Messages in this thread | | | Date | Fri, 17 Jun 2022 18:08:52 -0700 | From | Dan Williams <> | Subject | Re: [PATCH 3/3] cxl/core: Add sysfs attribute get_poison for list retrieval |
| |
Alison Schofield wrote: > On Fri, Jun 17, 2022 at 11:42:11AM -0700, Dan Williams wrote: > > alison.schofield@ wrote: > > > From: Alison Schofield <alison.schofield@intel.com> > > > > > > The sysfs attribute, get_poison, allows user space to request the > > > retrieval of a CXL devices poison list for its persistent memory. > > > > If the device supports get poison list for volatile memory, just grab > > that too. With the "to be released soon" region patches userspace can > > trivially translate DPA addresses to media type. > > > > Dan, > > The only way I know to discover if the device supports poison list for > volatile is to do the get_poison_list on the volatile range and see > what happens. Am I missing a capability setting somewhere?
If someone executes "echo 1 > trace_poison_list" I expect that the driver does:
get_poison_list(volatile_range); get_poison_list(pmem_range);
...and if scanning the volatile partition ends in error then that just means no error records appear. When the error is "Invalid Physical Address" the driver can just remember that's a permanent error and never try again. So it's more like:
if (volatile_range_valid) { if (get_poison_list(volatile_range) == INVALID_PHYS_ADDR) volatile_range_valid = false; } get_poison_list(pmem_range);
...but that's probably overkill since get_poison_list() is cheap. Just treat it like the zero error records case.
In the to be released region provisioning patches there is a DPA resource tree partitioned by DPA mode type, so the poison list code probably wants to do something like:
down_read(&cxl_dpa_rwsem); for (p = cxlds->dpa_res.child; p; p = p->sibling) get_poison_list(p->start, resource_size(p)); up_read(&cxl_dpa_rwsem);
| |