Re: [Linux-nvdimm] [PATCH] SQUASHME: Fixes to e820 handling of pmem
On Wed, Apr 01, 2015 at 05:25:22PM +0300, Boaz Harrosh wrote:
pfn = PFN_DOWN(ei->addr + ei->size);
- switch (ei->type) {
- case E820_RAM:
- case E820_PRAM:
- case E820_RESERVED_KERN:
- break;
- default:
+ if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
register_nosave_region(PFN_UP(ei->addr), pfn);
- }
I guess this makes sense - if the content is persistent already we don't need
to save it.
- if (e820.map[i].type != E820_RESERVED || res->start <
(1ULL<<20)) {
- if (e820.map[i].type != E820_PRAM)
- res->flags |= IORESOURCE_BUSY;
+ if (((e820.map[i].type != E820_RESERVED) &&
+ (e820.map[i].type != E820_PRAM)) ||
+ res->start < (1ULL<<20)) {
So now we also trigger for PRAM regions under 1ULL<<20, was that the
intentional change? Honestly I don't really understand this 1ULL<<20
magic here even for the existing case. Guess this is magic from the
old ISA PC days?
+ res->flags |= IORESOURCE_BUSY;
Guess this is the real change, and I'd love to understand why this
makes a difference for you. IORESOURCE_BUSY is checked almost never,
and is intented to mean it's a driver mapping.