On Thu 23-08-18 10:56:30, Mike Kravetz wrote:
On 08/23/2018 10:01 AM, Mike Kravetz wrote:
On 08/23/2018 05:48 AM, Michal Hocko wrote:
On Tue 21-08-18 18:10:42, Mike Kravetz wrote: [...]
OK, after burning myself when trying to be clever here it seems like your proposed solution is indeed simpler.
+bool huge_pmd_sharing_possible(struct vm_area_struct *vma,
unsigned long *start, unsigned long *end)+{
- unsigned long check_addr = *start;
- bool ret = false;
- if (!(vma->vm_flags & VM_MAYSHARE))
return ret;- for (check_addr = *start; check_addr < *end; check_addr += PUD_SIZE) {
unsigned long a_start = check_addr & PUD_MASK;unsigned long a_end = a_start + PUD_SIZE;I guess this should be rather in HPAGE_SIZE * PTRS_PER_PTE units as huge_pmd_unshare does.
Sure, I can do that.
On second thought, this is more similar to vma_shareable() which uses PUD_MASK and PUD_SIZE. In fact Kirill asked me to put in a common helper for this and vma_shareable. So, I would prefer to leave it as PUD* unless you feel strongly.
I don't
IMO, it would make more sense to change this in huge_pmd_unshare as PMD sharing is pretty explicitly tied to PUD_SIZE. But, that is a future cleanup.
Fair enough. I didn't realize we are PUD explicit elsewhere. So if you plan to update huge_pmd_unshare to be in sync then no objections from me at all. I merely wanted to be in sync with this because it is a central point to look at wrt pmd sharing.