This gives the OOM killer an additional hint which processes are
referencing shmem files with potentially no other accounting for them.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
mm/shmem.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/mm/shmem.c b/mm/shmem.c
index a6f565308133..b068ac5ba4bf 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2209,6 +2209,21 @@ unsigned long shmem_get_unmapped_area(struct file *file,
return inflated_addr;
}
+static long shmem_file_rss(struct file *file)
+{
+ struct inode *inode = file_inode(file);
+ unsigned long nrpages;
+
+ /* Only account shmem files which aren't part of any fs */
+ if (atomic_read(&inode->i_count) > 1)
+ return 0;
+
+ xa_lock(&file->f_mapping->i_pages);
+ nrpages = file->f_mapping->nrpages;
+ xa_unlock(&file->f_mapping->i_pages);
+ return nrpages;
+}
+
#ifdef CONFIG_NUMA
static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
{
@@ -3811,6 +3826,7 @@ EXPORT_SYMBOL(shmem_aops);
static const struct file_operations shmem_file_operations = {
.mmap = shmem_mmap,
.get_unmapped_area = shmem_get_unmapped_area,
+ .file_rss = shmem_file_rss,
#ifdef CONFIG_TMPFS
.llseek = shmem_file_llseek,
.read_iter = shmem_file_read_iter,
--
2.25.1
