Messages in this thread | | | Subject | Re: [PATCH] blk-iocost: do not WARNING if iocg has already offlined | From | Yu Kuai <> | Date | Thu, 18 Apr 2024 16:52:24 +0800 |
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在 2024/04/18 15:23, linan666@huaweicloud.com 写道: > From: Li Nan <linan122@huawei.com> > > In iocg_pay_debt(), warn is triggered if 'active_list' is empty, which > is intended to confirm iocg is avitve when it has debt. However, warn > can be triggered during removing cgroup controller, as > iocg_waitq_timer_fn() is awakened at that time. > > WARNING: CPU: 0 PID: 2344971 at block/blk-iocost.c:1402 iocg_pay_debt+0x14c/0x190
This line doesn't match the code from mainline, please mention that which kernel release you're testing.
Other than that, ioc_pd_free() indeed clear 'active_list' before canceling the timer, this patch looks good to me.
Reviewed-by: Yu Kuai <yukuai3@huawei.com> > Call trace: > iocg_pay_debt+0x14c/0x190 > iocg_kick_waitq+0x438/0x4c0 > iocg_waitq_timer_fn+0xd8/0x130 > __run_hrtimer+0x144/0x45c > __hrtimer_run_queues+0x16c/0x244 > hrtimer_interrupt+0x2cc/0x7b0 > > The warn in this situation is meaningless. Since this iocg is being > removed, the state of the 'active_list' is irrelevant, and 'waitq_timer' > is canceled after removing 'active_list' in ioc_pd_free(), which ensure > iocg is freed after iocg_waitq_timer_fn() returns. > > Therefore, add the check if iocg has already offlined to avoid warn > when removing cgroup controller. > > Signed-off-by: Li Nan <linan122@huawei.com> > --- > block/blk-iocost.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/block/blk-iocost.c b/block/blk-iocost.c > index baa20c85799d..2e109c016a39 100644 > --- a/block/blk-iocost.c > +++ b/block/blk-iocost.c > @@ -1440,7 +1440,7 @@ static void iocg_pay_debt(struct ioc_gq *iocg, u64 abs_vpay, > lockdep_assert_held(&iocg->waitq.lock); > > /* make sure that nobody messed with @iocg */ > - WARN_ON_ONCE(list_empty(&iocg->active_list)); > + WARN_ON_ONCE(list_empty(&iocg->active_list) && iocg->pd.online); > WARN_ON_ONCE(iocg->inuse > 1); > > iocg->abs_vdebt -= min(abs_vpay, iocg->abs_vdebt); >
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