From: Waiman Long <longman@redhat.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Muchun Song <songmuchun@bytedance.com>,
Waiman Long <longman@redhat.com>
Subject: [PATCH v2 0/3] mm/kmemleak: Avoid soft lockup in kmemleak_scan()
Date: Tue, 14 Jun 2022 18:03:56 -0400 [thread overview]
Message-ID: <20220614220359.59282-1-longman@redhat.com> (raw)
v2:
- Update patch 3 to count the objects checked instead of being
gray for determining when to do cond_resched(). This is more
reliable.
There are 3 RCU-based object iteration loops in kmemleak_scan(). Because
of the need to take RCU read lock, we can't insert cond_resched() into
the loop like other parts of the function. As there can be millions of
objects to be scanned, it takes a while to iterate all of them. The
kmemleak functionality is usually enabled in a debug kernel which is
much slower than a non-debug kernel. With sufficient number of kmemleak
objects, the time to iterate them all may exceed 22s causing soft lockup.
watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [kmemleak:625]
This patch series make changes to the 3 object iteration loops in
kmemleak_scan() to prevent them from causing soft lockup.
Waiman Long (3):
mm/kmemleak: Use _irq lock/unlock variants in kmemleak_scan/_clear()
mm/kmemleak: Skip unlikely objects in kmemleak_scan() without taking
lock
mm/kmemleak: Prevent soft lockup in first object iteration loop of
kmemleak_scan()
mm/kmemleak.c | 60 +++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 49 insertions(+), 11 deletions(-)
--
2.31.1
next reply other threads:[~2022-06-14 22:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-14 22:03 Waiman Long [this message]
2022-06-14 22:03 ` [PATCH v2 1/3] mm/kmemleak: Use _irq lock/unlock variants in kmemleak_scan/_clear() Waiman Long
2022-06-14 22:03 ` [PATCH v2 2/3] mm/kmemleak: Skip unlikely objects in kmemleak_scan() without taking lock Waiman Long
2022-06-14 22:03 ` [PATCH v2 3/3] mm/kmemleak: Prevent soft lockup in first object iteration loop of kmemleak_scan() Waiman Long
2022-06-15 15:11 ` Catalin Marinas
2022-06-15 16:07 ` Waiman Long
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