[PATCH v2 3/4] mm/migrate: add tracepoint for folios unmapped during migration
From: Wandun Chen <hidden>
Date: 2026-07-07 13:00:23
Also in:
linux-mm, linux-rt-devel, lkml
Subsystem:
memory management, memory management - rmap (reverse mapping), the rest, tracing · Maintainers:
Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
From: Wandun Chen <redacted> Add mm_migrate_unmap_folio tracepoint, fired in try_to_migrate_one() after a folio's mapping has been replaced by a migration entry. It records the pfn, address, folio flags and vm_flags, making mlocked folios under migration easy to observe. Signed-off-by: Wandun Chen <redacted> --- include/trace/events/migrate.h | 29 +++++++++++++++++++++++++++++ mm/rmap.c | 4 ++++ 2 files changed, 33 insertions(+)
diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h
index 15ee2ef201b5..1264593ecaee 100644
--- a/include/trace/events/migrate.h
+++ b/include/trace/events/migrate.h@@ -6,6 +6,7 @@ #define _TRACE_MIGRATE_H #include <linux/tracepoint.h> +#include <trace/events/mmflags.h> #define MIGRATE_MODE \ EM( MIGRATE_ASYNC, "MIGRATE_ASYNC") \
@@ -137,6 +138,34 @@ DEFINE_EVENT(migration_pte, set_migration_pte, TP_ARGS(addr, pte, order) ); +TRACE_EVENT(mm_migrate_unmap_folio, + + TP_PROTO(unsigned long pfn, unsigned long addr, + unsigned long page_flags, unsigned long vm_flags), + + TP_ARGS(pfn, addr, page_flags, vm_flags), + + TP_STRUCT__entry( + __field(unsigned long, pfn) + __field(unsigned long, addr) + __field(unsigned long, page_flags) + __field(unsigned long, vm_flags) + ), + + TP_fast_assign( + __entry->pfn = pfn; + __entry->addr = addr; + __entry->page_flags = page_flags; + __entry->vm_flags = vm_flags; + ), + + TP_printk("pfn=0x%lx addr=0x%lx page_flags=%s vm_flags=%s", + __entry->pfn, + __entry->addr, + show_page_flags(__entry->page_flags & PAGEFLAGS_MASK), + show_vma_flags(__entry->vm_flags)) +); + DEFINE_EVENT(migration_pte, remove_migration_pte, TP_PROTO(unsigned long addr, unsigned long pte, int order), TP_ARGS(addr, pte, order)
diff --git a/mm/rmap.c b/mm/rmap.c
index 3cb7f6337d38..b110548bebae 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c@@ -2716,6 +2716,10 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, hugetlb_remove_rmap(folio); else folio_remove_rmap_pte(folio, subpage, vma); + + trace_mm_migrate_unmap_folio(folio_pfn(folio), address, + folio->flags.f, vma->vm_flags); + if (vma->vm_flags & VM_LOCKED) mlock_drain_local(); folio_put(folio);
--
2.43.0