* guangrong.xiao@xxxxxxxxx (guangrong.xiao@xxxxxxxxx) wrote:
> From: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxx>
>
> Adapt the compression code to the threaded workqueue
>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxx>
> ---
> migration/ram.c | 308 ++++++++++++++++++++------------------------------------
> 1 file changed, 110 insertions(+), 198 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 7e7deec4d8..254c08f27b 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/threaded-workqueue.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 +1766,25 @@ 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;
> +};
> +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)
Keep the const?
> {
> ram_counters.transferred += bytes_xmit;
>
> - if (param->zero_page) {
> + if (cd->zero_page) {
> ram_counters.duplicate++;
> return;
> }
> @@ -1924,81 +1794,123 @@ update_compress_thread_counts(const CompressParam *param, int bytes_xmit)
> compression_counters.pages++;
> }
>
> +static int compress_thread_data_init(void *request)
> +{
> + CompressData *cd = request;
> +
> + cd->originbuf = g_try_malloc(TARGET_PAGE_SIZE);
> + if (!cd->originbuf) {
> + return -1;
> + }
> +
> + if (deflateInit(&cd->stream, migrate_compress_level()) != Z_OK) {
> + g_free(cd->originbuf);
> + return -1;
> + }
Please print errors if you fail in any case so we can easily tell what
happened.
> + cd->file = qemu_fopen_ops(NULL, &empty_ops);
> + return 0;
> +}
> +
> +static void compress_thread_data_fini(void *request)
> +{
> + CompressData *cd = request;
> +
> + qemu_fclose(cd->file);
> + deflateEnd(&cd->stream);
> + g_free(cd->originbuf);
> +}
> +
> +static void compress_thread_data_handler(void *request)
> +{
> + CompressData *cd = 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(void *request)
> +{
> + CompressData *cd = 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 const ThreadedWorkqueueOps compress_ops = {
> + .thread_request_init = compress_thread_data_init,
> + .thread_request_uninit = compress_thread_data_fini,
> + .thread_request_handler = compress_thread_data_handler,
> + .thread_request_done = compress_thread_data_done,
> + .request_size = sizeof(CompressData),
> +};
> +
> +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);
> + threaded_workqueue_wait_for_requests(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;
> }
> +
> + threaded_workqueue_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 = threaded_workqueue_create("compress",
> + migrate_compress_threads(),
> + DEFAULT_THREAD_REQUEST_NR, &compress_ops);
> + 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;
> 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;
> + cd = threaded_workqueue_get_request(compress_threads);
> + if (!cd) {
> + /*
> + * 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;
Is there nothing better we can use to wait without eating CPU time?
Dave
> }
> - }
>
> - /*
> - * 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 pages;
> + return -1;
> + }
> + cd->block = block;
> + cd->offset = offset;
> + threaded_workqueue_submit_request(compress_threads, cd);
> + return 1;
> }
>
> /**
> --
> 2.14.5
>
--
Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK
