Hi, On Mon, Jun 25, 2018 at 10:09:41AM -0600, Rob Herring wrote: > On Mon, Jun 25, 2018 at 8:08 AM Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > > > Hi, > > I am wondering why do we still keep mm/bootmem.c when most architectures > > already moved to nobootmem. Is there any fundamental reason why others > > cannot or this is just a matter of work? > > Just because no one has done the work. I did a couple of arches > recently (sh, microblaze, and h8300) mainly because I broke them with > some DT changes. I've tried running the current upstream on h8300 gdb simulator and it failed: [ 0.000000] BUG: Bad page state in process swapper pfn:00004 [ 0.000000] page:007ed080 count:0 mapcount:-128 mapping:00000000 index:0x0 [ 0.000000] flags: 0x0() [ 0.000000] raw: 00000000 0040bdac 0040bdac 00000000 00000000 00000002 ffffff7f 00000000 [ 0.000000] page dumped because: nonzero mapcount ---Type <return> to continue, or q <return> to quit--- [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18.0-rc2+ #50 [ 0.000000] Stack from 00401f2c: [ 0.000000] 00401f2c 001116cb 007ed080 00401f40 000e20e6 00401f54 0004df14 00000000 [ 0.000000] 007ed080 007ed000 00401f5c 0004df8c 00401f90 0004e982 00000044 00401fd1 [ 0.000000] 007ed000 007ed000 00000000 00000004 00000008 00000000 00000003 00000011 [ 0.000000] [ 0.000000] Call Trace: [ 0.000000] [<000e20e6>] [<0004df14>] [<0004df8c>] [<0004e982>] [ 0.000000] [<00051a28>] [<00001000>] [<00000100>] [ 0.000000] Disabling lock debugging due to kernel taint With v4.13 I was able to get to "no valid init found". I had a quick look at h8300 memory initialization and it seems it has starting pfn set to 0 while fdt defines memory start at 4M. > > Btw. what really needs to be > > done? Btw. is there any documentation telling us what needs to be done > > in that regards? > > No. The commits converting the arches are the only documentation. It's > a bit more complicated for platforms that have NUMA support. > > Rob > -- Sincerely yours, Mike.
