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[192.41.125.253]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4923fc47b48sm82606645e9.0.2026.06.19.09.32.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Jun 2026 09:32:02 -0700 (PDT) Date: Fri, 19 Jun 2026 17:32:01 +0100 From: Karim Manaouil To: Shivank Garg Cc: akpm@linux-foundation.org, david@kernel.org, kinseyho@google.com, weixugc@google.com, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, willy@infradead.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, dave@stgolabs.net, Jonathan.Cameron@huawei.com, rkodsara@amd.com, vkoul@kernel.org, bharata@amd.com, sj@kernel.org, rientjes@google.com, xuezhengchu@huawei.com, yiannis@zptcorp.com, dave.hansen@intel.com, hannes@cmpxchg.org, jhubbard@nvidia.com, peterx@redhat.com, riel@surriel.com, shakeel.butt@linux.dev, stalexan@redhat.com, tj@kernel.org, nifan.cxl@gmail.com, jic23@kernel.org, aneesh.kumar@kernel.org, nathan.lynch@amd.com, Frank.li@nxp.com, djbw@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 6/7] drivers/migrate_offload: add DMA batch copy driver (dcbm) Message-ID: <20260619163201.ldbjaqcphke3fcvg@wrangler> References: <20260428155043.39251-2-shivankg@amd.com> <20260428155043.39251-14-shivankg@amd.com> <20260619160725.lfcxrbj5go67qy6u@wrangler> 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: <20260619160725.lfcxrbj5go67qy6u@wrangler> On Fri, Jun 19, 2026 at 05:07:25PM +0100, Karim Manaouil wrote: > Btw, waiting for an interrupt adds massive scheduling overhead. If we > also add the logic above, it'll get even worse. In my measurements, this > can easily add up to 6ms, by which CPU page copy have easily completed > the entire copy, which again adds to the list of latency concerns I > raised in my other reply. Sorry, I meant 6us. -- ~karim