On 3/5/21 1:13 AM, Xunlei Pang wrote: > The current blkio.throttle.io_service_bytes_recursive doesn't > work correctly. > > As an example, for the following blkcg hierarchy: > (Made 1GB READ in test1, 512MB READ in test2) > test > / \ > test1 test2 > > $ head -n 1 test/test1/blkio.throttle.io_service_bytes_recursive > 8:0 Read 1073684480 > $ head -n 1 test/test2/blkio.throttle.io_service_bytes_recursive > 8:0 Read 537448448 > $ head -n 1 test/blkio.throttle.io_service_bytes_recursive > 8:0 Read 537448448 > > Clearly, above data of "test" reflects "test2" not "test1"+"test2". > > Do the correct summary in blkg_rwstat_recursive_sum().
LGTM, Tejun? > > Signed-off-by: Xunlei Pang <[email protected]> > --- > block/blk-cgroup-rwstat.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/block/blk-cgroup-rwstat.c b/block/blk-cgroup-rwstat.c > index 85d5790..3304e84 100644 > --- a/block/blk-cgroup-rwstat.c > +++ b/block/blk-cgroup-rwstat.c > @@ -109,6 +109,7 @@ void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, > struct blkcg_policy *pol, > > lockdep_assert_held(&blkg->q->queue_lock); > > + memset(sum, 0, sizeof(*sum)); > rcu_read_lock(); > blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) { > struct blkg_rwstat *rwstat; > @@ -122,7 +123,7 @@ void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, > struct blkcg_policy *pol, > rwstat = (void *)pos_blkg + off; > > for (i = 0; i < BLKG_RWSTAT_NR; i++) > - sum->cnt[i] = blkg_rwstat_read_counter(rwstat, i); > + sum->cnt[i] += blkg_rwstat_read_counter(rwstat, i); > } > rcu_read_unlock(); > } > -- Jens Axboe
