kernel/tools/testing/selftests/vm/khugepaged.c, branch linux-6.2.y

selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd

2022-10-03T21:03:34Z

This test tests that MADV_COLLAPSE acting on file/shmem memory for which (1) the file extent mapping by the memory is already a huge page in the page cache, and (2) the pmd mapping this memory in the target process is none. In practice, (1)+(2) is the state left over after khugepaged has successfully collapsed file/shmem memory for a target VMA, but the memory has not yet been refaulted. So, this test in-effect tests MADV_COLLAPSE racing with khugepaged to collapse the memory first. Link: https://lkml.kernel.org/r/20220907144521.3115321-10-zokeefe@google.com Link: https://lkml.kernel.org/r/20220922224046.1143204-10-zokeefe@google.com Signed-off-by: Zach O'Keefe Cc: Axel Rasmussen Cc: Chris Kennelly Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: James Houghton Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Minchan Kim Cc: Pasha Tatashin Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton

selftests/vm: add thp collapse shmem testing

2022-10-03T21:03:34Z

Add memory operations for shmem (memfd) memory, and reuse existing tests with the new memory operations. Shmem tests can be called with "shmem" mem_type, and shmem tests are ran with "all" mem_type as well. Link: https://lkml.kernel.org/r/20220907144521.3115321-9-zokeefe@google.com Link: https://lkml.kernel.org/r/20220922224046.1143204-9-zokeefe@google.com Signed-off-by: Zach O'Keefe Cc: Axel Rasmussen Cc: Chris Kennelly Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: James Houghton Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Minchan Kim Cc: Pasha Tatashin Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton

selftests/vm: add thp collapse file and tmpfs testing

2022-10-03T21:03:34Z

Add memory operations for file-backed and tmpfs memory. Call existing tests with these new memory operations to test collapse functionality of khugepaged and MADV_COLLAPSE on file-backed and tmpfs memory. Not all tests are reusable; for example, collapse_swapin_single_pte() which checks swap usage. Refactor test arguments. Usage is now: Usage: ./khugepaged [dir] : : : [all|khugepaged|madvise] : [all|anon|file] "file,all" mem_type requires [dir] argument "file,all" mem_type requires kernel built with CONFIG_READ_ONLY_THP_FOR_FS=y if [dir] is a (sub)directory of a tmpfs mount, tmpfs must be mounted with huge=madvise option for khugepaged tests to work Refactor calling tests to make it clear what collapse context / memory operations they support, but only invoke tests requested by user. Also log what test is being ran, and with what context / memory, to make test logs more human readable. A new test file is created and deleted for every test to ensure no pages remain in the page cache between tests (tests also may attempt to collapse different amount of memory). For file-backed memory where the file is stored on a block device, disable /sys/block//queue/read_ahead_kb so that pages don't find their way into the page cache without the tests faulting them in. Add file and shmem wrappers to vm_utils check for file and shmem hugepages in smaps. [zokeefe@google.com: fix "add thp collapse file and tmpfs testing" for tmpfs] Link: https://lkml.kernel.org/r/20220913212517.3163701-1-zokeefe@google.com Link: https://lkml.kernel.org/r/20220907144521.3115321-8-zokeefe@google.com Link: https://lkml.kernel.org/r/20220922224046.1143204-8-zokeefe@google.com Signed-off-by: Zach O'Keefe Cc: Axel Rasmussen Cc: Chris Kennelly Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: James Houghton Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Minchan Kim Cc: Pasha Tatashin Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton

selftests/vm: modularize thp collapse memory operations

2022-10-03T21:03:34Z

Modularize operations to setup, cleanup, fault, and check for huge pages, for a given memory type. This allows reusing existing tests with additional memory types by defining new memory operations. Following patches will add file and shmem memory types. Link: https://lkml.kernel.org/r/20220907144521.3115321-7-zokeefe@google.com Link: https://lkml.kernel.org/r/20220922224046.1143204-7-zokeefe@google.com Signed-off-by: Zach O'Keefe Cc: Axel Rasmussen Cc: Chris Kennelly Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: James Houghton Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Minchan Kim Cc: Pasha Tatashin Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton

selftests/vm: dedup THP helpers

2022-10-03T21:03:34Z

These files: tools/testing/selftests/vm/vm_util.c tools/testing/selftests/vm/khugepaged.c Both contain logic to: 1) Determine hugepage size on current system 2) Read /proc/self/smaps to determine number of THPs at an address Refactor selftests/vm/khugepaged.c to use the vm_util common helpers and add it as a build dependency. Since selftests/vm/khugepaged.c is the largest user of check_huge(), change the signature of check_huge() to match selftests/vm/khugepaged.c's useage: take an expected number of hugepages, and return a bool indicating if the correct number of hugepages were found. Add a wrapper, check_huge_anon(), in anticipation of checking smaps for file and shmem hugepages. Update existing callsites to use the new pattern / function. Likewise, check_for_pattern() was duplicated, and it's a general enough helper to include in vm_util helpers as well. Link: https://lkml.kernel.org/r/20220907144521.3115321-6-zokeefe@google.com Link: https://lkml.kernel.org/r/20220922224046.1143204-6-zokeefe@google.com Signed-off-by: Zach O'Keefe Reviewed-by: Zi Yan Cc: Axel Rasmussen Cc: Chris Kennelly Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: James Houghton Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Minchan Kim Cc: Pasha Tatashin Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton

selftests/vm: retry on EAGAIN for MADV_COLLAPSE selftest

2022-10-03T21:03:33Z

MADV_COLLAPSE is a best-effort request that will set errno to an actionable value if the request cannot be performed. For example, if pages are not found on the LRU, or if they are currently locked by something else, MADV_COLLAPSE will fail and set errno to EAGAIN to inform callers that they may try again. Since the khugepaged selftest is the first public use of MADV_COLLAPSE, set a best practice of checking errno and retrying on EAGAIN. Link: https://lkml.kernel.org/r/20220922184651.1016461-2-zokeefe@google.com Fixes: 9330694de59f ("selftests/vm: add MADV_COLLAPSE collapse context to selftests") Signed-off-by: Zach O'Keefe Cc: Axel Rasmussen Cc: Chris Kennelly Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: James Houghton Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Minchan Kim Cc: Pasha Tatashin Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton

selftests/vm: add selftest to verify multi THP collapse

2022-09-12T03:25:47Z

Add support to allocate and verify collapse of multiple hugepage-sized regions into multiple THPs. Add "nr" argument to check_huge() that instructs check_huge() to check for exactly "nr_hpages" THPs. This has the added benefit of now being able to check for exactly 0 THPs, and so callsites that previously checked the negation of exactly 1 THP are now more correct. ->collapse struct collapse_context hook has been expanded with a "nr_hpages" argument to collapse "nr_hpages" hugepages. The collapse_full() test has been repurposed to collapse 4 THPs at once. It is expected more tests will want to test multi THP collapse (e.g. file/shmem). This is of particular benefit to madvise collapse context given that it may do many THP collapses during a single syscall. Link: https://lkml.kernel.org/r/20220706235936.2197195-19-zokeefe@google.com Signed-off-by: Zach O'Keefe Cc: Alex Shi Cc: Andrea Arcangeli Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Chris Kennelly Cc: Chris Zankel Cc: David Hildenbrand Cc: David Rientjes Cc: Helge Deller Cc: Hugh Dickins Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jens Axboe Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Miaohe Lin Cc: Michal Hocko Cc: Minchan Kim Cc: Pasha Tatashin Cc: Pavel Begunkov Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Thomas Bogendoerfer Cc: Vlastimil Babka Cc: Yang Shi Cc: Zi Yan Cc: Dan Carpenter Cc: "Souptick Joarder (HPE)" Signed-off-by: Andrew Morton

selftests/vm: add selftest to verify recollapse of THPs

2022-09-12T03:25:47Z

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@google.com Signed-off-by: Zach O'Keefe Cc: Alex Shi Cc: Andrea Arcangeli Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Chris Kennelly Cc: Chris Zankel Cc: David Hildenbrand Cc: David Rientjes Cc: Helge Deller Cc: Hugh Dickins Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jens Axboe Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Miaohe Lin Cc: Michal Hocko Cc: Minchan Kim Cc: Pasha Tatashin Cc: Pavel Begunkov Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Thomas Bogendoerfer Cc: Vlastimil Babka Cc: Yang Shi Cc: Zi Yan Cc: Dan Carpenter Cc: "Souptick Joarder (HPE)" Signed-off-by: Andrew Morton

selftests/vm: add MADV_COLLAPSE collapse context to selftests

2022-09-12T03:25:47Z

Add madvise collapse context to hugepage collapse selftests. This context is tested with /sys/kernel/mm/transparent_hugepage/enabled set to "never" in order to avoid unwanted interaction with khugepaged during testing. Also, refactor updates to sysfs THP settings using a stack so that the THP settings from nested callers can be restored. Link: https://lkml.kernel.org/r/20220706235936.2197195-17-zokeefe@google.com Signed-off-by: Zach O'Keefe Cc: Alex Shi Cc: Andrea Arcangeli Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Chris Kennelly Cc: Chris Zankel Cc: David Hildenbrand Cc: David Rientjes Cc: Helge Deller Cc: Hugh Dickins Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jens Axboe Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Miaohe Lin Cc: Michal Hocko Cc: Minchan Kim Cc: Pasha Tatashin Cc: Pavel Begunkov Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Thomas Bogendoerfer Cc: Vlastimil Babka Cc: Yang Shi Cc: Zi Yan Cc: Dan Carpenter Cc: "Souptick Joarder (HPE)" Signed-off-by: Andrew Morton

selftests/vm: dedup hugepage allocation logic

2022-09-12T03:25:47Z

The code p = alloc_mapping(); printf("Allocate huge page..."); madvise(p, hpage_pmd_size, MADV_HUGEPAGE); fill_memory(p, 0, hpage_pmd_size); if (check_huge(p)) success("OK"); else fail("Fail"); Is repeated many times in different tests. Add a helper, alloc_hpage() to handle this. Link: https://lkml.kernel.org/r/20220706235936.2197195-16-zokeefe@google.com Signed-off-by: Zach O'Keefe Cc: Alex Shi Cc: Andrea Arcangeli Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Chris Kennelly Cc: Chris Zankel Cc: David Hildenbrand Cc: David Rientjes Cc: Helge Deller Cc: Hugh Dickins Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jens Axboe Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Miaohe Lin Cc: Michal Hocko Cc: Minchan Kim Cc: Pasha Tatashin Cc: Pavel Begunkov Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Thomas Bogendoerfer Cc: Vlastimil Babka Cc: Yang Shi Cc: Zi Yan Cc: Dan Carpenter Cc: "Souptick Joarder (HPE)" Signed-off-by: Andrew Morton