From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45905) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZxHN8-0002dm-52 for qemu-devel@nongnu.org; Fri, 13 Nov 2015 11:38:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZxHN3-0004JA-SB for qemu-devel@nongnu.org; Fri, 13 Nov 2015 11:38:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37144) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZxHN3-0004Iy-Kc for qemu-devel@nongnu.org; Fri, 13 Nov 2015 11:38:41 -0500 Date: Fri, 13 Nov 2015 16:38:35 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20151113163834.GM2456@work-vm> References: <1446551816-15768-1-git-send-email-zhang.zhanghailiang@huawei.com> <1446551816-15768-17-git-send-email-zhang.zhanghailiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1446551816-15768-17-git-send-email-zhang.zhanghailiang@huawei.com> Subject: Re: [Qemu-devel] [PATCH COLO-Frame v10 16/38] COLO: Flush PVM's cached RAM into SVM's memory List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: zhanghailiang Cc: lizhijian@cn.fujitsu.com, quintela@redhat.com, yunhong.jiang@intel.com, eddie.dong@intel.com, peter.huangpeng@huawei.com, qemu-devel@nongnu.org, arei.gonglei@huawei.com, stefanha@redhat.com, amit.shah@redhat.com * zhanghailiang (zhang.zhanghailiang@huawei.com) wrote: > During the time of VM's running, PVM may dirty some pages, we will transfer > PVM's dirty pages to SVM and store them into SVM's RAM cache at next checkpoint > time. So, the content of SVM's RAM cache will always be some with PVM's memory > after checkpoint. > > Instead of flushing all content of PVM's RAM cache into SVM's MEMORY, > we do this in a more efficient way: > Only flush any page that dirtied by PVM since last checkpoint. > In this way, we can ensure SVM's memory same with PVM's. > > Besides, we must ensure flush RAM cache before load device state. Yes, just a couple of minor comments below; mostly OK. > Signed-off-by: zhanghailiang > Signed-off-by: Li Zhijian > Signed-off-by: Gonglei > --- > v10: trace the number of dirty pages that be received. > --- > include/migration/colo.h | 1 + > migration/colo.c | 2 -- > migration/ram.c | 40 ++++++++++++++++++++++++++++++++++++++++ > trace-events | 1 + > 4 files changed, 42 insertions(+), 2 deletions(-) > > diff --git a/include/migration/colo.h b/include/migration/colo.h > index 8edd5f1..be2890b 100644 > --- a/include/migration/colo.h > +++ b/include/migration/colo.h > @@ -32,4 +32,5 @@ bool migration_incoming_in_colo_state(void); > /* ram cache */ > int colo_init_ram_cache(void); > void colo_release_ram_cache(void); > +void colo_flush_ram_cache(void); > #endif > diff --git a/migration/colo.c b/migration/colo.c > index 1339774..0efab21 100644 > --- a/migration/colo.c > +++ b/migration/colo.c > @@ -381,8 +381,6 @@ void *colo_process_incoming_thread(void *opaque) > } > qemu_mutex_unlock_iothread(); > > - /* TODO: flush vm state */ > - > ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED, 0); > if (ret < 0) { > goto out; > diff --git a/migration/ram.c b/migration/ram.c > index 70879bd..d7e0e37 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1601,6 +1601,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > int flags = 0, ret = 0; > static uint64_t seq_iter; > int len = 0; > + bool need_flush = false; > > seq_iter++; > > @@ -1669,6 +1670,8 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > ret = -EINVAL; > break; > } > + > + need_flush = true; > ch = qemu_get_byte(f); > ram_handle_compressed(host, ch, TARGET_PAGE_SIZE); > break; > @@ -1679,6 +1682,8 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > ret = -EINVAL; > break; > } > + > + need_flush = true; > qemu_get_buffer(f, host, TARGET_PAGE_SIZE); > break; > case RAM_SAVE_FLAG_COMPRESS_PAGE: > @@ -1711,6 +1716,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > ret = -EINVAL; > break; > } > + need_flush = true; You can probably move the 'need_flush' to the big if near the top of the loop in the current version. > break; > case RAM_SAVE_FLAG_EOS: > /* normal exit */ > @@ -1730,6 +1736,11 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > } > > rcu_read_unlock(); > + > + if (!ret && ram_cache_enable && need_flush) { > + DPRINTF("Flush ram_cache\n"); trace_ > + colo_flush_ram_cache(); > + } > DPRINTF("Completed load of VM with exit code %d seq iteration " > "%" PRIu64 "\n", ret, seq_iter); > return ret; > @@ -1799,6 +1810,35 @@ void colo_release_ram_cache(void) > rcu_read_unlock(); > } > > +/* > + * Flush content of RAM cache into SVM's memory. > + * Only flush the pages that be dirtied by PVM or SVM or both. > + */ > +void colo_flush_ram_cache(void) > +{ > + RAMBlock *block = NULL; > + void *dst_host; > + void *src_host; > + ram_addr_t offset = 0; > + > + trace_colo_flush_ram_cache(migration_dirty_pages); > + rcu_read_lock(); > + block = QLIST_FIRST_RCU(&ram_list.blocks); > + while (block) { > + offset = migration_bitmap_find_and_reset_dirty(block, offset); You'll need to rework that a little (I split that into migration_bitmap_find_dirty and migration_bitmap_clear_dirty) > + if (offset >= block->used_length) { > + offset = 0; > + block = QLIST_NEXT_RCU(block, next); > + } else { > + dst_host = block->host + offset; > + src_host = block->host_cache + offset; > + memcpy(dst_host, src_host, TARGET_PAGE_SIZE); > + } > + } > + rcu_read_unlock(); > + assert(migration_dirty_pages == 0); > +} > + > static SaveVMHandlers savevm_ram_handlers = { > .save_live_setup = ram_save_setup, > .save_live_iterate = ram_save_iterate, > diff --git a/trace-events b/trace-events > index ee4679c..c98bc13 100644 > --- a/trace-events > +++ b/trace-events > @@ -1232,6 +1232,7 @@ qemu_file_fclose(void) "" > migration_bitmap_sync_start(void) "" > migration_bitmap_sync_end(uint64_t dirty_pages) "dirty_pages %" PRIu64"" > migration_throttle(void) "" > +colo_flush_ram_cache(uint64_t dirty_pages) "dirty_pages %" PRIu64"" > > # hw/display/qxl.c > disable qxl_interface_set_mm_time(int qid, uint32_t mm_time) "%d %d" > -- > 1.8.3.1 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK