From: Ma Wupeng <mawupeng1(a)huawei.com>
hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6RKHX
--------------------------------
After the fork operation, it is erroneous for the child process to have a
reliable page size twice that of its parent process.
Upon examining the mm_struct structure, it was discovered that
reliable_nr_page should be initialized to 0, similar to how RSS is
initialized during mm_init(). This particular problem that arises during
forking is merely one such example.
To resolve this issue, it is recommended to set reliable_nr_page to 0
during the mm_init() operation.
Fixes: 8fc2546f8508 ("proc: mem_reliable: Count reliable memory usage of reliable tasks")
Signed-off-by: Ma Wupeng <mawupeng1(a)huawei.com>
---
include/linux/mem_reliable.h | 9 +++++++++
kernel/fork.c | 1 +
2 files changed, 10 insertions(+)
diff --git a/include/linux/mem_reliable.h b/include/linux/mem_reliable.h
index d8cabf94f4a32..1e928ff69d997 100644
--- a/include/linux/mem_reliable.h
+++ b/include/linux/mem_reliable.h
@@ -216,6 +216,14 @@ static inline void add_reliable_page_counter(struct page *page,
reliable_page_counter_inner(mm, val);
}
+
+static inline void reliable_clear_page_counter(struct mm_struct *mm)
+{
+ if (!mem_reliable_is_enabled())
+ return;
+
+ atomic_long_set(&mm->reliable_nr_page, 0);
+}
#else
#define reliable_enabled 0
@@ -259,6 +267,7 @@ static inline void add_reliable_folio_counter(struct folio *folio,
struct mm_struct *mm, int val) {}
static inline void reliable_report_usage(struct seq_file *m,
struct mm_struct *mm) {}
+static inline void reliable_clear_page_counter(struct mm_struct *mm) {}
#endif
#endif
diff --git a/kernel/fork.c b/kernel/fork.c
index e033388b11bd9..27d605c64b45d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1326,6 +1326,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
mm->locked_vm = 0;
atomic64_set(&mm->pinned_vm, 0);
memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
+ reliable_clear_page_counter(mm);
spin_lock_init(&mm->page_table_lock);
spin_lock_init(&mm->arg_lock);
mm_init_cpumask(mm);
--
2.25.1