Hi I created patches that convert dm-thin to use dm-bufio interface (so that it is consistent with dm-zeroed and dm-multisnap). The patches are here: http://people.redhat.com/mpatocka/patches/kernel/dm-thinp-bufio/ Advantages: * It uses kmalloc, __get_free_pages or __vmalloc, so the block size is not limited and memory fragmentation is not an issue. The original code only used kmalloc. * It has dynamic cache sizing, cache size can be configured by the user. In case of inactivity over some time (a buffer is unused for a minute), the buffers are freed. The original code had cache size hardcoded and it couldn't be changed. * Submit bios directly (if we can) without dm-io layer. Notes: * Buffer locking is not supported, I suppose it is not used for anything anyway. If it is used, tell me, I can add it after reviewing it. * dm_bm_rebind_block_device changes the block device, but it is not used for anything (dm-thinp never changes the device). I think it could be removed. * Two small bugs in dm-thin are fixed --- not closing the superblock buffer on exit and improper termination sequence (the block devices were closed before the buffer interface exited). Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
