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Peter Anvin" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, x86@kernel.org, bp@alien8.de, brauner@kernel.org, bristot@redhat.com, bsegall@google.com, dave.hansen@linux.intel.com, dianders@chromium.org, dietmar.eggemann@arm.com, eric.devolder@oracle.com, hca@linux.ibm.com, hch@infradead.org, jacob.jun.pan@linux.intel.com, jgg@ziepe.ca, jpoimboe@kernel.org, jroedel@suse.de, juri.lelli@redhat.com, kinseyho@google.com, kirill.shutemov@linux.intel.com, lstoakes@gmail.com, luto@kernel.org, mgorman@suse.de, mic@digikod.net, michael.christie@oracle.com, mingo@redhat.com, mjguzik@gmail.com, mst@redhat.com, npiggin@gmail.com, peterz@infradead.org, pmladek@suse.com, rick.p.edgecombe@intel.com, rostedt@goodmis.org, surenb@google.com, tglx@linutronix.de, urezki@gmail.com, vincent.guittot@linaro.org, vschneid@redhat.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 27C144000C X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 9womhkboucmwkhktxj3wj14hgof5rrii X-HE-Tag: 1710444226-925824 X-HE-Meta: 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 BO7iVwKG Xdw2PhQ0MUu+HbDRNhfZOUUL1ncF+zysradJNnQKkpp7vHSKO9PvVwpl40A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000024, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > > > > My point is that what matters is total memory use, not just memory used in > > the kernel. Amdahl's law. > > If userspace is running a few processes with many threads and the > userspace stacks are small, kernel stacks could end up dominating. > > I'd like to see some numbers though. The unused kernel stack pages occupy petabytes of memory across the fleet [1]. I also submitted a patch [2] that can help visualize the maximum stack page access distribution. [1] https://lore.kernel.org/all/CA+CK2bBYt9RAVqASB2eLyRQxYT5aiL0fGhUu3TumQCyJCNTWvw@mail.gmail.com [2] https://lore.kernel.org/all/20240314145457.1106299-1-pasha.tatashin@soleen.com