From: Bart Van Assche <bvanassche@acm.org>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will.deacon@arm.com>, Yuyang Du <duyuyang@gmail.com>,
Waiman Long <longman@redhat.com>
Subject: Re: [PATCH 3/4] locking/lockdep: Reduce space occupied by stack traces
Date: Wed, 24 Jul 2019 08:47:00 -0700 [thread overview]
Message-ID: <ee1cd751-cc8a-ca03-e30c-34b4cf8a13bf@acm.org> (raw)
In-Reply-To: <20190724045610.GC643@sol.localdomain>
On 7/23/19 9:56 PM, Eric Biggers wrote:
> Does this also fix any of the other bugs listed at
> https://lore.kernel.org/lkml/20190710055838.GC2152@sol.localdomain/
> ?
>
> BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
> BUG: MAX_LOCKDEP_CHAINS too low!
> BUG: MAX_LOCK_DEPTH too low! (2)
> BUG: MAX_LOCKDEP_ENTRIES too low!
Hi Eric,
I don't think so. This patch only affects the space occupied by stack
traces and not the space occupied by any of the other lockdep data
strutures. BTW, in that report I found the following:
Title: BUG: MAX_LOCKDEP_CHAINS too low!
Last occurred: 5 days ago
Reported: 284 days ago
Title: BUG: MAX_LOCK_DEPTH too low! (2)
Last occurred: 362 days ago
Reported: 392 days ago
Since these bugs were reported more than 150 days ago these bugs are
older than my lockdep changes and hence not a regression due to my
lockdep changes.
My patch series did not increase the number of "list_entries" tracked by
lockdep so I don't think that the "BUG: MAX_LOCKDEP_ENTRIES too low"
behavior can be triggered more easily due to my lockdep changes.
The "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" complaint however may be
related. I will check whether it is possible to reduce the space
occupied by held lock chains again to what was needed before my patch
series.
Bart.
next prev parent reply other threads:[~2019-07-24 15:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 18:24 [PATCH 0/4] Lockdep: Reduce stack trace memory usage Bart Van Assche
2019-07-22 18:24 ` [PATCH 1/4] locking/lockdep: Make it clear that what lock_class::key points at is not modified Bart Van Assche
2019-07-25 16:08 ` [tip:locking/core] " tip-bot for Bart Van Assche
2019-07-22 18:24 ` [PATCH 2/4] stacktrace: Constify 'entries' arguments Bart Van Assche
2019-07-25 16:09 ` [tip:locking/core] " tip-bot for Bart Van Assche
2019-07-22 18:24 ` [PATCH 3/4] locking/lockdep: Reduce space occupied by stack traces Bart Van Assche
2019-07-24 4:56 ` Eric Biggers
2019-07-24 15:47 ` Bart Van Assche [this message]
2019-07-25 16:10 ` [tip:locking/core] " tip-bot for Bart Van Assche
2019-07-22 18:24 ` [PATCH 4/4] locking/lockdep: Report more stack trace statistics Bart Van Assche
2019-07-25 16:10 ` [tip:locking/core] " tip-bot for Bart Van Assche
2019-07-23 9:27 ` [PATCH 0/4] Lockdep: Reduce stack trace memory usage Peter Zijlstra
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