On 6/21/2021 5:15 PM, Luis Chamberlain wrote:
On Tue, Jun 15, 2021 at 11:55:19AM -0700, Jane Chu wrote:
Hi, Dan,
It appears the fact pmem region is of WB memtype renders set_memory_uc()
to fail due to inconsistency between the requested memtype(UC-) and the
cached
memtype(WB).
# cat /proc/iomem |grep -A 8 -i persist
1840000000-d53fffffff : Persistent Memory
1840000000-1c3fffffff : namespace0.0
5740000000-76bfffffff : namespace2.0
# cat /sys/kernel/debug/x86/pat_memtype_list
PAT memtype list:
PAT: [mem 0x0000001840000000-0x0000001c40000000] write-back
PAT: [mem 0x0000005740000000-0x00000076c0000000] write-back
[10683.418072] Memory failure: 0x1850600: recovery action for dax page:
Recovered
[10683.426147] x86/PAT: fsdax_poison_v1:5018 conflicting memory types
1850600000-1850601000 uncached-minus<->write-back
cscope search shows that unlike pmem, set_memory_uc() is primarily used by
drivers dealing with ioremap(),
Yes, when a driver *knows* the type must follow certain rules, it
requests it.
perhaps the pmem case needs another way to suppress prefetch?
Your thoughts?
The way to think about this problem is, who did the ioremap call for the
ioremap'd area? That's the driver that needs changing.
I'm not sure if the pmem driver is doing something wrong, but rather the
pmem memory failure handler.
thanks,
-jane
Luis
