Hello, On Wed, Jul 17, 2024 at 02:18:39PM -0400, Waiman Long wrote: > Well, it can be confusing whether we are dealing with blkg->iostat or > blkg->iostat_cpu. In many cases, we are dealing with iostat_cpu instead of > iostat like __blkcg_rstat_flush() and blkg_clear_stat(). So we can't > eliminate the use of u64_stats_update_begin_irqsave() in those cases. I mean, we need to distinguish them. For 32bits, blkg->iostat has multiple updaters, so we can't use u64_sync; however, blkg->iostat_cpu has only one updater (except blkg_clear_stat() which I don't think we need to worry too much about), so u64_sync is fine. Thanks. -- tejun
