[ add Stephen and Juergen ]
On Mon, Feb 25, 2019 at 11:02 AM Dave Hansen
<dave.hansen@xxxxxxxxxxxxxxx> wrote:
>
> This is a relatively small delta from v4. The review comments seem
> to be settling down, so it seems like we should start thinking about
> how this might get merged. Are there any objections to taking it in
> via the nvdimm tree?
>
> Dan Williams, our intrepid nvdimm maintainer has said he would
> appreciate acks on these from relevant folks before merging them.
> Reviews/acks on any in the series would be welcome, but the last
> two especially are lacking any non-Intel acks:
>
> mm/resource: let walk_system_ram_range() search child resources
> dax: "Hotplug" persistent memory for use like normal RAM
I've gone ahead and added this to the libnvdimm-for-next branch for
wider exposure. Acks of course still welcome.
Stephen, this collides with commit 357b4da50a62 "x86: respect memory
size limiting via mem= parameter" in current -next. Here's my
resolution for reference, basically just add the max_mem_size
statement to Dave's rework. Holler if this causes any other problems.
diff --cc mm/memory_hotplug.c
index a9d5787044e1,b37f3a5c4833..c4f59ac21014
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@@ -102,28 -99,21 +102,24 @@@ u64 max_mem_size = U64_MAX
/* add this memory to iomem resource */
static struct resource *register_memory_resource(u64 start, u64 size)
{
- struct resource *res, *conflict;
+ struct resource *res;
+ unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+ char *resource_name = "System RAM";
+ if (start + size > max_mem_size)
+ return ERR_PTR(-E2BIG);
+
- res = kzalloc(sizeof(struct resource), GFP_KERNEL);
- if (!res)
- return ERR_PTR(-ENOMEM);
-
- res->name = "System RAM";
- res->start = start;
- res->end = start + size - 1;
- res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
- conflict = request_resource_conflict(&iomem_resource, res);
- if (conflict) {
- if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
- pr_debug("Device unaddressable memory block "
- "memory hotplug at %#010llx !\n",
- (unsigned long long)start);
- }
- pr_debug("System RAM resource %pR cannot be added\n", res);
- kfree(res);
+ /*
+ * Request ownership of the new memory range. This might be
+ * a child of an existing resource that was present but
+ * not marked as busy.
+ */
+ res = __request_region(&iomem_resource, start, size,
+ resource_name, flags);
+
+ if (!res) {
+ pr_debug("Unable to reserve System RAM region:
%016llx->%016llx\n",
+ start, start + size);
return ERR_PTR(-EEXIST);
}
return res;
