This patch series starts the conversion of the hugetlb code to operate on struct folios rather than struct pages. This removes the ambiguitiy of whether functions are operating on head pages, tail pages of compound pages, or base pages. This series passes the linux test project hugetlb test cases. Patch 1 adds hugeltb specific page macros that can operate on folios. Patch 2 adds the private field of the first tail page to struct page. For 32-bit, _private_1 alinging with page[1].private was confirmed by using pahole. This patch depends on Matthew Wilcox's patch mm: Add the first tail page to struct folio[1]: Patchs 3-4 introduce hugetlb subpool helper functions which operate on struct folios. These patches were tested using the hugepage-mmap.c selftest along with the migratepages command. Patch 5 converts hugetlb_delete_from_page_cache() to use folios. This patch depends on Mike Kravetz's patch: hugetlb: rename remove_huge_page to hugetlb_delete_from_page_cache[2]. Patch 6 adds a folio_hstate() function to get hstate information from a folio and adds a user of folio_hstate(). Bpftrace was used to track time spent in the free_huge_pages function during the ltp test cases as it is a caller of the hugetlb subpool functions. From the histogram, the performance is similar before and after the patch series. Time spent in 'free_huge_page' 6.0.0-rc2.master.20220823 @nsecs: [256, 512) 14770 |@@@@@@@@@@@@@@@@@@@@@@@@@@@ |@@@@@@@@@@@@@@@@@@@@@@@@@ | [512, 1K) 155 | | [1K, 2K) 169 | | [2K, 4K) 50 | | [4K, 8K) 14 | | [8K, 16K) 3 | | [16K, 32K) 3 | | 6.0.0-rc2.master.20220823 + patch series @nsecs: [256, 512) 13678 |@@@@@@@@@@@@@@@@@@@@@@@@@@@ | |@@@@@@@@@@@@@@@@@@@@@@@@@ | [512, 1K) 142 | | [1K, 2K) 199 | | [2K, 4K) 44 | | [4K, 8K) 13 | | [8K, 16K) 4 | | [16K, 32K) 1 | | [1] https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next/+/f0a284d27efbfcc1a46c2a6075a259e628ad29c0 [2] https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next/+/e829be3202116d9aeb94cc1ff64e89dcbf7c47d3 v2 -> v3: - fix build error by defining folio_hsate() when CONFIG_HUGETLB_PAGE=n v1 --> v2: - test compiling on i386. - change return type from int to bool in patch 1 - move _private_1 field in struct page to within a CONFIG_64BIT block in patch 2 - squash patch 7 from v1 into patch 6 Sidhartha Kumar (6): mm/hugetlb: add folio support to hugetlb specific flag macros mm: add private field of first tail to struct page and struct folio mm/hugetlb: add hugetlb_folio_subpool() helper mm/hugetlb: add hugetlb_set_folio_subpool() helper hugetlbfs: convert hugetlb_delete_from_page_cache() to use folios mm/hugetlb: add folio_hstate() fs/hugetlbfs/inode.c | 22 ++++++++--------- include/linux/hugetlb.h | 53 +++++++++++++++++++++++++++++++++++++--- include/linux/mm_types.h | 14 +++++++++++ mm/migrate.c | 2 +- 4 files changed, 75 insertions(+), 16 deletions(-) -- 2.31.1
