Hello, Boy. On Fri, Jul 26, 2024 at 03:43:27AM +0000, Boy Wu (吳勃誼) wrote: ... > The use of a spinlock with u64 sync is suggested in > include/linux/u64_stats_sync.h:33. > > * Usage : > * > * Stats producer (writer) should use following template granted it > already got > * an exclusive access to counters (a lock is already taken, or per cpu > * data is used [in a non preemptable context]) > * > * spin_lock_bh(...) or other synchronization to get exclusive access > * ... > * u64_stats_update_begin(&stats->syncp); > * u64_stats_add(&stats->bytes64, len); // non atomic operation > * u64_stats_inc(&stats->packets64); // non atomic operation > * u64_stats_update_end(&stats->syncp); > > Is this a incorrect statment? That's not incorrect and it'd make sense if we really want to use u64_sync - e.g. the reader is hot path. Here, just a spinlock would be simpler and do fine. Thanks. -- tejun
