The patch titled
Subject: selftests/vm: add selftest to verify recollapse of THPs
has been added to the -mm mm-unstable branch. Its filename is
selftests-vm-add-selftest-to-verify-recollapse-of-thps.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-vm-add-selftest-to-verify-recollapse-of-thps.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Zach O'Keefe" <zokeefe@xxxxxxxxxx>
Subject: selftests/vm: add selftest to verify recollapse of THPs
Date: Wed, 6 Jul 2022 16:59:35 -0700
Add selftest specific to madvise collapse context that tests MADV_COLLAPSE
is "successful" if a hugepage-aligned/sized region is already pmd-mapped.
This test also verifies that MADV_COLLAPSE can collapse memory into THPs
even in "madvise" THP mode and the memory isn't marked VM_HUGEPAGE.
Link: https://lkml.kernel.org/r/20220706235936.2197195-18-zokeefe@xxxxxxxxxx
Signed-off-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Cc: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Chris Kennelly <ckennelly@xxxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Pavel Begunkov <asml.silence@xxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Rongwei Wang <rongwei.wang@xxxxxxxxxxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/vm/khugepaged.c | 31 ++++++++++++++++++++++
1 file changed, 31 insertions(+)
--- a/tools/testing/selftests/vm/khugepaged.c~selftests-vm-add-selftest-to-verify-recollapse-of-thps
+++ a/tools/testing/selftests/vm/khugepaged.c
@@ -990,6 +990,36 @@ static void collapse_max_ptes_shared(str
munmap(p, hpage_pmd_size);
}
+static void madvise_collapse_existing_thps(void)
+{
+ void *p;
+ int err;
+
+ p = alloc_mapping();
+ fill_memory(p, 0, hpage_pmd_size);
+
+ printf("Collapse fully populated PTE table...");
+ /*
+ * Note that we don't set MADV_HUGEPAGE here, which
+ * also tests that VM_HUGEPAGE isn't required for
+ * MADV_COLLAPSE in "madvise" mode.
+ */
+ err = madvise(p, hpage_pmd_size, MADV_COLLAPSE);
+ if (err == 0 && check_huge(p)) {
+ success("OK");
+ printf("Re-collapse PMD-mapped hugepage");
+ err = madvise(p, hpage_pmd_size, MADV_COLLAPSE);
+ if (err == 0 && check_huge(p))
+ success("OK");
+ else
+ fail("Fail");
+ } else {
+ fail("Fail");
+ }
+ validate_memory(p, 0, hpage_pmd_size);
+ munmap(p, hpage_pmd_size);
+}
+
int main(int argc, const char **argv)
{
struct collapse_context c;
@@ -1057,6 +1087,7 @@ int main(int argc, const char **argv)
collapse_fork(&c);
collapse_fork_compound(&c);
collapse_max_ptes_shared(&c);
+ madvise_collapse_existing_thps();
}
restore_settings(0);
_
Patches currently in -mm which might be from zokeefe@xxxxxxxxxx are
mm-khugepaged-remove-redundant-transhuge_vma_suitable-check.patch
mm-khugepaged-add-struct-collapse_control.patch
mm-khugepaged-dedup-and-simplify-hugepage-alloc-and-charging.patch
mm-khugepaged-pipe-enum-scan_result-codes-back-to-callers.patch
mm-khugepaged-add-flag-to-predicate-khugepaged-only-behavior.patch
mm-thp-add-flag-to-enforce-sysfs-thp-in-hugepage_vma_check.patch
mm-khugepaged-record-scan_pmd_mapped-when-scan_pmd-finds-hugepage.patch
mm-madvise-introduce-madv_collapse-sync-hugepage-collapse.patch
mm-khugepaged-rename-prefix-of-shared-collapse-functions.patch
mm-madvise-add-huge_memory-mm_madvise_collapse-tracepoint.patch
mm-madvise-add-madv_collapse-to-process_madvise.patch
proc-smaps-add-pmdmappable-field-to-smaps.patch
selftests-vm-modularize-collapse-selftests.patch
selftests-vm-dedup-hugepage-allocation-logic.patch
selftests-vm-add-madv_collapse-collapse-context-to-selftests.patch
selftests-vm-add-selftest-to-verify-recollapse-of-thps.patch
selftests-vm-add-selftest-to-verify-multi-thp-collapse.patch
