From: Uladzislau Rezki <urezki@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Uladzislau Rezki <urezki@gmail.com>,
Mel Gorman <mgorman@techsingularity.net>,
"Paul E. McKenney" <paulmck@kernel.org>,
Michal Hocko <mhocko@suse.com>,
LKML <linux-kernel@vger.kernel.org>, RCU <rcu@vger.kernel.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Thomas Gleixner <tglx@linutronix.de>,
"Theodore Y . Ts'o" <tytso@mit.edu>,
Joel Fernandes <joel@joelfernandes.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>,
Mel Gorman <mgorman@suse.de>
Subject: Re: [RFC-PATCH 2/4] mm: Add __rcu_alloc_page_lockless() func.
Date: Thu, 24 Sep 2020 17:16:25 +0200 [thread overview]
Message-ID: <20200924151625.GA19013@pc636> (raw)
In-Reply-To: <20200924111632.GD2628@hirez.programming.kicks-ass.net>
On Thu, Sep 24, 2020 at 01:16:32PM +0200, Peter Zijlstra wrote:
> On Thu, Sep 24, 2020 at 10:16:14AM +0200, Uladzislau Rezki wrote:
> > Other option is if we had unconditionally enabled PREEMPT_COUNT config.
> > It would be easy to identify a context type and invoke a page allocator
> > if a context is preemtale. But as of now preemptable() is "half" working.
> > Thomas uploaded patches to make it unconditional. But it can be blocked.
>
> While I in principle support Thomas' patch, I think this is an abuse and
> still complete wrong.
>
Good that you support it :)
>
> Not all preemptible() context can deal with GFP_KERNEL (GFP_NOFS
> existing should be a clue). !preemptible context cannot unconditionally
> deal with GFP_NOWAIT, consider using it while holding zone->lock.
>
Not sure if i fully follow you here. What i tried to express, if we had
preemtable() fully working, including !PREEMPT, we can at least detect
the following:
if (!preemptable())
by pass using any ATOMIC/NOWAIT flags because they do not work;
as an example you mentioned z->lock that is sleepable.
>
> The preemption context does not say antying much useful about the
> allocation context.
>
I am talking about taking a decision.
--
Vlad Rezki
next prev parent reply other threads:[~2020-09-24 15:16 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 19:48 [PATCH 0/4] kvfree_rcu() and _LOCK_NESTING/_PREEMPT_RT Uladzislau Rezki (Sony)
2020-09-18 19:48 ` [PATCH 1/4] rcu/tree: Add a work to allocate pages from regular context Uladzislau Rezki (Sony)
2020-09-18 19:48 ` [RFC-PATCH 2/4] mm: Add __rcu_alloc_page_lockless() func Uladzislau Rezki (Sony)
2020-09-21 7:47 ` Michal Hocko
2020-09-21 15:45 ` Paul E. McKenney
2020-09-21 16:03 ` Michal Hocko
2020-09-21 19:48 ` Uladzislau Rezki
2020-09-22 7:50 ` Michal Hocko
2020-09-22 13:12 ` Uladzislau Rezki
2020-09-22 15:35 ` Michal Hocko
2020-09-23 10:37 ` Mel Gorman
2020-09-23 15:41 ` Paul E. McKenney
2020-09-23 23:22 ` Mel Gorman
2020-09-24 8:16 ` Uladzislau Rezki
2020-09-24 11:16 ` Peter Zijlstra
2020-09-24 15:16 ` Uladzislau Rezki [this message]
2020-09-24 11:19 ` Peter Zijlstra
2020-09-24 15:21 ` Uladzislau Rezki
2020-09-25 8:15 ` Peter Zijlstra
2020-09-25 10:25 ` Uladzislau Rezki
2020-09-24 15:38 ` Paul E. McKenney
2020-09-25 8:26 ` Peter Zijlstra
2020-09-26 14:37 ` Paul E. McKenney
2020-09-25 8:05 ` Michal Hocko
2020-09-25 15:31 ` Uladzislau Rezki
2020-09-25 15:47 ` Michal Hocko
2020-09-29 16:25 ` Uladzislau Rezki
2020-09-30 9:27 ` Michal Hocko
2020-09-30 12:35 ` Uladzislau Rezki
2020-09-30 12:44 ` Michal Hocko
2020-09-30 13:39 ` Uladzislau Rezki
2020-09-30 16:46 ` Michal Hocko
2020-09-30 20:36 ` Uladzislau Rezki
2020-09-30 15:25 ` Joel Fernandes
2020-09-30 16:48 ` Michal Hocko
2020-09-30 17:03 ` Joel Fernandes
2020-09-30 17:22 ` Michal Hocko
2020-09-30 17:48 ` Joel Fernandes
2020-09-25 16:17 ` Mel Gorman
2020-09-25 17:57 ` Uladzislau Rezki
2020-09-22 15:49 ` Paul E. McKenney
2020-09-22 3:35 ` Paul E. McKenney
2020-09-22 8:03 ` Michal Hocko
2020-09-22 15:46 ` Paul E. McKenney
2020-09-23 11:27 ` Uladzislau Rezki
2020-09-29 10:15 ` Vlastimil Babka
2020-09-29 22:07 ` Uladzislau Rezki
2020-09-30 10:35 ` Michal Hocko
2020-10-01 19:32 ` Uladzislau Rezki
2020-09-30 14:39 ` Vlastimil Babka
2020-09-30 15:37 ` Joel Fernandes
2020-10-01 19:26 ` Uladzislau Rezki
2020-10-02 7:11 ` Michal Hocko
2020-10-02 8:50 ` Mel Gorman
2020-10-02 9:05 ` Michal Hocko
2020-10-05 15:08 ` Uladzislau Rezki
2020-10-05 15:41 ` Michal Hocko
2020-10-06 22:25 ` Uladzislau Rezki
2020-10-07 10:02 ` Michal Hocko
2020-10-07 11:02 ` Uladzislau Rezki
2020-10-02 9:07 ` Peter Zijlstra
2020-10-02 9:45 ` Mel Gorman
2020-10-02 9:58 ` Peter Zijlstra
2020-10-02 10:19 ` Mel Gorman
2020-10-02 14:41 ` Paul E. McKenney
2020-10-06 10:03 ` Mel Gorman
2020-10-06 15:41 ` Paul E. McKenney
2020-10-05 13:58 ` Uladzislau Rezki
2020-10-02 8:06 ` Mel Gorman
2020-10-05 14:12 ` Uladzislau Rezki
2020-09-18 19:48 ` [PATCH 3/4] rcu/tree: use " Uladzislau Rezki (Sony)
2020-09-18 19:48 ` [PATCH 4/4] rcu/tree: Use schedule_delayed_work() instead of WQ_HIGHPRI queue Uladzislau Rezki (Sony)
2020-09-20 15:06 ` Paul E. McKenney
2020-09-21 13:27 ` Uladzislau Rezki
2020-09-18 22:15 ` [PATCH 0/4] kvfree_rcu() and _LOCK_NESTING/_PREEMPT_RT Paul E. McKenney
2020-09-30 15:52 ` Joel Fernandes
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