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Re: [Qemu-devel] [PATCH 01/31] ram: move more fields into RAMState
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH 01/31] ram: move more fields into RAMState |
Date: |
Thu, 16 Mar 2017 12:09:22 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
* Juan Quintela (address@hidden) wrote:
> last_seen_block, last_sent_block, last_offset, last_version and
> ram_bulk_stage are globals that are really related together.
>
> Signed-off-by: Juan Quintela <address@hidden>
> ---
> migration/ram.c | 136
> ++++++++++++++++++++++++++++++++------------------------
> 1 file changed, 79 insertions(+), 57 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 719425b..c20a539 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -136,6 +136,23 @@ out:
> return ret;
> }
>
> +/* State of RAM for migration */
> +struct RAMState {
> + /* Last block that we have visited searching for dirty pages */
> + RAMBlock *last_seen_block;
> + /* Last block from where we have sent data */
> + RAMBlock *last_sent_block;
> + /* Last offeset we have sent data from */
^
One extra e
Other than that (and the minor formatting things the bot found)
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> + ram_addr_t last_offset;
> + /* last ram version we have seen */
> + uint32_t last_version;
> + /* We are in the first round */
> + bool ram_bulk_stage;
> +};
> +typedef struct RAMState RAMState;
> +
> +static RAMState ram_state;
> +
> /* accounting for migration statistics */
> typedef struct AccountingInfo {
> uint64_t dup_pages;
> @@ -211,16 +228,8 @@ uint64_t xbzrle_mig_pages_overflow(void)
> return acct_info.xbzrle_overflows;
> }
>
> -/* This is the last block that we have visited serching for dirty pages
> - */
> -static RAMBlock *last_seen_block;
> -/* This is the last block from where we have sent data */
> -static RAMBlock *last_sent_block;
> -static ram_addr_t last_offset;
> static QemuMutex migration_bitmap_mutex;
> static uint64_t migration_dirty_pages;
> -static uint32_t last_version;
> -static bool ram_bulk_stage;
>
> /* used by the search for pages to send */
> struct PageSearchStatus {
> @@ -437,9 +446,9 @@ static void mig_throttle_guest_down(void)
> * As a bonus, if the page wasn't in the cache it gets added so that
> * when a small write is made into the 0'd page it gets XBZRLE sent
> */
> -static void xbzrle_cache_zero_page(ram_addr_t current_addr)
> +static void xbzrle_cache_zero_page(RAMState *rs, ram_addr_t current_addr)
> {
> - if (ram_bulk_stage || !migrate_use_xbzrle()) {
> + if (rs->ram_bulk_stage || !migrate_use_xbzrle()) {
> return;
> }
>
> @@ -539,7 +548,7 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t
> **current_data,
> * Returns: byte offset within memory region of the start of a dirty page
> */
> static inline
> -ram_addr_t migration_bitmap_find_dirty(RAMBlock *rb,
> +ram_addr_t migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
> ram_addr_t start,
> ram_addr_t *ram_addr_abs)
> {
> @@ -552,7 +561,7 @@ ram_addr_t migration_bitmap_find_dirty(RAMBlock *rb,
> unsigned long next;
>
> bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> - if (ram_bulk_stage && nr > base) {
> + if (rs->ram_bulk_stage && nr > base) {
> next = nr + 1;
> } else {
> next = find_next_bit(bitmap, size, nr);
> @@ -740,6 +749,7 @@ static void ram_release_pages(MigrationState *ms, const
> char *block_name,
> * >=0 - Number of pages written - this might legally be 0
> * if xbzrle noticed the page was the same.
> *
> + * @rs: The RAM state
> * @ms: The current migration state.
