[PATCH] mm: add cond_resched() in swapin_walk_pmd_entry()

From: Kefeng Wang
Date: Mon Dec 05 2022 - 08:49:27 EST


When handle MADV_WILLNEED in madvise(), the soflockup may be occurred
in swapin_walk_pmd_entry() if swapin lots of memory on slow device,
add a cond_resched() into it to avoid the possible softlockup.

Fixes: 1998cc048901 ("mm: make madvise(MADV_WILLNEED) support swap file prefetch")
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
mm/madvise.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/mm/madvise.c b/mm/madvise.c
index b913ba6efc10..fea589d8a2fb 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -226,6 +226,7 @@ static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
put_page(page);
}
swap_read_unplug(splug);
+ cond_resched();

return 0;
}
--
2.35.3