Re: [PATCH 05/17] asm-generic/tlb: Rename HAVE_RCU_TABLE_NO_INVALIDATE

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

On 12/16/19 6:07 PM, Peter Zijlstra wrote:
> On Mon, Dec 16, 2019 at 06:01:58PM +0530, Aneesh Kumar K.V wrote:
>> Peter Zijlstra <peterz@infradead.org> writes:
>>
>>> Towards a more consistent naming scheme.
>>>
>>> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>>> ---
>>>   arch/Kconfig              |    3 ++-
>>>   arch/powerpc/Kconfig      |    2 +-
>>>   arch/sparc/Kconfig        |    2 +-
>>>   include/asm-generic/tlb.h |    2 +-
>>>   mm/mmu_gather.c           |    2 +-
>>>   5 files changed, 6 insertions(+), 5 deletions(-)
>>>
>>> --- a/arch/Kconfig
>>> +++ b/arch/Kconfig
>>> @@ -396,8 +396,9 @@ config HAVE_ARCH_JUMP_LABEL_RELATIVE
>>>   config MMU_GATHER_RCU_TABLE_FREE
>>>   	bool
>>>   
>>> -config HAVE_RCU_TABLE_NO_INVALIDATE
>>> +config MMU_GATHER_NO_TABLE_INVALIDATE
>>>   	bool
>>> +	depends on MMU_GATHER_RCU_TABLE_FREE
>>
>>
>> Can we drop this Kernel config option instead use
>> MMU_GATHER_RCU_TABLE_FREE? IMHO reducing the kernel config related to
>> mmu_gather can reduce the complexity.
> 
> I'm confused, are you saing you're happy to have PowerPC eat the extra
> TLB invalidates? I thought you cared about PPC performance :-)
> 
> 

Instead can we do

static inline void tlb_table_invalidate(struct mmu_gather *tlb)
{
#ifndef CONFIG_MMU_GATHER_RCU_TABLE_FREE
	 * Invalidate page-table caches used by hardware walkers. Then we still
	 * need to RCU-sched wait while freeing the pages because software
	 * walkers can still be in-flight.
	 */
	tlb_flush_mmu_tlbonly(tlb);
#endif
}

-aneesh