mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status

Currently there's no easy way to get per-process usage of hugetlb pages,
which is inconvenient because userspace applications which use hugetlb
typically want to control their processes on the basis of how much memory
(including hugetlb) they use.  So this patch simply provides easy access
to the info via /proc/PID/status.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Joern Engel <joern@logfs.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 22 insertions, 0 deletions

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 5e35379f58a5..685c262e0be8 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -483,6 +483,17 @@ static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
 #define hugepages_supported() (HPAGE_SHIFT != 0)
 #endif
 
+void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm);
+
+static inline void hugetlb_count_add(long l, struct mm_struct *mm)
+{
+        atomic_long_add(l, &mm->hugetlb_usage);
+}
+
+static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
+{
+        atomic_long_sub(l, &mm->hugetlb_usage);
+}
 #else   /* CONFIG_HUGETLB_PAGE */
 struct hstate {};
 #define alloc_huge_page(v, a, r) NULL
@@ -519,6 +530,14 @@ static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
 {
         return &mm->page_table_lock;
 }
+
+static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m)
+{
+}
+
+static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
+{
+}
 #endif  /* CONFIG_HUGETLB_PAGE */
 
 static inline spinlock_t *huge_pte_lock(struct hstate *h,
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3d6baa7d4534..0a85da25a822 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -486,6 +486,9 @@ struct mm_struct {
         /* address of the bounds directory */
         void __user *bd_addr;
 #endif
+#ifdef CONFIG_HUGETLB_PAGE
+        atomic_long_t hugetlb_usage;
+#endif
 };
 
 static inline void mm_init_cpumask(struct mm_struct *mm)