From: Cong Wang <xiyou.wangcong@gmail.com>
To: Vlad Buslov <vladbu@mellanox.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>, David Miller <davem@davemloft.net>,
Stephen Hemminger <stephen@networkplumber.org>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
Nicolas Dichtel <nicolas.dichtel@6wind.com>,
Greg KH <gregkh@linuxfoundation.org>,
mark.rutland@arm.com, Leon Romanovsky <leon@kernel.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Florian Westphal <fw@strlen.de>, David Ahern <dsahern@gmail.com>,
christian@brauner.io, lucien xin <lucien.xin@gmail.com>,
Jakub Kicinski <jakub.kicinski@netronome.com>,
Jiri Benc <jbenc@redhat.com>
Subject: Re: [PATCH net-next v2 08/10] net: sched: protect block idr with spinlock
Date: Fri, 21 Sep 2018 12:33:15 -0700 [thread overview]
Message-ID: <CAM_iQpUr8GLdwZ_0P_RBcPD0iGHXxC4C68RzTy3Sc2idaJZJRg@mail.gmail.com> (raw)
In-Reply-To: <vbftvmkzkln.fsf@reg-r-vrt-018-180.mtr.labs.mlnx>
On Thu, Sep 20, 2018 at 12:36 AM Vlad Buslov <vladbu@mellanox.com> wrote:
>
>
> On Wed 19 Sep 2018 at 22:09, Cong Wang <xiyou.wangcong@gmail.com> wrote:
> > On Mon, Sep 17, 2018 at 12:19 AM Vlad Buslov <vladbu@mellanox.com> wrote:
> >> @@ -482,16 +483,25 @@ static int tcf_block_insert(struct tcf_block *block, struct net *net,
> >> struct netlink_ext_ack *extack)
> >> {
> >> struct tcf_net *tn = net_generic(net, tcf_net_id);
> >> + int err;
> >> +
> >> + idr_preload(GFP_KERNEL);
> >> + spin_lock(&tn->idr_lock);
> >> + err = idr_alloc_u32(&tn->idr, block, &block->index, block->index,
> >> + GFP_NOWAIT);
> >
> >
> > Why GFP_NOWAIT rather than GFP_ATOMIC here?
>
> I checked how idr_preload is used in kernel and in most places following
> allocation uses GFP_NOWAIT (including idr-test.c). You suggest I should
> change it to GFP_ATOMIC?
No, I am just curious, as GFP_ATOMIC is more widely used when holding
spinlock. I thought you have a special reason to use GFP_NOWAIT here,
but anyway, GFP_NOWAIT is probably fine too.
next prev parent reply other threads:[~2018-09-22 1:23 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 7:17 [PATCH net-next v2 00/10] Refactor classifier API to work with Qdisc/blocks without rtnl lock Vlad Buslov
2018-09-17 7:17 ` [PATCH net-next v2 01/10] net: core: netlink: add helper refcount dec and lock function Vlad Buslov
2018-09-19 21:46 ` Cong Wang
2018-09-17 7:17 ` [PATCH net-next v2 02/10] net: sched: rename qdisc_destroy() to qdisc_put() Vlad Buslov
2018-09-17 7:17 ` [PATCH net-next v2 03/10] net: sched: extend Qdisc with rcu Vlad Buslov
2018-09-19 2:45 ` David Miller
2018-09-17 7:17 ` [PATCH net-next v2 04/10] net: sched: add helper function to take reference to Qdisc Vlad Buslov
2018-09-17 7:17 ` [PATCH net-next v2 05/10] net: sched: use Qdisc rcu API instead of relying on rtnl lock Vlad Buslov
2018-09-19 22:04 ` Cong Wang
2018-09-20 7:20 ` Vlad Buslov
2018-09-21 19:29 ` Cong Wang
2018-09-17 7:17 ` [PATCH net-next v2 06/10] net: sched: change tcf block reference counter type to refcount_t Vlad Buslov
2018-09-17 7:17 ` [PATCH net-next v2 07/10] net: sched: implement functions to put and flush all chains Vlad Buslov
2018-09-17 7:17 ` [PATCH net-next v2 08/10] net: sched: protect block idr with spinlock Vlad Buslov
2018-09-19 22:09 ` Cong Wang
2018-09-20 7:36 ` Vlad Buslov
2018-09-21 19:33 ` Cong Wang [this message]
2018-09-17 7:17 ` [PATCH net-next v2 09/10] net: sched: implement tcf_block_refcnt_{get|put}() Vlad Buslov
2018-09-17 7:17 ` [PATCH net-next v2 10/10] net: sched: use reference counting for tcf blocks on rules update Vlad Buslov
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