diff options
| -rw-r--r-- | migration/ram.c | 112 |
1 files changed, 61 insertions, 51 deletions
diff --git a/migration/ram.c b/migration/ram.c index d81bf7b..3194997 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -85,6 +85,46 @@ XBZRLECacheStats xbzrle_counters; +/* used by the search for pages to send */ +struct PageSearchStatus { + /* The migration channel used for a specific host page */ + QEMUFile *pss_channel; + /* Current block being searched */ + RAMBlock *block; + /* Current page to search from */ + unsigned long page; + /* Set once we wrap around */ + bool complete_round; + /* + * [POSTCOPY-ONLY] Whether current page is explicitly requested by + * postcopy. When set, the request is "urgent" because the dest QEMU + * threads are waiting for us. + */ + bool postcopy_requested; + /* + * [POSTCOPY-ONLY] The target channel to use to send current page. + * + * Note: This may _not_ match with the value in postcopy_requested + * above. Let's imagine the case where the postcopy request is exactly + * the page that we're sending in progress during precopy. In this case + * we'll have postcopy_requested set to true but the target channel + * will be the precopy channel (so that we don't split brain on that + * specific page since the precopy channel already contains partial of + * that page data). + * + * Besides that specific use case, postcopy_target_channel should + * always be equal to postcopy_requested, because by default we send + * postcopy pages via postcopy preempt channel. + */ + bool postcopy_target_channel; + /* Whether we're sending a host page */ + bool host_page_sending; + /* The start/end of current host page. Invalid if host_page_sending==false */ + unsigned long host_page_start; + unsigned long host_page_end; +}; +typedef struct PageSearchStatus PageSearchStatus; + /* struct contains XBZRLE cache and a static page used by the compression */ static struct { @@ -319,6 +359,11 @@ typedef struct { struct RAMState { /* QEMUFile used for this migration */ QEMUFile *f; + /* + * PageSearchStatus structures for the channels when send pages. + * Protected by the bitmap_mutex. + */ + PageSearchStatus pss[RAM_CHANNEL_MAX]; /* UFFD file descriptor, used in 'write-tracking' migration */ int uffdio_fd; /* Last block that we have visited searching for dirty pages */ @@ -362,7 +407,12 @@ struct RAMState { uint64_t target_page_count; /* number of dirty bits in the bitmap */ uint64_t migration_dirty_pages; - /* Protects modification of the bitmap and migration dirty pages */ + /* + * Protects: + * - dirty/clear bitmap + * - migration_dirty_pages + * - pss structures + */ QemuMutex bitmap_mutex; /* The RAMBlock used in the last src_page_requests */ RAMBlock *last_req_rb; @@ -451,46 +501,6 @@ void dirty_sync_missed_zero_copy(void) ram_counters.dirty_sync_missed_zero_copy++; } -/* used by the search for pages to send */ -struct PageSearchStatus { - /* The migration channel used for a specific host page */ - QEMUFile *pss_channel; - /* Current block being searched */ - RAMBlock *block; - /* Current page to search from */ - unsigned long page; - /* Set once we wrap around */ - bool complete_round; - /* - * [POSTCOPY-ONLY] Whether current page is explicitly requested by - * postcopy. When set, the request is "urgent" because the dest QEMU - * threads are waiting for us. - */ - bool postcopy_requested; - /* - * [POSTCOPY-ONLY] The target channel to use to send current page. - * - * Note: This may _not_ match with the value in postcopy_requested - * above. Let's imagine the case where the postcopy request is exactly - * the page that we're sending in progress during precopy. In this case - * we'll have postcopy_requested set to true but the target channel - * will be the precopy channel (so that we don't split brain on that - * specific page since the precopy channel already contains partial of - * that page data). - * - * Besides that specific use case, postcopy_target_channel should - * always be equal to postcopy_requested, because by default we send - * postcopy pages via postcopy preempt channel. - */ - bool postcopy_target_channel; - /* Whether we're sending a host page */ - bool host_page_sending; - /* The start/end of current host page. Only valid if host_page_sending==true */ - unsigned long host_page_start; - unsigned long host_page_end; -}; -typedef struct PageSearchStatus PageSearchStatus; - CompressionStats compression_counters; struct CompressParam { @@ -2637,7 +2647,7 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss) */ static int ram_find_and_save_block(RAMState *rs) { - PageSearchStatus pss; + PageSearchStatus *pss = &rs->pss[RAM_CHANNEL_PRECOPY]; int pages = 0; bool again, found; @@ -2658,11 +2668,11 @@ static int ram_find_and_save_block(RAMState *rs) rs->last_page = 0; } - pss_init(&pss, rs->last_seen_block, rs->last_page); + pss_init(pss, rs->last_seen_block, rs->last_page); do { again = true; - found = get_queued_page(rs, &pss); + found = get_queued_page(rs, pss); if (!found) { /* @@ -2670,27 +2680,27 @@ static int ram_find_and_save_block(RAMState *rs) * preempted precopy. Otherwise find the next dirty bit. */ if (postcopy_preempt_triggered(rs)) { - postcopy_preempt_restore(rs, &pss, false); + postcopy_preempt_restore(rs, pss, false); found = true; } else { /* priority queue empty, so just search for something dirty */ - found = find_dirty_block(rs, &pss, &again); + found = find_dirty_block(rs, pss, &again); } } if (found) { /* Update rs->f with correct channel */ if (postcopy_preempt_active()) { - postcopy_preempt_choose_channel(rs, &pss); + postcopy_preempt_choose_channel(rs, pss); } /* Cache rs->f in pss_channel (TODO: remove rs->f) */ - pss.pss_channel = rs->f; - pages = ram_save_host_page(rs, &pss); + pss->pss_channel = rs->f; + pages = ram_save_host_page(rs, pss); } } while (!pages && again); - rs->last_seen_block = pss.block; - rs->last_page = pss.page; + rs->last_seen_block = pss->block; + rs->last_page = pss->page; return pages; } |