The patch titled
Subject: mm/page_alloc: add scheduling point to free_unref_page_list
has been added to the -mm tree. Its filename is
mm-page_alloc-add-scheduling-point-to-free_unref_page_list.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-add-scheduling-point-to-free_unref_page_list.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-add-scheduling-point-to-free_unref_page_list.patch
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------------------------------------------------------
From: wangjianxing <wangjianxing@xxxxxxxxxxx>
Subject: 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/20220302013825.2290315-1-wangjianxing@xxxxxxxxxxx
Signed-off-by: wangjianxing <wangjianxing@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/page_alloc.c~mm-page_alloc-add-scheduling-point-to-free_unref_page_list
+++ a/mm/page_alloc.c
@@ -3479,6 +3479,9 @@ void free_unref_page_list(struct list_he
*/
if (++batch_count == SWAP_CLUSTER_MAX) {
local_unlock_irqrestore(&pagesets.lock, flags);
+
+ cond_resched();
+
batch_count = 0;
local_lock_irqsave(&pagesets.lock, flags);
}
_
Patches currently in -mm which might be from wangjianxing@xxxxxxxxxxx are
mm-page_alloc-add-scheduling-point-to-free_unref_page_list.patch
