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author | Juan Quintela <quintela@redhat.com> | 2012-05-22 16:27:59 +0200 |
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committer | Juan Quintela <quintela@redhat.com> | 2012-06-29 13:31:04 +0200 |
commit | 4508bd9ed8053cef0a1a849bf2f1896a5dd86580 (patch) | |
tree | 68ae1cf5495a0c97dbfdad293b7e80e79c7e99ab /arch_init.c | |
parent | 5b3c96388741a99988497d734edec19c4f995cd7 (diff) | |
download | hqemu-4508bd9ed8053cef0a1a849bf2f1896a5dd86580.zip hqemu-4508bd9ed8053cef0a1a849bf2f1896a5dd86580.tar.gz |
Exit loop if we have been there too long
Checking each 64 pages is a random magic number as good as any other.
We don't want to test too many times, but on the other hand,
qemu_get_clock_ns() is not so expensive either. We want to be sure
that we spent less than 50ms (half of buffered_file timer), if we
spent more than 100ms, all the accounting got wrong.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'arch_init.c')
-rw-r--r-- | arch_init.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch_init.c b/arch_init.c index 3633f4c..64b85fd 100644 --- a/arch_init.c +++ b/arch_init.c @@ -309,12 +309,15 @@ static void migration_end(void) memory_global_dirty_log_stop(); } +#define MAX_WAIT 50 /* ms, half buffered_file limit */ + int ram_save_live(QEMUFile *f, int stage, void *opaque) { ram_addr_t addr; uint64_t bytes_transferred_last; double bwidth = 0; int ret; + int i; if (stage < 0) { migration_end(); @@ -354,6 +357,7 @@ int ram_save_live(QEMUFile *f, int stage, void *opaque) bytes_transferred_last = bytes_transferred; bwidth = qemu_get_clock_ns(rt_clock); + i = 0; while ((ret = qemu_file_rate_limit(f)) == 0) { int bytes_sent; @@ -362,6 +366,20 @@ int ram_save_live(QEMUFile *f, int stage, void *opaque) if (bytes_sent == 0) { /* no more blocks */ break; } + /* we want to check in the 1st loop, just in case it was the 1st time + and we had to sync the dirty bitmap. + qemu_get_clock_ns() is a bit expensive, so we only check each some + iterations + */ + if ((i & 63) == 0) { + uint64_t t1 = (qemu_get_clock_ns(rt_clock) - bwidth) / 1000000; + if (t1 > MAX_WAIT) { + DPRINTF("big wait: " PRIu64 " milliseconds, %d iterations\n", + t1, i); + break; + } + } + i++; } if (ret < 0) { |