Re[2]: [PATCH 01/11] async_tx: don't use src_list argument of async_xor() for dma addresses

On Tuesday, December 9, 2008 you wrote:

On Mon, Dec 8, 2008 at 2:55 PM, Yuri Tikhonov [off-list ref] wrote:

quoted

Using src_list argument of async_xor() as a storage for dma addresses
implies sizeof(dma_addr_t) <=3D sizeof(struct page *) restriction which =

is

quoted

not always true (e.g. ppc440spe).

ppc440spe runs with CONFIG_PHYS_64BIT?

 Yep. It uses 36-bit addressing, so this CONFIG is turned on.

If we do this then we need to also change md to limit the number of
allowed disks based on the kernel stack size.  Because with 256 disks
a 4K stack can be consumed by one call to async_pq ((256 sources in
raid5.c + 256 sources async_pq.c) * 8 bytes per source on 64-bit).

 On ppc440spe we have 8KB stack, so the things are not worse than on=20
32-bit archs with 4KB stack. Thus, I guess no changes to md are=20
required because of this patch. Right?

 Regards, Yuri

 --
 Yuri Tikhonov, Senior Software Engineer
 Emcraft Systems, www.emcraft.com