diff options
| -rw-r--r-- | util/oslib-posix.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 5a291cc982..897e8f3ba6 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -76,6 +76,10 @@ static MemsetThread *memset_thread; static int memset_num_threads; static bool memset_thread_failed; +static QemuMutex page_mutex; +static QemuCond page_cond; +static bool threads_created_flag; + int qemu_get_thread_id(void) { #if defined(__linux__) @@ -403,6 +407,17 @@ static void *do_touch_pages(void *arg) MemsetThread *memset_args = (MemsetThread *)arg; sigset_t set, oldset; + /* + * On Linux, the page faults from the loop below can cause mmap_sem + * contention with allocation of the thread stacks. Do not start + * clearing until all threads have been created. + */ + qemu_mutex_lock(&page_mutex); + while(!threads_created_flag){ + qemu_cond_wait(&page_cond, &page_mutex); + } + qemu_mutex_unlock(&page_mutex); + /* unblock SIGBUS */ sigemptyset(&set); sigaddset(&set, SIGBUS); @@ -451,27 +466,28 @@ static inline int get_memset_num_threads(int smp_cpus) static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, int smp_cpus) { - size_t numpages_per_thread; - size_t size_per_thread; + size_t numpages_per_thread, leftover; char *addr = area; int i = 0; memset_thread_failed = false; + threads_created_flag = false; memset_num_threads = get_memset_num_threads(smp_cpus); memset_thread = g_new0(MemsetThread, memset_num_threads); - numpages_per_thread = (numpages / memset_num_threads); - size_per_thread = (hpagesize * numpages_per_thread); + numpages_per_thread = numpages / memset_num_threads; + leftover = numpages % memset_num_threads; 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].numpages = numpages_per_thread + (i < leftover); 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; + addr += memset_thread[i].numpages * hpagesize; } + threads_created_flag = true; + qemu_cond_broadcast(&page_cond); + for (i = 0; i < memset_num_threads; i++) { qemu_thread_join(&memset_thread[i].pgthread); } |