From: Michal Hocko <mhocko@suse.com>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Valentin Schneider <vschneid@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org
Subject: Re: [PATCH 6/6] mm: Drain LRUs upon resume to userspace on nohz_full CPUs
Date: Thu, 3 Jul 2025 16:24:10 +0200 [thread overview]
Message-ID: <aGaSivYVquqLjvUl@tiehlicka> (raw)
In-Reply-To: <20250703140717.25703-7-frederic@kernel.org>
On Thu 03-07-25 16:07:17, Frederic Weisbecker wrote:
[...]
> @@ -864,6 +888,10 @@ static inline void __lru_add_drain_all(bool force_all_cpus)
> for_each_online_cpu(cpu) {
> struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
>
> + /* Isolated CPUs handle their cache upon return to userspace */
> + if (IS_ENABLED(CONFIG_NO_HZ_FULL_WORK) && !housekeeping_cpu(cpu, HK_TYPE_KERNEL_NOISE))
> + continue;
> +
Two questions. Where do you actually queue the work to be executed on
the return to the userspace? And why don't you do that only if
cpu_needs_drain?
> if (cpu_needs_drain(cpu)) {
> INIT_WORK(work, lru_add_drain_per_cpu);
> queue_work_on(cpu, mm_percpu_wq, work);
> --
> 2.48.1
>
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2025-07-03 14:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-03 14:07 [PATCH 0/6 v4] sched/mm: LRU drain flush on nohz_full Frederic Weisbecker
2025-07-03 14:07 ` [PATCH 1/6] task_work: Provide means to check if a work is queued Frederic Weisbecker
2025-07-03 14:07 ` [PATCH 2/6] sched/fair: Use task_work_queued() on numa_work Frederic Weisbecker
2025-07-03 14:07 ` [PATCH 3/6] sched: Use task_work_queued() on cid_work Frederic Weisbecker
2025-07-17 16:32 ` Valentin Schneider
2025-07-03 14:07 ` [PATCH 4/6] tick/nohz: Move nohz_full related fields out of hot task struct's places Frederic Weisbecker
2025-07-17 16:32 ` Valentin Schneider
2025-07-03 14:07 ` [PATCH 5/6] sched/isolation: Introduce isolated task work Frederic Weisbecker
2025-07-17 17:29 ` Vlastimil Babka
2025-07-18 9:52 ` Valentin Schneider
2025-07-18 14:23 ` Frederic Weisbecker
2025-07-03 14:07 ` [PATCH 6/6] mm: Drain LRUs upon resume to userspace on nohz_full CPUs Frederic Weisbecker
2025-07-03 14:24 ` Michal Hocko [this message]
2025-07-03 14:28 ` Matthew Wilcox
2025-07-03 16:12 ` Michal Hocko
2025-07-17 19:33 ` Vlastimil Babka
-- strict thread matches above, loose matches on Subject: below --
2025-04-10 15:23 [PATCH 0/6 v3] sched/mm: LRU drain flush on nohz_full Frederic Weisbecker
2025-04-10 15:23 ` [PATCH 6/6] mm: Drain LRUs upon resume to userspace on nohz_full CPUs Frederic Weisbecker
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