On Sat, May 19, 2018 at 07:25:07AM +0200, Mikulas Patocka wrote: > Use new API for flushing persistent memory. The sentence doesnt make much sense. 'A new API', 'A better abstraction' maybe? > > The problem is this: > * on X86-64, non-temporal stores have the best performance > * ARM64 doesn't have non-temporal stores, so we must flush cache. We > should flush cache as late as possible, because it performs better this > way. > > We introduce functions pmem_memcpy, pmem_flush and pmem_commit. To commit > data persistently, all three functions must be called. > > The macro pmem_assign may be used instead of pmem_memcpy. pmem_assign > (unlike pmem_memcpy) guarantees that 8-byte values are written atomically. > > On X86, pmem_memcpy is memcpy_flushcache, pmem_flush is empty and > pmem_commit is wmb. > > On ARM64, pmem_memcpy is memcpy, pmem_flush is arch_wb_cache_pmem and > pmem_commit is empty. All these should be provided by the pmem layer, and be properly documented. And be sorted before adding your new target that uses them. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
