From: Jason Gunthorpe <jgg-uk2M96/98Pc@public.gmane.org>
To: Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
RDMA mailing list
<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Mark Bloch <markb-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
Steve Wise
<swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>,
Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Subject: Re: [PATCH rdma-next v5 3/8] RDMA/restrack: Add general infrastructure to track RDMA resources
Date: Tue, 23 Jan 2018 10:58:48 -0700 [thread overview]
Message-ID: <20180123175848.GK30670@ziepe.ca> (raw)
In-Reply-To: <20180123175433.GI30670-uk2M96/98Pc@public.gmane.org>
On Tue, Jan 23, 2018 at 10:54:33AM -0700, Jason Gunthorpe wrote:
> On Mon, Jan 22, 2018 at 02:51:14PM +0200, Leon Romanovsky wrote:
> > + mutex_lock(&dev->res.mutex);
> > + hash_del_rcu(&res->node);
> > + mutex_unlock(&dev->res.mutex);
> > +
> > + res->valid = false;
> > +
> > + if (res->task)
> > + put_task_struct(res->task);
> > + synchronize_srcu(&dev->res.srcu);
> > +}
>
> This locking is wrong..
Actually, just don't use RCU.
We can't afford to call synchronize_srcu in the destroy() path of
every object and the netlink user is not critical enough to bother
optimizing the read side.
Replace the rcu and the mutex with a simple rwlock.
Jason
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next prev parent reply other threads:[~2018-01-23 17:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-22 12:51 [PATCH rdma-next v5 0/8] RDMA resource tracking Leon Romanovsky
[not found] ` <20180122125119.26419-1-leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2018-01-22 12:51 ` [PATCH rdma-next v5 1/8] RDMA/core: Print caller name instead of function name Leon Romanovsky
2018-01-22 12:51 ` [PATCH rdma-next v5 2/8] RDMA/core: Save kernel caller name in PD and CQ objects Leon Romanovsky
2018-01-22 12:51 ` [PATCH rdma-next v5 3/8] RDMA/restrack: Add general infrastructure to track RDMA resources Leon Romanovsky
[not found] ` <20180122125119.26419-4-leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2018-01-23 17:54 ` Jason Gunthorpe
[not found] ` <20180123175433.GI30670-uk2M96/98Pc@public.gmane.org>
2018-01-23 17:58 ` Jason Gunthorpe [this message]
[not found] ` <20180123175848.GK30670-uk2M96/98Pc@public.gmane.org>
2018-01-23 18:35 ` Leon Romanovsky
[not found] ` <20180123183552.GW1393-U/DQcQFIOTAAJjI8aNfphQ@public.gmane.org>
2018-01-23 22:00 ` Jason Gunthorpe
2018-01-23 18:31 ` Leon Romanovsky
2018-01-22 12:51 ` [PATCH rdma-next v5 4/8] RDMA/core: Add resource tracking for create and destroy QPs Leon Romanovsky
2018-01-22 12:51 ` [PATCH rdma-next v5 5/8] RDMA/core: Add resource tracking for create and destroy CQs Leon Romanovsky
2018-01-22 12:51 ` [PATCH rdma-next v5 6/8] RDMA/core: Add resource tracking for create and destroy PDs Leon Romanovsky
2018-01-22 12:51 ` [PATCH rdma-next v5 7/8] RDMA/nldev: Provide global resource utilization Leon Romanovsky
2018-01-22 12:51 ` [PATCH rdma-next v5 8/8] RDMA/nldev: Provide detailed QP information Leon Romanovsky
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