> * @f: QEMUFile where to send the data
> * @block: block that contains the page we want to send
> @@ -747,8 +757,9 @@ static void ram_release_pages(MigrationState *ms, const
> char *block_name,
> * @last_stage: if we are at the completion stage
> * @bytes_transferred: increase it with the number of transferred bytes
> */
> -static int ram_save_page(MigrationState *ms, QEMUFile *f, PageSearchStatus
> *pss,
> - bool last_stage, uint64_t *bytes_transferred)
> +static int ram_save_page(RAMState *rs, MigrationState *ms, QEMUFile *f,
> + PageSearchStatus *pss, bool last_stage,
> + uint64_t *bytes_transferred)
> {
> int pages = -1;
> uint64_t bytes_xmit;
> @@ -774,7 +785,7 @@ static int ram_save_page(MigrationState *ms, QEMUFile *f,
> PageSearchStatus *pss,
>
> current_addr = block->offset + offset;
>
> - if (block == last_sent_block) {
> + if (block == rs->last_sent_block) {
> offset |= RAM_SAVE_FLAG_CONTINUE;
> }
> if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
> @@ -791,9 +802,9 @@ static int ram_save_page(MigrationState *ms, QEMUFile *f,
> PageSearchStatus *pss,
> /* Must let xbzrle know, otherwise a previous (now 0'd) cached
> * page would be stale
> */
> - xbzrle_cache_zero_page(current_addr);
> + xbzrle_cache_zero_page(rs, current_addr);
> ram_release_pages(ms, block->idstr, pss->offset, pages);
> - } else if (!ram_bulk_stage &&
> + } else if (!rs->ram_bulk_stage &&
> !migration_in_postcopy(ms) && migrate_use_xbzrle()) {
> pages = save_xbzrle_page(f, &p, current_addr, block,
> offset, last_stage, bytes_transferred);
> @@ -925,6 +936,7 @@ static int compress_page_with_multi_thread(QEMUFile *f,
> RAMBlock *block,
> *
> * Returns: Number of pages written.
> *
> + * @rs: The RAM state
> * @ms: The current migration state.
> * @f: QEMUFile where to send the data
> * @block: block that contains the page we want to send
> @@ -932,7 +944,8 @@ static int compress_page_with_multi_thread(QEMUFile *f,
> RAMBlock *block,
> * @last_stage: if we are at the completion stage
> * @bytes_transferred: increase it with the number of transferred bytes
> */
> -static int ram_save_compressed_page(MigrationState *ms, QEMUFile *f,
> +static int ram_save_compressed_page(RAMState *rs, MigrationState *ms,
> + QEMUFile *f,
> PageSearchStatus *pss, bool last_stage,
> uint64_t *bytes_transferred)
> {
> @@ -966,7 +979,7 @@ static int ram_save_compressed_page(MigrationState *ms,
> QEMUFile *f,
> * out, keeping this order is important, because the 'cont' flag
> * is used to avoid resending the block name.
> */
> - if (block != last_sent_block) {
> + if (block != rs->last_sent_block) {
> flush_compressed_data(f);
> pages = save_zero_page(f, block, offset, p, bytes_transferred);
> if (pages == -1) {
> @@ -1008,19 +1021,20 @@ static int ram_save_compressed_page(MigrationState
> *ms, QEMUFile *f,
> *
> * Returns: True if a page is found
> *
> + * @rs: The RAM state
> * @f: Current migration stream.
> * @pss: Data about the state of the current dirty page scan.
> * @*again: Set to false if the search has scanned the whole of RAM
> * *ram_addr_abs: Pointer into which to store the address of the dirty page
> * within the global ram_addr space
> */
> -static bool find_dirty_block(QEMUFile *f, PageSearchStatus *pss,
> +static bool find_dirty_block(RAMState *rs, QEMUFile *f, PageSearchStatus
> *pss,
> bool *again, ram_addr_t *ram_addr_abs)
> {
> - pss->offset = migration_bitmap_find_dirty(pss->block, pss->offset,
> + pss->offset = migration_bitmap_find_dirty(rs, pss->block, pss->offset,
> ram_addr_abs);
> - if (pss->complete_round && pss->block == last_seen_block &&
> - pss->offset >= last_offset) {
> + if (pss->complete_round && pss->block == rs->last_seen_block &&
> + pss->offset >= rs->last_offset) {
> /*
> * We've been once around the RAM and haven't found anything.
