Boaz Harrosh wrote on 2016-10-26:
> On 10/26/2016 06:50 PM, Brian Boylston wrote:
>> copy_from_iter_nocache() now uses nocache copies for all types of iovecs
>> on x86, so the flush in arch_copy_from_iter_pmem() is no longer needed.
>>
>> Cc: Ross Zwisler <ross.zwis...@linux.intel.com>
>> Cc: Thomas Gleixner <t...@linutronix.de>
>> Cc: Ingo Molnar <mi...@redhat.com>
>> Cc: "H. Peter Anvin" <h...@zytor.com>
>> Cc: <x...@kernel.org>
>> Cc: Al Viro <v...@zeniv.linux.org.uk>
>> Cc: Dan Williams <dan.j.willi...@intel.com>
>> Signed-off-by: Brian Boylston <brian.boyls...@hpe.com>
>> Reviewed-by: Toshi Kani <toshi.k...@hpe.com>
>> Reported-by: Oliver Moreno <oliver.mor...@hpe.com>
>> ---
>> arch/x86/include/asm/pmem.h | 19 +------------------
>> 1 file changed, 1 insertion(+), 18 deletions(-)
>> diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h
>> index 643eba4..2fbf4ae 100644
>> --- a/arch/x86/include/asm/pmem.h
>> +++ b/arch/x86/include/asm/pmem.h
>> @@ -72,15 +72,6 @@ static inline void arch_wb_cache_pmem(void *addr, size_t
>> size)
>> clwb(p);
>> }
>> -/*
>> - * copy_from_iter_nocache() on x86 only uses non-temporal stores for iovec
>> - * iterators, so for other types (bvec & kvec) we must do a cache
>> write-back.
>> - */
>> -static inline bool __iter_needs_pmem_wb(struct iov_iter *i)
>> -{
>> - return iter_is_iovec(i) == false;
>> -}
>> -
>> /**
>> * arch_copy_from_iter_pmem - copy data from an iterator to PMEM
>> * @addr: PMEM destination address
>> @@ -92,15 +83,7 @@ static inline bool __iter_needs_pmem_wb(struct iov_iter
>> *i)
>> static inline size_t arch_copy_from_iter_pmem(void *addr, size_t bytes,
>> struct iov_iter *i)
>> {
>> - size_t len;
>> -
>> - /* TODO: skip the write-back by always using non-temporal stores */
>> - len = copy_from_iter_nocache(addr, bytes, i);
>> -
>> - if (__iter_needs_pmem_wb(i))
>> - arch_wb_cache_pmem(addr, bytes);
>> -
>> - return len;
>> + return copy_from_iter_nocache(addr, bytes, i);
>
> I wish you would remove all this completely. Don't see the point for it
> anymore
>
At first, I was just targeting bvecs for the splice() case, so I had left the
check and the flush in there for kvecs. When doing this v2 of the patch set,
I made kvecs nocache as well, so removed the check and flush, but didn't follow
through completely as you suggest. Will revisit.
Thanks!
Brian
> Thanks a lot for doing this. I have this patch for ages in my trees and was
> too
> lasy to fight them through. Yes it is a big boost for many workloads.
>
> Lots of gratitude
> Boaz
>
>> }
>> /**
