| b79d51e9 | 19-Sep-2026 |
Kiryl Shutsemau (Meta) <kas@kernel.org> |
selftests/mm: add khugepaged completion barrier helper
A khugepaged test has to tell "not collapsed" from "not scanned yet", and
nothing in the selftests can. wait_for_scan() in khugepaged.c comes
selftests/mm: add khugepaged completion barrier helper
A khugepaged test has to tell "not collapsed" from "not scanned yet", and
nothing in the selftests can. wait_for_scan() in khugepaged.c comes
closest: it polls full_scans until the counter has advanced by two, since
the pass in progress may already have passed the test's mm. But it only
returns in time if scan_sleep_millisecs happens to be short, and it is
private to that one test.
Add khugepaged_full_pass() to hugepage_settings, built on the same
advance-by-two wait but driven through sysfs: a store to
scan_sleep_millisecs wakes the daemon, so the barrier completes whatever
the scan cadence. A store made while the daemon is scanning rather than
sleeping is lost, so the helper keeps storing until the pass lands.
One wake completes one pass only if pages_to_scan covers every mm on the
list, so callers need it large.
Settings pushes must not start passes of their own. A store to either
sleep knob wakes the daemon, so thp_write_settings() now writes a
khugepaged knob only when its value changes.
Link: https://lore.kernel.org/20260919002451.496763-11-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Assisted-by: LLM
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: "David Hildenbrand (arm)" <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickens <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: kernel-team@meta.com
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Nico Pache (Red Hat) <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
show more ...
|
| ceffb8ff | 19-Sep-2026 |
Kiryl Shutsemau (Meta) <kas@kernel.org> |
selftests/mm: skip khugepaged page cache cases without a PMD folio
The page cache caps folio order at MAX_PAGECACHE_ORDER, which is below the
PMD order on arm64 with 64K pages, where a PMD is 512M.
selftests/mm: skip khugepaged page cache cases without a PMD folio
The page cache caps folio order at MAX_PAGECACHE_ORDER, which is below the
PMD order on arm64 with 64K pages, where a PMD is 512M. A PMD-sized page
cache folio is impossible there, so the kernel refuses these collapses:
MADV_COLLAPSE answers -EINVAL and khugepaged passes over the range. Four
shmem cases ask for a PMD-sized folio anyway, fail, and the run bails out
in the middle.
Skip the shmem and file mem types where the cap is below the PMD order.
The cap is not shmem-specific: it applies to every file folio. Add
thp_file_supported_orders() to read the orders the page cache allows.
Anonymous collapse is unaffected: its orders are not capped this way.
Link: https://lore.kernel.org/20260919002451.496763-5-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Assisted-by: LLM
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: "David Hildenbrand (arm)" <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickens <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: kernel-team@meta.com
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache (Red Hat) <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
show more ...
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