From: Uladzislau Rezki <urezki@gmail.com>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: Uladzislau Rezki <urezki@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
LKML <linux-kernel@vger.kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
rcu <rcu@vger.kernel.org>, Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH RFC] rcu/tree: Refactor object allocation and try harder for array allocation
Date: Fri, 24 Apr 2020 14:28:35 +0200 [thread overview]
Message-ID: <20200424122835.GA4686@pc636> (raw)
In-Reply-To: <CAEXW_YSt=yLDS4Fj7atqB_OYiKAvt2472eTKcytEkzVABUMPkQ@mail.gmail.com>
>
> I think Johannes said that waking up kswapd is Ok. OTOH, I did not see
> the drawback in waking up kswapd to do background reclaim since it
> does not happen synchronously right? I think Johannes said we can do
> better than just waking kswapd by also doing light direct reclaim
> using __GFP_NORETRY but let me know if I missed something.
>
Then i misunderstood that point. So, seems it is settled now. We just
use GFP_NOWAIT | __GFP_RECLAIM | __GFP_NORETRY | __GFP_NOWARN for headless
case, i.e. when we can sleep. It will do direct reclaim(slow path), but
light one because of __GFP_NORETRY.
Does it sound good?
> > For single argument we inline freeing into current context after
> > synchronize_rcu() because it follows might_sleep() annotation.
>
> Yes.
>
> Also, with the additional caching being planned, we could avoid the
> chances of hitting the synchronize_rcu inlining.
>
Or minimize it.
There is also one question i would like to clarify. That is dynamic head
attaching that requires small allocations. Do we drop it?
Thanks!
--
Vlad Rezki
next prev parent reply other threads:[~2020-04-24 12:29 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-13 21:15 [PATCH RFC] rcu/tree: Refactor object allocation and try harder for array allocation Joel Fernandes (Google)
2020-04-14 19:43 ` Paul E. McKenney
2020-04-16 10:30 ` Uladzislau Rezki
2020-04-16 13:17 ` Joel Fernandes
2020-04-16 18:01 ` Paul E. McKenney
2020-04-22 14:57 ` Johannes Weiner
2020-04-22 15:35 ` Paul E. McKenney
2020-04-23 17:48 ` Johannes Weiner
2020-04-23 18:02 ` Paul E. McKenney
2020-04-23 18:27 ` Uladzislau Rezki
2020-04-23 19:21 ` Paul E. McKenney
2020-04-23 19:59 ` Uladzislau Rezki
2020-04-24 4:16 ` Joel Fernandes
2020-04-24 12:28 ` Uladzislau Rezki [this message]
2020-05-05 18:17 ` Johannes Weiner
2020-05-05 18:33 ` Uladzislau Rezki
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