On 4/8/21 8:01 PM, Miaohe Lin wrote: > On 2021/4/9 6:53, Mike Kravetz wrote: >> >> Yes, add a comment to hugetlb_unreserve_pages saying that !resv_map >> implies freed == 0. >> > > Sounds good! > >> It would also be helpful to check for (chg - freed) == 0 and skip the >> calls to hugepage_subpool_put_pages() and hugetlb_acct_memory(). Both >> of those routines may perform an unnecessary lock/unlock cycle in this >> case. >> >> A simple >> if (chg == free) >> return 0; >> before the call to hugepage_subpool_put_pages would work. > > This may not be really helpful because hugepage_subpool_put_pages() and hugetlb_acct_memory() > both would handle delta == 0 case without unnecessary lock/unlock cycle. > Does this make sense for you? If so, I will prepare v2 with the changes to add a comment > to hugetlb_unreserve_pages() __without__ the check for (chg - freed) == 0. Sorry, I forgot about the recent changes to check for delta == 0. No need for the check here, just the comment. -- Mike Kravetz
