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Tue, 16 Oct 2018 04:10:26 -0700 (PDT) From: guangrong.xiao@gmail.com X-Google-Original-From: xiaoguangrong@tencent.com To: pbonzini@redhat.com, mst@redhat.com, mtosatti@redhat.com Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, dgilbert@redhat.com, peterx@redhat.com, wei.w.wang@intel.com, jiang.biao2@zte.com.cn, eblake@redhat.com, quintela@redhat.com, Xiao Guangrong Subject: [PATCH 3/4] migration: use lockless Multithread model for compression Date: Tue, 16 Oct 2018 19:10:05 +0800 Message-Id: <20181016111006.629-4-xiaoguangrong@tencent.com> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20181016111006.629-1-xiaoguangrong@tencent.com> References: <20181016111006.629-1-xiaoguangrong@tencent.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Xiao Guangrong Adapt the compression code to the lockless multithread model Signed-off-by: Xiao Guangrong --- 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; } /**