From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Tejun Heo <tj@kernel.org>
Cc: Radu Rendec <radu.rendec@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] Improve kernfs_notify() poll notification latency
Date: Tue, 20 Nov 2018 17:58:42 +0100 [thread overview]
Message-ID: <20181120165842.GB28793@kroah.com> (raw)
In-Reply-To: <20181120161419.GS2509588@devbig004.ftw2.facebook.com>
On Tue, Nov 20, 2018 at 08:14:19AM -0800, Tejun Heo wrote:
> On Thu, Nov 15, 2018 at 09:09:54PM -0500, Radu Rendec wrote:
> > kernfs_notify() does two notifications: poll and fsnotify. Originally,
> > both notifications were done from scheduled work context and all that
> > kernfs_notify() did was schedule the work.
> >
> > This patch simply moves the poll notification from the scheduled work
> > handler to kernfs_notify(). The fsnotify notification still needs to be
> > done from scheduled work context because it can sleep (it needs to lock
> > a mutex).
> >
> > If the poll notification is time critical (the notified thread needs to
> > wake as quickly as possible), it's better to do it from kernfs_notify()
> > directly. One example is calling sysfs_notify_dirent() from a hardware
> > interrupt handler to wake up a thread and handle the interrupt in user
> > space.
> >
> > Signed-off-by: Radu Rendec <radu.rendec@gmail.com>
>
> Acked-by: Tejun Heo <tj@kernel.org>
>
> Greg, can you please route this one?
Sure, I'll queue it up soon...
greg k-h
prev parent reply other threads:[~2018-11-20 16:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-16 2:09 [PATCH 0/1] kernfs_notify() poll latency Radu Rendec
2018-11-16 2:09 ` [PATCH 1/1] Improve kernfs_notify() poll notification latency Radu Rendec
2018-11-20 16:14 ` Tejun Heo
2018-11-20 16:58 ` Greg Kroah-Hartman [this message]
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