@@ -232,7 +232,7 @@ 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, backend->prealloc_threads, &local_err);
+ qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
@@ -393,8 +393,8 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
* specified NUMA policy in place.
*/
if (backend->prealloc) {
- os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
- backend->prealloc_threads, &local_err);
+ qemu_prealloc_mem(memory_region_get_fd(&backend->mr), ptr, sz,
+ backend->prealloc_threads, &local_err);
if (local_err) {
goto out;
}
@@ -467,7 +467,7 @@ static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa,
int fd = memory_region_get_fd(&vmem->memdev->mr);
Error *local_err = NULL;
- os_mem_prealloc(fd, area, size, 1, &local_err);
+ qemu_prealloc_mem(fd, area, size, 1, &local_err);
if (local_err) {
static bool warned;
@@ -568,8 +568,21 @@ 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, int smp_cpus,
- Error **errp);
+/**
+ * qemu_prealloc_mem:
+ * @fd: the fd mapped into the area, -1 for anonymous memory
+ * @area: start address of the are to preallocate
+ * @sz: the size of the area to preallocate
+ * @max_threads: maximum number of threads to use
+ * @errp: returns an error if this function fails
+ *
+ * Preallocate memory (populate/prefault page tables writable) for the virtual
+ * memory area starting at @area with the size of @sz. After a successful call,
+ * each page in the area was faulted in writable at least once, for example,
+ * after allocating file blocks for mapped files.
+ */
+void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
+ Error **errp);
/**
* qemu_get_pid_name:
@@ -354,7 +354,7 @@ static void qemu_init_sigbus(void)
/*
* ALERT: when modifying this, take care that SIGBUS forwarding in
- * os_mem_prealloc() will continue working as expected.
+ * qemu_prealloc_mem() will continue working as expected.
*/
memset(&action, 0, sizeof(action));
action.sa_flags = SA_SIGINFO;
@@ -314,7 +314,7 @@ static void sigbus_handler(int signal)
return;
}
#endif /* CONFIG_LINUX */
- warn_report("os_mem_prealloc: unrelated SIGBUS detected and ignored");
+ warn_report("qemu_prealloc_mem: unrelated SIGBUS detected and ignored");
}
static void *do_touch_pages(void *arg)
@@ -384,13 +384,13 @@ static void *do_madv_populate_write_pages(void *arg)
}
static inline int get_memset_num_threads(size_t hpagesize, size_t numpages,
- int smp_cpus)
+ int max_threads)
{
long host_procs = sysconf(_SC_NPROCESSORS_ONLN);
int ret = 1;
if (host_procs > 0) {
- ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus);
+ ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), max_threads);
}
/* Especially with gigantic pages, don't create more threads than pages. */
@@ -403,11 +403,11 @@ static inline int get_memset_num_threads(size_t hpagesize, size_t numpages,
}
static int touch_all_pages(char *area, size_t hpagesize, size_t numpages,
- int smp_cpus, bool use_madv_populate_write)
+ int max_threads, bool use_madv_populate_write)
{
static gsize initialized = 0;
MemsetContext context = {
- .num_threads = get_memset_num_threads(hpagesize, numpages, smp_cpus),
+ .num_threads = get_memset_num_threads(hpagesize, numpages, max_threads),
};
size_t numpages_per_thread, leftover;
void *(*touch_fn)(void *);
@@ -479,13 +479,13 @@ static bool madv_populate_write_possible(char *area, size_t pagesize)
errno != EINVAL;
}
-void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
- Error **errp)
+void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
+ Error **errp)
{
static gsize initialized;
int ret;
size_t hpagesize = qemu_fd_getpagesize(fd);
- size_t numpages = DIV_ROUND_UP(memory, hpagesize);
+ size_t numpages = DIV_ROUND_UP(sz, hpagesize);
bool use_madv_populate_write;
struct sigaction act;
@@ -515,24 +515,24 @@ void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
if (ret) {
qemu_mutex_unlock(&sigbus_mutex);
error_setg_errno(errp, errno,
- "os_mem_prealloc: failed to install signal handler");
+ "qemu_prealloc_mem: failed to install signal handler");
return;
}
}
/* touch pages simultaneously */
- ret = touch_all_pages(area, hpagesize, numpages, smp_cpus,
+ ret = touch_all_pages(area, hpagesize, numpages, max_threads,
use_madv_populate_write);
if (ret) {
error_setg_errno(errp, -ret,
- "os_mem_prealloc: preallocating memory failed");
+ "qemu_prealloc_mem: preallocating memory failed");
}
if (!use_madv_populate_write) {
ret = sigaction(SIGBUS, &sigbus_oldact, NULL);
if (ret) {
/* Terminate QEMU since it can't recover from error */
- perror("os_mem_prealloc: failed to reinstall signal handler");
+ perror("qemu_prealloc_mem: failed to reinstall signal handler");
exit(1);
}
qemu_mutex_unlock(&sigbus_mutex);
@@ -268,14 +268,14 @@ int getpagesize(void)
return system_info.dwPageSize;
}
-void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
- Error **errp)
+void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
+ Error **errp)
{
int i;
size_t pagesize = qemu_real_host_page_size();
- memory = (memory + pagesize - 1) & -pagesize;
- for (i = 0; i < memory / pagesize; i++) {
+ sz = (sz + pagesize - 1) & -pagesize;
+ for (i = 0; i < sz / pagesize; i++) {
memset(area + pagesize * i, 0, 1);
}
}
Let's * give the function a "qemu_*" style name * make sure the parameters in the implementation match the prototype * rename smp_cpus to max_threads, which makes the semantics of that parameter clearer ... and add a function documentation. Signed-off-by: David Hildenbrand <david@redhat.com> --- backends/hostmem.c | 6 +++--- hw/virtio/virtio-mem.c | 2 +- include/qemu/osdep.h | 17 +++++++++++++++-- softmmu/cpus.c | 2 +- util/oslib-posix.c | 24 ++++++++++++------------ util/oslib-win32.c | 8 ++++---- 6 files changed, 36 insertions(+), 23 deletions(-)