[PATCH] mm/madvise: break reclaim when lock race

[xf2017140389]

From: xiaofeng <xiaofeng5@xxxxxxxxxx>

In Android phones, the recycling thread is likely to hold the mmap_lock to reclaim the memory of the application When the top-App is switched to the background. Once the user switches the application to the top during the recycling process, there is a high possibility that the memory will be allocated due to the inability to obtain the lock, which may cause lag or other problem.

Signed-off-by: xiaofeng <xiaofeng5@xxxxxxxxxx>
---
 mm/madvise.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/madvise.c b/mm/madvise.c
index 8c927202bbe6..8f1e325873e0 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -322,6 +322,9 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
 	if (fatal_signal_pending(current))
 		return -EINTR;
 
+	if (mmap_lock_is_contended(mm))
+		return -EINTR;
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	if (pmd_trans_huge(*pmd)) {
 		pmd_t orig_pmd;
-- 
2.17.1