This uses the new annotation to determine if an mm has mmu notifiers with
blockable invalidate range callbacks to avoid oom reaping. Otherwise, the
callbacks are used around unmap_page_range().
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/oom_kill.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -514,15 +514,12 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm)
}
/*
- * If the mm has notifiers then we would need to invalidate them around
- * unmap_page_range and that is risky because notifiers can sleep and
- * what they do is basically undeterministic. So let's have a short
+ * If the mm has invalidate_{start,end}() notifiers that could block,
* sleep to give the oom victim some more time.
* TODO: we really want to get rid of this ugly hack and make sure that
- * notifiers cannot block for unbounded amount of time and add
- * mmu_notifier_invalidate_range_{start,end} around unmap_page_range
+ * notifiers cannot block for unbounded amount of time
*/
- if (mm_has_notifiers(mm)) {
+ if (mm_has_blockable_invalidate_notifiers(mm)) {
up_read(&mm->mmap_sem);
schedule_timeout_idle(HZ);
goto unlock_oom;
@@ -565,10 +562,14 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm)
* count elevated without a good reason.
*/
if (vma_is_anonymous(vma) || !(vma->vm_flags & VM_SHARED)) {
- tlb_gather_mmu(&tlb, mm, vma->vm_start, vma->vm_end);
- unmap_page_range(&tlb, vma, vma->vm_start, vma->vm_end,
- NULL);
- tlb_finish_mmu(&tlb, vma->vm_start, vma->vm_end);
+ const unsigned long start = vma->vm_start;
+ const unsigned long end = vma->vm_end;
+
+ tlb_gather_mmu(&tlb, mm, start, end);
+ mmu_notifier_invalidate_range_start(mm, start, end);
+ unmap_page_range(&tlb, vma, start, end, NULL);
+ mmu_notifier_invalidate_range_end(mm, start, end);
+ tlb_finish_mmu(&tlb, start, end);
}
}
pr_info("oom_reaper: reaped process %d (%s), now anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
--
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