From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9C7A6455192; Fri, 28 Aug 2026 14:35:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787927757; cv=none; b=cOSA8KeI0QYi3fdckNYvQCb9sRbnLPy7enSvcgoGtwCEK+keE6xLEMTt9JEHRoO/eZzXw3dnzfQk/Yl81+ElcRVe5TatLIHmhdsQtd5uA8/yWxXWt0K4aITTX4knBbj7a+w8gKNCfiiQ6k5w+iFMA4GsuGi9x0puu9jbkEEE8Ko= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787927757; c=relaxed/simple; bh=qt1fLQhXwiuhTakqhObvInwVmK3ImTBo4G1+BsTtet0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XXy0Hz2O8yfRZPtL/SNcaBYDJj8ujuTopWd9q0yw8q9/RjDCbRF+98fPCD9xnsEU4gMsewJrDasd9RkWXCUtrSvkL1wduSlzg0YYQqa1/Gze12g4uT9E4ust/eGpK4MGMOLJEgP7THpk9Xu4Vv0kE71PlS6kyd7GaK3tlp2Ypv4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=j/13ETx4; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="j/13ETx4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ckaGVw74rY49wuwKahOscpW27wYJycDGKErZJGjW1ng=; b=j/13ETx4G/dFNQw+O8eobyyQgc vb65HchRPDcYLjcyC/fkNRFPF7qas14vbb7S1GpoV2I2Af6KgW93+TAewKnJQ9jPgtqk2OZ4eDYpF 0eGT9oIxEXXxMOGJnz+Zvxpz77VhnwgFGBfGc5FM67FuzGeN+I5Mafj28D5LTj5F8G/dZkV4yJK4+ g/PyiaahSQ3iyujx49bRLJZiZUJ+yXgaIlR0W2Rw3AYelbw6TU3UACtgxtALW4lUBvYYMD2rKLFE7 q1zfp3Kbtkb7ki2dRGweNoxO9hxDIgG19FTnmrcPYemQ1XaAxnkT1xTxBpc0pWM6eJJY7vgg4Z1ww by1BAlOw==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.99.2 #2 (Red Hat Linux)) id 1wzxgE-00000008KRq-2kIR; Fri, 28 Aug 2026 14:35:42 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id AC76130030F; Fri, 28 Aug 2026 16:35:40 +0200 (CEST) Date: Fri, 28 Aug 2026 16:35:40 +0200 From: Peter Zijlstra To: Steven Rostedt Cc: David Stevens , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . 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 , Sebastian Andrzej Siewior , 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, jstultz@google.com Subject: Re: [RFC 00/10] Reclaimable kernel stacks Message-ID: <20260828143540.GV776954@noisy.programming.kicks-ass.net> References: <20260827232948.2520558-1-stevensd@google.com> <20260828124758.GP687043@noisy.programming.kicks-ass.net> <20260828103328.633bbfbc@gandalf.local.home> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260828103328.633bbfbc@gandalf.local.home> On Fri, Aug 28, 2026 at 10:33:28AM -0400, Steven Rostedt wrote: > On Fri, 28 Aug 2026 14:47:58 +0200 > Peter Zijlstra wrote: > > > > On Android, system processes typically have 2000-3000 threads. App > > > processes add 1000s more threads on top of this. > > > > WTF ?!? Why does that all spawn *that* many threads? Perhaps work on > > reducing that some? > > I guess you never ran Java ;-) Of course not; why would you want to do something that silly ;-)