linux-kernel - Re: [RESEND PATCH] fput: Use unbound workqueue for scheduling delayed fput works

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Message-ID: <20191217153045.GZ4203@ZenIV.linux.org.uk>
Date:   Tue, 17 Dec 2019 15:30:45 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     qiwuchen55@...il.com
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        chenqiwu <chenqiwu@...omi.com>
Subject: Re: [RESEND PATCH] fput: Use unbound workqueue for scheduling
 delayed fput works

On Tue, Dec 17, 2019 at 11:11:12PM +0800, qiwuchen55@...il.com wrote:
> From: chenqiwu <chenqiwu@...omi.com>
> 
> There is a potential starvation that the number of delayed fput works
> increase rapidly if task exit storm or fs unmount issue happens.

Err...  Details, please, ideally along with a reproducer.  In particular,
I would like to understand what does any of that have to do with umount.
Or to task exits, for that matter - exit_files() is called before
exit_task_work(), so you shouldn't normally be seeing task_work_add()
failures when files get closed on exit(2)...

If you are really observing such problems, it might be worth looking
into the underlying situation - something odd appears to be going
on and I'd rather understand what it is.