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AJvYcCXl9fWHwFcD4IvP9ZKNvu1suSwk3okhut+QRSBxjDdy/DMQPyrMiLBMGiRsUwlEi1yX3KyS/1LzmE81XCIE/oe5QkVwHQ6c8NPrWqe6 X-Gm-Message-State: AOJu0YzM1OAbmQcp9v3CQerCGR+Otvm2CIF+W4gY9WofXiuUlG5e2rA7 Nko6CyQhqVXo4RZBbZW1nimoRYBXu8+pbhhz0Ahei0vXSppSTrm9 X-Google-Smtp-Source: AGHT+IF6ouiokiVEyFL/FkVwCikSYFZ+WjrqZx3MbtO/OSdFIf0J9kZ/NtSEdTkFp9kIx9hLWh3+/A== X-Received: by 2002:a17:90a:fe04:b0:2c1:ea2e:20b2 with SMTP id 98e67ed59e1d1-2c27db57d16mr1342743a91.30.1717559068626; Tue, 04 Jun 2024 20:44:28 -0700 (PDT) Received: from [192.168.255.10] ([43.132.141.20]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2c2806d1be2sm302326a91.55.2024.06.04.20.44.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Jun 2024 20:44:28 -0700 (PDT) Message-ID: <0a6603c4-ac05-460c-8bad-66813570b426@gmail.com> Date: Wed, 5 Jun 2024 11:44:24 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 09/10] mm/ksm: calc_checksum for folio To: David Hildenbrand , alexs@kernel.org, Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, izik.eidus@ravellosystems.com, willy@infradead.org, aarcange@redhat.com, chrisw@sous-sol.org, hughd@google.com References: <20240604042454.2012091-1-alexs@kernel.org> <20240604042454.2012091-10-alexs@kernel.org> Content-Language: en-US From: Alex Shi In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 6/4/24 9:18 PM, David Hildenbrand wrote: >> @@ -2369,7 +2371,7 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite >>        * don't want to insert it in the unstable tree, and we don't want >>        * to waste our time searching for something identical to it there. >>        */ >> -    checksum = calc_checksum(page); >> +    checksum = calc_checksum(folio); > > So for a large folio you suddenly checksum more than a single page? That's wrong. > > Or am I missing something? I am not sure if this change are good too, anyway, comparing the whole folio may have it advantages on efficiency, but more splitting do save more pages. Anyway, this change could be dropped. Thanks!