From: Thomas Gleixner <tglx@linutronix•de>
To: "Costa Shulyupin" <costa.shul@redhat•com>,
longman@redhat•com, ming.lei@redhat•com, pauld@redhat•com,
juri.lelli@redhat•com, vschneid@redhat•com,
"Michael Ellerman" <mpe@ellerman•id.au>,
"Nicholas Piggin" <npiggin@gmail•com>,
"Christophe Leroy" <christophe.leroy@csgroup•eu>,
"Naveen N Rao" <naveen@kernel•org>,
"Zefan Li" <lizefan.x@bytedance•com>, "Tejun Heo" <tj@kernel•org>,
"Johannes Weiner" <hannes@cmpxchg•org>,
"Michal Koutný" <mkoutny@suse•com>,
"Ingo Molnar" <mingo@redhat•com>,
"Peter Zijlstra" <peterz@infradead•org>,
"Vincent Guittot" <vincent.guittot@linaro•org>,
"Dietmar Eggemann" <dietmar.eggemann@arm•com>,
"Steven Rostedt" <rostedt@goodmis•org>,
"Ben Segall" <bsegall@google•com>, "Mel Gorman" <mgorman@suse•de>,
"Costa Shulyupin" <costa.shul@redhat•com>,
"Bjorn Helgaas" <bhelgaas@google•com>,
linuxppc-dev@lists•ozlabs.org, linux-kernel@vger•kernel.org,
cgroups@vger•kernel.org
Subject: Re: [RFC PATCH v3 1/3] sched/isolation: Add infrastructure for dynamic CPU isolation
Date: Wed, 02 Oct 2024 11:44:22 +0200 [thread overview]
Message-ID: <87jzeqyh3d.ffs@tglx> (raw)
In-Reply-To: <20240916122044.3056787-2-costa.shul@redhat.com>
On Mon, Sep 16 2024 at 15:20, Costa Shulyupin wrote:
> +/*
> + * housekeeping_update - change housekeeping.cpumasks[type] and propagate the
> + * change.
> + */
> +static int housekeeping_update(enum hk_type type, const struct cpumask *update)
> +{
> + struct {
> + struct cpumask changed;
> + struct cpumask enable;
> + struct cpumask disable;
> + } *masks;
> +
> + masks = kmalloc(sizeof(*masks), GFP_KERNEL);
> + if (!masks)
> + return -ENOMEM;
> +
> + lockdep_assert_cpus_held();
> + cpumask_xor(&masks->changed, housekeeping_cpumask(type), update);
> + cpumask_and(&masks->enable, &masks->changed, update);
> + cpumask_andnot(&masks->disable, &masks->changed, update);
> + cpumask_copy(housekeeping.cpumasks[type], update);
> + WRITE_ONCE(housekeeping.flags, housekeeping.flags | BIT(type));
So this sets the bit for the type
> + if (!static_branch_unlikely(&housekeeping_overridden))
> + static_key_enable_cpuslocked(&housekeeping_overridden.key);
What's the point of doing this on every iteration?
> + kfree(masks);
> +
> + return 0;
> +}
> +
> static int __init housekeeping_setup(char *str, unsigned long flags)
> {
> cpumask_var_t non_housekeeping_mask, housekeeping_staging;
> @@ -327,8 +357,11 @@ int housekeeping_exlude_isolcpus(const struct cpumask *isolcpus, unsigned long f
> /*
> * Reset housekeeping to bootup default
> */
> +
> + for_each_clear_bit(type, &boot_hk_flags, HK_TYPE_MAX)
> + housekeeping_update(type, cpu_possible_mask);
Even for those which are clear
> for_each_set_bit(type, &boot_hk_flags, HK_TYPE_MAX)
> - cpumask_copy(housekeeping.cpumasks[type], boot_hk_cpumask);
> + housekeeping_update(type, boot_hk_cpumask);
>
> WRITE_ONCE(housekeeping.flags, boot_hk_flags);
Just to overwrite them with boot_hk_flags afterwards. That does not make
any sense at all.
Thanks,
tglx
next prev parent reply other threads:[~2024-10-02 9:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-16 12:20 [RFC PATCH v3 0/3] genirq/cpuhotplug: Adjust managed interrupts according to change of housekeeping cpumask Costa Shulyupin
2024-09-16 12:20 ` [RFC PATCH v3 1/3] sched/isolation: Add infrastructure for dynamic CPU isolation Costa Shulyupin
2024-10-02 9:44 ` Thomas Gleixner [this message]
2024-09-16 12:20 ` [RFC PATCH v3 2/3] genirq/cpuhotplug: Adjust managed irqs according to change of housekeeping CPU Costa Shulyupin
2024-10-02 10:09 ` Thomas Gleixner
2024-09-16 12:20 ` [RFC PATCH v3 3/3] DO NOT MERGE: test for managed irqs adjustment Costa Shulyupin
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