On Fri, Dec 22, 2006 at 11:20:08PM +0300, Alex Tomas wrote: > > Good day, > > probably the previous set of patches (including mballoc/lg) > is too large. so, I reworked delayed allocation a bit so > that it can be used on top of regular balloc, though it > still can be used with extents-enabled files only. > > this time series contains just 3 patches: > > - booked-page-flag.patch > adds PG_booked bit to page->flags. it's used in delayed > allocation to mark space is already reserved for page > (including possible metadata) So that mean's we'll have 2 separate mechanisms for marking pages as delalloc. XFS uses the BH_delay flag to indicate that a buffer (block) attached to the page is using delalloc. FWIW, how does this mechanism deal with block size < page size? Don't you have to track delalloc on a block basis rather than a page basis? > - ext4-block-reservation.patch > this is scalable free space management. every time we > delay allocation of some page, a space (including metadata) > should be reserved > > - ext4-delayed-allocation.patch > delayed allocation itself, enabled by "delalloc" mount option. > extents support is also required. currently it works only > with blocksize=pagesize. Ah, that's why you can get away with a page flag - you've ignored the partial page delay state problem. Any plans to use the existing method in the future so we will be able to use ext4 delalloc on machines with a page size larger than 4k? Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
