On Tue, Mar 31, 2026 at 05:34:44PM +1100, Alistair Popple wrote: > Several HMM tests hardcode TWOMEG as the THP size. This is wrong on > architectures where the PMD size is not 2MB such as arm64 with 64K base
+1 But one question… Can’t the THP size be derived via HPAGE_PMD_ORDER? If not, then some DRM common code I’ve written will break on arm64. Matt > pages where THP is 512MB. Fix this by using read_pmd_pagesize() from > vm_util instead. > > While here also replace the custom file_read_ulong() helper used to > parse the default hugetlbfs page size from /proc/meminfo with the > existing default_huge_page_size() from vm_util. > > [1] > https://lore.kernel.org/linux-mm/[email protected]/ > > Fixes: fee9f6d1b8df ("mm/hmm/test: add selftests for HMM") > Fixes: 519071529d2a ("selftests/mm/hmm-tests: new tests for zone device THP > migration") > Reported-by: Zenghui Yu <[email protected]> > Closes: > https://lore.kernel.org/linux-mm/[email protected]/ > Signed-off-by: Alistair Popple <[email protected]> > --- > tools/testing/selftests/mm/hmm-tests.c | 83 +++++--------------------- > 1 file changed, 16 insertions(+), 67 deletions(-) > > diff --git a/tools/testing/selftests/mm/hmm-tests.c > b/tools/testing/selftests/mm/hmm-tests.c > index e8328c89d855..788689497e92 100644 > --- a/tools/testing/selftests/mm/hmm-tests.c > +++ b/tools/testing/selftests/mm/hmm-tests.c > @@ -34,6 +34,7 @@ > */ > #include <lib/test_hmm_uapi.h> > #include <mm/gup_test.h> > +#include <mm/vm_util.h> > > struct hmm_buffer { > void *ptr; > @@ -548,7 +549,7 @@ TEST_F(hmm, anon_write_child) > > for (migrate = 0; migrate < 2; ++migrate) { > for (use_thp = 0; use_thp < 2; ++use_thp) { > - npages = ALIGN(use_thp ? TWOMEG : HMM_BUFFER_SIZE, > + npages = ALIGN(use_thp ? read_pmd_pagesize() : > HMM_BUFFER_SIZE, > self->page_size) >> self->page_shift; > ASSERT_NE(npages, 0); > size = npages << self->page_shift; > @@ -728,7 +729,7 @@ TEST_F(hmm, anon_write_huge) > int *ptr; > int ret; > > - size = 2 * TWOMEG; > + size = 2 * read_pmd_pagesize(); > > buffer = malloc(sizeof(*buffer)); > ASSERT_NE(buffer, NULL); > @@ -744,7 +745,7 @@ TEST_F(hmm, anon_write_huge) > buffer->fd, 0); > ASSERT_NE(buffer->ptr, MAP_FAILED); > > - size = TWOMEG; > + size /= 2; > npages = size >> self->page_shift; > map = (void *)ALIGN((uintptr_t)buffer->ptr, size); > ret = madvise(map, size, MADV_HUGEPAGE); > @@ -770,54 +771,6 @@ TEST_F(hmm, anon_write_huge) > hmm_buffer_free(buffer); > } > > -/* > - * Read numeric data from raw and tagged kernel status files. Used to read > - * /proc and /sys data (without a tag) and from /proc/meminfo (with a tag). > - */ > -static long file_read_ulong(char *file, const char *tag) > -{ > - int fd; > - char buf[2048]; > - int len; > - char *p, *q; > - long val; > - > - fd = open(file, O_RDONLY); > - if (fd < 0) { > - /* Error opening the file */ > - return -1; > - } > - > - len = read(fd, buf, sizeof(buf)); > - close(fd); > - if (len < 0) { > - /* Error in reading the file */ > - return -1; > - } > - if (len == sizeof(buf)) { > - /* Error file is too large */ > - return -1; > - } > - buf[len] = '\0'; > - > - /* Search for a tag if provided */ > - if (tag) { > - p = strstr(buf, tag); > - if (!p) > - return -1; /* looks like the line we want isn't there */ > - p += strlen(tag); > - } else > - p = buf; > - > - val = strtol(p, &q, 0); > - if (*q != ' ') { > - /* Error parsing the file */ > - return -1; > - } > - > - return val; > -} > - > /* > * Write huge TLBFS page. > */ > @@ -826,15 +779,13 @@ TEST_F(hmm, anon_write_hugetlbfs) > struct hmm_buffer *buffer; > unsigned long npages; > unsigned long size; > - unsigned long default_hsize; > + unsigned long default_hsize = default_huge_page_size(); > unsigned long i; > int *ptr; > int ret; > > - default_hsize = file_read_ulong("/proc/meminfo", "Hugepagesize:"); > - if (default_hsize < 0 || default_hsize*1024 < default_hsize) > + if (!default_hsize) > SKIP(return, "Huge page size could not be determined"); > - default_hsize = default_hsize*1024; /* KB to B */ > > size = ALIGN(TWOMEG, default_hsize); > npages = size >> self->page_shift; > @@ -1606,7 +1557,7 @@ TEST_F(hmm, compound) > struct hmm_buffer *buffer; > unsigned long npages; > unsigned long size; > - unsigned long default_hsize; > + unsigned long default_hsize = default_huge_page_size(); > int *ptr; > unsigned char *m; > int ret; > @@ -1614,10 +1565,8 @@ TEST_F(hmm, compound) > > /* Skip test if we can't allocate a hugetlbfs page. */ > > - default_hsize = file_read_ulong("/proc/meminfo", "Hugepagesize:"); > - if (default_hsize < 0 || default_hsize*1024 < default_hsize) > + if (!default_hsize) > SKIP(return, "Huge page size could not be determined"); > - default_hsize = default_hsize*1024; /* KB to B */ > > size = ALIGN(TWOMEG, default_hsize); > npages = size >> self->page_shift; > @@ -2106,7 +2055,7 @@ TEST_F(hmm, migrate_anon_huge_empty) > int *ptr; > int ret; > > - size = TWOMEG; > + size = read_pmd_pagesize(); > > buffer = malloc(sizeof(*buffer)); > ASSERT_NE(buffer, NULL); > @@ -2158,7 +2107,7 @@ TEST_F(hmm, migrate_anon_huge_zero) > int ret; > int val; > > - size = TWOMEG; > + size = read_pmd_pagesize(); > > buffer = malloc(sizeof(*buffer)); > ASSERT_NE(buffer, NULL); > @@ -2221,7 +2170,7 @@ TEST_F(hmm, migrate_anon_huge_free) > int *ptr; > int ret; > > - size = TWOMEG; > + size = read_pmd_pagesize(); > > buffer = malloc(sizeof(*buffer)); > ASSERT_NE(buffer, NULL); > @@ -2280,7 +2229,7 @@ TEST_F(hmm, migrate_anon_huge_fault) > int *ptr; > int ret; > > - size = TWOMEG; > + size = read_pmd_pagesize(); > > buffer = malloc(sizeof(*buffer)); > ASSERT_NE(buffer, NULL); > @@ -2332,7 +2281,7 @@ TEST_F(hmm, migrate_partial_unmap_fault) > { > struct hmm_buffer *buffer; > unsigned long npages; > - unsigned long size = TWOMEG; > + unsigned long size = read_pmd_pagesize(); > unsigned long i; > void *old_ptr; > void *map; > @@ -2398,7 +2347,7 @@ TEST_F(hmm, migrate_remap_fault) > { > struct hmm_buffer *buffer; > unsigned long npages; > - unsigned long size = TWOMEG; > + unsigned long size = read_pmd_pagesize(); > unsigned long i; > void *old_ptr, *new_ptr = NULL; > void *map; > @@ -2498,7 +2447,7 @@ TEST_F(hmm, migrate_anon_huge_err) > int *ptr; > int ret; > > - size = TWOMEG; > + size = read_pmd_pagesize(); > > buffer = malloc(sizeof(*buffer)); > ASSERT_NE(buffer, NULL); > @@ -2593,7 +2542,7 @@ TEST_F(hmm, migrate_anon_huge_zero_err) > int *ptr; > int ret; > > - size = TWOMEG; > + size = read_pmd_pagesize(); > > buffer = malloc(sizeof(*buffer)); > ASSERT_NE(buffer, NULL); > -- > 2.53.0 >
