log: Add rate-limiting macros for log messages

Currently, some log messages that would be useful at info or warn level
are kept at debug level because there is no way to throttle them, and a
guest could otherwise flood the host logs.

Add a logmsg_ratelimit() macro that uses per-call-site static variables
to independently track each call site's rate.  It allows up to
LOG_RATELIMIT_BURST (5) messages per LOG_RATELIMIT_INTERVAL (1 second)
window, then prints a suppression notice.  When a new window opens and
messages were suppressed, the count is reported after the next allowed
message.

Link: https://bugs.passt.top/show_bug.cgi?id=134
Signed-off-by: Anshu Kumari <anskuma@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

0 files changed, 0 insertions, 0 deletions