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From: Valentin Schneider <vschneid@redhat.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	cgroups@vger.kernel.org, linux-mm@kvack.org
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Michal Hocko" <mhocko@kernel.org>,
	"Michal Koutný" <mkoutny@suse.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Vladimir Davydov" <vdavydov.dev@gmail.com>,
	"Waiman Long" <longman@redhat.com>,
	"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
	"Roman Gushchin" <guro@fb.com>,
	"Shakeel Butt" <shakeelb@google.com>,
	"Michal Hocko" <mhocko@suse.com>
Subject: Re: [PATCH v5 2/6] mm/memcg: Disable threshold event handlers on PREEMPT_RT
Date: Wed, 01 Mar 2023 18:23:19 +0000	[thread overview]
Message-ID: <xhsmh4jr4pbzc.mognet@vschneid.remote.csb> (raw)
In-Reply-To: <20220226204144.1008339-3-bigeasy@linutronix.de>

On 26/02/22 21:41, Sebastian Andrzej Siewior wrote:
> During the integration of PREEMPT_RT support, the code flow around
> memcg_check_events() resulted in `twisted code'. Moving the code around
> and avoiding then would then lead to an additional local-irq-save
> section within memcg_check_events(). While looking better, it adds a
> local-irq-save section to code flow which is usually within an
> local-irq-off block on non-PREEMPT_RT configurations.
>

Hey, sorry for necro'ing a year-old thread - would you happen to remember
what the issues were with memcg_check_events()? I ran tests against
cgroupv1 using an eventfd on OOM with the usual debug arsenal and didn't
detect anything, I'm guessing it has to do with the IRQ-off region
memcg_check_events() is called from?

I want cgroupv1 to die as much as the next person, but in that specific
situation I kinda need cgroupv1 to behave somewhat sanely on RT with
threshold events :/

Cheers



  reply	other threads:[~2023-03-01 18:23 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-26 20:41 [PATCH v5 0/6] mm/memcg: Address PREEMPT_RT problems instead of disabling it Sebastian Andrzej Siewior
2022-02-26 20:41 ` [PATCH v5 1/6] mm/memcg: Revert ("mm/memcg: optimize user context object stock access") Sebastian Andrzej Siewior
2022-02-26 20:41 ` [PATCH v5 2/6] mm/memcg: Disable threshold event handlers on PREEMPT_RT Sebastian Andrzej Siewior
2023-03-01 18:23   ` Valentin Schneider [this message]
2023-03-02  7:45     ` Michal Hocko
2023-03-02 10:18       ` Valentin Schneider
2023-03-02 11:24         ` Michal Hocko
2023-03-02 12:30           ` Valentin Schneider
2023-03-02 12:56             ` Michal Hocko
2023-03-02 14:34               ` Valentin Schneider
2023-03-02 19:52                 ` Valentin Schneider
2022-02-26 20:41 ` [PATCH v5 3/6] mm/memcg: Protect per-CPU counter by disabling preemption on PREEMPT_RT where needed Sebastian Andrzej Siewior
2022-02-28  8:05   ` Michal Hocko
2022-02-28 11:08     ` Sebastian Andrzej Siewior
2022-02-28 11:23       ` Michal Hocko
2022-02-28 12:35         ` Sebastian Andrzej Siewior
2022-02-26 20:41 ` [PATCH v5 4/6] mm/memcg: Opencode the inner part of obj_cgroup_uncharge_pages() in drain_obj_stock() Sebastian Andrzej Siewior
2022-02-26 20:41 ` [PATCH v5 5/6] mm/memcg: Protect memcg_stock with a local_lock_t Sebastian Andrzej Siewior
2022-02-28  8:06   ` Michal Hocko
2022-02-26 20:41 ` [PATCH v5 6/6] mm/memcg: Disable migration instead of preemption in drain_all_stock() Sebastian Andrzej Siewior

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