diff options
| -rw-r--r-- | backends/hostmem.c | 4 | ||||
| -rw-r--r-- | exec.c | 2 | ||||
| -rw-r--r-- | include/qemu/osdep.h | 3 | ||||
| -rw-r--r-- | util/oslib-posix.c | 108 | ||||
| -rw-r--r-- | util/oslib-win32.c | 3 |
5 files changed, 94 insertions, 26 deletions
diff --git a/backends/hostmem.c b/backends/hostmem.c index 7f5de70609..162c2187d8 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 aabb035e92..68135a9391 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 af37195fef..122ff06ff6 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 cd686aae3d..956f66ab4a 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 0b1890fd33..80e4668935 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(); |