On 04.02.23 07:18, yang.yang29@xxxxxxxxxx wrote:
[sorry, was on vacation last week]
Why use flags if they both conditions are mutually exclusive?
Just to make the return value of break_ksm_pmd_entry() more expressive and
understandable. because break_ksm_pmd_entry have three types of returned
values (0, 1, 2).
It adds confusion. Just simplify it please.
MADV_UNMERGEABLE -> unmerge_ksm_pages() will never unshare the shared
zeropage? I thought the patch description mentions that that is one of
the goals?
No, MADV_UNMERGEABLE will trigger KSM to unshare the shared zeropages in the
context of "get_next_rmap_item() -> unshare_zero_pages(), but not directly in the
context of " madvise()-> unmerge_ksm_pages() ". The reason for this is to avoid
increasing long delays of madvise() calling on unsharing zero pages.
Why do we care and make this case special?
--
Thanks,
David / dhildenb
