From: Nadav Amit <namit@vmware.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Rik van Riel <riel@surriel.com>,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH v5 1/8] smp: Run functions concurrently in smp_call_function_many_cond()
Date: Tue, 16 Feb 2021 18:49:28 +0000 [thread overview]
Message-ID: <AE387DFD-770B-47EB-AF85-4AB8950D8ABF@vmware.com> (raw)
In-Reply-To: <YCu0wleNK9a/rUWr@hirez.programming.kicks-ass.net>
> On Feb 16, 2021, at 4:04 AM, Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Tue, Feb 09, 2021 at 02:16:46PM -0800, Nadav Amit wrote:
>> @@ -894,17 +911,12 @@ EXPORT_SYMBOL(on_each_cpu_mask);
>> void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
>> void *info, bool wait, const struct cpumask *mask)
>> {
>> - int cpu = get_cpu();
>> + unsigned int scf_flags = SCF_RUN_LOCAL;
>>
>> - smp_call_function_many_cond(mask, func, info, wait, cond_func);
>> - if (cpumask_test_cpu(cpu, mask) && cond_func(cpu, info)) {
>> - unsigned long flags;
>> + if (wait)
>> + scf_flags |= SCF_WAIT;
>>
>> - local_irq_save(flags);
>> - func(info);
>> - local_irq_restore(flags);
>> - }
>> - put_cpu();
>> + smp_call_function_many_cond(mask, func, info, scf_flags, cond_func);
>> }
>> EXPORT_SYMBOL(on_each_cpu_cond_mask);
>
> You lost the preempt_disable() there, I've added it back:
>
> ---
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -920,7 +920,9 @@ void on_each_cpu_cond_mask(smp_cond_func
> if (wait)
> scf_flags |= SCF_WAIT;
>
> + preempt_disable();
> smp_call_function_many_cond(mask, func, info, scf_flags, cond_func);
> + preempt_enable();
> }
> EXPORT_SYMBOL(on_each_cpu_cond_mask);
Indeed. I will add lockdep_assert_preemption_disabled() to
smp_call_function_many_cond() to prevent this mistake from reoccurring.
next prev parent reply other threads:[~2021-02-16 18:50 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 22:16 [PATCH v5 0/8] x86/tlb: Concurrent TLB flushes Nadav Amit
2021-02-09 22:16 ` [PATCH v5 1/8] smp: Run functions concurrently in smp_call_function_many_cond() Nadav Amit
2021-02-16 12:04 ` Peter Zijlstra
2021-02-16 18:49 ` Nadav Amit [this message]
2021-02-16 12:06 ` Peter Zijlstra
2021-02-16 16:32 ` Peter Zijlstra
2021-02-16 18:53 ` Nadav Amit
2021-02-16 18:59 ` Peter Zijlstra
2021-02-16 19:04 ` Nadav Amit
2021-02-17 1:02 ` Nadav Amit
2021-02-18 12:55 ` Peter Zijlstra
2021-02-18 8:09 ` Christoph Hellwig
2021-02-18 9:36 ` Nadav Amit
2021-02-18 11:12 ` Peter Zijlstra
2021-02-09 22:16 ` [PATCH v5 2/8] x86/mm/tlb: Unify flush_tlb_func_local() and flush_tlb_func_remote() Nadav Amit
2021-02-09 22:16 ` [PATCH v5 3/8] x86/mm/tlb: Open-code on_each_cpu_cond_mask() for tlb_is_not_lazy() Nadav Amit
2021-02-18 8:16 ` Christoph Hellwig
2021-02-18 8:24 ` Nadav Amit
2021-02-18 8:28 ` Christoph Hellwig
2021-02-09 22:16 ` [PATCH v5 4/8] x86/mm/tlb: Flush remote and local TLBs concurrently Nadav Amit
2021-02-16 12:10 ` Peter Zijlstra
2021-02-16 19:17 ` Nadav Amit
2021-02-18 8:14 ` Christoph Hellwig
2021-02-09 22:16 ` [PATCH v5 5/8] x86/mm/tlb: Privatize cpu_tlbstate Nadav Amit
2021-02-09 22:16 ` [PATCH v5 6/8] x86/mm/tlb: Do not make is_lazy dirty for no reason Nadav Amit
2021-02-09 22:16 ` [PATCH v5 7/8] cpumask: Mark functions as pure Nadav Amit
2021-02-16 12:14 ` Peter Zijlstra
2021-02-09 22:16 ` [PATCH v5 8/8] x86/mm/tlb: Remove unnecessary uses of the inline keyword Nadav Amit
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