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b=gyqobui6rYQTAebrCWDZPK0gedEEN7i4TvoU3uCxeMd1kf1ngOdrBFQ7SYlG63SsS 9rqFpnZ2KFHCOzcR9crvoB7RksYs1FbbhirX1eslyijWcTGem0dUpUNUSyevsc7Z6V aQ2OvlTHFxFUJTu0HLLV97UkGmQ7NCBqXkw+LtDE= Date: Thu, 31 Oct 2024 17:20:05 -0700 From: Andrew Morton To: Wei Yang Cc: Liam.Howlett@oracle.com, maple-tree@lists.infradead.org, linux-mm@kvack.org Subject: Re: [PATCH v5 0/5] refine storing null Message-Id: <20241031172005.b129619e6832e23db8e9f21e@linux-foundation.org> In-Reply-To: <20241031231627.14316-1-richard.weiyang@gmail.com> References: <20241031231627.14316-1-richard.weiyang@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 6235318001A X-Rspamd-Server: rspam11 X-Stat-Signature: 48n5w1bn7z9xapmc7dsqyanfpssjuwum X-HE-Tag: 1730469255-255164 X-HE-Meta: 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 Q3qqRYIU zOZSvXyWAAfIpHvqCCvk0Y+k1wqbm7qUgYJ/vykjEDCSkr1GDhwSQCM1zPTL5d1vNJ7iLS5LG6Qtix8taCSAGCDI9Y3IO19Ga6M+QXJCUAbgXFJM0T8BUn4uP4n3TkPTBEbziMJKasjQxhmg/Ca6EVCT+cfzWgWC9fnXq4Vpii2m/DbuGIRjkuAbKnjVIpIH5+JN3pQ5sXkRYxFnI0aym4xlJeXaT8lhH68W0LkAOYqE8cqw18AgTiOqwhNHEJ3LiEHVj6KLfdeYLlnEMIQhIZXVvpZlHe9zdj7nJ+9sLtBh/ESAaaLd9pICncKM0HV2Y3hfGNlKovSpCBWv01pO6qnkRvT1BemoGznDj0bt6AWomqjs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 31 Oct 2024 23:16:22 +0000 Wei Yang wrote: > The original thread[1] thoughts it is a problem in mas_new_root(). But after > discussion, this should be an improvement on storing NULL. I hate to be a bureaucrat, but that isn't a very satisfying [0/N]. > > [1]: https://lkml.kernel.org/r/20241015233909.23592-1-richard.weiyang@gmail.com >From here I extracted "When overwriting the whole range with NULL, current behavior is not correct", but that's still very thin. What is incorrect about it and what is the impact of all of this to Linux users?