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Re: [Qemu-devel] [PATCH v2 2/4] migration: Introduce ignore-shared capab
|
From: |
Dr. David Alan Gilbert |
|
Subject: |
Re: [Qemu-devel] [PATCH v2 2/4] migration: Introduce ignore-shared capability |
|
Date: |
Mon, 11 Feb 2019 12:45:20 +0000 |
|
User-agent: |
Mutt/1.10.1 (2018-07-13) |
* Yury Kotov (address@hidden) wrote:
> We want to use local migration to update QEMU for running guests.
> In this case we don't need to migrate shared (file backed) RAM.
> So, add a capability to ignore such blocks during live migration.
>
> Also, move qemu_ram_foreach_migratable_block (and rename) to the
> migration code, because it requires access to the migration capabilities.
>
> Signed-off-by: Yury Kotov <address@hidden>
You could split this patch into the one that introduces the capability
and then the one that wires it up. We could also remove the x- at some
point.
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> ---
> exec.c | 19 -------
> include/exec/cpu-common.h | 1 -
> migration/migration.c | 9 ++++
> migration/migration.h | 5 +-
> migration/postcopy-ram.c | 12 ++---
> migration/ram.c | 110 +++++++++++++++++++++++++++++---------
> migration/rdma.c | 2 +-
> qapi/migration.json | 5 +-
> stubs/ram-block.c | 15 ++++++
> 9 files changed, 123 insertions(+), 55 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index a61d501568..91bfe5fb62 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -3984,25 +3984,6 @@ int qemu_ram_foreach_block(RAMBlockIterFunc func, void
> *opaque)
> return ret;
> }
>
> -int qemu_ram_foreach_migratable_block(RAMBlockIterFunc func, void *opaque)
> -{
> - RAMBlock *block;
> - int ret = 0;
> -
> - rcu_read_lock();
> - RAMBLOCK_FOREACH(block) {
> - if (!qemu_ram_is_migratable(block)) {
> - continue;
> - }
> - ret = func(block, opaque);
> - if (ret) {
> - break;
> - }
> - }
> - rcu_read_unlock();
> - return ret;
> -}
> -
> /*
> * Unmap pages of memory from start to start+length such that
> * they a) read as 0, b) Trigger whatever fault mechanism
> diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
> index bdae5446d7..403463d7bb 100644
> --- a/include/exec/cpu-common.h
> +++ b/include/exec/cpu-common.h
> @@ -122,7 +122,6 @@ extern struct MemoryRegion io_mem_notdirty;
> typedef int (RAMBlockIterFunc)(RAMBlock *rb, void *opaque);
>
> int qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque);
> -int qemu_ram_foreach_migratable_block(RAMBlockIterFunc func, void *opaque);
> int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length);
>
> #endif
> diff --git a/migration/migration.c b/migration/migration.c
> index 37e06b76dc..c40776a40c 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1983,6 +1983,15 @@ bool migrate_dirty_bitmaps(void)
> return s->enabled_capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS];
> }
>
> +bool migrate_ignore_shared(void)
> +{
> + MigrationState *s;
> +
> + s = migrate_get_current();
> +
> + return s->enabled_capabilities[MIGRATION_CAPABILITY_X_IGNORE_SHARED];
> +}
> +
> bool migrate_use_events(void)
> {
> MigrationState *s;
> diff --git a/migration/migration.h b/migration/migration.h
> index dcd05d9f87..2c88f8a555 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -261,6 +261,7 @@ bool migrate_release_ram(void);
> bool migrate_postcopy_ram(void);
> bool migrate_zero_blocks(void);
> bool migrate_dirty_bitmaps(void);
> +bool migrate_ignore_shared(void);
>
> bool migrate_auto_converge(void);
> bool migrate_use_multifd(void);
> @@ -301,8 +302,10 @@ void migrate_send_rp_resume_ack(MigrationIncomingState
> *mis, uint32_t value);
> void dirty_bitmap_mig_before_vm_start(void);
