From: Xiao Guangrong <xiaoguangr...@tencent.com>
Adapt the compression code to the lockless multithread model
Signed-off-by: Xiao Guangrong <xiaoguangr...@tencent.com>
---
migration/ram.c | 312 +++++++++++++++++++++-----------------------------------
1 file changed, 115 insertions(+), 197 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index bc38d98cc3..2356bc255c 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -57,6 +57,7 @@
#include "qemu/uuid.h"
#include "savevm.h"
#include "qemu/iov.h"
+#include "qemu/lockless-threads.h"
/***********************************************************/
/* ram save/restore */
@@ -349,22 +350,6 @@ typedef struct PageSearchStatus PageSearchStatus;
CompressionStats compression_counters;
-struct CompressParam {
- bool done;
- bool quit;
- bool zero_page;
- QEMUFile *file;
- QemuMutex mutex;
- QemuCond cond;
- RAMBlock *block;
- ram_addr_t offset;
-
- /* internally used fields */
- z_stream stream;
- uint8_t *originbuf;
-};
-typedef struct CompressParam CompressParam;
-
struct DecompressParam {
bool done;
bool quit;
@@ -377,15 +362,6 @@ struct DecompressParam {
};
typedef struct DecompressParam DecompressParam;
-static CompressParam *comp_param;
-static QemuThread *compress_threads;
-/* comp_done_cond is used to wake up the migration thread when
- * one of the compression threads has finished the compression.
- * comp_done_lock is used to co-work with comp_done_cond.
- */
-static QemuMutex comp_done_lock;
-static QemuCond comp_done_cond;
-/* The empty QEMUFileOps will be used by file in CompressParam */
static const QEMUFileOps empty_ops = { };
static QEMUFile *decomp_file;
@@ -394,125 +370,6 @@ static QemuThread *decompress_threads;
static QemuMutex decomp_done_lock;
static QemuCond decomp_done_cond;
-static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock
*block,
- ram_addr_t offset, uint8_t *source_buf);
-
-static void *do_data_compress(void *opaque)
-{
- CompressParam *param = opaque;
- RAMBlock *block;
- ram_addr_t offset;
- bool zero_page;
-
- qemu_mutex_lock(¶m->mutex);
- while (!param->quit) {
- if (param->block) {
- block = param->block;
- offset = param->offset;
- param->block = NULL;
- qemu_mutex_unlock(¶m->mutex);
-
- zero_page = do_compress_ram_page(param->file, ¶m->stream,
- block, offset, param->originbuf);
-
- qemu_mutex_lock(&comp_done_lock);
- param->done = true;
- param->zero_page = zero_page;
- qemu_cond_signal(&comp_done_cond);
- qemu_mutex_unlock(&comp_done_lock);
-
- qemu_mutex_lock(¶m->mutex);
- } else {
- qemu_cond_wait(¶m->cond, ¶m->mutex);
- }
- }
- qemu_mutex_unlock(¶m->mutex);
-
- return NULL;
-}
-
-static void compress_threads_save_cleanup(void)
-{
- int i, thread_count;
-
- if (!migrate_use_compression() || !comp_param) {
- return;
- }
-
- thread_count = migrate_compress_threads();
- for (i = 0; i < thread_count; i++) {
- /*
- * we use it as a indicator which shows if the thread is
- * properly init'd or not
- */
- if (!comp_param[i].file) {
- break;
- }
-
- qemu_mutex_lock(&comp_param[i].mutex);
- comp_param[i].quit = true;
- qemu_cond_signal(&comp_param[i].cond);
- qemu_mutex_unlock(&comp_param[i].mutex);
-
- qemu_thread_join(compress_threads + i);
- qemu_mutex_destroy(&comp_param[i].mutex);
- qemu_cond_destroy(&comp_param[i].cond);
- deflateEnd(&comp_param[i].stream);
- g_free(comp_param[i].originbuf);
- qemu_fclose(comp_param[i].file);
- comp_param[i].file = NULL;
- }
- qemu_mutex_destroy(&comp_done_lock);
- qemu_cond_destroy(&comp_done_cond);
- g_free(compress_threads);
- g_free(comp_param);
- compress_threads = NULL;
- comp_param = NULL;
-}
-
-static int compress_threads_save_setup(void)
-{
- int i, thread_count;
-
- if (!migrate_use_compression()) {
- return 0;
- }
- thread_count = migrate_compress_threads();
- compress_threads = g_new0(QemuThread, thread_count);
- comp_param = g_new0(CompressParam, thread_count);
- qemu_cond_init(&comp_done_cond);
- qemu_mutex_init(&comp_done_lock);
- for (i = 0; i < thread_count; i++) {
- comp_param[i].originbuf = g_try_malloc(TARGET_PAGE_SIZE);
- if (!comp_param[i].originbuf) {
- goto exit;
- }
-
- if (deflateInit(&comp_param[i].stream,
- migrate_compress_level()) != Z_OK) {
- g_free(comp_param[i].originbuf);
- goto exit;
- }
-
- /* comp_param[i].file is just used as a dummy buffer to save data,
- * set its ops to empty.
