From: Elena Ufimtseva Date: Wed, 11 Oct 2023 18:43:55 +0000 (-0700) Subject: migration: check for rate_limit_max for RATE_LIMIT_DISABLED X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=60c7981aa3e84eb6d926fd4f7bb4aca4d2edf7cc;p=qemu.git migration: check for rate_limit_max for RATE_LIMIT_DISABLED In migration rate limiting atomic operations are used to read the rate limit variables and transferred bytes and they are expensive. Check first if rate_limit_max is equal to RATE_LIMIT_DISABLED and return false immediately if so. Note that with this patch we will also will stop flushing by not calling qemu_fflush() from migration_transferred_bytes() if the migration rate is not exceeded. This should be fine since migration thread calls in the loop migration_update_counters from migration_rate_limit() that calls the migration_transferred_bytes() and flushes there. Signed-off-by: Elena Ufimtseva Reviewed-by: Fabiano Rosas Reviewed-by: Peter Xu Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela Message-ID: <20231011184358.97349-2-elena.ufimtseva@oracle.com> --- diff --git a/migration/migration-stats.c b/migration/migration-stats.c index 84e11e6dd8..4cc989d975 100644 --- a/migration/migration-stats.c +++ b/migration/migration-stats.c @@ -24,14 +24,15 @@ bool migration_rate_exceeded(QEMUFile *f) return true; } + uint64_t rate_limit_max = migration_rate_get(); + if (rate_limit_max == RATE_LIMIT_DISABLED) { + return false; + } + uint64_t rate_limit_start = stat64_get(&mig_stats.rate_limit_start); uint64_t rate_limit_current = migration_transferred_bytes(f); uint64_t rate_limit_used = rate_limit_current - rate_limit_start; - uint64_t rate_limit_max = stat64_get(&mig_stats.rate_limit_max); - if (rate_limit_max == RATE_LIMIT_DISABLED) { - return false; - } if (rate_limit_max > 0 && rate_limit_used > rate_limit_max) { return true; }