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author | Juan Quintela <quintela@redhat.com> | 2016-01-15 11:40:13 +0100 |
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committer | Juan Quintela <quintela@redhat.com> | 2018-06-27 13:28:11 +0200 |
commit | b9ee2f7d701457f205a3329ea67b33e0b63a0f43 (patch) | |
tree | 914e97b8a3dc09884e24e5c2bc68ba06ded5994a /migration/ram.c | |
parent | a61c45bd227951cd792f22b00d4e502c01ae8d9b (diff) | |
download | qemu-b9ee2f7d701457f205a3329ea67b33e0b63a0f43.zip qemu-b9ee2f7d701457f205a3329ea67b33e0b63a0f43.tar.gz qemu-b9ee2f7d701457f205a3329ea67b33e0b63a0f43.tar.bz2 |
migration: Create ram_save_multifd_page
The function still don't use multifd, but we have simplified
ram_save_page, xbzrle and RDMA stuff is gone. We have added a new
counter.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
--
Add last_page parameter
Add commets for done and address
Remove multifd field, it is the same than normal pages
Merge next patch, now we send multiple pages at a time
Remove counter for multifd pages, it is identical to normal pages
Use iovec's instead of creating the equivalent.
Clear memory used by pages (dave)
Use g_new0(danp)
define MULTIFD_CONTINUE
now pages member is a pointer
Fix off-by-one in number of pages in one packet
Remove RAM_SAVE_FLAG_MULTIFD_PAGE
s/multifd_pages_t/MultiFDPages_t/
add comment explaining what it means
Diffstat (limited to 'migration/ram.c')
-rw-r--r-- | migration/ram.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/migration/ram.c b/migration/ram.c index 77c66a4..050e2f2 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -55,6 +55,7 @@ #include "sysemu/sysemu.h" #include "qemu/uuid.h" #include "savevm.h" +#include "qemu/iov.h" /***********************************************************/ /* ram save/restore */ @@ -811,8 +812,87 @@ struct { QemuSemaphore sem_sync; /* global number of generated multifd packets */ uint64_t packet_num; + /* send channels ready */ + QemuSemaphore channels_ready; } *multifd_send_state; +/* + * How we use multifd_send_state->pages and channel->pages? + * + * We create a pages for each channel, and a main one. Each time that + * we need to send a batch of pages we interchange the ones between + * multifd_send_state and the channel that is sending it. There are + * two reasons for that: + * - to not have to do so many mallocs during migration + * - to make easier to know what to free at the end of migration + * + * This way we always know who is the owner of each "pages" struct, + * and we don't need any loocking. It belongs to the migration thread + * or to the channel thread. Switching is safe because the migration + * thread is using the channel mutex when changing it, and the channel + * have to had finish with its own, otherwise pending_job can't be + * false. + */ + +static void multifd_send_pages(void) +{ + int i; + static int next_channel; + MultiFDSendParams *p = NULL; /* make happy gcc */ + MultiFDPages_t *pages = multifd_send_state->pages; + uint64_t transferred; + + qemu_sem_wait(&multifd_send_state->channels_ready); + for (i = next_channel;; i = (i + 1) % migrate_multifd_channels()) { + p = &multifd_send_state->params[i]; + + qemu_mutex_lock(&p->mutex); + if (!p->pending_job) { + p->pending_job++; + next_channel = (i + 1) % migrate_multifd_channels(); + break; + } + qemu_mutex_unlock(&p->mutex); + } + p->pages->used = 0; + + p->packet_num = multifd_send_state->packet_num++; + p->pages->block = NULL; + multifd_send_state->pages = p->pages; + p->pages = pages; + transferred = pages->used * TARGET_PAGE_SIZE + p->packet_len; + ram_counters.multifd_bytes += transferred; + ram_counters.transferred += transferred;; + qemu_mutex_unlock(&p->mutex); + qemu_sem_post(&p->sem); +} + +static void multifd_queue_page(RAMBlock *block, ram_addr_t offset) +{ + MultiFDPages_t *pages = multifd_send_state->pages; + + if (!pages->block) { + pages->block = block; + } + + if (pages->block == block) { + pages->offset[pages->used] = offset; + pages->iov[pages->used].iov_base = block->host + offset; + pages->iov[pages->used].iov_len = TARGET_PAGE_SIZE; + pages->used++; + + if (pages->used < pages->allocated) { + return; + } + } + + multifd_send_pages(); + + if (pages->block != block) { + multifd_queue_page(block, offset); + } +} + static void multifd_send_terminate_threads(Error *err) { int i; @@ -867,6 +947,7 @@ int multifd_save_cleanup(Error **errp) g_free(p->packet); p->packet = NULL; } + qemu_sem_destroy(&multifd_send_state->channels_ready); qemu_sem_destroy(&multifd_send_state->sem_sync); g_free(multifd_send_state->params); multifd_send_state->params = NULL; @@ -884,12 +965,17 @@ static void multifd_send_sync_main(void) if (!migrate_use_multifd()) { return; } + if (multifd_send_state->pages->used) { + multifd_send_pages(); + } for (i = 0; i < migrate_multifd_channels(); i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; trace_multifd_send_sync_main_signal(p->id); qemu_mutex_lock(&p->mutex); + + p->packet_num = multifd_send_state->packet_num++; p->flags |= MULTIFD_FLAG_SYNC; p->pending_job++; qemu_mutex_unlock(&p->mutex); @@ -944,6 +1030,7 @@ static void *multifd_send_thread(void *opaque) if (flags & MULTIFD_FLAG_SYNC) { qemu_sem_post(&multifd_send_state->sem_sync); } + qemu_sem_post(&multifd_send_state->channels_ready); } else if (p->quit) { qemu_mutex_unlock(&p->mutex); break; @@ -1003,6 +1090,7 @@ int multifd_save_setup(void) atomic_set(&multifd_send_state->count, 0); multifd_send_state->pages = multifd_pages_init(page_count); qemu_sem_init(&multifd_send_state->sem_sync, 0); + qemu_sem_init(&multifd_send_state->channels_ready, 0); for (i = 0; i < thread_count; i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; @@ -1724,6 +1812,23 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage) return pages; } +static int ram_save_multifd_page(RAMState *rs, RAMBlock *block, + ram_addr_t offset) +{ + uint8_t *p; + + p = block->host + offset; + + ram_counters.transferred += save_page_header(rs, rs->f, block, + offset | RAM_SAVE_FLAG_PAGE); + multifd_queue_page(block, offset); + qemu_put_buffer(rs->f, p, TARGET_PAGE_SIZE); + ram_counters.transferred += TARGET_PAGE_SIZE; + ram_counters.normal++; + + return 1; +} + static int do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block, ram_addr_t offset, uint8_t *source_buf) { @@ -2129,6 +2234,8 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss, */ if (block == rs->last_sent_block && save_page_use_compression(rs)) { return compress_page_with_multi_thread(rs, block, offset); + } else if (migrate_use_multifd()) { + return ram_save_multifd_page(rs, block, offset); } return ram_save_page(rs, pss, last_stage); |