From 4f2e425267327719ee71ba6f191f7d66507a6c02 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Thu, 5 Nov 2015 18:10:38 +0000 Subject: [PATCH] ram_debug_dump_bitmap: Dump a migration bitmap as text Useful for debugging the migration bitmap and other bitmaps of the same format (including the sentmap in postcopy). The bitmap is printed to stderr. Lines that are all the expected value are excluded so the output can be quite compact for many bitmaps. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Amit Shah Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- include/migration/migration.h | 1 + migration/ram.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+) diff --git a/include/migration/migration.h b/include/migration/migration.h index 83fba23511..51bc348fc2 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -145,6 +145,7 @@ uint64_t xbzrle_mig_pages_cache_miss(void); double xbzrle_mig_cache_miss_rate(void); void ram_handle_compressed(void *host, uint8_t ch, uint64_t size); +void ram_debug_dump_bitmap(unsigned long *todump, bool expected); /** * @migrate_add_blocker - prevent migration from proceeding diff --git a/migration/ram.c b/migration/ram.c index d654a73808..86bf6574e3 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1160,6 +1160,45 @@ void migration_bitmap_extend(ram_addr_t old, ram_addr_t new) } } +/* + * 'expected' is the value you expect the bitmap mostly to be full + * of; it won't bother printing lines that are all this value. + * If 'todump' is null the migration bitmap is dumped. + */ +void ram_debug_dump_bitmap(unsigned long *todump, bool expected) +{ + int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS; + + int64_t cur; + int64_t linelen = 128; + char linebuf[129]; + + if (!todump) { + todump = atomic_rcu_read(&migration_bitmap_rcu)->bmap; + } + + for (cur = 0; cur < ram_pages; cur += linelen) { + int64_t curb; + bool found = false; + /* + * Last line; catch the case where the line length + * is longer than remaining ram + */ + if (cur + linelen > ram_pages) { + linelen = ram_pages - cur; + } + for (curb = 0; curb < linelen; curb++) { + bool thisbit = test_bit(cur + curb, todump); + linebuf[curb] = thisbit ? '1' : '.'; + found = found || (thisbit != expected); + } + if (found) { + linebuf[curb] = '\0'; + fprintf(stderr, "0x%08" PRIx64 " : %s\n", cur, linebuf); + } + } +} + /* Each of ram_save_setup, ram_save_iterate and ram_save_complete has * long-running RCU critical section. When rcu-reclaims in the code * start to become numerous it will be necessary to reduce the -- 2.11.0