> * Give up.
> @@ -1037,7 +1051,7 @@ static bool find_dirty_block(QEMUFile *f,
> PageSearchStatus *pss,
> pss->block = QLIST_FIRST_RCU(&ram_list.blocks);
> /* Flag that we've looped */
> pss->complete_round = true;
> - ram_bulk_stage = false;
> + rs->ram_bulk_stage = false;
> if (migrate_use_xbzrle()) {
> /* If xbzrle is on, stop using the data compression at this
> * point. In theory, xbzrle can do better than compression.
> @@ -1097,13 +1111,14 @@ static RAMBlock *unqueue_page(MigrationState *ms,
> ram_addr_t *offset,
> * Unqueue a page from the queue fed by postcopy page requests; skips pages
> * that are already sent (!dirty)
> *
> + * rs: The RAM state
> * ms: MigrationState in
> * pss: PageSearchStatus structure updated with found block/offset
> * ram_addr_abs: global offset in the dirty/sent bitmaps
> *
> * Returns: true if a queued page is found
> */
> -static bool get_queued_page(MigrationState *ms, PageSearchStatus *pss,
> +static bool get_queued_page(RAMState *rs, MigrationState *ms,
> PageSearchStatus *pss,
> ram_addr_t *ram_addr_abs)
> {
> RAMBlock *block;
> @@ -1144,7 +1159,7 @@ static bool get_queued_page(MigrationState *ms,
> PageSearchStatus *pss,
> * in (migration_bitmap_find_and_reset_dirty) that every page is
> * dirty, that's no longer true.
> */
> - ram_bulk_stage = false;
> + rs->ram_bulk_stage = false;
>
> /*
> * We want the background search to continue from the queued page
> @@ -1248,6 +1263,7 @@ err:
> * ram_save_target_page: Save one target page
> *
> *
> + * @rs: The RAM state
> * @f: QEMUFile where to send the data
> * @block: pointer to block that contains the page we want to send
> * @offset: offset inside the block for the page;
> @@ -1257,7 +1273,7 @@ err:
> *
> * Returns: Number of pages written.
> */
> -static int ram_save_target_page(MigrationState *ms, QEMUFile *f,
> +static int ram_save_target_page(RAMState *rs, MigrationState *ms, QEMUFile
> *f,
> PageSearchStatus *pss,
> bool last_stage,
> uint64_t *bytes_transferred,
> @@ -1269,11 +1285,11 @@ static int ram_save_target_page(MigrationState *ms,
> QEMUFile *f,
> if (migration_bitmap_clear_dirty(dirty_ram_abs)) {
> unsigned long *unsentmap;
> if (compression_switch && migrate_use_compression()) {
> - res = ram_save_compressed_page(ms, f, pss,
> + res = ram_save_compressed_page(rs, ms, f, pss,
> last_stage,
> bytes_transferred);
> } else {
> - res = ram_save_page(ms, f, pss, last_stage,
> + res = ram_save_page(rs, ms, f, pss, last_stage,
> bytes_transferred);
> }
>
> @@ -1289,7 +1305,7 @@ static int ram_save_target_page(MigrationState *ms,
> QEMUFile *f,
> * to the stream.
> */
> if (res > 0) {
> - last_sent_block = pss->block;
> + rs->last_sent_block = pss->block;
> }
> }
>
> @@ -1307,6 +1323,7 @@ static int ram_save_target_page(MigrationState *ms,
> QEMUFile *f,
> *
> * Returns: Number of pages written.
