- * under non-exclusive lock(e.g., mmap_sem read-side) but defer TLB
- * flush by batching, a thread has stable TLB entry can fail to flush
- * the TLB by observing pte_none|!pte_dirty, for example so flush TLB
- * forcefully if we detect parallel PTE batching threads.
+ * under non-exclusive lock (e.g., mmap_sem read-side) but defer TLB
+ * flush by batching, one thread may end up seeing inconsistent PTEs
+ * and result in having stale TLB entries. So flush TLB forcefully
+ * if we detect parallel PTE batching threads.
+ *
+ * However, some syscalls, e.g. munmap(), may free page tables, this
+ * needs force flush everything in the given range. Otherwise this
+ * may result in having stale TLB entries for some architectures,
+ * e.g. aarch64, that could specify flush what level TLB.