On 8/25/21 05:48, Alex Sierra wrote: > From: Ralph Campbell <rcampbell@xxxxxxxxxx> > > ZONE_DEVICE struct pages have an extra reference count that complicates the > code for put_page() and several places in the kernel that need to check the > reference count to see that a page is not being used (gup, compaction, > migration, etc.). Clean up the code so the reference count doesn't need to > be treated specially for ZONE_DEVICE. That's certainly welcome. I just wonder what was the reason to use 1 in the first place and why it's no longer necessary?