- */
- comp_param[i].file = qemu_fopen_ops(NULL, &empty_ops);
- comp_param[i].done = true;
- comp_param[i].quit = false;
- qemu_mutex_init(&comp_param[i].mutex);
- qemu_cond_init(&comp_param[i].cond);
- qemu_thread_create(compress_threads + i, "compress",
- do_data_compress, comp_param + i,
- QEMU_THREAD_JOINABLE);
- }
- return 0;
-
-exit:
- compress_threads_save_cleanup();
- return -1;
-}
-
/* Multiple fd's */
#define MULTIFD_MAGIC 0x11223344U
@@ -1909,12 +1766,27 @@ exit:
return zero_page;
}
+struct CompressData {
+ /* filled by migration thread.*/
+ RAMBlock *block;
+ ram_addr_t offset;
+
+ /* filled by compress thread. */
+ QEMUFile *file;
+ z_stream stream;
+ uint8_t *originbuf;
+ bool zero_page;
+
+ ThreadRequest request;
+};
+typedef struct CompressData CompressData;
+
static void
-update_compress_thread_counts(const CompressParam *param, int bytes_xmit)
+update_compress_thread_counts(CompressData *cd, int bytes_xmit)
{
ram_counters.transferred += bytes_xmit;
- if (param->zero_page) {
+ if (cd->zero_page) {
ram_counters.duplicate++;
return;
}
@@ -1924,81 +1796,127 @@ update_compress_thread_counts(const CompressParam
*param, int bytes_xmit)
compression_counters.pages++;
}
+static ThreadRequest *compress_thread_data_init(void)
+{
+ CompressData *cd = g_new0(CompressData, 1);
+
+ cd->originbuf = g_try_malloc(TARGET_PAGE_SIZE);
+ if (!cd->originbuf) {
+ goto exit;
+ }
+
+ if (deflateInit(&cd->stream, migrate_compress_level()) != Z_OK) {
+ g_free(cd->originbuf);
+ goto exit;
+ }
+
+ cd->file = qemu_fopen_ops(NULL, &empty_ops);
+ return &cd->request;
+
+exit:
+ g_free(cd);
+ return NULL;
+}
+
+static void compress_thread_data_fini(ThreadRequest *request)
+{
+ CompressData *cd = container_of(request, CompressData, request);
+
+ qemu_fclose(cd->file);
+ deflateEnd(&cd->stream);
+ g_free(cd->originbuf);
+ g_free(cd);
+}
+
+static void compress_thread_data_handler(ThreadRequest *request)
+{
+ CompressData *cd = container_of(request, CompressData, request);
+
+ /*
+ * if compression fails, it will be indicated by
+ * migrate_get_current()->to_dst_file.
