From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44738) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aOQsK-0002iV-0l for qemu-devel@nongnu.org; Wed, 27 Jan 2016 09:15:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aOQsF-0007MV-U9 for qemu-devel@nongnu.org; Wed, 27 Jan 2016 09:15:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51110) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aOQsF-0007ME-Jo for qemu-devel@nongnu.org; Wed, 27 Jan 2016 09:15:07 -0500 Date: Wed, 27 Jan 2016 14:14:59 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20160127141459.GD2394@work-vm> References: <1451372975-5048-1-git-send-email-zhang.zhanghailiang@huawei.com> <1451372975-5048-33-git-send-email-zhang.zhanghailiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1451372975-5048-33-git-send-email-zhang.zhanghailiang@huawei.com> Subject: Re: [Qemu-devel] [PATCH COLO-Frame v13 32/39] COLO: Separate the process of saving/loading ram and device state List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: zhanghailiang Cc: xiecl.fnst@cn.fujitsu.com, 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, zhangchen.fnst@cn.fujitsu.com, hongyang.yang@easystack.cn * zhanghailiang (zhang.zhanghailiang@huawei.com) wrote: > We separate the process of saving/loading ram and device state when do checkpoint, > we add new helpers for save/load ram/device. With this change, we can directly > transfer ram from master to slave without using QEMUSizeBuffer as assistant, > which also reduce the size of extra memory been used during checkpoint. > > Besides, we move the colo_flush_ram_cache to the proper position after the > above change. > > Signed-off-by: zhanghailiang > Signed-off-by: Li Zhijian > --- > v13: > - Re-use some existed helper functions to realize saving/loading ram and device. > v11: > - Remove load configuration section in qemu_loadvm_state_begin() > --- > include/sysemu/sysemu.h | 6 +++++ > migration/colo.c | 47 ++++++++++++++++++++++++++--------- > migration/ram.c | 5 ---- > migration/savevm.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++--- > 4 files changed, 104 insertions(+), 20 deletions(-) > > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h > index 91eeda3..f553f8a 100644 > --- a/include/sysemu/sysemu.h > +++ b/include/sysemu/sysemu.h > @@ -133,7 +133,13 @@ void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name, > uint64_t *start_list, > uint64_t *length_list); > > +void qemu_savevm_live_state(QEMUFile *f); > +int qemu_save_device_state(QEMUFile *f); > + > int qemu_loadvm_state(QEMUFile *f); > +int qemu_loadvm_state_begin(QEMUFile *f); > +int qemu_load_ram_state(QEMUFile *f); > +int qemu_load_device_state(QEMUFile *f); > > typedef enum DisplayType > { > diff --git a/migration/colo.c b/migration/colo.c > index fd87f34..4a99819 100644 > --- a/migration/colo.c > +++ b/migration/colo.c > @@ -290,21 +290,34 @@ static int colo_do_checkpoint_transaction(MigrationState *s, > goto out; > } > > + colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND, &local_err); > + if (local_err) { > + goto out; > + } > + > /* Disable block migration */ > s->params.blk = 0; > s->params.shared = 0; > - qemu_savevm_state_header(trans); > - qemu_savevm_state_begin(trans, &s->params); > - qemu_mutex_lock_iothread(); > - qemu_savevm_state_complete_precopy(trans, false); > - qemu_mutex_unlock_iothread(); > - > - qemu_fflush(trans); > + qemu_savevm_state_begin(s->to_dst_file, &s->params); > + ret = qemu_file_get_error(s->to_dst_file); > + if (ret < 0) { > + error_report("save vm state begin error"); > + goto out; > + } > > - colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND, &local_err); > - if (local_err) { > + qemu_mutex_lock_iothread(); > + /* Only save VM's live state, which not including device state */ > + qemu_savevm_live_state(s->to_dst_file); I'm a little worried that this is done with the lock held; if the destination hung during this point and there was enough data to fill the network buffers, couldn't we hang and then we wouldn't be able to issue the colo_lost_heartbeat command? > + /* Note: device state is saved into buffer */ > + ret = qemu_save_device_state(trans); > + if (ret < 0) { > + error_report("save device state error\n"); > + qemu_mutex_unlock_iothread(); > goto out; > } > + qemu_fflush(trans); > + qemu_mutex_unlock_iothread(); You can save an unlock by doing: ret = ... qemu_mutex_unlock_iothread(); if (ret < 0) { > /* we send the total size of the vmstate first */ > size = qsb_get_length(buffer); > colo_put_cmd_value(s->to_dst_file, COLO_COMMAND_VMSTATE_SIZE, > @@ -573,6 +586,16 @@ void *colo_process_incoming_thread(void *opaque) > goto out; > } > > + ret = qemu_loadvm_state_begin(mis->from_src_file); > + if (ret < 0) { > + error_report("load vm state begin error, ret=%d", ret); > + goto out; > + } > + ret = qemu_load_ram_state(mis->from_src_file); > + if (ret < 0) { > + error_report("load ram state error"); > + goto out; > + } > /* read the VM state total size first */ > value = colo_get_cmd_value(mis->from_src_file, > COLO_COMMAND_VMSTATE_SIZE, &local_err); > @@ -605,8 +628,10 @@ void *colo_process_incoming_thread(void *opaque) > qemu_mutex_lock_iothread(); > qemu_system_reset(VMRESET_SILENT); > vmstate_loading = true; > - if (qemu_loadvm_state(fb) < 0) { > - error_report("COLO: loadvm failed"); > + colo_flush_ram_cache(); > + ret = qemu_load_device_state(fb); > + if (ret < 0) { > + error_report("COLO: load device state failed\n"); Unneeded \n > vmstate_loading = false; > qemu_mutex_unlock_iothread(); > goto out; > diff --git a/migration/ram.c b/migration/ram.c > index 8ff7f7c..45d9332 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -2458,7 +2458,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > * be atomic > */ > bool postcopy_running = postcopy_state_get() >= POSTCOPY_INCOMING_LISTENING; > - bool need_flush = false; > > seq_iter++; > > @@ -2493,7 +2492,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > /* After going into COLO, we should load the Page into colo_cache */ > if (ram_cache_enable) { > host = colo_cache_from_block_offset(block, addr); > - need_flush = true; > } else { > host = host_from_ram_block_offset(block, addr); > } > @@ -2588,9 +2586,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > > rcu_read_unlock(); > > - if (!ret && ram_cache_enable && need_flush) { > - colo_flush_ram_cache(); > - } > DPRINTF("Completed load of VM with exit code %d seq iteration " > "%" PRIu64 "\n", ret, seq_iter); > return ret; > diff --git a/migration/savevm.c b/migration/savevm.c > index 7ceec2d..7892070 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -50,6 +50,7 @@ > #include "qemu/iov.h" > #include "block/snapshot.h" > #include "block/qapi.h" > +#include "migration/colo.h" > > > #ifndef ETH_P_RARP > @@ -923,6 +924,10 @@ void qemu_savevm_state_begin(QEMUFile *f, > break; > } > } > + if (migration_in_colo_state()) { > + qemu_put_byte(f, QEMU_VM_EOF); > + qemu_fflush(f); > + } > } > > /* > @@ -1192,13 +1197,20 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp) > return ret; > } > > -static int qemu_save_device_state(QEMUFile *f) > +void qemu_savevm_live_state(QEMUFile *f) > { > - SaveStateEntry *se; > + /* save QEMU_VM_SECTION_END section */ > + qemu_savevm_state_complete_precopy(f, true); > + qemu_put_byte(f, QEMU_VM_EOF); > +} > > - qemu_put_be32(f, QEMU_VM_FILE_MAGIC); > - qemu_put_be32(f, QEMU_VM_FILE_VERSION); > +int qemu_save_device_state(QEMUFile *f) > +{ > + SaveStateEntry *se; > > + if (!migration_in_colo_state()) { > + qemu_savevm_state_header(f); > + } > cpu_synchronize_all_states(); > > QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { > @@ -1957,6 +1969,52 @@ int qemu_loadvm_state(QEMUFile *f) > return ret; > } > > +int qemu_loadvm_state_begin(QEMUFile *f) > +{ > + MigrationIncomingState *mis = migration_incoming_get_current(); > + Error *local_err = NULL; > + int ret; > + > + if (qemu_savevm_state_blocked(&local_err)) { > + error_report_err(local_err); > + return -EINVAL; > + } > + /* Load QEMU_VM_SECTION_START section */ > + ret = qemu_loadvm_state_main(f, mis); > + if (ret < 0) { > + error_report("Failed to loadvm begin work: %d", ret); > + } > + return ret; > +} > + > +int qemu_load_ram_state(QEMUFile *f) > +{ > + MigrationIncomingState *mis = migration_incoming_get_current(); > + int ret; > + > + ret = qemu_loadvm_state_main(f, mis); > + if (ret < 0) { > + error_report("Failed to load ram state: %d", ret); > + } > + return ret; > +} This function does very little; why not just make qemu_loadvm_state_main non-static and call that directly? Dave > +int qemu_load_device_state(QEMUFile *f) > +{ > + MigrationIncomingState *mis = migration_incoming_get_current(); > + int ret; > + > + /* Load QEMU_VM_SECTION_FULL section */ > + ret = qemu_loadvm_state_main(f, mis); > + if (ret < 0) { > + error_report("Failed to load device state: %d", ret); > + return ret; > + } > + > + cpu_synchronize_all_post_init(); > + return 0; > +} > + > void hmp_savevm(Monitor *mon, const QDict *qdict) > { > BlockDriverState *bs, *bs1; > -- > 1.8.3.1 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK