On 19 Aug 2025, at 12:50, Zi Yan wrote: > On 19 Aug 2025, at 4:54, David Hildenbrand wrote: > >> On 18.08.25 20:46, Zi Yan wrote: >>> and rename it to is_backed_by_folio(). >>> >>> is_backed_by_folio() checks if the given vaddr is backed a folio with >>> a given order. It does so by: >>> 1. getting the pfn of the vaddr; >>> 2. checking kpageflags of the pfn; >>> >>> if order is greater than 0: >>> 3. checking kpageflags of the head pfn; >>> 4. checking kpageflags of all tail pfns. >>> >>> pmd_order is added to split_huge_page_test.c and replaces max_order. >>> >>> Signed-off-by: Zi Yan <[email protected]> >>> Reviewed-by: Wei Yang <[email protected]> >>> Reviewed-by: wang lian <[email protected]> >>> --- >>> .../selftests/mm/split_huge_page_test.c | 88 ++++++++++++++----- >>> tools/testing/selftests/mm/vm_util.c | 13 +++ >>> tools/testing/selftests/mm/vm_util.h | 4 + >>> 3 files changed, 81 insertions(+), 24 deletions(-) >>> >>> diff --git a/tools/testing/selftests/mm/split_huge_page_test.c >>> b/tools/testing/selftests/mm/split_huge_page_test.c >>> index 089e146efeab..56d1eaf9a860 100644 >>> --- a/tools/testing/selftests/mm/split_huge_page_test.c >>> +++ b/tools/testing/selftests/mm/split_huge_page_test.c >>> @@ -25,6 +25,7 @@ >>> uint64_t pagesize; >>> unsigned int pageshift; >>> uint64_t pmd_pagesize; >>> +unsigned int pmd_order; >>> #define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages" >>> #define SMAP_PATH "/proc/self/smaps" >>> @@ -34,26 +35,66 @@ uint64_t pmd_pagesize; >>> #define PID_FMT_OFFSET "%d,0x%lx,0x%lx,%d,%d" >>> #define PATH_FMT "%s,0x%lx,0x%lx,%d" >>> -#define PFN_MASK ((1UL<<55)-1) >>> -#define KPF_THP (1UL<<22) >>> - >>> -static int is_backed_by_thp(char *vaddr, int pagemap_file, int >>> kpageflags_file) >>> +static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, >>> + int kpageflags_fd) >>> { >>> - uint64_t paddr; >>> - uint64_t page_flags; >>> + unsigned long pfn_head; >>> + uint64_t pfn_flags; >>> + unsigned long pfn; >>> + unsigned long i; >> >> Final nit (sorry!) :) >> >> const unsigned long nr_pages = 1ul << order; >> >> so you can make some of the code below easier to read. > > Sure. Will send a fixup. > >> >> Acked-by: David Hildenbrand <[email protected]> >> > Thanks.
Hi Andrew, The fixup below replaced 1 << order with nr_pages based on David's suggestion. Do you mind folding it in? Thanks. From c07eb882465b938a70acb84e4cdc5b6598536322 Mon Sep 17 00:00:00 2001 From: Zi Yan <[email protected]> Date: Tue, 19 Aug 2025 12:52:13 -0400 Subject: [PATCH] fixup: selftests/mm: use nr_pages instead of 1UL << order. Signed-off-by: Zi Yan <[email protected]> --- tools/testing/selftests/mm/split_huge_page_test.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 56d1eaf9a860..f2882cfab568 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -38,6 +38,7 @@ unsigned int pmd_order; static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, int kpageflags_fd) { + const unsigned long nr_pages = 1UL << order; unsigned long pfn_head; uint64_t pfn_flags; unsigned long pfn; @@ -63,7 +64,7 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, if (!(pfn_flags & KPF_THP)) return false; - pfn_head = pfn & ~((1 << order) - 1); + pfn_head = pfn & ~(nr_pages - 1); if (pageflags_get(pfn_head, kpageflags_fd, &pfn_flags)) goto fail; @@ -73,7 +74,7 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, return false; /* check all tail PFN flags */ - for (i = 1; i < 1UL << order; i++) { + for (i = 1; i < nr_pages; i++) { if (pageflags_get(pfn_head + i, kpageflags_fd, &pfn_flags)) goto fail; if (!(pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL))) @@ -84,7 +85,7 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, * check the PFN after this folio, but if its flags cannot be obtained, * assume this folio has the expected order */ - if (pageflags_get(pfn_head + (1UL << order), kpageflags_fd, &pfn_flags)) + if (pageflags_get(pfn_head + nr_pages, kpageflags_fd, &pfn_flags)) return true; /* this folio is bigger than the given order */ -- 2.50.1 -- Best Regards, Yan, Zi
