* @area: start address of the are to preallocate
* @sz: the size of the area to preallocate
* @max_threads: maximum number of threads to use
+ * @tc: prealloc context threads pointer, NULL if not in use
+ * @async: request asynchronous preallocation, requires @tc
* @errp: returns an error if this function fails
*
* Preallocate memory (populate/prefault page tables writable) for the virtual
* each page in the area was faulted in writable at least once, for example,
* after allocating file blocks for mapped files.
*
+ * When setting @async, allocation might be performed asynchronously.
+ * qemu_finish_async_prealloc_mem() must be called to finish any asynchronous
+ * preallocation.
+ *
* Return: true on success, else false setting @errp with error.
*/
bool qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
- ThreadContext *tc, Error **errp);
+ ThreadContext *tc, bool async, Error **errp);
+
+/**
+ * qemu_finish_async_prealloc_mem:
+ * @errp: returns an error if this function fails
+ *
+ * Finish all outstanding asynchronous memory preallocation.
+ *
+ * Return: true on success, else false setting @errp with error.
+ */
+bool qemu_finish_async_prealloc_mem(Error **errp);
/**
* qemu_get_pid_name:
#include "qemu/cutils.h"
#include "qemu/units.h"
#include "qemu/thread-context.h"
+#include "qemu/main-loop.h"
#ifdef CONFIG_LINUX
#include <sys/syscall.h>
struct MemsetThread;
+static QLIST_HEAD(, MemsetContext) memset_contexts =
+ QLIST_HEAD_INITIALIZER(memset_contexts);
+
typedef struct MemsetContext {
bool all_threads_created;
bool any_thread_failed;
struct MemsetThread *threads;
int num_threads;
+ QLIST_ENTRY(MemsetContext) next;
} MemsetContext;
struct MemsetThread {
return ret;
}
+static int wait_and_free_mem_prealloc_context(MemsetContext *context)
+{
+ int i, ret = 0, tmp;
+
+ for (i = 0; i < context->num_threads; i++) {
+ tmp = (uintptr_t)qemu_thread_join(&context->threads[i].pgthread);
+
+ if (tmp) {
+ ret = tmp;
+ }
+ }
+ g_free(context->threads);
+ g_free(context);
+ return ret;
+}
+
static int touch_all_pages(char *area, size_t hpagesize, size_t numpages,
- int max_threads, ThreadContext *tc,
+ int max_threads, ThreadContext *tc, bool async,
bool use_madv_populate_write)
{
static gsize initialized = 0;
- MemsetContext context = {
- .num_threads = get_memset_num_threads(hpagesize, numpages, max_threads),
- };
+ MemsetContext *context = g_malloc0(sizeof(MemsetContext));
size_t numpages_per_thread, leftover;
void *(*touch_fn)(void *);
- int ret = 0, i = 0;
+ int ret, i = 0;
char *addr = area;
+ /*
+ * Asynchronous preallocation is only allowed when using MADV_POPULATE_WRITE
+ * and prealloc context for thread placement.
+ */
+ if (!use_madv_populate_write || !tc) {
+ async = false;
+ }
+
+ context->num_threads =
+ get_memset_num_threads(hpagesize, numpages, max_threads);
+
if (g_once_init_enter(&initialized)) {
qemu_mutex_init(&page_mutex);
qemu_cond_init(&page_cond);
}
if (use_madv_populate_write) {
- /* Avoid creating a single thread for MADV_POPULATE_WRITE */
- if (context.num_threads == 1) {
+ /*
+ * Avoid creating a single thread for MADV_POPULATE_WRITE when
+ * preallocating synchronously.
