From: Jerome Glisse <jglisse@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Jeff Layton <jlayton@kernel.org>,
Dave Chinner <david@fromorbit.com>,
linux-mm@kvack.org, lsf-pc@lists.linux-foundation.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-block@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>
Subject: Re: [LSF/MM] schedule suggestion
Date: Thu, 19 Apr 2018 16:15:02 -0400 [thread overview]
Message-ID: <20180419201502.GA11372@redhat.com> (raw)
In-Reply-To: <20180419195637.GA14024@bombadil.infradead.org>
On Thu, Apr 19, 2018 at 12:56:37PM -0700, Matthew Wilcox wrote:
> On Thu, Apr 19, 2018 at 03:31:08PM -0400, Jerome Glisse wrote:
> > > > Basicly i want a callback in __fd_install(), do_dup2(), dup_fd() and
> > > > add void * *private_data; to struct fdtable (also a default array to
> > > > struct files_struct). The callback would be part of struct file_operations.
> > > > and only call if it exist (os overhead is only for device driver that
> > > > care).
> > > >
> > > > Did i miss something fundamental ? copy_files() call dup_fd() so i
> > > > should be all set here.
> > > >
> > > > I will work on patches i was hoping this would not be too much work.
> >
> > Well scratch that whole idea, i would need to add a new array to task
> > struct which make it a lot less appealing. Hence a better solution is
> > to instead have this as part of mm (well indirectly).
>
> It shouldn't be too bad to add a struct radix_tree to the fdtable.
>
> I'm sure we could just not support weird cases like sharing the fdtable
> without sharing the mm. Does anyone actually do that?
Well like you pointed out what i really want is a 1:1 structure linking
a device struct an a mm_struct. Given that this need to be cleanup when
mm goes away hence tying this to mmu_notifier sounds like a better idea.
I am thinking of adding a hashtable to mmu_notifier_mm using file id for
hash as this should be a good hash value for common cases. I only expect
few drivers to need that (GPU drivers, RDMA). Today GPU drivers do have
a hashtable inside their driver and they has on the mm struct pointer,
i believe hash mmu_notifier_mm using file id will be better.
J�r�me
next prev parent reply other threads:[~2018-04-19 20:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-18 21:19 [LSF/MM] schedule suggestion Jerome Glisse
2018-04-19 0:48 ` Dave Chinner
2018-04-19 1:55 ` Dave Chinner
2018-04-19 14:38 ` Jerome Glisse
2018-04-19 14:43 ` Matthew Wilcox
2018-04-19 16:30 ` Jerome Glisse
2018-04-19 16:58 ` Jeff Layton
2018-04-19 17:26 ` Jerome Glisse
2018-04-19 18:31 ` Jeff Layton
2018-04-19 19:31 ` Jerome Glisse
2018-04-19 19:56 ` Matthew Wilcox
2018-04-19 20:15 ` Jerome Glisse [this message]
2018-04-19 20:25 ` Matthew Wilcox
2018-04-19 20:39 ` Al Viro
2018-04-19 21:08 ` Jerome Glisse
2018-04-19 20:51 ` Al Viro
2018-04-19 20:33 ` Al Viro
2018-04-19 20:58 ` Jerome Glisse
2018-04-19 21:21 ` Al Viro
2018-04-19 21:47 ` Jerome Glisse
2018-04-19 22:13 ` Al Viro
2018-04-19 14:51 ` Chris Mason
2018-04-19 15:07 ` Martin K. Petersen
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