> void init_dirty_bitmap_incoming_migration(void);
>
> +int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque);
> +
> #define qemu_ram_foreach_block \
> - #warning "Use qemu_ram_foreach_block_migratable in migration code"
> + #warning "Use foreach_not_ignored_block in migration code"
>
> void migration_make_urgent_request(void);
> void migration_consume_urgent_request(void);
> diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> index b098816221..e2aa57a701 100644
> --- a/migration/postcopy-ram.c
> +++ b/migration/postcopy-ram.c
> @@ -374,7 +374,7 @@ bool
> postcopy_ram_supported_by_host(MigrationIncomingState *mis)
> }
>
> /* We don't support postcopy with shared RAM yet */
> - if (qemu_ram_foreach_migratable_block(test_ramblock_postcopiable, NULL))
> {
> + if (foreach_not_ignored_block(test_ramblock_postcopiable, NULL)) {
> goto out;
> }
>
> @@ -508,7 +508,7 @@ static int cleanup_range(RAMBlock *rb, void *opaque)
> */
> int postcopy_ram_incoming_init(MigrationIncomingState *mis)
> {
> - if (qemu_ram_foreach_migratable_block(init_range, NULL)) {
> + if (foreach_not_ignored_block(init_range, NULL)) {
> return -1;
> }
>
> @@ -550,7 +550,7 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState
> *mis)
> return -1;
> }
>
> - if (qemu_ram_foreach_migratable_block(cleanup_range, mis)) {
> + if (foreach_not_ignored_block(cleanup_range, mis)) {
> return -1;
> }
>
> @@ -617,7 +617,7 @@ static int nhp_range(RAMBlock *rb, void *opaque)
> */
> int postcopy_ram_prepare_discard(MigrationIncomingState *mis)
> {
> - if (qemu_ram_foreach_migratable_block(nhp_range, mis)) {
> + if (foreach_not_ignored_block(nhp_range, mis)) {
> return -1;
> }
>
> @@ -628,7 +628,7 @@ int postcopy_ram_prepare_discard(MigrationIncomingState
> *mis)
>
> /*
> * Mark the given area of RAM as requiring notification to unwritten areas
> - * Used as a callback on qemu_ram_foreach_migratable_block.
> + * Used as a callback on foreach_not_ignored_block.
> * host_addr: Base of area to mark
> * offset: Offset in the whole ram arena
> * length: Length of the section
> @@ -1122,7 +1122,7 @@ int postcopy_ram_enable_notify(MigrationIncomingState
> *mis)
> mis->have_fault_thread = true;
>
> /* Mark so that we get notified of accesses to unwritten areas */
> - if (qemu_ram_foreach_migratable_block(ram_block_enable_notify, mis)) {
> + if (foreach_not_ignored_block(ram_block_enable_notify, mis)) {
> error_report("ram_block_enable_notify failed");
> return -1;
> }
> diff --git a/migration/ram.c b/migration/ram.c
> index 59191c1ed2..01315edd66 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -159,18 +159,44 @@ out:
> return ret;
> }
>
> +static bool ramblock_is_ignored(RAMBlock *block)
> +{
> + return !qemu_ram_is_migratable(block) ||
> + (migrate_ignore_shared() && qemu_ram_is_shared(block));
> +}
> +
> /* Should be holding either ram_list.mutex, or the RCU lock. */
> +#define RAMBLOCK_FOREACH_NOT_IGNORED(block) \
> + INTERNAL_RAMBLOCK_FOREACH(block) \
> + if (ramblock_is_ignored(block)) {} else
> +
> #define RAMBLOCK_FOREACH_MIGRATABLE(block) \
> INTERNAL_RAMBLOCK_FOREACH(block) \
> if (!qemu_ram_is_migratable(block)) {} else
>
> #undef RAMBLOCK_FOREACH
>
> +int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque)
> +{
> + RAMBlock *block;
> + int ret = 0;
> +
> + rcu_read_lock();
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> + ret = func(block, opaque);
> + if (ret) {
> + break;
> + }
> + }
> + rcu_read_unlock();
> + return ret;
> +}
> +
> static void ramblock_recv_map_init(void)
> {
> RAMBlock *rb;
>
> - RAMBLOCK_FOREACH_MIGRATABLE(rb) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(rb) {
