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[142.167.219.86]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6eec965a18dsm63016516d6.55.2025.04.01.08.19.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Apr 2025 08:19:51 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1tzdP5-00000001Lxl-1sHc; Tue, 01 Apr 2025 12:19:51 -0300 Date: Tue, 1 Apr 2025 12:19:51 -0300 From: Jason Gunthorpe To: Xu Lu Cc: akpm@linux-foundation.org, jhubbard@nvidia.com, kirill.shutemov@linux.intel.com, tjeznach@rivosinc.com, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, lihangjing@bytedance.com, xieyongji@bytedance.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH RESEND v2 3/4] iommu/riscv: Introduce IOMMU page table lock Message-ID: <20250401151951.GG186258@ziepe.ca> References: <20250318035930.11855-1-luxu.kernel@bytedance.com> <20250318035930.11855-4-luxu.kernel@bytedance.com> 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: <20250318035930.11855-4-luxu.kernel@bytedance.com> On Tue, Mar 18, 2025 at 11:59:29AM +0800, Xu Lu wrote: > Introduce page table lock to address competition issues when modifying > multiple PTEs, for example, when applying Svnapot. We use fine-grained > page table locks to minimize lock contention. This does not seem right, there is no need for locks to manage a cont bit on the iommu side. Jason