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b=P/LKqi2LqAKG2z2uozCnUWME8OGZ9RbIIELAHHwTXvdmqJNNhcB+P6+T4o1eQ8bff emGEtPWT0PNKHunU+e67JP0rY4/3Tgr8kyp6GDWN5FCOr2JHeXpqhM1RzrzJHkb9Ew brC89Jmwg9/AeYM1XEAol1WvLn6e+jB9Z2r8WtID8EVVzKhebhWUcARXEcnzhnt6y3 r34S5YxuU4zLWiUFw7Zf3wQagohKhQK4vsCUZTFh3QOxASwCM3MANSEXJOLdQMuvVu 1hUCQ3DHh2wB0WW/fnGCHvw1eL+/L2pnuOVar83DD1+R3aG+zlkAmPp42idM32aMKO /aI0Z7fDCQizQ== Date: Fri, 18 Sep 2026 00:04:24 -0700 From: Namhyung Kim To: Peter Zijlstra Cc: Harry Yoo , Tim Menninger , linux-mm@kvack.org, Chuck Lever , linux-nfs@vger.kernel.org, Jon Curley , Eric Badger , Vlastimil Babka , Andrew Morton , Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , 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 Message-ID: References: <20260916232227.4098143-1-tmenninger@everpuredata.com> <20260917152959.GI4121339@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260917152959.GI4121339@noisy.programming.kicks-ass.net> X-Stat-Signature: 8799gc8boko7isqm3j3419773aed5p4s X-Rspam-User: X-Rspamd-Queue-Id: 636594000E X-Rspamd-Server: rspam03 X-HE-Tag: 1789715067-404298 X-HE-Meta: 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 N2Wlfa8R Ju8SdQWV1PLs0iaLIq4LD7bLanfEqJ4HMenyt0AC8vS78oT1wtfEKcnwhnKCwDPAjyPEM61A72zHaMWcWQsOio6YwJ8AfZuFPaU0n3JWlgQCz2OGtFzNC0k4zuVVwbpsZxd3eS3N6MpfUXXuhd0boMRpjQ1SkXgocA+OeypSfoe9zq5X6Gby7hfLxA2Ir7mZOzCbSCcVVDb3Udl+BHDhxa4RQLqoIlkN+ukQ9197Cwu8kCh62DWLen4xIyy0lHbE/7rpUm3HnvIpXsZKbBlhoP5NvCX7P5Fm38aR4OOZ0jzBWVZs= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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