From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 389DCC61DD3 for ; Tue, 1 Sep 2026 17:12:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=BvuC7m29cQzQFOvz516cPzomVQq1dbk1Rusms0ATFrs=; b=L+eQyqfRaw8UyR DTVSaVov/OeDleotVBZBxHVaL+aiuSFeJHJOnrxqB52Pcdz1oJkjKwG4BsqXBR1lGXlBZ34LYa9KI 2vBv4R7KW70dfcLwXs0grS3a6/cs3M6ladxyM7T+MWqt4HJsVa2DPlp4NXEkpa9PDCfAxW4pxVVl6 tjStbdZWuh8GeQPNgcp2cSracE8/luNuN85iempGZ8t0RFWACpWjYGSrt0yk5zbU9Sk5sP4US4c6L GPRrmJ9bzHorwity09bMdWxafoGUuRDMvmBn56NxlyHNoG0UTotxg31AxX3YPiU/SGXwmtC/JKlCB jUL156cmeV2YphmRuUWg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1S26-0000000CmEW-3P4a; Tue, 01 Sep 2026 17:12:26 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1S24-0000000CmDw-3CBa; Tue, 01 Sep 2026 17:12:24 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id ECEA9602D0; Tue, 1 Sep 2026 17:12:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57D9A1F00A3A; Tue, 1 Sep 2026 17:12:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788282743; bh=StaeALLek35hMlcSHa6BZyUhT0ljTsLx6yTS5xCyYM0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=F7xGurub5lZpjDs1aDGfwYQjsUqqlOosQvLNchGQQWzDsAsXjm/bfgFuGkM+2goEl A3tZmuNFbM2kRhPZvh9S1P22IeFE5iiGfDDDDd17F5D804y5rPdv5sEw5oeDGtpjHk 8fMhWsj66KRnRGkecbBoYbTDb8JlfScb/+tAumYYrtdivETCM9805zMhAy2jNPFBgG 3+rxVhNNGTh6W8+MHuBjYezyNfaAPbKmDaQDJzZEL8uqbRiqCFQhAdUZPRkTUZSKA5 Y/Jp66nLB14uDCATCQFaq6J05pPq9ClrATCE9vY0dAVxZMs/4MGJpMLvDMj+NbBsPA VSWBMdQkIOIhg== Received: from phl-compute-01.internal (phl-compute-01.internal [10.202.2.41]) by mailfauth.ams.internal (Postfix) with ESMTP id 509151980082; Tue, 1 Sep 2026 13:12:02 -0400 (EDT) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-01.internal (MEProxy); Tue, 01 Sep 2026 13:12:17 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTE95wHRzu4Jku/uqR1uWajKbrR5zJX2cXnYtALksDxTaOWWCUqT0ALShYzFchhR19 jABbL3NMpQdq2Q4yk1wxABfpkhz1tXbwJ0ETPbBKtnkrOsetjBDE6HJPSHCSzQ+lV8p7hR m8B5tw0NCYc8nr5KG+JJnI7EqrKbJ9j/iB4uBQ8v3yh2BnmhuMnsKxLkWZCbcUsikaiaIb afOgG11+NHa8fIFfGiaQPV11ZUcZ/PxqcPGfORQq/nrNuM+iA2OtyKWdZtMIzuN7Y+Bitk xOhO/HMBDeF+31R8MKrPNSYAO9QueQgK/MZ6ZozJxRSVjUBLpeca5t06PFY2rHErDLj+iW 2yn2As7fL8DmU2YIyhDqY4qqwa2/ZrsmjL2YjjyNf5Ut5V+o1Q2jHYwdnRpVE4qQekDIlA 0QFGDvxUI/D1PW8k3h1xG2sm2CMe+07Xc1+6x36TyY7o9SD12A1XaguCEJgvlOl/E4/LPo GFNx+zoYsO4VdClgp1h7hc4suTeM5K0X91cofeEj76CiP8ubXYR9unXAMBRmzaTibsCFRl htnRbe1HGqYqK8cW0PalkL3qgmd3CH6stsr7YLE6PHlCrh2N2VCi400sm4iXeFTUQOgmsx q+kN/77vj/DcD2YNv53dz8Mkn5XTiexA6E9lSNNFtklTEqyElGj/pD/1naEQ X-ME-Proxy: Feedback-ID: i10464835:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 1 Sep 2026 13:11:59 -0400 (EDT) Date: Tue, 1 Sep 2026 18:11:57 +0100 From: Kiryl Shutsemau To: "Lorenzo Stoakes (ARM)" Cc: Jason Gunthorpe , Andrew Morton , David Hildenbrand , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Guo Ren , Brian Cain , Geert Uytterhoeven , Dinh Nguyen , Simon Schuster , Jonas Bonn , Stefan Kristiansson , Stafford Horne , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Russell King , Vineet Gupta , Michal Simek , Chris Zankel , Max Filippov , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Peter Zijlstra , "David S. Miller" , Andreas Larsson , Richard Henderson , Matt Turner , Magnus Lindholm , Catalin Marinas , Mark Rutland , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Madhavan Srinivasan , Michael Ellerman , "Christophe Leroy (CS GROUP)" , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , John Hubbard , Peter Xu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-openrisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-snps-arc@lists.infradead.org, linux-arch@vger.kernel.org, sparclinux@vger.kernel.org, linux-alpha@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, Hugh Dickins , Qi Zheng Subject: Re: [PATCH 01/12] mm/huge_memory: zap deposited page tables after an RCU grace period Message-ID: References: <20260901-rcu-pagetable-freeing-v1-0-5456a81c8212@kernel.org> <20260901-rcu-pagetable-freeing-v1-1-5456a81c8212@kernel.org> <20260901142408.GA56830@ziepe.ca> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org On Tue, Sep 01, 2026 at 04:45:14PM +0100, Lorenzo Stoakes (ARM) wrote: > > munmap() of 64G worth of THP should be enough to demonstrate the > > problem. > > I mean you're going to hit that from RCU freeing page tables already, which > most architectures already do right? Not at the same rate -- tlb_remove_table() batches into struct mmu_table_batch. One call_rcu() per MAX_TABLE_BATCH. > So if RCU saturation is a problem, that problem already exists, but I've > not heard of that being a problem at all? I did quick test and I don't see a measurable difference in munmap() wall time of 40G of THPs. I see ~17x more softirqs, but this is expected. The objection is retracted. We can return to this later if it is going to be visible anywhere. -- Kiryl Shutsemau / Kirill A. Shutemov _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc