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Tue, 13 May 2025 06:25:01 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGWSwUOUh7vlm/ltHVRqMb5l8+jKcoxi+lnHiIKQ34OJ3QJBNItngQ2T8pL8akuEcm6Y1CpyQ== X-Received: by 2002:a05:6214:5197:b0:6e4:4331:aae0 with SMTP id 6a1803df08f44-6f6e47bc67amr236648066d6.1.1747142701124; Tue, 13 May 2025 06:25:01 -0700 (PDT) Received: from x1.local ([85.131.185.92]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6f6e3a0c668sm67122246d6.68.2025.05.13.06.25.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 May 2025 06:25:00 -0700 (PDT) Date: Tue, 13 May 2025 09:24:58 -0400 From: Peter Xu To: Kyle Huey Cc: Andrew Morton , open list , linux-mm@kvack.org, criu@lists.linux.dev, Robert O'Callahan , Axel Rasmussen , Mike Rapoport , Andrea Arcangeli Subject: Re: Suppress pte soft-dirty bit with UFFDIO_COPY? Message-ID: References: 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=utf-8 Content-Disposition: inline In-Reply-To: On Mon, May 12, 2025 at 10:16:12AM -0700, Kyle Huey wrote: > Personally I don't think it's a real issue to have to create a > sacrificial fd once at process initialization to see what features are > available. I wouldn't have even said anything if the man page hadn't > explicitly told me there was another way. Yes, that's indeed the part that could be confusing and needs fixing. Just to keep a record (I have you copied), I sent the man-pages changes here: https://lore.kernel.org/r/20250512171922.356408-1-peterx@redhat.com We can stick with the sacrificial fd until there's a solid clue showing that we should introduce a new way to probe. Thanks, -- Peter Xu