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

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Date:   Tue,  7 Dec 2021 11:22:02 +0800
From:   xf2017140389@...il.com
To:     akpm@...ux-foundation.org, christian@...uner.io
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        zhangcang@...omi.com, wangju@...omi.com, surenb@...gle.com,
        fangzhirong@...omi.com, xiaofeng <xiaofeng5@...omi.com>
Subject: [PATCH] mm/madvise: break reclaim when lock race

From: xiaofeng <xiaofeng5@...omi.com>

When the process_madvise() system call is being used, it takes mmap_lock and blocks the application from allocating memory, leading to unreasonable delays. This patchset aims to fix it.

Signed-off-by: xiaofeng <xiaofeng5@...omi.com>
---
 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