From: Qian Cai <cai@lca.pw>
To: Waiman Long <longman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] locking/lockdep: Increase MAX_LOCKDEP_ENTRIES by half
Date: Tue, 26 May 2020 15:28:56 -0400 [thread overview]
Message-ID: <20200526192856.GF991@lca.pw> (raw)
In-Reply-To: <20200526185850.GE991@lca.pw>
On Tue, May 26, 2020 at 02:58:53PM -0400, Qian Cai wrote:
> On Tue, May 26, 2020 at 01:43:49PM -0400, Waiman Long wrote:
> > It was found by Qian Cai that lockdep splat sometimes appears with the
> > "BUG: MAX_LOCKDEP_ENTRIES too low" message on linux-next. On a 32-vcpu VM
> > guest with a v5.7-rc7 based kernel, I looked at how many of the various
> > table entries were being used after bootup and after a parallel kernel
> > build (make -j32). The tables below show the usage statistics.
>
> I think this approach could help the situatin on this AMD server.
> However, I don't understand why this particular system starts to exceed
> the MAX_LOCKDEP_ENTRIES. All other Intel, powerpc, amd64 and s390
> running the same workload have only < 20k at the end, but on this AMD
> server,
Correction -- Intel is also quite close to exceed it.
direct dependencies: 29836 [max: 32768]
arm64:
direct dependencies: 25268 [max: 32768]
next prev parent reply other threads:[~2020-05-26 19:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 17:43 [PATCH] locking/lockdep: Increase MAX_LOCKDEP_ENTRIES by half Waiman Long
2020-05-26 18:58 ` Qian Cai
2020-05-26 19:28 ` Qian Cai [this message]
2020-05-26 19:56 ` Peter Zijlstra
2020-05-26 20:17 ` Qian Cai
2020-05-26 20:30 ` Waiman Long
2020-05-26 21:24 ` Qian Cai
2020-05-26 21:27 ` Peter Zijlstra
2020-05-26 22:27 ` Waiman Long
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