> assert(!rb->receivedmap);
> rb->receivedmap = bitmap_new(rb->max_length >>
> qemu_target_page_bits());
> }
> @@ -1545,7 +1571,7 @@ unsigned long migration_bitmap_find_dirty(RAMState *rs,
> RAMBlock *rb,
> unsigned long *bitmap = rb->bmap;
> unsigned long next;
>
> - if (!qemu_ram_is_migratable(rb)) {
> + if (ramblock_is_ignored(rb)) {
> return size;
> }
>
> @@ -1594,7 +1620,7 @@ uint64_t ram_pagesize_summary(void)
> RAMBlock *block;
> uint64_t summary = 0;
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> summary |= block->page_size;
> }
>
> @@ -1664,7 +1690,7 @@ static void migration_bitmap_sync(RAMState *rs)
>
> qemu_mutex_lock(&rs->bitmap_mutex);
> rcu_read_lock();
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> migration_bitmap_sync_range(rs, block, 0, block->used_length);
> }
> ram_counters.remaining = ram_bytes_remaining();
> @@ -2388,7 +2414,7 @@ static int ram_save_host_page(RAMState *rs,
> PageSearchStatus *pss,
> size_t pagesize_bits =
> qemu_ram_pagesize(pss->block) >> TARGET_PAGE_BITS;
>
> - if (!qemu_ram_is_migratable(pss->block)) {
> + if (ramblock_is_ignored(pss->block)) {
> error_report("block %s should not be migrated !", pss->block->idstr);
> return 0;
> }
> @@ -2486,19 +2512,30 @@ void acct_update_position(QEMUFile *f, size_t size,
> bool zero)
> }
> }
>
> -uint64_t ram_bytes_total(void)
> +static uint64_t ram_bytes_total_common(bool count_ignored)
> {
> RAMBlock *block;
> uint64_t total = 0;
>
> rcu_read_lock();
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> - total += block->used_length;
> + if (count_ignored) {
> + RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + total += block->used_length;
> + }
> + } else {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> + total += block->used_length;
> + }
> }
> rcu_read_unlock();
> return total;
> }
>
> +uint64_t ram_bytes_total(void)
> +{
> + return ram_bytes_total_common(false);
> +}
> +
> static void xbzrle_load_setup(void)
> {
> XBZRLE.decoded_buf = g_malloc(TARGET_PAGE_SIZE);
> @@ -2547,7 +2584,7 @@ static void ram_save_cleanup(void *opaque)
> */
> memory_global_dirty_log_stop();
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> g_free(block->bmap);
> block->bmap = NULL;
> g_free(block->unsentmap);
> @@ -2610,7 +2647,7 @@ void
> ram_postcopy_migrated_memory_release(MigrationState *ms)
> {
> struct RAMBlock *block;
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> unsigned long *bitmap = block->bmap;
> unsigned long range = block->used_length >> TARGET_PAGE_BITS;
> unsigned long run_start = find_next_zero_bit(bitmap, range, 0);
> @@ -2688,7 +2725,7 @@ static int
> postcopy_each_ram_send_discard(MigrationState *ms)
> struct RAMBlock *block;
> int ret;
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> PostcopyDiscardState *pds =
> postcopy_discard_send_init(ms, block->idstr);
>
> @@ -2896,7 +2933,7 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms)
> rs->last_sent_block = NULL;
> rs->last_page = 0;
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> unsigned long pages = block->used_length >> TARGET_PAGE_BITS;
> unsigned long *bitmap = block->bmap;
> unsigned long *unsentmap = block->unsentmap;
> @@ -3062,7 +3099,7 @@ static void ram_list_init_bitmaps(void)
>
> /* Skip setting bitmap if there is no RAM */
> if (ram_bytes_total()) {
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> pages = block->max_length >> TARGET_PAGE_BITS;
> block->bmap = bitmap_new(pages);
> bitmap_set(block->bmap, 0, pages);
> @@ -3117,7 +3154,7 @@ static void ram_state_resume_prepare(RAMState *rs,
> QEMUFile *out)
> * about dirty page logging as well.
