From: Namhyung Kim <namhyung@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Harry Yoo <harry@kernel.org>,
Tim Menninger <tmenninger@everpuredata.com>,
linux-mm@kvack.org, Chuck Lever <cel@kernel.org>,
linux-nfs@vger.kernel.org, Jon Curley <jcurley@everpuredata.com>,
Eric Badger <ebadger@everpuredata.com>,
Vlastimil Babka <vbabka@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Hao Li <hao.li@linux.dev>, Christoph Lameter <cl@gentwo.org>,
David Rientjes <rientjes@google.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
James Clark <james.clark@linaro.org>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [SLUB] nfs_page cmpxchg_double_fail and perf lock perturbation on dual-socket NFS/RDMA
Date: Fri, 18 Sep 2026 00:04:24 -0700 [thread overview]
Message-ID: <aqzieNW5GmhnU_EJ@z2> (raw)
In-Reply-To: <20260917152959.GI4121339@noisy.programming.kicks-ass.net>
Hello,
On Thu, Sep 17, 2026 at 05:29:59PM +0200, Peter Zijlstra wrote:
> On Thu, Sep 17, 2026 at 03:10:47PM +0100, Harry Yoo wrote:
> > ... now I realize we need to add PERFORMANCE EVENTS SUBSYSTEM folks
> > as well ;-)
> >
> > Hmm, sounds like perf lock is somehow triggering slab allocations
> > and interfering the workload.
>
> perf should not have runtime memory allocation, its build to run from
> NMI context. It can allocate some memory on event creation and the like,
> but once its on, there should be no more allocations happening.
Right, perf lock record command will save the event info to a ring
buffer without allocation. It may lose some events when the buffer is
full though.
Thanks,
Namhyung
next prev parent reply other threads:[~2026-09-18 7:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-16 23:22 [SLUB] nfs_page cmpxchg_double_fail and perf lock perturbation on dual-socket NFS/RDMA Tim Menninger
2026-09-17 13:46 ` Harry Yoo
2026-09-17 14:10 ` Harry Yoo
2026-09-17 15:29 ` Peter Zijlstra
2026-09-18 7:04 ` Namhyung Kim [this message]
2026-09-17 16:25 ` Tim Menninger
2026-09-18 7:08 ` Vlastimil Babka (SUSE)
2026-09-21 15:31 ` Harry Yoo
2026-09-21 23:27 ` Tim Menninger
2026-09-18 7:14 ` Namhyung Kim
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