On 4/24/20 7:22 PM, Song Liu wrote: > > >> On Mar 30, 2020, at 9:00 AM, Jason Baron <jbaron@xxxxxxxxxx> wrote: >> >> Let's add some CONFIG_* options to directly configure the raid0 layout >> if you know in advance how your raid0 array was created. This can be >> simpler than having to manage module or kernel command-line parameters. >> >> If the raid0 array was created by a pre-3.14 kernel, use >> RAID0_ORIG_LAYOUT. If the raid0 array was created by a 3.14 or newer >> kernel then select RAID0_ALT_MULTIZONE_LAYOUT. Otherwise, the default >> setting is RAID0_LAYOUT_NONE, in which case the current behavior of >> needing to specify a module parameter raid0.default_layout=1|2 is >> preserved. >> >> Cc: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx> >> Cc: NeilBrown <neilb@xxxxxxx> >> Cc: Song Liu <songliubraving@xxxxxx> >> Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx> > > This patch looks good. However, I am not sure whether the user will > recompile the kernel for a different default value. Do you have real > world use case for this? > > Thanks, > Song > Hi Song, Yes, we knew that all our raid0 arrays were created with >=3.14 kernels, and thus we wanted a way to specify the new layout without needing to add to the command line or a module parameter. For us, maintaining a CONFIG_* option is just simpler. Thanks, -Jason