> */
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> pages += bitmap_count_one(block->bmap,
> block->used_length >> TARGET_PAGE_BITS);
> }
> @@ -3176,7 +3213,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
>
> rcu_read_lock();
>
> - qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
> + qemu_put_be64(f, ram_bytes_total_common(true) | RAM_SAVE_FLAG_MEM_SIZE);
>
> RAMBLOCK_FOREACH_MIGRATABLE(block) {
> qemu_put_byte(f, strlen(block->idstr));
> @@ -3185,6 +3222,10 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
> if (migrate_postcopy_ram() && block->page_size !=
> qemu_host_page_size) {
> qemu_put_be64(f, block->page_size);
> }
> + if (migrate_ignore_shared()) {
> + qemu_put_be64(f, block->mr->addr);
> + qemu_put_byte(f, ramblock_is_ignored(block) ? 1 : 0);
> + }
> }
>
> rcu_read_unlock();
> @@ -3443,7 +3484,7 @@ static inline RAMBlock *ram_block_from_stream(QEMUFile
> *f, int flags)
> return NULL;
> }
>
> - if (!qemu_ram_is_migratable(block)) {
> + if (ramblock_is_ignored(block)) {
> error_report("block %s should not be migrated !", id);
> return NULL;
> }
> @@ -3698,7 +3739,7 @@ int colo_init_ram_cache(void)
> RAMBlock *block;
>
> rcu_read_lock();
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> block->colo_cache = qemu_anon_ram_alloc(block->used_length,
> NULL,
> false);
> @@ -3719,7 +3760,7 @@ int colo_init_ram_cache(void)
> if (ram_bytes_total()) {
> RAMBlock *block;
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> unsigned long pages = block->max_length >> TARGET_PAGE_BITS;
>
> block->bmap = bitmap_new(pages);
> @@ -3734,7 +3775,7 @@ int colo_init_ram_cache(void)
>
> out_locked:
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> if (block->colo_cache) {
> qemu_anon_ram_free(block->colo_cache, block->used_length);
> block->colo_cache = NULL;
> @@ -3751,14 +3792,14 @@ void colo_release_ram_cache(void)
> RAMBlock *block;
>
> memory_global_dirty_log_stop();
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> g_free(block->bmap);
> block->bmap = NULL;
> }
>
> rcu_read_lock();
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> if (block->colo_cache) {
> qemu_anon_ram_free(block->colo_cache, block->used_length);
> block->colo_cache = NULL;
> @@ -3794,7 +3835,7 @@ static int ram_load_cleanup(void *opaque)
> {
> RAMBlock *rb;
>
> - RAMBLOCK_FOREACH_MIGRATABLE(rb) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(rb) {
> if (ramblock_is_pmem(rb)) {
> pmem_persist(rb->host, rb->used_length);
> }
> @@ -3803,7 +3844,7 @@ static int ram_load_cleanup(void *opaque)
> xbzrle_load_cleanup();
> compress_threads_load_cleanup();
>
> - RAMBLOCK_FOREACH_MIGRATABLE(rb) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(rb) {
> g_free(rb->receivedmap);
> rb->receivedmap = NULL;
> }
> @@ -4003,7 +4044,7 @@ static void colo_flush_ram_cache(void)
>
> memory_global_dirty_log_sync();
> rcu_read_lock();
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> migration_bitmap_sync_range(ram_state, block, 0, block->used_length);
> }
> rcu_read_unlock();
> @@ -4146,6 +4187,23 @@ static int ram_load(QEMUFile *f, void *opaque, int
> version_id)
> ret = -EINVAL;
> }
> }
> + if (migrate_ignore_shared()) {
