6 files changed, 50 insertions, 4 deletions

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index cac1c0904d5f..9b50325e4ddf 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -23,9 +23,13 @@ enum migrate_reason {
         MR_SYSCALL,             /* also applies to cpusets */
         MR_MEMPOLICY_MBIND,
         MR_NUMA_MISPLACED,
-        MR_CMA
+        MR_CMA,
+        MR_TYPES
 };
 
+/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
+extern char *migrate_reason_names[MR_TYPES];
+
 #ifdef CONFIG_MIGRATION
 
 extern void putback_movable_pages(struct list_head *l);
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index 17f118a82854..e1fe7cf5bddf 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -45,6 +45,7 @@ struct page_ext {
         unsigned int order;
         gfp_t gfp_mask;
         unsigned int nr_entries;
+        int last_migrate_reason;
         unsigned long trace_entries[8];
 #endif
 };
diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index 6440daab4ef8..555893bf13d7 100644
--- a/include/linux/page_owner.h
+++ b/include/linux/page_owner.h
@@ -12,6 +12,7 @@ extern void __set_page_owner(struct page *page,
                         unsigned int order, gfp_t gfp_mask);
 extern gfp_t __get_page_owner_gfp(struct page *page);
 extern void __copy_page_owner(struct page *oldpage, struct page *newpage);
+extern void __set_page_owner_migrate_reason(struct page *page, int reason);
 
 static inline void reset_page_owner(struct page *page, unsigned int order)
 {
@@ -38,6 +39,11 @@ static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
         if (static_branch_unlikely(&page_owner_inited))
                 __copy_page_owner(oldpage, newpage);
 }
+static inline void set_page_owner_migrate_reason(struct page *page, int reason)
+{
+        if (static_branch_unlikely(&page_owner_inited))
+                __set_page_owner_migrate_reason(page, reason);
+}
 #else
 static inline void reset_page_owner(struct page *page, unsigned int order)
 {
@@ -53,5 +59,8 @@ static inline gfp_t get_page_owner_gfp(struct page *page)
 static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
 {
 }
+static inline void set_page_owner_migrate_reason(struct page *page, int reason)
+{
+}
 #endif /* CONFIG_PAGE_OWNER */
 #endif /* __LINUX_PAGE_OWNER_H */
diff --git a/mm/debug.c b/mm/debug.c
index 231e1452a912..78dc54877075 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -10,9 +10,20 @@
 #include <linux/trace_events.h>
 #include <linux/memcontrol.h>
 #include <trace/events/mmflags.h>
+#include <linux/migrate.h>
 
 #include "internal.h"
 
+char *migrate_reason_names[MR_TYPES] = {
+        "compaction",
+        "memory_failure",
+        "memory_hotplug",
+        "syscall_or_cpuset",
+        "mempolicy_mbind",
+        "numa_misplaced",
+        "cma",
+};
+
 const struct trace_print_flags pageflag_names[] = {
         __def_pageflag_names,
         {0, NULL}
diff --git a/mm/migrate.c b/mm/migrate.c
index 8133805431ba..432ecd0172cd 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -955,8 +955,10 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
         }
 
         rc = __unmap_and_move(page, newpage, force, mode);
-        if (rc == MIGRATEPAGE_SUCCESS)
+        if (rc == MIGRATEPAGE_SUCCESS) {
                 put_new_page = NULL;
+                set_page_owner_migrate_reason(newpage, reason);
+        }
 
 out:
         if (rc != -EAGAIN) {
@@ -1021,7 +1023,7 @@ out:
 static int unmap_and_move_huge_page(new_page_t get_new_page,
                                 free_page_t put_new_page, unsigned long private,
                                 struct page *hpage, int force,
-                                enum migrate_mode mode)
+                                enum migrate_mode mode, int reason)
 {
         int rc = -EAGAIN;
         int *result = NULL;
@@ -1079,6 +1081,7 @@ put_anon:
         if (rc == MIGRATEPAGE_SUCCESS) {
                 hugetlb_cgroup_migrate(hpage, new_hpage);
                 put_new_page = NULL;
+                set_page_owner_migrate_reason(new_hpage, reason);
         }
 
         unlock_page(hpage);
@@ -1151,7 +1154,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
                         if (PageHuge(page))
                                 rc = unmap_and_move_huge_page(get_new_page,
                                                 put_new_page, private, page,
-                                                pass > 2, mode);
+                                                pass > 2, mode, reason);
                         else
                                 rc = unmap_and_move(get_new_page, put_new_page,
                                                 private, page, pass > 2, mode,
@@ -1842,6 +1845,7 @@ fail_putback:
         set_page_memcg(new_page, page_memcg(page));
         set_page_memcg(page, NULL);
         page_remove_rmap(page, true);
+        set_page_owner_migrate_reason(new_page, MR_NUMA_MISPLACED);
 
         spin_unlock(ptl);
         mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 774b55623212..a57068cfe52f 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -6,6 +6,7 @@
 #include <linux/stacktrace.h>
 #include <linux/page_owner.h>
 #include <linux/jump_label.h>
+#include <linux/migrate.h>
 #include "internal.h"
 
 static bool page_owner_disabled = true;
@@ -73,10 +74,18 @@ void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask)
         page_ext->order = order;
         page_ext->gfp_mask = gfp_mask;
         page_ext->nr_entries = trace.nr_entries;
+        page_ext->last_migrate_reason = -1;
 
         __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
 }
 
+void __set_page_owner_migrate_reason(struct page *page, int reason)
+{
+        struct page_ext *page_ext = lookup_page_ext(page);
+
+        page_ext->last_migrate_reason = reason;
+}
+
 gfp_t __get_page_owner_gfp(struct page *page)
 {
         struct page_ext *page_ext = lookup_page_ext(page);
@@ -151,6 +160,14 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
         if (ret >= count)
                 goto err;
 
+        if (page_ext->last_migrate_reason != -1) {
+                ret += snprintf(kbuf + ret, count - ret,
+                        "Page has been migrated, last migrate reason: %s\n",
+                        migrate_reason_names[page_ext->last_migrate_reason]);
+                if (ret >= count)
+                        goto err;
+        }
+
         ret += snprintf(kbuf + ret, count - ret, "\n");
         if (ret >= count)
                 goto err;