From 6f37bb8bf31e98be5cbe536aec881e65ec985526 Mon Sep 17 00:00:00 2001 From: Juan Quintela Date: Mon, 13 Mar 2017 19:26:29 +0100 Subject: [PATCH] ram: Create RAMState We create a struct where to put all the ram state Start with the following fields: 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 Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Peter Xu -- Fix typo and warnings --- migration/ram.c | 140 ++++++++++++++++++++++++++++-------------------- 1 file changed, 83 insertions(+), 57 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 776f8a79df..3eb4430ce5 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -142,6 +142,23 @@ 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 offset we have sent data from */ + 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; @@ -217,16 +234,8 @@ 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 { @@ -444,6 +453,7 @@ static void mig_throttle_guest_down(void) /** * xbzrle_cache_zero_page: insert a zero page in the XBZRLE cache * + * @rs: current RAM state * @current_addr: address for the zero page * * Update the xbzrle cache to reflect a page that's been sent as all 0. @@ -452,9 +462,9 @@ 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; } @@ -552,13 +562,14 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data, * * Returns the byte offset within memory region of the start of a dirty page * + * @rs: current RAM state * @rb: RAMBlock where to search for dirty pages * @start: starting address (typically so we can continue from previous page) * @ram_addr_abs: pointer into which to store the address of the dirty page * within the global ram_addr space */ 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) { @@ -571,7 +582,7 @@ 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); @@ -761,6 +772,7 @@ static void ram_release_pages(MigrationState *ms, const char *rbname, * >=0 - Number of pages written - this might legally be 0 * if xbzrle noticed the page was the same. * + * @rs: current RAM state * @ms: current migration state * @f: QEMUFile where to send the data * @block: block that contains the page we want to send @@ -768,8 +780,9 @@ static void ram_release_pages(MigrationState *ms, const char *rbname, * @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; @@ -795,7 +808,7 @@ 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) { @@ -812,9 +825,9 @@ 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); @@ -946,6 +959,7 @@ static int compress_page_with_multi_thread(QEMUFile *f, RAMBlock *block, * * Returns the number of pages written. * + * @rs: current RAM state * @ms: current migration state * @f: QEMUFile where to send the data * @block: block that contains the page we want to send @@ -953,7 +967,8 @@ 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) { @@ -987,7 +1002,7 @@ 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) { @@ -1029,19 +1044,20 @@ static int ram_save_compressed_page(MigrationState *ms, QEMUFile *f, * * Returns if a page is found * + * @rs: current RAM state * @f: QEMUFile where to send the data * @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. @@ -1058,7 +1074,7 @@ 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. @@ -1125,12 +1141,14 @@ static RAMBlock *unqueue_page(MigrationState *ms, ram_addr_t *offset, * * Returns if a queued page is found * + * @rs: current RAM state * @ms: current migration state * @pss: data about the state of the current dirty page scan * @ram_addr_abs: pointer into which to store the address of the dirty page * within the global ram_addr space */ -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; @@ -1171,7 +1189,7 @@ 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 @@ -1283,6 +1301,7 @@ err: * * Returns the number of pages written * + * @rs: current RAM state * @ms: current migration state * @f: QEMUFile where to send the data * @pss: data about the page we want to send @@ -1290,7 +1309,7 @@ err: * @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_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, @@ -1302,11 +1321,11 @@ 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); } @@ -1322,7 +1341,7 @@ 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; } } @@ -1340,6 +1359,7 @@ static int ram_save_target_page(MigrationState *ms, QEMUFile *f, * * Returns the number of pages written or negative on error * + * @rs: current RAM state * @ms: current migration state * @f: QEMUFile where to send the data * @pss: data about the page we want to send @@ -1347,7 +1367,7 @@ 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, @@ -1357,7 +1377,7 @@ 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; @@ -1380,6 +1400,7 @@ static int ram_save_host_page(MigrationState *ms, QEMUFile *f, * * Returns the number of pages written where zero means no dirty pages * + * @rs: current 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 @@ -1388,7 +1409,7 @@ 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; @@ -1403,8 +1424,8 @@ 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) { @@ -1413,22 +1434,22 @@ 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; } @@ -1510,13 +1531,13 @@ 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 */ @@ -1848,12 +1869,13 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, */ static int postcopy_chunk_hostpages(MigrationState *ms) { + RAMState *rs = &ram_state; 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; + rs->last_seen_block = NULL; + rs->last_sent_block = NULL; + rs->last_offset = 0; QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { unsigned long first = block->offset >> TARGET_PAGE_BITS; @@ -1972,7 +1994,7 @@ 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 */ @@ -2018,7 +2040,7 @@ 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 */ @@ -2065,11 +2087,12 @@ 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; } } @@ -2107,14 +2130,15 @@ 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 */ @@ -2127,7 +2151,7 @@ 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; @@ -2181,6 +2205,8 @@ static int ram_save_iterate(QEMUFile *f, void *opaque) */ static int ram_save_complete(QEMUFile *f, void *opaque) { + RAMState *rs = opaque; + rcu_read_lock(); if (!migration_in_postcopy(migrate_get_current())) { @@ -2195,7 +2221,7 @@ 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) { @@ -2779,5 +2805,5 @@ 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); }