The oom killer use get_mm_rss() function to estimate how free memory
will be reclaimed when the oom killer select victim task.
However, the returned rss size by get_mm_rss() function was changed from
"mm, shmem: add internal shmem resident memory accounting" commit.
This commit makes the get_mm_rss() return size including SHMEM pages.
The oom killer can't get free memory from SHMEM pages directly after
kill victim process, it leads to mis-calculate victim points.
Therefore, make new API as get_mm_rss_wo_shmem() which returns the rss
value excluding SHMEM_PAGES.
Signed-off-by: Junil Lee <junil0814.lee@xxxxxxx>
---
include/linux/mm.h | 6 ++++++
mm/oom_kill.c | 4 ++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2d483db..bca3acc 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1701,6 +1701,12 @@ static inline int mm_counter(struct page *page)
return mm_counter_file(page);
}
+static inline unsigned long get_mm_rss_wo_shmem(struct mm_struct *mm)
+{
+ return get_mm_counter(mm, MM_FILEPAGES) +
+ get_mm_counter(mm, MM_ANONPAGES);
+}
+
static inline unsigned long get_mm_rss(struct mm_struct *mm)
{
return get_mm_counter(mm, MM_FILEPAGES) +
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 3a24848..e569737 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -230,7 +230,7 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
* The baseline for the badness score is the proportion of RAM that each
* task's rss, pagetable and swap space use.
*/
- points = get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS) +
+ points = get_mm_rss_wo_shmem(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS) +
mm_pgtables_bytes(p->mm) / PAGE_SIZE;
task_unlock(p);
@@ -419,7 +419,7 @@ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask)
pr_info("[%7d] %5d %5d %8lu %8lu %8ld %8lu %5hd %s\n",
task->pid, from_kuid(&init_user_ns, task_uid(task)),
- task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
+ task->tgid, task->mm->total_vm, get_mm_rss_wo_shmem(task->mm),
mm_pgtables_bytes(task->mm),
get_mm_counter(task->mm, MM_SWAPENTS),
task->signal->oom_score_adj, task->comm);
--
2.6.2
