From: Jason Gunthorpe <jgg@ziepe.ca>
To: Parav Pandit <parav@mellanox.com>
Cc: Leon Romanovsky <leon@kernel.org>,
Doug Ledford <dledford@redhat.com>,
RDMA mailing list <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH rdma-next] IB/core: Avoid deadlock during netlink message handling
Date: Thu, 24 Oct 2019 20:53:04 -0300 [thread overview]
Message-ID: <20191024235304.GG23952@ziepe.ca> (raw)
In-Reply-To: <AM0PR05MB4866CA70E3711F8BE19F294ED16A0@AM0PR05MB4866.eurprd05.prod.outlook.com>
On Thu, Oct 24, 2019 at 07:53:56PM +0000, Parav Pandit wrote:
> Jason's memory size point made be curious about the srcu_struct
> size. On my x86 5.x kernel I see srcu_struct costs 70+Kbytes!
> Likely due to some debug info in my kernel. Which is probably a
> good reason in this case to shift to rwsem. (rwsem is 80 bytes).
Yikes, I knew it was bad, but I didn't think that bad.. So
unbelievable I checked here and I got +4752 bytes using SRCU on my
much less debug kernel. Crazy.
> One small comment correction needed is,
>
> - rdma_nl_types[index].cb_table = cb_table;
> - mutex_unlock(&rdma_nl_mutex);
> + /* Pairs with the READ_ONCE in is_nl_valid() */
> + smp_store_release(&rdma_nl_types[index].cb_table, cb_table);
>
> It should be "Pairs with the READ_ONE in get_cb_table() */
Done, applied to for-rc, thanks
Jason
prev parent reply other threads:[~2019-10-24 23:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-15 8:07 [PATCH rdma-next] IB/core: Avoid deadlock during netlink message handling Leon Romanovsky
2019-10-24 13:17 ` Jason Gunthorpe
2019-10-24 13:26 ` Leon Romanovsky
2019-10-24 13:50 ` Jason Gunthorpe
2019-10-24 16:02 ` Leon Romanovsky
2019-10-24 16:08 ` Jason Gunthorpe
2019-10-24 16:13 ` Leon Romanovsky
2019-10-24 18:28 ` Parav Pandit
2019-10-24 18:36 ` Jason Gunthorpe
2019-10-24 19:19 ` Leon Romanovsky
2019-10-24 19:53 ` Parav Pandit
2019-10-24 23:53 ` Jason Gunthorpe [this message]
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