> *
> + * @rs: The RAM state
> * @f: QEMUFile where to send the data
> * @block: pointer to block that contains the page we want to send
> * @offset: offset inside the block for the page; updated to last target page
> @@ -1315,7 +1332,7 @@ static int ram_save_target_page(MigrationState *ms,
> QEMUFile *f,
> * @bytes_transferred: increase it with the number of transferred bytes
> * @dirty_ram_abs: Address of the start of the dirty page in ram_addr_t space
> */
> -static int ram_save_host_page(MigrationState *ms, QEMUFile *f,
> +static int ram_save_host_page(RAMState *rs, MigrationState *ms, QEMUFile *f,
> PageSearchStatus *pss,
> bool last_stage,
> uint64_t *bytes_transferred,
> @@ -1325,7 +1342,7 @@ static int ram_save_host_page(MigrationState *ms,
> QEMUFile *f,
> size_t pagesize = qemu_ram_pagesize(pss->block);
>
> do {
> - tmppages = ram_save_target_page(ms, f, pss, last_stage,
> + tmppages = ram_save_target_page(rs, ms, f, pss, last_stage,
> bytes_transferred, dirty_ram_abs);
> if (tmppages < 0) {
> return tmppages;
> @@ -1349,6 +1366,7 @@ static int ram_save_host_page(MigrationState *ms,
> QEMUFile *f,
> * Returns: The number of pages written
> * 0 means no dirty pages
> *
> + * @rs: The RAM state
> * @f: QEMUFile where to send the data
> * @last_stage: if we are at the completion stage
> * @bytes_transferred: increase it with the number of transferred bytes
> @@ -1357,7 +1375,7 @@ static int ram_save_host_page(MigrationState *ms,
> QEMUFile *f,
> * pages in a host page that are dirty.
> */
>
> -static int ram_find_and_save_block(QEMUFile *f, bool last_stage,
> +static int ram_find_and_save_block(RAMState *rs, QEMUFile *f, bool
> last_stage,
> uint64_t *bytes_transferred)
> {
> PageSearchStatus pss;
> @@ -1372,8 +1390,8 @@ static int ram_find_and_save_block(QEMUFile *f, bool
> last_stage,
> return pages;
> }
>
> - pss.block = last_seen_block;
> - pss.offset = last_offset;
> + pss.block = rs->last_seen_block;
> + pss.offset = rs->last_offset;
> pss.complete_round = false;
>
> if (!pss.block) {
> @@ -1382,22 +1400,22 @@ static int ram_find_and_save_block(QEMUFile *f, bool
> last_stage,
>
> do {
> again = true;
> - found = get_queued_page(ms, &pss, &dirty_ram_abs);
> + found = get_queued_page(rs, ms, &pss, &dirty_ram_abs);
>
> if (!found) {
> /* priority queue empty, so just search for something dirty */
> - found = find_dirty_block(f, &pss, &again, &dirty_ram_abs);
> + found = find_dirty_block(rs, f, &pss, &again, &dirty_ram_abs);
> }
>
> if (found) {
> - pages = ram_save_host_page(ms, f, &pss,
> + pages = ram_save_host_page(rs, ms, f, &pss,
> last_stage, bytes_transferred,
> dirty_ram_abs);
> }
> } while (!pages && again);
>
> - last_seen_block = pss.block;
> - last_offset = pss.offset;
> + rs->last_seen_block = pss.block;
> + rs->last_offset = pss.offset;
>
> return pages;
> }
> @@ -1479,13 +1497,13 @@ static void ram_migration_cleanup(void *opaque)
> XBZRLE_cache_unlock();
> }
>
> -static void reset_ram_globals(void)
> +static void ram_state_reset(RAMState *rs)
> {
> - last_seen_block = NULL;
> - last_sent_block = NULL;
> - last_offset = 0;
> - last_version = ram_list.version;
> - ram_bulk_stage = true;
> + rs->last_seen_block = NULL;
> + rs->last_sent_block = NULL;
> + rs->last_offset = 0;
> + rs->last_version = ram_list.version;
> + rs->ram_bulk_stage = true;
> }
>
> #define MAX_WAIT 50 /* ms, half buffered_file limit */
> @@ -1800,9 +1818,9 @@ static int postcopy_chunk_hostpages(MigrationState *ms)
> struct RAMBlock *block;
>
> /* Easiest way to make sure we don't resume in the middle of a host-page
> */
> - last_seen_block = NULL;
> - last_sent_block = NULL;
> - last_offset = 0;
> + ram_state.last_seen_block = NULL;