+ */
+ if (context->num_threads == 1 && !async) {
if (qemu_madvise(area, hpagesize * numpages,
QEMU_MADV_POPULATE_WRITE)) {
return -errno;
touch_fn = do_touch_pages;
}
- context.threads = g_new0(MemsetThread, context.num_threads);
- numpages_per_thread = numpages / context.num_threads;
- leftover = numpages % context.num_threads;
- for (i = 0; i < context.num_threads; i++) {
- context.threads[i].addr = addr;
- context.threads[i].numpages = numpages_per_thread + (i < leftover);
- context.threads[i].hpagesize = hpagesize;
- context.threads[i].context = &context;
+ context->threads = g_new0(MemsetThread, context->num_threads);
+ numpages_per_thread = numpages / context->num_threads;
+ leftover = numpages % context->num_threads;
+ for (i = 0; i < context->num_threads; i++) {
+ context->threads[i].addr = addr;
+ context->threads[i].numpages = numpages_per_thread + (i < leftover);
+ context->threads[i].hpagesize = hpagesize;
+ context->threads[i].context = context;
if (tc) {
- thread_context_create_thread(tc, &context.threads[i].pgthread,
+ thread_context_create_thread(tc, &context->threads[i].pgthread,
"touch_pages",
- touch_fn, &context.threads[i],
+ touch_fn, &context->threads[i],
QEMU_THREAD_JOINABLE);
} else {
- qemu_thread_create(&context.threads[i].pgthread, "touch_pages",
- touch_fn, &context.threads[i],
+ qemu_thread_create(&context->threads[i].pgthread, "touch_pages",
+ touch_fn, &context->threads[i],
QEMU_THREAD_JOINABLE);
}
- addr += context.threads[i].numpages * hpagesize;
+ addr += context->threads[i].numpages * hpagesize;
+ }
+
+ if (async) {
+ /*
+ * async requests currently require the BQL. Add it to the list and kick
+ * preallocation off during qemu_finish_async_prealloc_mem().
+ */
+ assert(bql_locked());
+ QLIST_INSERT_HEAD(&memset_contexts, context, next);
+ return 0;
}
if (!use_madv_populate_write) {
- sigbus_memset_context = &context;
+ sigbus_memset_context = context;
}
qemu_mutex_lock(&page_mutex);
- context.all_threads_created = true;
+ context->all_threads_created = true;
qemu_cond_broadcast(&page_cond);
qemu_mutex_unlock(&page_mutex);
- for (i = 0; i < context.num_threads; i++) {
- int tmp = (uintptr_t)qemu_thread_join(&context.threads[i].pgthread);
+ ret = wait_and_free_mem_prealloc_context(context);
+ if (!use_madv_populate_write) {
+ sigbus_memset_context = NULL;
+ }
+ return ret;
+}
+
+bool qemu_finish_async_prealloc_mem(Error **errp)
+{
+ int ret = 0, tmp;
+ MemsetContext *context, *next_context;
+
+ /* Waiting for preallocation requires the BQL. */
+ assert(bql_locked());
+ if (QLIST_EMPTY(&memset_contexts)) {
+ return true;
+ }
+
+ qemu_mutex_lock(&page_mutex);
+ QLIST_FOREACH(context, &memset_contexts, next) {
+ context->all_threads_created = true;
+ }
+ qemu_cond_broadcast(&page_cond);
+ qemu_mutex_unlock(&page_mutex);
+
+ QLIST_FOREACH_SAFE(context, &memset_contexts, next, next_context) {
+ QLIST_REMOVE(context, next);
+ tmp = wait_and_free_mem_prealloc_context(context);
if (tmp) {
ret = tmp;
}
}
- if (!use_madv_populate_write) {
- sigbus_memset_context = NULL;
+ if (ret) {
+ error_setg_errno(errp, -ret,
+ "qemu_prealloc_mem: preallocating memory failed");
+ return false;
}
- g_free(context.threads);
-
- return ret;
+ return true;
}
static bool madv_populate_write_possible(char *area, size_t pagesize)
}
bool qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
- ThreadContext *tc, Error **errp)
+ ThreadContext *tc, bool async, Error **errp)
{
static gsize initialized;
int ret;
}
/* touch pages simultaneously */
- ret = touch_all_pages(area, hpagesize, numpages, max_threads, tc,
+ ret = touch_all_pages(area, hpagesize, numpages, max_threads, tc, async,
use_madv_populate_write);
if (ret) {
error_setg_errno(errp, -ret,
projects / mirror_qemu.git / commitdiff