+ */
+ cd->zero_page = do_compress_ram_page(cd->file, &cd->stream, cd->block,
+ cd->offset, cd->originbuf);
+}
+
+static void compress_thread_data_done(ThreadRequest *request)
+{
+ CompressData *cd = container_of(request, CompressData, request);
+ RAMState *rs = ram_state;
+ int bytes_xmit;
+
+ bytes_xmit = qemu_put_qemu_file(rs->f, cd->file);
+ update_compress_thread_counts(cd, bytes_xmit);
+}
+
+static Threads *compress_threads;
+
static bool save_page_use_compression(RAMState *rs);
static void flush_compressed_data(RAMState *rs)
{
- int idx, len, thread_count;
-
if (!save_page_use_compression(rs)) {
return;
}
- thread_count = migrate_compress_threads();
- qemu_mutex_lock(&comp_done_lock);
- for (idx = 0; idx < thread_count; idx++) {
- while (!comp_param[idx].done) {
- qemu_cond_wait(&comp_done_cond, &comp_done_lock);
- }
- }
- qemu_mutex_unlock(&comp_done_lock);
+ threads_wait_done(compress_threads);
+}
- for (idx = 0; idx < thread_count; idx++) {
- qemu_mutex_lock(&comp_param[idx].mutex);
- if (!comp_param[idx].quit) {
- len = qemu_put_qemu_file(rs->f, comp_param[idx].file);
- /*
- * it's safe to fetch zero_page without holding comp_done_lock
- * as there is no further request submitted to the thread,
- * i.e, the thread should be waiting for a request at this point.
- */
- update_compress_thread_counts(&comp_param[idx], len);
- }
- qemu_mutex_unlock(&comp_param[idx].mutex);
+static void compress_threads_save_cleanup(void)
+{
+ if (!compress_threads) {
+ return;
}
+
+ threads_destroy(compress_threads);
+ compress_threads = NULL;
}
-static inline void set_compress_params(CompressParam *param, RAMBlock *block,
- ram_addr_t offset)
+static int compress_threads_save_setup(void)
{
- param->block = block;
- param->offset = offset;
+ if (!migrate_use_compression()) {
+ return 0;
+ }
+
+ compress_threads = threads_create(migrate_compress_threads(),
+ "compress",
+ DEFAULT_THREAD_RING_SIZE,
+ compress_thread_data_init,
+ compress_thread_data_fini,
+ compress_thread_data_handler,
+ compress_thread_data_done);
+ return compress_threads ? 0 : -1;
}
static int compress_page_with_multi_thread(RAMState *rs, RAMBlock *block,
ram_addr_t offset)
{
- int idx, thread_count, bytes_xmit = -1, pages = -1;
+ CompressData *cd;
+ ThreadRequest *request;
bool wait = migrate_compress_wait_thread();
- thread_count = migrate_compress_threads();
- qemu_mutex_lock(&comp_done_lock);
retry:
- for (idx = 0; idx < thread_count; idx++) {
- if (comp_param[idx].done) {
- comp_param[idx].done = false;
- bytes_xmit = qemu_put_qemu_file(rs->f, comp_param[idx].file);
- qemu_mutex_lock(&comp_param[idx].mutex);
- set_compress_params(&comp_param[idx], block, offset);
- qemu_cond_signal(&comp_param[idx].cond);
- qemu_mutex_unlock(&comp_param[idx].mutex);
- pages = 1;
- update_compress_thread_counts(&comp_param[idx], bytes_xmit);
- break;
+ request = threads_submit_request_prepare(compress_threads);
+ if (!request) {
+ /*
+ * wait for the free thread if the user specifies
+ * 'compress-wait-thread', otherwise we will post
+ * the page out in the main thread as normal page.
+ */
+ if (wait) {
+ cpu_relax();
+ goto retry;
}
- }
- /*
- * wait for the free thread if the user specifies 'compress-wait-thread',
- * otherwise we will post the page out in the main thread as normal page.
- */
- if (pages < 0 && wait) {
- qemu_cond_wait(&comp_done_cond, &comp_done_lock);
- goto retry;
- }
- qemu_mutex_unlock(&comp_done_lock);
+ return -1;
+ }
- return pages;
+ cd = container_of(request, CompressData, request);
+ cd->block = block;
+ cd->offset = offset;
+ threads_submit_request_commit(compress_threads, request);
+ return 1;
}
/**
--
2.14.4
