[PATCH v5 08/12] mm: enable lazy_mmu sections to nest

[Kevin Brodsky]

On 04/12/2025 07:23, Anshuman Khandual wrote:
>> [...]
>>
>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
>> index 8ff6fdb4b13d..24fdb6f5c2e1 100644
>> --- a/include/linux/pgtable.h
>> +++ b/include/linux/pgtable.h
>> @@ -230,39 +230,140 @@ static inline int pmd_dirty(pmd_t pmd)
>>   * (In practice, for user PTE updates, the appropriate page table lock(s) are
>>   * held, but for kernel PTE updates, no lock is held). The mode is disabled in
>>   * interrupt context and calls to the lazy_mmu API have no effect.
>> - * Nesting is not permitted.
>> + *
>> + * The lazy MMU mode is enabled for a given block of code using:
>> + *
>> + *   lazy_mmu_mode_enable();
>> + *   <code>
>> + *   lazy_mmu_mode_disable();
>> + *
>> + * Nesting is permitted: <code> may itself use an enable()/disable() pair.
>> + * A nested call to enable() has no functional effect; however disable() causes
>> + * any batched architectural state to be flushed regardless of nesting. After a
> Just wondering if there is a method for these generic helpers to ensure that platform
> really does the required flushing on _disable() or the expected platform semantics is
> only described via this comment alone ?