On Nov. 15, 2007, 14:05 +0200, David Howells <dhowells@xxxxxxxxxx> wrote: > Nick Piggin <npiggin@xxxxxxx> wrote: > >> It can be pretty well any power of 2 from PAGE_SIZE upwards, with >> compound pages. None of the filesystems should really care at all. >> It's not even a new concept, hugetlbfs uses HPAGE_SIZE... > > Ummm... The filesystem has to care. If the VFS/VM says 'fill this page' you > do need to know how big the page is or whether it's even actually several > pages. I think that what Nick was trying to say is that PAGE_CACHE_SIZE should always be used properly as the size of the memory struct Page covers (while PAGE_SIZE is the hardware page size and the constraint is that PAGE_CACHE_SIZE == (PAGE_SIZE << k) for some k >= 0). If everybody does that then "None of the filesystems should really care at all". That said, it doesn't seem like the current usage in fs/ and drivers/ is consistent with this convention. > > David > - - 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
