From: Waiman Long <longman@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org,
Bart Van Assche <bvanassche@acm.org>,
Waiman Long <longman@redhat.com>
Subject: [PATCH v5 0/7] locking/lockdep: Reuse zapped chain_hlocks entries
Date: Mon, 3 Feb 2020 11:41:40 -0500 [thread overview]
Message-ID: <20200203164147.17990-1-longman@redhat.com> (raw)
v5:
- Fix more build errors reported by kbuild test robot.
v4:
- Fix build errors reported by kbuild test robot.
- Adopt the single chain block allocator code suggested by PeterZ which
combine the last 3 patches of v3 series.
- Add another patch to introduce a fast path in the chain block
allocator.
- In patch 1, move the inc_chains() out of CONFIG_TRACE_IRQFLAGS
conditional compilation block.
v3:
- Move the bug fix patches to the beginning of the series.
- Include a number of changes as suggested by PeterZ.
- Increase MAX_CHAIN_BUCKETS from 8 to 10 to reduce the chance of using
the unsized list.
- Add patch 7 to add a lockdep_early_init() call.
- Add patch 8 to allocate chain hlocks by splitting large chain block
as a last resort.
v2:
- Revamp the chain_hlocks reuse patch to store the freed chain_hlocks
information in the chain_hlocks entries themselves avoiding the
need of a separate set of tracking structures. This, however,
requires a minimum allocation size of at least 2. Thanks to PeterZ
for his review and inspiring this change.
- Remove the leakage counter as it is no longer applicable.
- Add patch 6 to make the output of /proc/lockdep_chains more readable.
It was found that when running a workload that kept on adding lock
classes and then zapping them repetitively, the system will eventually
run out of chain_hlocks[] entries even though there were still plenty
of other lockdep data buffers available.
[ 4318.443670] BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
[ 4318.444809] turning off the locking correctness validator.
In order to fix this problem, we have to make chain_hlocks[] entries
reusable just like other lockdep arrays. Besides that, the patchset
also adds some zapped class and chain_hlocks counters to be tracked by
/proc/lockdep_stats. It also fixes leakage in the irq context counters
and makes the output of /proc/lockdep_chains more readable.
Waiman Long (7):
locking/lockdep: Decrement irq context counters when removing lock
chain
locking/lockdep: Display irq_context names in /proc/lockdep_chains
locking/lockdep: Track number of zapped classes
locking/lockdep: Throw away all lock chains with zapped class
locking/lockdep: Track number of zapped lock chains
locking/lockdep: Reuse freed chain_hlocks entries
locking/lockdep: Add a fast path for chain_hlocks allocation
kernel/locking/lockdep.c | 335 ++++++++++++++++++++++++-----
kernel/locking/lockdep_internals.h | 13 +-
kernel/locking/lockdep_proc.c | 28 ++-
3 files changed, 311 insertions(+), 65 deletions(-)
--
2.18.1
next reply other threads:[~2020-02-03 16:42 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 16:41 Waiman Long [this message]
2020-02-03 16:41 ` [PATCH v5 1/7] locking/lockdep: Decrement irq context counters when removing lock chain Waiman Long
2020-02-03 16:41 ` [PATCH v5 2/7] locking/lockdep: Display irq_context names in /proc/lockdep_chains Waiman Long
2020-02-03 16:41 ` [PATCH v5 3/7] locking/lockdep: Track number of zapped classes Waiman Long
2020-02-03 16:41 ` [PATCH v5 4/7] locking/lockdep: Throw away all lock chains with zapped class Waiman Long
2020-02-03 16:41 ` [PATCH v5 5/7] locking/lockdep: Track number of zapped lock chains Waiman Long
2020-02-03 16:41 ` [PATCH v5 6/7] locking/lockdep: Reuse freed chain_hlocks entries Waiman Long
2020-02-04 12:36 ` Peter Zijlstra
2020-02-04 14:54 ` Waiman Long
2020-02-04 16:45 ` Waiman Long
2020-02-05 9:41 ` Peter Zijlstra
2020-02-05 13:59 ` Waiman Long
2020-02-04 15:42 ` Peter Zijlstra
2020-02-04 16:12 ` Waiman Long
2020-02-04 16:26 ` Waiman Long
2020-02-04 16:57 ` Waiman Long
2020-02-05 9:48 ` Peter Zijlstra
2020-02-05 14:03 ` Waiman Long
2020-02-03 16:41 ` [PATCH v5 7/7] locking/lockdep: Add a fast path for chain_hlocks allocation Waiman Long
2020-02-04 12:47 ` Peter Zijlstra
2020-02-04 15:07 ` Waiman Long
2020-02-04 13:18 ` Peter Zijlstra
2020-02-04 13:44 ` Peter Zijlstra
2020-02-04 18:02 ` Waiman Long
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