize;
}
-void os_mem_prealloc(int fd, char *area, size_t memory, Error **errp)
+void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
+ Error **errp)
{
int i;
size_t pagesize = getpagesize();