While discussing a series of hugetlb fixes in [1], it became evident that the hugetlb specific page state information is stored in a somewhat haphazard manner. Code dealing with state information would be easier to read, understand and maintain if this information was stored in a consistent manner. This RFC series uses page.private of the hugetlb head page for storing a set of hugetlb specific page flags. Routines to manipulate the flags are copied from normal page flag manipulation code and use atomic operations. This is likely overkill for the uses in hugetlb code, and can be changed after additional auditing of code. For now, only 3 state flags are added as part of this series. However, the suggested fix in [2] could use another flag. In addition, a flag could be used to track whether or not a huge page has been cleared to optimize code paths if the init_on_alloc security feature is enabled. [1] https://lore.kernel.org/r/20210106084739.63318-1-songmuchun@xxxxxxxxxxxxx [2] https://lore.kernel.org/r/20210110124017.86750-4-songmuchun@xxxxxxxxxxxxx Mike Kravetz (3): hugetlb: use page.private for hugetlb specific page flags hugetlb: convert page_huge_active() to HPageMigratable flag hugetlb: convert PageHugeTemporary() to HPageTempSurplus fs/hugetlbfs/inode.c | 11 +-- include/linux/hugetlb.h | 19 ++++ include/linux/page-flags.h | 6 -- mm/hugetlb.c | 178 ++++++++++++++++++++----------------- mm/memory_hotplug.c | 2 +- 5 files changed, 121 insertions(+), 95 deletions(-) -- 2.29.2
