Re: [PATCH] fs/f2fs: add cond_resched() to sync_dirty_dir_inodes()

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 03/03/2015 02:13 AM, Changman Lee wrote:

> Hi Sebastian,
Hi Jaegeuk,

> After this patch, your test is all done without any CPU stall, Right?

correct.

> IMHO, context should be switched without cond_resched() after consumed
> own time quota. So, it just reduces system latency due to yielding.
Correct but without preemption enabled there is no time quota. I still
have the >5sec printk but since the task schedules away I don't have a
"problem" anymore.

> I thought another way to discard pages of inode to be evicted in merged bio
> instead of submit. If so, evict() doesn't need to wait for writeback.
You are lucky that the workqueue code is aware of "that". That means it
will schedule another worker if the current task schedules away because
it waits for something. Otherwise you would stall other worker.

If you could solve it in another way, that would be better than just
polling for it.

> Just my curiousity out of this problem.
> 
> Thanks,

Sebastian

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