Best wishes, -- Ning Qu (曲宁) | Software Engineer | quning@xxxxxxxxxx | +1-408-418-6066 On Wed, Oct 16, 2013 at 5:09 AM, Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> wrote: > Ning Qu wrote: >> > Again. Here and below ifdef is redundant: PageTransHugeCache() is zero >> > compile-time and thp case will be optimize out. >> >> The problem is actually from HPAGE_CACHE_INDEX_MASK, it is marked as >> build bug when CONFIG_TRANSPARENT_HUGEPAGE_PAGECACHE is false. So we >> either wrap some logic inside a inline function, or we have to be like >> this .. Or we don't treat the HPAGE_CACHE_INDEX_MASK as a build bug? > > HPAGE_CACHE_INDEX_MASK shouldn't be a problem. > If it's wrapped into 'if PageTransHugeCache(page)' or similar it will be > eliminated by compiler if thp-pc disabled and build bug will not be > triggered. > >> >> > >> > And do we really need a copy of truncate logic here? Is there a way to >> > share code? >> > >> The truncate between tmpfs and general one is similar but not exactly >> the same (no readahead), so share the whole function might not be a >> good choice from the perspective of tmpfs? Anyway, there are other >> similar functions in tmpfs, e.g. the one you mentioned for >> shmem_add_to_page_cache. It is possible to share the code, I am just >> worried it will make the logic more complicated? > > I think introducing thp-pc is good opportunity to refactor all these code. I agree, I review the code of generate truncate and shmem_undo_range again. There are just too many differences in almost every major piece of logic. It's really not possible to extract any meaningful common function to share between them. And I agree, we will try to refactor any other functions which are possible. Thanks! > > -- > Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href