[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH V10 07/20] COLO: Load dirty pages into SVM's RAM
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH V10 07/20] COLO: Load dirty pages into SVM's RAM cache firstly |
Date: |
Tue, 7 Aug 2018 18:58:54 +0100 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
* Zhang Chen (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: Zhang Chen <address@hidden>
As mentioned before you do need to update this to skip non-migratable
blocks; there are also two blank-lines inserted in this patch which
should just go in the appropriate patch.
However, with those minor things fixed:
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> ---
> include/exec/ram_addr.h | 1 +
> migration/migration.c | 6 +++
> migration/ram.c | 83 ++++++++++++++++++++++++++++++++++++++++-
> migration/ram.h | 4 ++
> migration/savevm.c | 2 +-
> 5 files changed, 93 insertions(+), 3 deletions(-)
>
> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> index cf4ce06248..a78c1c99a7 100644
> --- a/include/exec/ram_addr.h
> +++ b/include/exec/ram_addr.h
> @@ -27,6 +27,7 @@ struct RAMBlock {
> struct rcu_head rcu;
> struct MemoryRegion *mr;
> uint8_t *host;
> + uint8_t *colo_cache; /* For colo, VM's ram cache */
> ram_addr_t offset;
> ram_addr_t used_length;
> ram_addr_t max_length;
> diff --git a/migration/migration.c b/migration/migration.c
> index c645f66f4e..d9683e06d3 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -441,6 +441,10 @@ static void process_incoming_migration_co(void *opaque)
> error_report_err(local_err);
> exit(EXIT_FAILURE);
> }
> + if (colo_init_ram_cache() < 0) {
> + error_report("Init ram cache failed");
> + exit(EXIT_FAILURE);
> + }
> mis->migration_incoming_co = qemu_coroutine_self();
> qemu_thread_create(&mis->colo_incoming_thread, "COLO incoming",
> colo_process_incoming_thread, mis, QEMU_THREAD_JOINABLE);
> @@ -449,6 +453,8 @@ static void process_incoming_migration_co(void *opaque)
>
> /* Wait checkpoint incoming thread exit before free resource */
> qemu_thread_join(&mis->colo_incoming_thread);
> + /* We hold the global iothread lock, so it is safe here */
> + colo_release_ram_cache();
> }
>
> if (ret < 0) {
> diff --git a/migration/ram.c b/migration/ram.c
> index 52dd678092..33ebd09d70 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -3314,6 +3314,20 @@ static inline void
> *host_from_ram_block_offset(RAMBlock *block,
> return block->host + offset;
> }
>
> +static inline void *colo_cache_from_block_offset(RAMBlock *block,
> + ram_addr_t offset)
> +{
> + if (!offset_in_ramblock(block, offset)) {
> + return NULL;
> + }
> + if (!block->colo_cache) {
> + error_report("%s: colo_cache is NULL in block :%s",
> + __func__, block->idstr);
> + return NULL;
> + }
> + return block->colo_cache + offset;
> +}
> +
> /**
> * ram_handle_compressed: handle the zero page case
> *
> @@ -3518,6 +3532,58 @@ static void
> decompress_data_with_multi_threads(QEMUFile *f,
> qemu_mutex_unlock(&decomp_done_lock);
> }
>
> +/*
> + * colo cache: this is for secondary VM, we cache the whole
> + * memory of the secondary VM, it is need to hold the global lock
> + * to call this helper.
> + */
> +int colo_init_ram_cache(void)
> +{
> + RAMBlock *block;
> +
> + rcu_read_lock();
> + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
> + block->colo_cache = qemu_anon_ram_alloc(block->used_length,
> + NULL,
> + false);
> + if (!block->colo_cache) {
> + error_report("%s: Can't alloc memory for COLO cache of block %s,"
> + "size 0x" RAM_ADDR_FMT, __func__, block->idstr,
> + block->used_length);
> + goto out_locked;
> + }
> + memcpy(block->colo_cache, block->host, block->used_length);
> + }
> + rcu_read_unlock();
> + return 0;
> +
> +out_locked:
> + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
> + if (block->colo_cache) {
> + qemu_anon_ram_free(block->colo_cache, block->used_length);
> + block->colo_cache = NULL;
> + }
> + }
> +
> + rcu_read_unlock();
> + return -errno;
> +}
> +
> +/* It is need to hold the global lock to call this helper */
> +void colo_release_ram_cache(void)
> +{
> + RAMBlock *block;
> +
> + rcu_read_lock();
> + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
> + if (block->colo_cache) {
> + qemu_anon_ram_free(block->colo_cache, block->used_length);
> + block->colo_cache = NULL;
> + }
> + }
> + rcu_read_unlock();
> +}
> +
> /**
> * ram_load_setup: Setup RAM for migration incoming side
> *
> @@ -3534,6 +3600,7 @@ static int ram_load_setup(QEMUFile *f, void *opaque)
>
> xbzrle_load_setup();
> ramblock_recv_map_init();
> +
> return 0;
> }
>
> @@ -3547,6 +3614,7 @@ static int ram_load_cleanup(void *opaque)
> g_free(rb->receivedmap);
> rb->receivedmap = NULL;
> }
> +
> return 0;
> }
>
> @@ -3784,13 +3852,24 @@ static int ram_load(QEMUFile *f, void *opaque, int
> version_id)
> RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) {
> RAMBlock *block = ram_block_from_stream(f, flags);
>
> - host = host_from_ram_block_offset(block, addr);
> + /*
> + * After going into COLO, we should load the Page into
> colo_cache.
> + */
> + if (migration_incoming_in_colo_state()) {
> + host = colo_cache_from_block_offset(block, addr);
> + } else {
> + host = host_from_ram_block_offset(block, addr);
> + }
> if (!host) {
> error_report("Illegal RAM offset " RAM_ADDR_FMT, addr);
> ret = -EINVAL;
> break;
> }
> - ramblock_recv_bitmap_set(block, host);
> +
> + if (!migration_incoming_in_colo_state()) {
> + ramblock_recv_bitmap_set(block, host);
> + }
> +
> trace_ram_load_loop(block->idstr, (uint64_t)addr, flags, host);
> }
>
> diff --git a/migration/ram.h b/migration/ram.h
> index 457bf54b8c..d009480494 100644
> --- a/migration/ram.h
> +++ b/migration/ram.h
> @@ -70,4 +70,8 @@ int64_t ramblock_recv_bitmap_send(QEMUFile *file,
> const char *block_name);
> int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *rb);
>
> +/* ram cache */
> +int colo_init_ram_cache(void);
> +void colo_release_ram_cache(void);
> +
> #endif
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 437308877a..33e9e7cda0 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1929,7 +1929,7 @@ static int
> loadvm_handle_recv_bitmap(MigrationIncomingState *mis,
> static int loadvm_process_enable_colo(MigrationIncomingState *mis)
> {
> migration_incoming_enable_colo();
> - return 0;
> + return colo_init_ram_cache();
> }
>
> /*
> --
> 2.17.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- Re: [Qemu-devel] [PATCH V10 07/20] COLO: Load dirty pages into SVM's RAM cache firstly,
Dr. David Alan Gilbert <=