> + ram_state.last_sent_block = NULL;
> + ram_state.last_offset = 0;
>
> QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
> unsigned long first = block->offset >> TARGET_PAGE_BITS;
> @@ -1913,7 +1931,7 @@ err:
> return ret;
> }
>
> -static int ram_save_init_globals(void)
> +static int ram_save_init_globals(RAMState *rs)
> {
> int64_t ram_bitmap_pages; /* Size of bitmap in pages, including gaps */
>
> @@ -1959,7 +1977,7 @@ static int ram_save_init_globals(void)
> qemu_mutex_lock_ramlist();
> rcu_read_lock();
> bytes_transferred = 0;
> - reset_ram_globals();
> + ram_state_reset(rs);
>
> migration_bitmap_rcu = g_new0(struct BitmapRcu, 1);
> /* Skip setting bitmap if there is no RAM */
> @@ -1997,11 +2015,12 @@ static int ram_save_init_globals(void)
>
> static int ram_save_setup(QEMUFile *f, void *opaque)
> {
> + RAMState *rs = opaque;
> RAMBlock *block;
>
> /* migration has already setup the bitmap, reuse it. */
> if (!migration_in_colo_state()) {
> - if (ram_save_init_globals() < 0) {
> + if (ram_save_init_globals(rs) < 0) {
> return -1;
> }
> }
> @@ -2031,14 +2050,15 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
>
> static int ram_save_iterate(QEMUFile *f, void *opaque)
> {
> + RAMState *rs = opaque;
> int ret;
> int i;
> int64_t t0;
> int done = 0;
>
> rcu_read_lock();
> - if (ram_list.version != last_version) {
> - reset_ram_globals();
> + if (ram_list.version != rs->last_version) {
> + ram_state_reset(rs);
> }
>
> /* Read version before ram_list.blocks */
> @@ -2051,7 +2071,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
> while ((ret = qemu_file_rate_limit(f)) == 0) {
> int pages;
>
> - pages = ram_find_and_save_block(f, false, &bytes_transferred);
> + pages = ram_find_and_save_block(rs, f, false, &bytes_transferred);
> /* no more pages to sent */
> if (pages == 0) {
> done = 1;
> @@ -2096,6 +2116,8 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
> /* Called with iothread lock */
> static int ram_save_complete(QEMUFile *f, void *opaque)
> {
> + RAMState *rs = opaque;
> +
> rcu_read_lock();
>
> if (!migration_in_postcopy(migrate_get_current())) {
> @@ -2110,7 +2132,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
> while (true) {
> int pages;
>
> - pages = ram_find_and_save_block(f, !migration_in_colo_state(),
> + pages = ram_find_and_save_block(rs, f, !migration_in_colo_state(),
> &bytes_transferred);
> /* no more blocks to sent */
> if (pages == 0) {
> @@ -2675,5 +2697,5 @@ static SaveVMHandlers savevm_ram_handlers = {
> void ram_mig_init(void)
> {
> qemu_mutex_init(&XBZRLE.lock);
> - register_savevm_live(NULL, "ram", 0, 4, &savevm_ram_handlers, NULL);
> + register_savevm_live(NULL, "ram", 0, 4, &savevm_ram_handlers,
> &ram_state);
> }
> --
> 2.9.3
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH 06/31] ram: Move num_dirty_pages_period into RAMState, (continued)
- [Qemu-devel] [PATCH 06/31] ram: Move num_dirty_pages_period into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 08/31] ram: Move iterations_prev into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 04/31] ram: Move start time into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 01/31] ram: move more fields into RAMState, Juan Quintela, 2017/03/15
- Re: [Qemu-devel] [PATCH 01/31] ram: move more fields into RAMState,
Dr. David Alan Gilbert <=
- [Qemu-devel] [PATCH 07/31] ram: Move xbzrle_cache_miss_prev into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 10/31] ram: Remove unused dump_mig_dbytes_transferred(), Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 12/31] ram: Move norm_pages to RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 09/31] ram: Move dup_pages into RAMState, Juan Quintela, 2017/03/15