* Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > > "Directly mapped pmem integrated into the page cache": > > ------------------------------------------------------ > Nice, I think it makes sense as an area that gets reserved at file > system creation time. You are not proposing that this gets > automatically reserved at the device level, right? [...] Well, it's most practical if the device does it automatically (the layout is determined prior filesystem creation), and the filesystem does not necessarily have to be aware of it - but obviously as a user opt-in. > [...] For the use cases of persistent memory in the absence of a > file system (in-kernel managed hierarchical storage driver, or > mmap() the pmem block device directly) there's still a need for > pfn-based DAX. [...] Yes, but knowing that there's a sane model we can take a hard stance against pfn proliferation and say: 'we let pfns this far and no farther'. > [...] In other words, simple usages skip the overhead. They assume > pfns only, discover those pmem pfns via ->direct_access(), and > arrange for exclusive block device ownership. Everything else that > requires struct page in turn requires a file system to have opt-ed > into this reservation and provide pmem-struct-page infrastructure, > pmem-aware-DIO etc. Yes. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
