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authorLiu Zixian <liuzixian4@huawei.com>2021-09-08 18:10:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-08 18:45:53 -0700
commit13db8c50477d83ad3e3b9b0ae247e5cd833a7ae4 (patch)
tree0fe230614629425aaff4d127426bfed9501f9cef /include/linux
parent4b42fb213678d2b6a9eeea92a9be200f23e49583 (diff)
mm/hugetlb: initialize hugetlb_usage in mm_init
After fork, the child process will get incorrect (2x) hugetlb_usage. If a process uses 5 2MB hugetlb pages in an anonymous mapping, HugetlbPages: 10240 kB and then forks, the child will show, HugetlbPages: 20480 kB The reason for double the amount is because hugetlb_usage will be copied from the parent and then increased when we copy page tables from parent to child. Child will have 2x actual usage. Fix this by adding hugetlb_count_init in mm_init. Link: https://lkml.kernel.org/r/20210826071742.877-1-liuzixian4@huawei.com Fixes: 5d317b2b6536 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status") Signed-off-by: Liu Zixian <liuzixian4@huawei.com> Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/hugetlb.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index f7ca1a3870ea..1faebe1cd0ed 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -858,6 +858,11 @@ static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm);
+static inline void hugetlb_count_init(struct mm_struct *mm)
+{
+ atomic_long_set(&mm->hugetlb_usage, 0);
+}
+
static inline void hugetlb_count_add(long l, struct mm_struct *mm)
{
atomic_long_add(l, &mm->hugetlb_usage);
@@ -1042,6 +1047,10 @@ static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
return &mm->page_table_lock;
}
+static inline void hugetlb_count_init(struct mm_struct *mm)
+{
+}
+
static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m)
{
}