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Peter Anvin" , Andrew Morton , Dave Chinner , Qi Zheng , Roman Gushchin , Muchun Song , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Uladzislau Rezki , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Clark Williams , suleiman@google.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-rt-devel@lists.linux.dev Subject: Re: [RFC 06/10] Reclaim memory from blocked kernel stacks Message-ID: <20260831111320.7b6b3946@gandalf.local.home> In-Reply-To: <20260831065509.qqEtERDB@linutronix.de> References: <20260827232948.2520558-1-stevensd@google.com> <20260827232948.2520558-7-stevensd@google.com> <20260828133620._x2XfJR_@linutronix.de> <20260828135947.GU776954@noisy.programming.kicks-ass.net> <20260828151018.HnR9xV1N@linutronix.de> <20260828150836.2d5b378c@gandalf.local.home> <20260828151313.5c4a5e4b@gandalf.local.home> <20260828151747.20035d50@gandalf.local.home> <20260831065509.qqEtERDB@linutronix.de> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1/3KtEVjKaohpMEOxH4xzYg00zpuzVZqIw= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=goodmis.org; h=date:from:to:cc:subject:message-id:in-reply-to:references:mime-version:content-type:content-transfer-encoding; s=dkim1; bh=IKf/qv+ZKDMiRuq6ap8IBmRH94f4tOFqUTBggMx1BmU=; b=cImwxCY5M6/MZq1vXrGpwXyJIW4H4hu5sS1KO7PpnpoXteZNbNQ+GhZzlHqKlL3ZkFB0HN34EWkqTzLeQyS8IcFKie7OGgIlnJDjKa6hVhBcyvMHmYDM/yhwmGkc1A/6BHmeSAl3QTXL0In4xCov5c0vPfeze8DOuvivudM+e4o= X-HE-Meta: U2FsdGVkX18dzhGCsgKCVwcrIISXc5+c8eAfc+lay5xArphhXwOHYX/nvWZLcCNFYp/sd112suTMB0NzpOGtFdRY72fbzgE39wDPlKiV4JS9YOYXjTah/tBYpd2756XDxPPscNMuqeK262zY2EEZNuLwXIXN/boqjUHRkq/XHc8VDiMguYSMX3Fw9u9/Ec2SavB2O6BTLoVKPnTjGCPjSORO1SLgGh0MREZxm6i8RaGqjgOEjD6WMtZo4umY6LccK88OvdVUTL+WTfjTOF+AZaafG8EqAzLRlgRtocOn6VnjyRlU2JmSCo78sE9rgM2F X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: zde79gjnjoi51h98gp5cfbbykcarusf8 X-Rspamd-Queue-Id: 59E76180005 X-HE-Tag-Orig: 1788189144-66867 X-HE-Tag: 1788189158-19827 X-HE-Meta: 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 Vie680Kq ic86JXlLC/FeWHzTjLa/XpSWwgOxVyDE+iYO0O6ES00yrx+KOqR6TY/LqcA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 31 Aug 2026 08:55:09 +0200 Sebastian Andrzej Siewior wrote: > Does this stack tracer distinguish between the kernel-stack and > IRQ-stack? It should only look at kernel-stack and not the irq stack. This stack trace may have triggered when the interrupt put back the kernel stack, as it is in the irqentry_exit code and about to do a schedule. The code has: kernel/trace/trace_stack.c: /* we do not handle interrupt stacks yet */ if (!object_is_on_stack(stack)) return; Which returns if the object is on the kernel-stack, and here "stack" is the parameter passed into this function. > I would expect asm_sysvec_apic_timer_interrupt() on the > IRQ-stack and not adding weight to the kernel stack. Right. But I believe this is where it switched back to the kernel-stack. > Given how close this is to 8192, I don't think two stack pages will > happen soon. Agreed :-( -- Steve