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| From: | zhanghailiang |
| Subject: | Re: [Qemu-devel] [PATCH COLO-Frame v10 13/38] COLO: Load PVM's dirty pages into SVM's RAM cache temporarily |
| Date: | Mon, 16 Nov 2015 15:57:55 +0800 |
| User-agent: | Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 |
On 2015/11/13 23:39, Dr. David Alan Gilbert wrote:
* zhanghailiang (address@hidden) wrote:We should not load PVM's state directly into SVM, because there maybe some errors happen when SVM is receving data, which will break SVM. We need to ensure receving all data before load the state into SVM. We use an extra memory to cache these data (PVM's ram). The ram cache in secondary side is initially the same as SVM/PVM's memory. And in the process of checkpoint, we cache the dirty pages of PVM into this ram cache firstly, so this ram cache always the same as PVM's memory at every checkpoint, then we flush this cached ram to SVM after we receive all PVM's state. Signed-off-by: zhanghailiang <address@hidden> Signed-off-by: Li Zhijian <address@hidden> Signed-off-by: Gonglei <address@hidden> --- v10: Split the process of dirty pages recording into a new patch --- include/exec/ram_addr.h | 1 + include/migration/colo.h | 3 +++ migration/colo.c | 14 +++++++++-- migration/ram.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++-- 4 files changed, 75 insertions(+), 4 deletions(-) diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index 3360ac5..e7c4310 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -28,6 +28,7 @@ struct RAMBlock { struct rcu_head rcu; struct MemoryRegion *mr; uint8_t *host; + uint8_t *host_cache; /* For colo, VM's ram cache */I suggest you make the name have 'colo' in it; e.g. colo_cache; 'host_cache' is a bit generic.
Hmm, this change makes sense, will update it in next version.
ram_addr_t offset; ram_addr_t used_length; ram_addr_t max_length; diff --git a/include/migration/colo.h b/include/migration/colo.h index 2676c4a..8edd5f1 100644 --- a/include/migration/colo.h +++ b/include/migration/colo.h @@ -29,4 +29,7 @@ bool migration_incoming_enable_colo(void); void migration_incoming_exit_colo(void); void *colo_process_incoming_thread(void *opaque); bool migration_incoming_in_colo_state(void); +/* ram cache */ +int colo_init_ram_cache(void); +void colo_release_ram_cache(void); #endif diff --git a/migration/colo.c b/migration/colo.c index b865513..25f85b2 100644 --- a/migration/colo.c +++ b/migration/colo.c @@ -304,6 +304,12 @@ void *colo_process_incoming_thread(void *opaque) goto out; } + ret = colo_init_ram_cache(); + if (ret < 0) { + error_report("Failed to initialize ram cache"); + goto out; + } + ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY, 0); if (ret < 0) { goto out; @@ -331,14 +337,14 @@ void *colo_process_incoming_thread(void *opaque) goto out; } - /* TODO: read migration data into colo buffer */ + /* TODO Load VM state */ ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED, 0); if (ret < 0) { goto out; } - /* TODO: load vm state */ + /* TODO: flush vm state */Do you really need to update/change the TODOs here?
No, i will drop this ;)
ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED, 0); if (ret < 0) { @@ -352,6 +358,10 @@ out: strerror(-ret)); } + qemu_mutex_lock_iothread(); + colo_release_ram_cache(); + qemu_mutex_unlock_iothread(); + if (mis->to_src_file) { qemu_fclose(mis->to_src_file); } diff --git a/migration/ram.c b/migration/ram.c index 5784c15..b094dc3 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -222,6 +222,7 @@ static RAMBlock *last_sent_block; static ram_addr_t last_offset; static QemuMutex migration_bitmap_mutex; static uint64_t migration_dirty_pages; +static bool ram_cache_enable; static uint32_t last_version; static bool ram_bulk_stage; @@ -1446,7 +1447,11 @@ static inline void *host_from_stream_offset(QEMUFile *f, return NULL; } - return block->host + offset; + if (ram_cache_enable) { + return block->host_cache + offset; + } else { + return block->host + offset; + } } len = qemu_get_byte(f); @@ -1456,7 +1461,11 @@ static inline void *host_from_stream_offset(QEMUFile *f, QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { if (!strncmp(id, block->idstr, sizeof(id)) && block->max_length > offset) { - return block->host + offset; + if (ram_cache_enable) { + return block->host_cache + offset; + } else { + return block->host + offset; + } } } @@ -1707,6 +1716,54 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) return ret; } +/* + * colo cache: this is for secondary VM, we cache the whole + * memory of the secondary VM, it will be called after first migration. + */ +int colo_init_ram_cache(void) +{ + RAMBlock *block; + + rcu_read_lock(); + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { + block->host_cache = qemu_anon_ram_alloc(block->used_length, NULL); + if (!block->host_cache) { + goto out_locked; + }Please print an error message; stating the function, block name and size that failed.
Good idea, will fix in next version, thanks.
+ memcpy(block->host_cache, block->host, block->used_length); + } + rcu_read_unlock(); + ram_cache_enable = true; + return 0; + +out_locked: + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { + if (block->host_cache) { + qemu_anon_ram_free(block->host_cache, block->used_length); + block->host_cache = NULL; + } + } + + rcu_read_unlock(); + return -errno; +} + +void colo_release_ram_cache(void) +{ + RAMBlock *block; + + ram_cache_enable = false; + + rcu_read_lock(); + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { + if (block->host_cache) { + qemu_anon_ram_free(block->host_cache, block->used_length); + block->host_cache = NULL; + } + } + rcu_read_unlock(); +} + static SaveVMHandlers savevm_ram_handlers = { .save_live_setup = ram_save_setup, .save_live_iterate = ram_save_iterate, -- 1.8.3.1-- Dr. David Alan Gilbert / address@hidden / Manchester, UK .
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