diff options
| author | Ran Xiaokai <ran.xiaokai@zte.com.cn> | 2024-07-05 10:43:43 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-07-12 15:52:21 -0700 |
| commit | 4c8763e84aae4d04d94b35aca9f7db6a8930ad77 (patch) | |
| tree | 04a8259e2d597f28574e77b53a0c6143e5ca692f | |
| parent | 00f58104202c472e487f0866fbd38832523fd4f9 (diff) | |
kpageflags: detect isolated KPF_THP folios
When folio is isolated, the PG_lru bit is cleared. So the PG_lru check in
stable_page_flags() will miss this kind of isolated folios. Use
folio_test_large_rmappable() instead to also include isolated folios.
Since pagecache supports large folios and the introduction of mTHP, the
semantics of KPF_THP have been expanded, now it indicates not only
PMD-sized THP. Update related documentation to clearly state that KPF_THP
indicates multiple order THPs.
[ran.xiaokai@zte.com.cn: directly use is_zero_folio(), per David]
Link: https://lkml.kernel.org/r/20240708062601.165215-1-ranxiaokai627@163.com
Link: https://lkml.kernel.org/r/20240705104343.112680-1-ranxiaokai627@163.com
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Svetly Todorov <svetly.todorov@memverge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | Documentation/admin-guide/mm/pagemap.rst | 4 | ||||
| -rw-r--r-- | fs/proc/page.c | 21 |
2 files changed, 11 insertions, 14 deletions
diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index f2817a801596..caba0f52dd36 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -118,7 +118,7 @@ Short descriptions to the page flags 21 - KSM Identical memory pages dynamically shared between one or more processes. 22 - THP - Contiguous pages which construct transparent hugepages. + Contiguous pages which construct THP of any size and mapped by any granularity. 23 - OFFLINE The page is logically offline. 24 - ZERO_PAGE @@ -231,7 +231,7 @@ Following flags about pages are currently supported: - ``PAGE_IS_PRESENT`` - Page is present in the memory - ``PAGE_IS_SWAPPED`` - Page is in swapped - ``PAGE_IS_PFNZERO`` - Page has zero PFN -- ``PAGE_IS_HUGE`` - Page is THP or Hugetlb backed +- ``PAGE_IS_HUGE`` - Page is PMD-mapped THP or Hugetlb backed - ``PAGE_IS_SOFT_DIRTY`` - Page is soft-dirty The ``struct pm_scan_arg`` is used as the argument of the IOCTL. diff --git a/fs/proc/page.c b/fs/proc/page.c index e8440db8cfbf..b7a5c84b5819 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -147,19 +147,16 @@ u64 stable_page_flags(const struct page *page) u |= 1 << KPF_COMPOUND_TAIL; if (folio_test_hugetlb(folio)) u |= 1 << KPF_HUGE; - /* - * We need to check PageLRU/PageAnon - * to make sure a given page is a thp, not a non-huge compound page. - */ - else if (folio_test_large(folio)) { - if ((k & (1 << PG_lru)) || is_anon) - u |= 1 << KPF_THP; - else if (is_huge_zero_folio(folio)) { - u |= 1 << KPF_ZERO_PAGE; - u |= 1 << KPF_THP; - } - } else if (is_zero_pfn(page_to_pfn(page))) + else if (folio_test_large(folio) && + folio_test_large_rmappable(folio)) { + /* Note: we indicate any THPs here, not just PMD-sized ones */ + u |= 1 << KPF_THP; + } else if (is_huge_zero_folio(folio)) { u |= 1 << KPF_ZERO_PAGE; + u |= 1 << KPF_THP; + } else if (is_zero_folio(folio)) { + u |= 1 << KPF_ZERO_PAGE; + } /* * Caveats on high order pages: PG_buddy and PG_slab will only be set |