> + hwaddr addr = qemu_get_be64(f);
> + bool ignored = qemu_get_byte(f);
> + if (ignored != ramblock_is_ignored(block)) {
> + error_report("RAM block %s should %s be
> migrated",
> + id, ignored ? "" : "not");
> + ret = -EINVAL;
> + }
> + if (ramblock_is_ignored(block) &&
> + block->mr->addr != addr) {
> + error_report("Mismatched GPAs for block %s "
> + "%" PRId64 "!= %" PRId64,
> + id, (uint64_t)addr,
> + (uint64_t)block->mr->addr);
> + ret = -EINVAL;
> + }
> + }
> ram_control_load_hook(f, RAM_CONTROL_BLOCK_REG,
> block->idstr);
> } else {
> @@ -4216,7 +4274,7 @@ static int ram_load(QEMUFile *f, void *opaque, int
> version_id)
> static bool ram_has_postcopy(void *opaque)
> {
> RAMBlock *rb;
> - RAMBLOCK_FOREACH_MIGRATABLE(rb) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(rb) {
> if (ramblock_is_pmem(rb)) {
> info_report("Block: %s, host: %p is a nvdimm memory, postcopy"
> "is not supported now!", rb->idstr, rb->host);
> @@ -4236,7 +4294,7 @@ static int ram_dirty_bitmap_sync_all(MigrationState *s,
> RAMState *rs)
>
> trace_ram_dirty_bitmap_sync_start();
>
> - RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> qemu_savevm_send_recv_bitmap(file, block->idstr);
> trace_ram_dirty_bitmap_request(block->idstr);
> ramblock_count++;
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 7eb38ee764..3cb579cc99 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -644,7 +644,7 @@ static int qemu_rdma_init_ram_blocks(RDMAContext *rdma)
>
> assert(rdma->blockmap == NULL);
> memset(local, 0, sizeof *local);
> - qemu_ram_foreach_migratable_block(qemu_rdma_init_one_block, rdma);
> + foreach_not_ignored_block(qemu_rdma_init_one_block, rdma);
> trace_qemu_rdma_init_ram_blocks(local->nb_blocks);
> rdma->dest_blocks = g_new0(RDMADestBlock,
> rdma->local_ram_blocks.nb_blocks);
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 7a795ecc16..7105570cd3 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -409,13 +409,16 @@
> # devices (and thus take locks) immediately at the end of
> migration.
> # (since 3.0)
> #
> +# @x-ignore-shared: If enabled, QEMU will not migrate shared memory (since
> 4.0)
> +#
> # Since: 1.2
> ##
> { 'enum': 'MigrationCapability',
> 'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
> 'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram',
> 'block', 'return-path', 'pause-before-switchover', 'x-multifd',
> - 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate' ] }
> + 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate',
> + 'x-ignore-shared' ] }
>
> ##
> # @MigrationCapabilityStatus:
> diff --git a/stubs/ram-block.c b/stubs/ram-block.c
> index cfa5d8678f..73c0a3ee08 100644
> --- a/stubs/ram-block.c
> +++ b/stubs/ram-block.c
> @@ -2,6 +2,21 @@
> #include "exec/ramlist.h"
> #include "exec/cpu-common.h"
>
> +void *qemu_ram_get_host_addr(RAMBlock *rb)
> +{
> + return 0;
> +}
> +
> +ram_addr_t qemu_ram_get_offset(RAMBlock *rb)
> +{
> + return 0;
> +}
> +
> +ram_addr_t qemu_ram_get_used_length(RAMBlock *rb)
> +{
> + return 0;
> +}
> +
> void ram_block_notifier_add(RAMBlockNotifier *n)
> {
> }
> --
> 2.20.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK