mm/page_alloc: add scheduling point to free_unref_page_list

Freeing a large list of pages may cause rcu_sched starvatoin on non-preemptible kernels rcu: rcu_sched kthread starved for 5359 jiffies! g454793 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=19 [...] Call Trace: free_unref_page_list+0x19c/0x270 release_pages+0x3cc/0x498 tlb_flush_mmu_free+0x44/0x70 zap_pte_range+0x450/0x738 unmap_page_range+0x108/0x240 unmap_vmas+0x74/0xf0 unmap_region+0xb0/0x120 do_munmap+0x264/0x438 vm_munmap+0x58/0xa0 sys_munmap+0x10/0x20 syscall_common+0x24/0x38 Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: wangjianxing <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>
martinberlin · Mar 4, 2022 · ef7fd62 · ef7fd62
1 parent 3363f18
commit ef7fd62
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
@@ -3479,6 +3479,9 @@ void free_unref_page_list(struct list_head *list)
 		 */
 		if (++batch_count == SWAP_CLUSTER_MAX) {
 			local_unlock_irqrestore(&pagesets.lock, flags);
+
+			cond_resched();
+
 			batch_count = 0;
 			local_lock_irqsave(&pagesets.lock, flags);
 		}